JP2013116848A - METHOD FOR PRODUCING GaAs-BASED FILM, AND COMPOSITE SUBSTRATE USED FOR THE METHOD - Google Patents

METHOD FOR PRODUCING GaAs-BASED FILM, AND COMPOSITE SUBSTRATE USED FOR THE METHOD Download PDF

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JP2013116848A
JP2013116848A JP2012128086A JP2012128086A JP2013116848A JP 2013116848 A JP2013116848 A JP 2013116848A JP 2012128086 A JP2012128086 A JP 2012128086A JP 2012128086 A JP2012128086 A JP 2012128086A JP 2013116848 A JP2013116848 A JP 2013116848A
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gaas
film
main surface
support substrate
substrate
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Kazunari Sato
一成 佐藤
Yuki Seki
裕紀 関
Koji Uematsu
康二 上松
Yoshiyuki Yamamoto
喜之 山本
Hideki Matsubara
秀樹 松原
Shinsuke Fujiwara
伸介 藤原
Masashi Yoshimura
雅司 吉村
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Sumitomo Electric Industries Ltd
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Abstract

PROBLEM TO BE SOLVED: To provide a method for producing GaAs-based film having large area of a main surface, little warpage and excellent crystallinity obtained at low cost, and to provide a composite substrate used for the method.SOLUTION: The method for producing GaAs-based film includes the steps of: preparing a composite substrate 10 which contains a support base 11 to be dissolved into hydrofluoric acid and a single crystal film 13 arranged on a main surface 11m of the support base 11, and has a thermal expansion coefficient in the main surface 11m of the support base 11 which is greater than 0.8 time and less than 1.2 time compared with the thermal expansion coefficient of the GaAs crystal; forming GaAs-based film 20 on a main surface 13 of the single crystal film 13 arranged on the main surface 11m side of the support base 11; and removing the support base 11 by dissolving into hydrofluoric acid.

Description

本発明は、主面の面積が大きく反りの小さいＧａＡｓ系膜の製造方法およびそれに用いられる複合基板に関する。   The present invention relates to a method for producing a GaAs-based film having a large principal surface area and a small warp, and a composite substrate used therefor.

ＧａＡｓ系膜は、発光デバイス、電子デバイスなどの半導体デバイスの基板および半導体層として、好適に用いられる。かかるＧａＡｓ系膜を製造するための基板としては、その基板とＧａＡｓ系膜との間で、格子定数および熱膨張係数を一致させるまたは一致に近づける観点から、ＧａＡｓ基板が最も優れている。ところが、ＧａＡｓ基板は、希少金属であるＧａを含有しているため、Ｓｉ基板などに比べて非常に高価である。   The GaAs-based film is suitably used as a substrate and a semiconductor layer of a semiconductor device such as a light emitting device or an electronic device. As a substrate for producing such a GaAs-based film, a GaAs substrate is most excellent from the viewpoint of matching or approaching the lattice constant and the thermal expansion coefficient between the substrate and the GaAs-based film. However, since the GaAs substrate contains Ga, which is a rare metal, it is very expensive compared to a Si substrate or the like.

このため、特開平０７−０１４７７６号公報（特許文献１）は、シリコン基板上にＧａＡｓ層をエピタキシャル成長させたＧａＡｓ基板の製造方法を開示する。   For this reason, Japanese Patent Laid-Open No. 07-014776 (Patent Document 1) discloses a method of manufacturing a GaAs substrate in which a GaAs layer is epitaxially grown on a silicon substrate.

特開平０７−０１４７７６号公報Japanese Patent Application Laid-Open No. 07-014776

特開平０７−０１４７７６号公報（特許文献１）で開示される製造方法により得られるシリコン基板上にＧａＡｓ層をエピタキシャル成長させたＧａＡｓ基板は、Ｓｉ基板とＧａＡｓ層との間の熱膨張係数が異なるため、反りが発生する場合があり、また主面の面積を大きくすることが難しいという問題点があった。   A GaAs substrate obtained by epitaxially growing a GaAs layer on a silicon substrate obtained by the manufacturing method disclosed in Japanese Patent Application Laid-Open No. 07-014776 (Patent Document 1) has a different thermal expansion coefficient between the Si substrate and the GaAs layer. In some cases, warpage may occur, and it is difficult to increase the area of the main surface.

本発明は、上記問題点を解決して、ＧａＡｓ結晶と熱膨張係数が一致または近似しかつ除去が容易な支持基板を含む低コストの複合基板を用いて主面の面積が大きく反りが小さく結晶性が良好なＧａＡｓ系膜を成膜し、その後支持基板を除去することにより、主面の面積が大きく反りが小さく結晶性が良好なＧａＡｓ系膜を効率よく低コストで取り出すことができるＧａＡｓ系膜の製造方法およびそれに用いられる複合基板を提供することを目的とする。   The present invention solves the above-described problems by using a low-cost composite substrate including a support substrate that has a thermal expansion coefficient that is the same as or close to that of a GaAs crystal and that can be easily removed. GaAs-based film with good crystallinity can be taken out efficiently and at low cost by forming a GaAs-based film with good crystallinity and then removing the support substrate, and then having a large main surface area and low warpage and good crystallinity An object of the present invention is to provide a film manufacturing method and a composite substrate used therefor.

本発明は、フッ化水素酸に溶解する支持基板と支持基板の主面側に配置されている単結晶膜とを含み、支持基板の主面内の熱膨張係数がＧａＡｓ結晶の熱膨張係数に比べて０．８倍より大きく１．２倍より小さい複合基板である。   The present invention includes a support substrate dissolved in hydrofluoric acid and a single crystal film disposed on the main surface side of the support substrate, and the thermal expansion coefficient in the main surface of the support substrate is equal to the thermal expansion coefficient of the GaAs crystal. In comparison, the composite substrate is larger than 0.8 times and smaller than 1.2 times.

本発明にかかる複合基板において、支持基板は、ジルコニアとシリカとで形成されるＺｒＯ2−ＳｉＯ2複合酸化物と、ジルコニアおよびシリカの少なくともいずれかと、を含むことができる。また、支持基板は、アルミナとシリカとで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、イットリア安定化ジルコニアと、を含むことができる。また、支持基板は、アルミナとシリカとで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、マグネシアと、を含むことができる。また、本発明にかかる複合基板における単結晶膜の主面の面積を４５ｃｍ2以上とすることができる。 In the composite substrate according to the present invention, the support substrate can include a ZrO 2 —SiO 2 composite oxide formed of zirconia and silica, and at least one of zirconia and silica. Further, the support substrate can include Al 2 O 3 —SiO 2 composite oxide formed of alumina and silica and yttria-stabilized zirconia. The support substrate can contain Al 2 O 3 —SiO 2 composite oxide formed of alumina and silica, and magnesia. In addition, the area of the main surface of the single crystal film in the composite substrate according to the present invention can be 45 cm 2 or more.

また、本発明は、フッ化水素酸に溶解する支持基板と支持基板の主面側に配置されている単結晶膜とを含み、支持基板の主面内の熱膨張係数がＧａＡｓ結晶の熱膨張係数に比べて０．８倍より大きく１．２倍より小さい複合基板を準備する工程と、支持基板の主面側に配置されている単結晶膜の主面上にＧａＡｓ系膜を成膜する工程と、支持基板をフッ化水素酸に溶解することにより除去する工程と、を含むＧａＡｓ系膜の製造方法である。   The present invention also includes a support substrate that dissolves in hydrofluoric acid and a single crystal film disposed on the main surface side of the support substrate, and the thermal expansion coefficient in the main surface of the support substrate is the thermal expansion of the GaAs crystal. A step of preparing a composite substrate larger than 0.8 times and smaller than 1.2 times compared with a coefficient, and forming a GaAs-based film on the main surface of the single crystal film disposed on the main surface side of the support substrate A method for producing a GaAs-based film, which includes a step and a step of removing a supporting substrate by dissolving it in hydrofluoric acid.

本発明にかかるＧａＡｓ系膜の製造方法において、支持基板は、ジルコニアとシリカとで形成されるＺｒＯ2−ＳｉＯ2複合酸化物と、ジルコニアおよびシリカの少なくともいずれかと、を含むことができる。また、支持基板は、アルミナとシリカとで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、イットリア安定化ジルコニアと、を含むことができる。また、支持基板は、アルミナとシリカとで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、マグネシアと、を含むことができる。また、本発明にかかる複合基板における単結晶膜の主面の面積を４５ｃｍ2以上とすることができる。また、ＧａＡｓ系膜を成膜する工程は、単結晶膜の主面上にＧａＡｓ系バッファ層を形成するサブ工程と、ＧａＡｓ系バッファ層の主面上にＧａＡｓ系単結晶層を形成するサブ工程と、を含むことができる。 In the method for producing a GaAs-based film according to the present invention, the support substrate can include a ZrO 2 —SiO 2 composite oxide formed of zirconia and silica, and at least one of zirconia and silica. Further, the support substrate can include Al 2 O 3 —SiO 2 composite oxide formed of alumina and silica and yttria-stabilized zirconia. The support substrate can contain Al 2 O 3 —SiO 2 composite oxide formed of alumina and silica, and magnesia. In addition, the area of the main surface of the single crystal film in the composite substrate according to the present invention can be 45 cm 2 or more. The step of forming a GaAs-based film includes a sub-step of forming a GaAs-based buffer layer on the main surface of the single crystal film and a sub-step of forming a GaAs-based single crystal layer on the main surface of the GaAs-based buffer layer. And can be included.

本発明によれば、ＧａＡｓ結晶と熱膨張係数が一致または近似しかつ除去が容易な支持基板を含む低コストの複合基板を用いて主面の面積が大きく反りが小さく結晶性が良好なＧａＡｓ系膜を成膜し、その後支持基板を除去することにより、主面の面積が大きく反りが小さく結晶性が良好なＧａＡｓ系膜を効率よく低コストで取り出すことができるＧａＡｓ系膜の製造方法およびそれに用いられる複合基板が提供される。   According to the present invention, a low cost composite substrate having a thermal expansion coefficient that is the same as or close to that of a GaAs crystal and includes a support substrate that is easy to remove is used. A method of manufacturing a GaAs-based film capable of efficiently and cost-effectively extracting a GaAs-based film having a large principal surface area, small warpage, and good crystallinity by forming a film and then removing the support substrate A composite substrate for use is provided.

本発明にかかる複合基板の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the composite substrate concerning this invention. 本発明にかかるＧａＡｓ系膜の製造方法の一例を示す概略断面図である。ここで、（Ａ）は複合基板を準備する工程を示し、（Ｂ）はＧａＡｓ系膜を成膜する工程を示し、（Ｃ）は支持基板を除去する工程を示す。It is a schematic sectional drawing which shows an example of the manufacturing method of the GaAs type film concerning this invention. Here, (A) shows a step of preparing a composite substrate, (B) shows a step of forming a GaAs-based film, and (C) shows a step of removing the support substrate. 本発明における複合基板を準備する工程の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of the process of preparing the composite substrate in this invention.

［複合基板］
図１を参照して、本発明の一実施形態である複合基板１０は、フッ化水素酸に溶解する支持基板１１と、支持基板１１の主面１１ｍ側に配置されている単結晶膜１３と、を含み、支持基板１１の主面１１ｍ内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて、０．８倍より大きく１．２倍より小さい。 [Composite substrate]
Referring to FIG. 1, a composite substrate 10 according to an embodiment of the present invention includes a support substrate 11 that is dissolved in hydrofluoric acid, and a single crystal film 13 that is disposed on the main surface 11m side of the support substrate 11. The thermal expansion coefficient in the main surface 11m of the support substrate 11 is larger than 0.8 times and smaller than 1.2 times compared to the thermal expansion coefficient of the GaAs crystal.

本実施形態の複合基板１０は、支持基板１１の主面１１ｍ内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて０．８倍より大きく１．２倍より小さいため、支持基板１１の主面１１ｍ上に形成された単結晶膜１３の主面１３ｍ上に、主面１３ｍの面積が大きくても、転位密度が低く結晶性が良好なＧａＡｓ系膜を成膜することができる。また、支持基板１１がフッ化水素酸に溶解するため、複合基板１０の単結晶膜１３の主面１３ｍ上にＧａＡｓ系膜を成膜した後、支持基板１１をフッ化水素酸により除去することにより、単結晶膜１３の主面１３ｍ上に成膜された転位密度が低く結晶性が良好なＧａＡｓ系膜が効率よく低コストで得られる。   In the composite substrate 10 of the present embodiment, the thermal expansion coefficient in the main surface 11m of the support substrate 11 is larger than 0.8 times and smaller than 1.2 times the thermal expansion coefficient of the GaAs crystal. Even if the area of the main surface 13m is large, a GaAs-based film having a low dislocation density and good crystallinity can be formed on the main surface 13m of the single crystal film 13 formed on the main surface 11m. Further, since the support substrate 11 is dissolved in hydrofluoric acid, a GaAs-based film is formed on the main surface 13m of the single crystal film 13 of the composite substrate 10, and then the support substrate 11 is removed with hydrofluoric acid. Thus, a GaAs-based film having a low dislocation density and good crystallinity formed on the main surface 13m of the single crystal film 13 can be obtained efficiently and at low cost.

（支持基板）
本実施形態の複合基板１０の支持基板１１は、支持基板１１の主面１１ｍ上に形成された単結晶膜１３の主面１３ｍ上に、主面の面積が大きく転位密度が低く結晶性が良好なＧａＡｓ系膜を成膜する観点から、支持基板１１の主面１１ｍ内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて０．８倍より大きく１．２倍より小さいことが必要であり、０．９倍より大きく１．１５倍より小さいことが好ましく、０．９５倍より大きく１．１倍より小さいことがより好ましい。また、支持基板１１は、成膜したＧａＡｓ系膜から支持基板を効率よく低コストで除去する観点から、フッ化水素酸に溶解する必要がある。 (Support substrate)
The support substrate 11 of the composite substrate 10 of the present embodiment has a large area of the main surface, a low dislocation density, and good crystallinity on the main surface 13m of the single crystal film 13 formed on the main surface 11m of the support substrate 11. From the viewpoint of forming a GaAs-based film, it is necessary that the thermal expansion coefficient in the main surface 11m of the support substrate 11 is larger than 0.8 times and smaller than 1.2 times as compared with the thermal expansion coefficient of the GaAs crystal. Yes, it is preferably larger than 0.9 times and smaller than 1.15 times, more preferably larger than 0.95 times and smaller than 1.1 times. The support substrate 11 needs to be dissolved in hydrofluoric acid from the viewpoint of efficiently removing the support substrate from the formed GaAs-based film at low cost.

支持基板１１は、支持基板１１の主面１１ｍ内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて０．８倍より大きく１．２倍より小さく、かつ、フッ化水素酸で溶解するものであれば特に制限はなく、単結晶であっても、多結晶であっても、非結晶であってもよい。支持基板１１は、その熱膨張係数の調整が容易で、フッ化水素酸に溶解する観点から、金属酸化物およびケイ素酸化物の少なくともいずれかを含むことが好ましい。   The support substrate 11 has a thermal expansion coefficient in the main surface 11m of the support substrate 11 that is larger than 0.8 times and smaller than 1.2 times that of the GaAs crystal, and is dissolved in hydrofluoric acid. Any material can be used as long as it is monocrystalline, polycrystalline, or amorphous. The support substrate 11 preferably contains at least one of a metal oxide and a silicon oxide from the viewpoint of easy adjustment of the thermal expansion coefficient and dissolution in hydrofluoric acid.

ここで、支持基板１１は、ジルコニア（ＺｒＯ2）とシリカ（ＳｉＯ2）とで形成されるＺｒＯ2−ＳｉＯ2複合酸化物と、ジルコニアおよびシリカの少なくともいずれかと、を含むことが特に好ましい。ここで、ＺｒＯ2−ＳｉＯ2複合酸化物とは、ＺｒＯ2とＳｉＯ2とにより形成されるジルコン（ＺｒＳｉＯ4）などの複合酸化物をいう。かかるＺｒＯ2−ＳｉＯ2複合酸化物は、フッ化水素酸に溶解しないかまたは溶解し難い。このため、支持基板１１は、ＺｒＯ2−ＳｉＯ2複合酸化物に加えて、フッ化水素酸に溶解する観点から、ジルコニア（ＺｒＯ2）およびシリカ（ＳｉＯ2）の少なくともいずれかを含む。ＺｒＳｉＯ4などの複合酸化物、ＺｒＯ2およびＳｉＯ2の存在の有無ならびにそれらの組成比率は、Ｘ線回折により測定することができる。 Here, the support substrate 11 particularly preferably includes a ZrO 2 —SiO 2 composite oxide formed of zirconia (ZrO 2 ) and silica (SiO 2 ), and at least one of zirconia and silica. Here, the ZrO 2 —SiO 2 composite oxide refers to a composite oxide such as zircon (ZrSiO 4 ) formed by ZrO 2 and SiO 2 . Such ZrO 2 —SiO 2 composite oxide does not dissolve or hardly dissolves in hydrofluoric acid. For this reason, the support substrate 11 contains at least one of zirconia (ZrO 2 ) and silica (SiO 2 ) from the viewpoint of dissolving in hydrofluoric acid in addition to the ZrO 2 —SiO 2 composite oxide. Presence / absence of composite oxides such as ZrSiO 4 , ZrO 2 and SiO 2 , and their composition ratios can be measured by X-ray diffraction.

上記のようなＺｒＯ2−ＳｉＯ2複合酸化物（たとえばＺｒＳｉＯ4）と、ジルコニア（ＺｒＯ2）およびシリカ（ＳｉＯ2）の少なくともいずれかとを含む支持基板１１は、ＺｒＯ2とＳｉＯ2とを１：１以外のモル比で完全に反応させることにより、または、ＺｒＯ2とＳｉＯ2とを１：１のモル比で不完全に反応させることにより、得られる。 The support substrate 11 containing the above-described ZrO 2 —SiO 2 composite oxide (for example, ZrSiO 4 ) and at least one of zirconia (ZrO 2 ) and silica (SiO 2 ) has a ratio of ZrO 2 and SiO 2 of 1: It can be obtained by reacting completely at a molar ratio other than 1, or by incompletely reacting ZrO 2 and SiO 2 at a molar ratio of 1: 1.

また、支持基板１１は、アルミナ（Ａｌ2Ｏ3）とシリカ（ＳｉＯ2）とで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、イットリア安定化ジルコニア（ＹＳＺ）と、を含むことが特に好ましい。ここで、Ａｌ2Ｏ3−ＳｉＯ2複合酸化物とは、Ａｌ2Ｏ3とＳｉＯ2とにより形成されるムライト（３Ａｌ2Ｏ3・２ＳｉＯ2〜２Ａｌ2Ｏ3・ＳｉＯ2）などの複合酸化物をいう。また、ＹＳＺ（イットリア安定化ジルコニア、以下同じ）とは、ジルコニア（ＺｒＯ2）にイットリア（Ｙ2Ｏ3）を添加することによりジルコニアの結晶構造を正方晶または立方晶で安定化させたものをいう。ムライトおよびＹＳＺの存在の有無ならびにそれらの組成比率は、Ｘ線回折により測定することができる。 The support substrate 11 may include an Al 2 O 3 —SiO 2 composite oxide formed of alumina (Al 2 O 3 ) and silica (SiO 2 ), and yttria-stabilized zirconia (YSZ). Particularly preferred. Here, the Al 2 O 3 —SiO 2 composite oxide is a composite oxide such as mullite (3Al 2 O 3 .2SiO 2 to 2Al 2 O 3 .SiO 2 ) formed by Al 2 O 3 and SiO 2. Say things. YSZ (yttria-stabilized zirconia, the same shall apply hereinafter) is a product in which the crystal structure of zirconia is stabilized with tetragonal or cubic crystals by adding yttria (Y 2 O 3 ) to zirconia (ZrO 2 ). Say. The presence or absence of mullite and YSZ and the composition ratio thereof can be measured by X-ray diffraction.

また、支持基板１１は、アルミナ（Ａｌ2Ｏ3）とシリカ（ＳｉＯ2）とで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、マグネシア（ＭｇＯ）と、を含むことが特に好ましい。ムライトおよびＭｇＯの存在の有無ならびにそれらの組成比率は、Ｘ線回折により測定することができる。 The support substrate 11 particularly preferably contains Al 2 O 3 —SiO 2 composite oxide formed of alumina (Al 2 O 3 ) and silica (SiO 2 ), and magnesia (MgO). The presence or absence of mullite and MgO and the composition ratio thereof can be measured by X-ray diffraction.

このとき、支持基板１１およびＧａＡｓ結晶の熱膨張係数は、一般に、それらの温度により大きく変動することから、如何なる温度または温度領域における熱膨張係数によって決めるかが重要である。本発明においては、複合基板上に反りの小さいＧａＡｓ系膜を製造することを目的とするものであり、室温から昇温させてＧａＡｓ系膜の成膜温度で複合基板上にＧａＡｓ系膜を成膜した後室温まで降温させて複合基板上に成膜されたＧａＡｓ系膜を取り出すことから、室温からＧａＡｓ系膜の成膜温度までにおける支持基板およびＧａＡｓ結晶の平均熱膨張係数を、それぞれ支持基板およびＧａＡｓ結晶の熱膨張係数として取り扱うことが適正と考えられる。このため、本発明においては、支持基板およびＧａＡｓ結晶の熱膨張係数は、室温（具体的に２５℃）から１０００℃までにおける平均熱膨張係数により決定することにする。   At this time, since the thermal expansion coefficients of the support substrate 11 and the GaAs crystal generally vary greatly depending on their temperatures, it is important to determine the temperature expansion coefficient in any temperature or temperature range. The object of the present invention is to produce a GaAs-based film having a small warp on a composite substrate, and the GaAs-based film is formed on the composite substrate at the film-forming temperature of the GaAs-based film by raising the temperature from room temperature. After the film formation, the temperature is lowered to room temperature and the GaAs-based film formed on the composite substrate is taken out. It is considered appropriate to handle them as thermal expansion coefficients of GaAs crystals. Therefore, in the present invention, the thermal expansion coefficients of the support substrate and the GaAs crystal are determined by the average thermal expansion coefficient from room temperature (specifically 25 ° C.) to 1000 ° C.

（単結晶膜）
本実施形態の複合基板１０の支持基板１１の主面１１ｍ側に配置される単結晶膜１３は、反りが小さく転位密度が低く結晶性の良好なＧａＡｓ系膜を成長させる観点から、ＧａＡｓ結晶（正方晶系の閃亜鉛鉱型構造）と同じ正方晶系の結晶構造を有するものが好ましく、主面１３ｍが（００１）面であるＳｉ膜（正方晶系のダイヤモンド型構造）、主面１３ｍが（００１）面であるＧａＡｓ膜（正方晶系の閃亜鉛鉱型構造）などが好ましい。 (Single crystal film)
The single crystal film 13 disposed on the main surface 11m side of the support substrate 11 of the composite substrate 10 of the present embodiment is a GaAs crystal (from the viewpoint of growing a GaAs-based film having low warpage, low dislocation density, and good crystallinity. It is preferable to have the same tetragonal crystal structure as that of the tetragonal zinc blende structure, and a Si film (tetragonal diamond type structure) whose principal surface 13m is the (001) plane, and the principal surface 13m is A GaAs film having a (001) plane (tetragonal zinc blende structure) is preferred.

また、複合基板１０における単結晶膜１３の主面１３ｍの面積は、特に制限はいが、主面の面積が大きいＧａＡｓ系膜を成長させる観点から、４５ｃｍ2以上であることが好ましい。 In addition, the area of the main surface 13m of the single crystal film 13 in the composite substrate 10 is not particularly limited, but is preferably 45 cm 2 or more from the viewpoint of growing a GaAs-based film having a large main surface area.

（接着層）
本実施形態の複合基板１０は、支持基板１１と単結晶膜１３との接合強度を高める観点から、支持基板１１と単結晶膜１３との間に接着層１２が形成されていることが好ましい。接着層１２は、特に制限はないが、支持基板１１と単結晶膜１３との接合強度を高める効果が高い観点から、ＳｉＯ2層、ＴｉＯ2層などが好ましい。さらに、フッ化水素酸により除去できる観点から、ＳｉＯ2層がより好ましい。 (Adhesive layer)
In the composite substrate 10 of the present embodiment, the adhesive layer 12 is preferably formed between the support substrate 11 and the single crystal film 13 from the viewpoint of increasing the bonding strength between the support substrate 11 and the single crystal film 13. The adhesive layer 12 is not particularly limited, from the effects is high in view of enhancing the bonding strength between the supporting substrate 11 and the single crystal film 13, SiO 2 layer, such as TiO 2 layer is preferable. Furthermore, a SiO 2 layer is more preferable from the viewpoint that it can be removed by hydrofluoric acid.

（複合基板の製造方法）
複合基板の製造方法は、後述するＧａＡｓ系膜の製造方法における複合基板の準備工程と同様である。 (Production method of composite substrate)
The manufacturing method of the composite substrate is the same as the preparation step of the composite substrate in the GaAs-based film manufacturing method described later.

［ＧａＡｓ系膜の製造方法］
図２を参照して、本発明の別の実施形態であるＧａＡｓ系膜の製造方法は、フッ化水素酸に溶解する支持基板１１と、支持基板１１の主面１１ｍ側に配置されている単結晶膜１３と、を含み、支持基板１１の主面１１ｍ内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて、０．８倍より大きく１．２倍より小さい複合基板１０を準備する工程（図２（Ａ））と、支持基板１１の主面１１ｍ側に配置されている単結晶膜１３の主面１３ｍ上にＧａＡｓ系膜を成膜する工程（図２（Ｂ））と、支持基板１１を、フッ化水素酸に溶解することにより、除去する工程（図２（Ｃ））と、を含む。ここで、ＧａＡｓ系膜とは、ＩＩＩ族元素としてＧａを含むＩＩＩ族ヒ化物で形成されている膜をいい、たとえばＧａxＩｎyＡｌ1-x-yＡｓ膜（ｘ＞０、ｙ≧０、ｘ＋ｙ≦１）が挙げられる。 [Method of manufacturing GaAs film]
Referring to FIG. 2, a GaAs-based film manufacturing method according to another embodiment of the present invention includes a support substrate 11 that is dissolved in hydrofluoric acid and a single substrate disposed on the main surface 11 m side of the support substrate 11. A composite substrate 10 including a crystal film 13 and having a thermal expansion coefficient in the main surface 11m of the support substrate 11 larger than 0.8 times and smaller than 1.2 times compared to the thermal expansion coefficient of GaAs crystal is prepared. A step (FIG. 2A), a step of forming a GaAs-based film on the main surface 13m of the single crystal film 13 disposed on the main surface 11m side of the support substrate 11 (FIG. 2B), A step of removing the support substrate 11 by dissolving it in hydrofluoric acid (FIG. 2C). Here, the GaAs-based film refers to a film formed of a group III arsenide containing Ga as a group III element. For example, a Ga x In y Al 1-xy As film (x> 0, y ≧ 0, x + y ≦ 1).

本実施形態のＧａＡｓＮ系膜の製造方法によれば、フッ化水素酸に溶解する支持基板１１と、支持基板１１の主面１１ｍ側に配置されている単結晶膜１３と、を含み、支持基板１１の主面１１ｍ内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて、０．８倍より大きく１．２倍より小さい複合基板１０を用いて、複合基板１０の単結晶膜１３の主面１３ｍ上にＧａＡｓ系膜２０を成膜した後、複合基板１０の支持基板１１をフッ化水素酸に溶解して除去することにより、主面の面積が大きく反りが小さく結晶性が良好なＧａＡｓ系膜が効率よく低コストで得られる。   According to the method of manufacturing a GaAsN-based film of this embodiment, the support substrate includes the support substrate 11 that is dissolved in hydrofluoric acid and the single crystal film 13 that is disposed on the main surface 11m side of the support substrate 11. 11 using the composite substrate 10 having a thermal expansion coefficient in the main surface 11m of greater than 0.8 times and less than 1.2 times the thermal expansion coefficient of the GaAs crystal. After the GaAs-based film 20 is formed on the main surface 13m, the support substrate 11 of the composite substrate 10 is removed by dissolving in hydrofluoric acid, so that the area of the main surface is large, the warp is small, and the crystallinity is good. A GaAs-based film can be obtained efficiently and at low cost.

（複合基板の準備工程）
図２（Ａ）を参照して、本実施形態のＧａＡｓＮ系膜の製造方法は、まず、フッ化水素酸に溶解する支持基板１１と、支持基板１１の主面１１ｍ側に配置されている単結晶膜１３と、を含み、支持基板１１の主面１１ｍ内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて、０．８倍より大きく１．２倍より小さい複合基板１０を準備する工程を含む。 (Preparation process of composite substrate)
Referring to FIG. 2A, in the method of manufacturing a GaAsN-based film according to this embodiment, first, a support substrate 11 that is dissolved in hydrofluoric acid and a single substrate disposed on the main surface 11m side of the support substrate 11 are used. A composite substrate 10 including a crystal film 13 and having a thermal expansion coefficient in the main surface 11m of the support substrate 11 larger than 0.8 times and smaller than 1.2 times compared to the thermal expansion coefficient of GaAs crystal is prepared. Process.

上記の複合基板１０は、支持基板１１の主面１１ｍ内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて、０．８倍より大きく１．２倍より小さい支持基板１１と単結晶膜１３を含んでいるため、単結晶膜１３の主面１３ｍ上に主面の面積が大きく反りが小さく結晶性が良好なＧａＡｓ系膜を成膜することができる。また、上記の複合基板１０は、支持基板１１がフッ化水素酸に溶解するため、支持基板１１を除去することにより、主面の面積が大きく反りが小さく結晶性が良好なＧａＡｓ系膜を効率よく低コストで取り出すことができる。   The composite substrate 10 has a support substrate 11 and a single crystal film having a thermal expansion coefficient in the main surface 11m of the support substrate 11 that is larger than 0.8 times and smaller than 1.2 times that of the GaAs crystal. 13 is included, a GaAs-based film having a large main surface area, a small warpage, and a good crystallinity can be formed on the main surface 13 m of the single crystal film 13. In the composite substrate 10 described above, since the support substrate 11 is dissolved in hydrofluoric acid, by removing the support substrate 11, a GaAs-based film having a large principal surface area, small warpage, and good crystallinity can be efficiently obtained. Can be taken out well at low cost.

また、複合基板１０の支持基板１１の主面１１ｍ側に単結晶膜１３を配置する方法には、特に制限はなく、支持基板１１の主面１１ｍ上に単結晶膜１３を成長させる方法（第１の方法）、支持基板１１の主面１１ｍに、下地基板の主面上に成膜させた単結晶膜１３を貼り合わせた後下地基板を除去する方法（第２の方法）、支持基板１１の主面１１ｍに単結晶（図示せず）を貼り合わせた後その単結晶を貼り合わせ面から所定の深さの面で分離することにより支持基板１１の主面１１ｍ上に単結晶膜１３を形成する方法（第３の方法）などが挙げられる。支持基板が多結晶の焼結体である場合には、上記の第１の方法が困難であるため、上記の第２および第３のいずれかの方法が好ましく用いられる。上記の第２の方法において、支持基板１１に単結晶膜１３を貼り合わせる方法には、特に制限はなく、支持基板１１の主面１１ｍに直接単結晶膜１３を貼り合わせる方法、支持基板１１の主面１１ｍに接着層１２を介在させて単結晶膜１３を貼り合わせる方法などが挙げられる。上記の第３の方法において、支持基板１１に単結晶を貼り合わせる方法には、特に制限はなく、支持基板１１の主面１１ｍに直接単結晶を貼り合わせる方法、支持基板１１の主面１１ｍに接着層１２を介在させて単結晶を貼り合わせる方法などが挙げられる。   In addition, the method of disposing the single crystal film 13 on the main surface 11m side of the support substrate 11 of the composite substrate 10 is not particularly limited, and a method of growing the single crystal film 13 on the main surface 11m of the support substrate 11 (first step). 1), a method of removing the base substrate after bonding the single crystal film 13 formed on the main surface of the base substrate to the main surface 11m of the support substrate 11 (second method), and the support substrate 11 A single crystal (not shown) is bonded to the main surface 11m of the support substrate 11, and then the single crystal is separated from the bonded surface at a predetermined depth to form a single crystal film 13 on the main surface 11m of the support substrate 11. A forming method (third method) is exemplified. When the support substrate is a polycrystalline sintered body, the first method is difficult, and therefore any one of the second and third methods is preferably used. In the second method, the method for bonding the single crystal film 13 to the support substrate 11 is not particularly limited. The method for bonding the single crystal film 13 directly to the main surface 11m of the support substrate 11, Examples thereof include a method in which the single crystal film 13 is bonded to the main surface 11m with the adhesive layer 12 interposed. In the third method, the method for attaching the single crystal to the support substrate 11 is not particularly limited, and the method of attaching the single crystal directly to the main surface 11m of the support substrate 11 or the main surface 11m of the support substrate 11 may be used. Examples thereof include a method of bonding single crystals with the adhesive layer 12 interposed.

上記の複合基板１０を準備する工程は、特に制限はないが、効率的に低コストで品質の高い複合基板１０を準備する観点から、たとえば、図３を参照して、上記の第２の方法においては、支持基板１１を準備するサブ工程（図３（Ａ））と、下地基板３０の主面３０ｎ上に単結晶膜１３を成膜するサブ工程（図３（Ｂ））と、支持基板１１と単結晶膜１３とを貼り合わせるサブ工程（図３（Ｃ））と、下地基板３０を除去するサブ工程（図３（Ｄ））と、含むことができる。   The step of preparing the composite substrate 10 is not particularly limited. From the viewpoint of efficiently preparing the composite substrate 10 with low cost and high quality, for example, the second method described above with reference to FIG. , A sub-process for preparing the support substrate 11 (FIG. 3A), a sub-process for forming the single crystal film 13 on the main surface 30n of the base substrate 30 (FIG. 3B), a support substrate, 11 and the single crystal film 13 (FIG. 3C) and a sub-process of removing the base substrate 30 (FIG. 3D).

図３（Ｃ）では、支持基板１１と単結晶膜１３とを貼り合わせるサブ工程において、支持基板１１の主面１１ｍ上に接着層１２ａに形成し（図３（Ｃ１））、下地基板３０の主面３０ｎ上に成長させられた単結晶膜１３の主面１３ｎ上に接着層１２ｂを形成した（図３（Ｃ２））後、支持基板１１上に形成された接着層１２ａの主面１２ａｍと下地基板３０上に成膜された単結晶膜１３上に形成された接着層１２ｂの主面１２ｂｎとを貼り合わせることにより、接着層１２ａと接着層１２ｂとが接合して形成された接着層１２を介在させて支持基板１１と単結晶膜１３とが貼り合わされる（図３（Ｃ３））。しかし、支持基板１１と単結晶膜１３とが互いに接合可能なものであれば、支持基板１１と単結晶膜１３とを、接着層１２を介在させることなく直接貼り合わせることができる。   In FIG. 3C, in a sub-process for bonding the support substrate 11 and the single crystal film 13, an adhesive layer 12a is formed on the main surface 11m of the support substrate 11 (FIG. 3C1). After forming the adhesive layer 12b on the main surface 13n of the single crystal film 13 grown on the main surface 30n (FIG. 3C2), the main surface 12am of the adhesive layer 12a formed on the support substrate 11 The adhesive layer 12 formed by bonding the adhesive layer 12a and the adhesive layer 12b to each other by bonding the main surface 12bn of the adhesive layer 12b formed on the single crystal film 13 formed on the base substrate 30. The supporting substrate 11 and the single crystal film 13 are bonded to each other with the intervening layer (FIG. 3 (C3)). However, as long as the support substrate 11 and the single crystal film 13 can be bonded to each other, the support substrate 11 and the single crystal film 13 can be directly bonded together without the adhesive layer 12 interposed.

支持基板１１と単結晶膜１３とを貼り合わせる具体的な手法としては、特に制限はないが、貼り合わせ後高温でも接合強度を保持できる観点から、貼り合わせ面を洗浄しそのまま貼り合わせた後６００℃〜１２００℃程度に昇温して接合する直接接合法、貼り合わせ面を洗浄しプラズマやイオンなどで活性化させた後に室温（たとえば２５℃）〜４００℃程度の低温で接合する表面活性化法などが好ましく用いられる。   A specific method for bonding the support substrate 11 and the single crystal film 13 is not particularly limited, but from the viewpoint of maintaining the bonding strength even at a high temperature after bonding, the bonded surface is washed and bonded as it is. Direct bonding method in which bonding is performed by raising the temperature to about 1 to 1200 ° C., surface activation for bonding at a low temperature of about room temperature (for example, 25 ° C.) to about 400 ° C. after cleaning the bonded surfaces and activating them with plasma or ions. The method is preferably used.

こうして得られる複合基板１０において、支持基板１１、単結晶膜１３および接着層１２の材料および物性については、上述の通りであるため、ここでは繰り返さない。   In the composite substrate 10 thus obtained, the materials and physical properties of the support substrate 11, the single crystal film 13, and the adhesive layer 12 are as described above, and thus are not repeated here.

（ＧａＡｓ系膜の成膜工程）
図２（Ｂ）を参照して、本実施形態のＧａＡｓ系膜の製造方法は、次に、複合基板１０における単結晶膜１３の主面１３ｍ上にＧａＡｓ系膜２０を成膜する工程を含む。 (Deposition process of GaAs film)
With reference to FIG. 2B, the method for manufacturing a GaAs-based film according to this embodiment includes a step of forming a GaAs-based film 20 on the main surface 13 m of the single crystal film 13 in the composite substrate 10. .

上記の複合基板の準備工程において準備された複合基板１０は、支持基板１１の主面１１ｍ内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて、０．８倍より大きく１．２倍より小さい支持基板１１と単結晶膜１３を含んでいるため、単結晶膜１３の主面１３ｍ上に主面２０ｍの面積が大きく反りが小さく結晶性が良好なＧａＡｓ系膜２０を成膜することができる。   In the composite substrate 10 prepared in the composite substrate preparation step, the thermal expansion coefficient in the main surface 11m of the support substrate 11 is larger than 0.8 times and 1.2 times larger than the thermal expansion coefficient of the GaAs crystal. Since the smaller supporting substrate 11 and the single crystal film 13 are included, the GaAs-based film 20 having a large area of the main surface 20m, a small warpage, and good crystallinity is formed on the main surface 13m of the single crystal film 13. Can do.

ＧａＡｓ系膜を成膜する方法には、特に制限はないが、転位密度が低く結晶性の良好なＧａＡｓ系膜を成膜する観点から、ＭＯＣＶＤ（有機金属化学気相堆積）法、ＭＢＥ（分子線エピタキシ）法などの気相法、ＨＢ（水平ブリッジマン）法、ＶＢ（垂直ブリッジマン）法、ＬＥＣ（液体封止チョクラルスキー）法などの液相法などが好ましく挙げられる。   The method for forming a GaAs film is not particularly limited, but from the viewpoint of forming a GaAs film having a low dislocation density and good crystallinity, MOCVD (metal organic chemical vapor deposition), MBE (molecular Preferred examples include gas phase methods such as a line epitaxy method, liquid phase methods such as an HB (horizontal Bridgman) method, a VB (vertical Bridgman) method, and an LEC (liquid sealing Czochralski) method.

ＧａＡｓ系膜を成膜する工程は、特に制限はないが、転位密度が低く結晶性が良好なＧａＡｓ系膜を成膜する観点から、複合基板１０の単結晶膜１３の主面１３ｍ上にＧａＡｓ系バッファ層２１を形成するサブ工程と、ＧａＡｓ系バッファ層２１の主面２１ｍ上にＧａＡｓ系単結晶層２３を形成するサブ工程と、を含むことが好ましい。ここで、ＧａＡｓ系バッファ層２１とは、ＧａＡｓ系膜２０の一部分であり、ＧａＡｓ系膜２０の別の一部分であるＧａＡｓ系単結晶層２３の成長温度に比べて低い温度で成長させられる結晶性が低いまたは非結晶の層をいう。   The step of forming the GaAs film is not particularly limited, but from the viewpoint of forming a GaAs film having a low dislocation density and good crystallinity, GaAs is formed on the main surface 13m of the single crystal film 13 of the composite substrate 10. It is preferable to include a sub-process for forming the system buffer layer 21 and a sub-process for forming the GaAs single crystal layer 23 on the main surface 21 m of the GaAs buffer layer 21. Here, the GaAs-based buffer layer 21 is a part of the GaAs-based film 20 and has a crystallinity that can be grown at a temperature lower than the growth temperature of the GaAs-based single crystal layer 23 that is another part of the GaAs-based film 20. Refers to a low or amorphous layer.

ＧａＡｓ系バッファ層２１を形成することにより、ＧａＡｓ系バッファ層２１上に形成されるＧａＡｓ系単結晶層２３と単結晶膜１３との間の格子定数の不整合が緩和されるため、ＧａＡｓ系単結晶層２３の結晶性が向上しその転位密度が低くなる。この結果、ＧａＡｓ系膜２０の結晶性が向上しその転位密度が低くなる。   By forming the GaAs buffer layer 21, the lattice constant mismatch between the GaAs single crystal layer 23 and the single crystal film 13 formed on the GaAs buffer layer 21 is relaxed. The crystallinity of the crystal layer 23 is improved and the dislocation density is lowered. As a result, the crystallinity of the GaAs-based film 20 is improved and the dislocation density is lowered.

なお、単結晶膜１３上にＧａＡｓ系膜２０として、ＧａＡｓ系バッファ層２１を成長させることなく、ＧａＡｓ系単結晶層２３を成長させることもできる。かかる方法は、単結晶膜１３とその上に成膜するＧａＡｓ系膜２０との間の格子定数の不整合が小さい場合に好適である。   Note that the GaAs-based single crystal layer 23 can be grown as the GaAs-based film 20 on the single-crystal film 13 without growing the GaAs-based buffer layer 21. Such a method is suitable when the mismatch of the lattice constant between the single crystal film 13 and the GaAs-based film 20 formed thereon is small.

（支持基板の除去工程）
図２（Ｃ）を参照して、本実施形態のＧａＡｓ系膜の製造方法は、次に、支持基板１１を、フッ化水素酸に溶解することにより、除去する工程を含む。 (Support substrate removal process)
Referring to FIG. 2C, the method of manufacturing a GaAs-based film according to this embodiment includes a step of removing the support substrate 11 by dissolving it in hydrofluoric acid.

上記の複合基板の準備工程において準備された複合基板１０は、支持基板１１がフッ化水素酸に溶解するため、フッ化水素酸に溶解させて支持基板１１を除去することにより、単結晶膜１３の主面１３ｍ上に成膜された主面２０ｍの面積が大きく反りが小さく結晶性が良好なＧａＡｓ系膜２０が得られる。ここで、単結晶膜１３がＧａＡｓ単結晶膜などのＧａＡｓ系単結晶膜で形成されている場合には、全体がＧａＡｓ系材料で形成されているＧａＡｓ系膜が得られる。   Since the support substrate 11 is dissolved in hydrofluoric acid, the composite substrate 10 prepared in the above-described composite substrate preparation step is dissolved in hydrofluoric acid to remove the support substrate 11, thereby removing the single crystal film 13. Thus, a GaAs-based film 20 having a large area of the main surface 20m formed on the main surface 13m and a small warpage and good crystallinity is obtained. Here, when the single crystal film 13 is formed of a GaAs single crystal film such as a GaAs single crystal film, a GaAs film that is entirely formed of a GaAs material is obtained.

（実施例１）
１．ＧａＡｓ結晶の熱膨張係数の測定
ＶＢ法により成長させた、転位密度が１×１０6ｃｍ-2、Ｓｉ濃度が１×１０18ｃｍ-2、酸素濃度が１×１０17ｃｍ-2、炭素濃度が１×１０16ｃｍ-2のＧａＡｓ単結晶から、サイズが２×２×２０ｍｍの評価用サンプルを切り出した。ここで、ＧａＡｓ単結晶は熱膨張係数に関して方向特異性がないため、切り出し方向は任意とした。 Example 1
1. Measurement of thermal expansion coefficient of GaAs crystal Dislocation density 1 × 10 6 cm −2 , Si concentration 1 × 10 18 cm −2 , oxygen concentration 1 × 10 17 cm −2 , carbon concentration grown by VB method A sample for evaluation having a size of 2 × 2 × 20 mm was cut out from a GaAs single crystal having a size of 1 × 10 16 cm −2 . Here, since the GaAs single crystal has no direction specificity with respect to the thermal expansion coefficient, the cutting direction was arbitrary.

上記の評価用サンプルについて、室温（２５℃）から１０００℃まで昇温したときの平均熱膨張係数をＴＭＡ（熱機械分析）により測定した。具体的には、（株）リガク製ＴＭＡ８３１０を用いて示差膨張方式により窒素ガス流通雰囲気下で評価サンプルの熱膨張係数を測定した。かかる測定により得られたＧａＡｓ結晶の２５℃から１０００℃までにおける平均熱膨張係数αGaAsは、５．８４×１０-6／℃であった。 About said sample for evaluation, the average thermal expansion coefficient when it heated up from room temperature (25 degreeC) to 1000 degreeC was measured by TMA (thermomechanical analysis). Specifically, the thermal expansion coefficient of the evaluation sample was measured in a nitrogen gas flow atmosphere by a differential expansion method using TMA8310 manufactured by Rigaku Corporation. The average thermal expansion coefficient α GaAs from 25 ° C. to 1000 ° C. of the GaAs crystal obtained by such measurement was 5.84 × 10 −6 / ° C.

２．複合基板の準備工程
（１）支持基板を準備するサブ工程
図３（Ａ）を参照して、支持基板１１の材料として、ＺｒＯ2とＳｉＯ2との所定のモル比の混合物をアルゴンガス雰囲気下一軸方向に５０ＭＰａの圧力をかけて１７００℃で１時間焼結させることにより、１３種類のＺｒＯ2−ＳｉＯ2系焼結体Ａ〜Ｍを準備した。かかる１３種類のＺｒＯ2−ＳｉＯ2系焼結体Ａ〜Ｍには、Ｘ線回折により確認したところ、いずれについてもＺｒＳｉＯ4、ＺｒＯ2およびＳｉＯ2が存在していた。また、上記１３種類のＺｒＯ2−ＳｉＯ2系焼結体のそれぞれからサイズが２×２×２０ｍｍ（長手方向は焼結体から切り出される支持基板の主面に実質的に平行な方向）の測定用サンプルを切り出した。ここで、ＺｒＯ2−ＳｉＯ2系焼結体は熱膨張係数に関して方向特異性がないため、切り出し方向は任意とした。それらの測定用サンプルについて、上記と同様にして、室温（２５℃）から１０００℃まで昇温下時の平均熱膨張係数αSを測定した。 2. Step of preparing composite substrate (1) Sub-step of preparing support substrate Referring to FIG. 3 (A), as a material of support substrate 11, a mixture of ZrO 2 and SiO 2 in a predetermined molar ratio is placed in an argon gas atmosphere. Thirteen types of ZrO 2 —SiO 2 sintered bodies A to M were prepared by sintering at 1700 ° C. for 1 hour under a pressure of 50 MPa in a uniaxial direction. These 13 types of ZrO 2 —SiO 2 sintered bodies A to M were confirmed by X-ray diffraction. As a result, ZrSiO 4 , ZrO 2 and SiO 2 were present in all of them. Further, each of the 13 types of ZrO 2 —SiO 2 sintered bodies has a size of 2 × 2 × 20 mm (the longitudinal direction is a direction substantially parallel to the main surface of the support substrate cut out from the sintered body). A sample was cut out. Here, since the ZrO 2 —SiO 2 sintered body has no direction specificity with respect to the coefficient of thermal expansion, the cutting direction was arbitrary. With respect to these measurement samples, the average thermal expansion coefficient α S when the temperature was raised from room temperature (25 ° C.) to 1000 ° C. was measured in the same manner as described above.

ＺｒＯ2−ＳｉＯ2系焼結体Ａは、ＺｒＯ2とＳｉＯ2とのモル比（以下、モル比ＺｒＯ2：ＳｉＯ2という）が８２：１８であり、２５℃から１０００℃までにおける平均熱膨張係数αS（以下、単に平均熱膨張係数αSという）は４．２５×１０-6／℃であり、ＧａＡｓ結晶の平均熱膨張係数αGaAsに対する焼結体の熱膨張係数αSの比（以下、αS／αGaAs比という）は０．７２８であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｂは、モル比ＺｒＯ2：ＳｉＯ2が７７：２３であり、平均熱膨張係数αSが４．７５×１０-6／℃であり、αS／αGaAs比が０．８１３であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｃは、モル比ＺｒＯ2：ＳｉＯ2が７１：２９であり、平均熱膨張係数αSが５．００×１０-6／℃であり、αS／αGaAs比が０．８５６であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｄは、モル比ＺｒＯ2：ＳｉＯ2は６９：３１であり、平均熱膨張係数αSが５．２０×１０-6／℃であり、αS／αGaAs比が０．８９０であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｅは、モル比ＺｒＯ2：ＳｉＯ2が６６：３４であり、平均熱膨張係数αSが５．４０×１０-6／℃であり、αS／αGaAs比が０．９２５であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｆは、モル比ＺｒＯ2：ＳｉＯ2が６３：３７であり、平均熱膨張係数αSが５．６０×１０-6／℃であり、αS／αGaAs比が０．９５９であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｇは、モル比ＺｒＯ2：ＳｉＯ2が５８：４２であり、平均熱膨張係数αSが５．８０×１０-6／℃であり、αS／αGaAs比が０．９９３であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｈは、モル比ＺｒＯ2：ＳｉＯ2が５７：４３であり、平均熱膨張係数αSが６．００×１０-6／℃であり、αS／αGaAs比が１．０２７であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｉは、モル比ＺｒＯ2：ＳｉＯ2が５３：４７であり、平均熱膨張係数αSが６．３３×１０-6／℃であり、αS／αGaAs比が１．０８４であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｊは、モル比ＺｒＯ2：ＳｉＯ2が４６：５４であり、平均熱膨張係数αSが６．６７×１０-6／℃であり、αS／αGaAs比が１．１４２であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｋは、モル比ＺｒＯ2：ＳｉＯ2が４２：５８であり、平均熱膨張係数αSが７．００×１０-6／℃であり、αS／αGaAs比が１．１９９であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｌは、モル比ＺｒＯ2：ＳｉＯ2が３８：６２であり、平均熱膨張係数αSが７．２５×１０-6／℃であり、αS／αGaAs比が１．２４１であった。ＺｒＯ2−ＳｉＯ2系焼結体Ｍは、モル比ＺｒＯ2：ＳｉＯ2が３５：６５であり、平均熱膨張係数αSが７．５０×１０-6／℃であり、αS／αGaAs比が１．２８４であった。 The ZrO 2 —SiO 2 sintered body A has a molar ratio of ZrO 2 to SiO 2 (hereinafter referred to as a molar ratio ZrO 2 : SiO 2 ) of 82:18, and an average thermal expansion from 25 ° C. to 1000 ° C. The coefficient α S (hereinafter simply referred to as the average thermal expansion coefficient α S ) is 4.25 × 10 −6 / ° C., and the ratio of the thermal expansion coefficient α S of the sintered body to the average thermal expansion coefficient α GaAs of the GaAs crystal ( (Hereinafter referred to as α S / α GaAs ratio) was 0.728. The ZrO 2 —SiO 2 sintered body B has a molar ratio ZrO 2 : SiO 2 of 77:23, an average coefficient of thermal expansion α S of 4.75 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.813. The ZrO 2 —SiO 2 based sintered body C has a molar ratio ZrO 2 : SiO 2 of 71:29, an average thermal expansion coefficient α S of 5.00 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.856. The ZrO 2 —SiO 2 sintered body D has a molar ratio ZrO 2 : SiO 2 of 69:31, an average coefficient of thermal expansion α S of 5.20 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.890. The ZrO 2 —SiO 2 sintered body E has a molar ratio ZrO 2 : SiO 2 of 66:34, an average thermal expansion coefficient α S of 5.40 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.925. The ZrO 2 —SiO 2 based sintered body F has a molar ratio ZrO 2 : SiO 2 of 63:37, an average thermal expansion coefficient α S of 5.60 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.959. The ZrO 2 —SiO 2 based sintered body G has a molar ratio ZrO 2 : SiO 2 of 58:42, an average thermal expansion coefficient α S of 5.80 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.993. The ZrO 2 —SiO 2 based sintered body H has a molar ratio ZrO 2 : SiO 2 of 57:43, an average thermal expansion coefficient α S of 6.00 × 10 −6 / ° C., and α S / α GaAs. The ratio was 1.027. The ZrO 2 —SiO 2 sintered body I has a molar ratio ZrO 2 : SiO 2 of 53:47, an average coefficient of thermal expansion α S of 6.33 × 10 −6 / ° C., and α S / α GaAs. The ratio was 1.084. The ZrO 2 —SiO 2 based sintered body J has a molar ratio ZrO 2 : SiO 2 of 46:54, an average thermal expansion coefficient α S of 6.67 × 10 −6 / ° C., and α S / α GaAs. The ratio was 1.142. The ZrO 2 —SiO 2 based sintered body K has a molar ratio ZrO 2 : SiO 2 of 42:58, an average thermal expansion coefficient α S of 7.00 × 10 −6 / ° C., and α S / α GaAs. The ratio was 1.199. The ZrO 2 —SiO 2 sintered body L has a molar ratio ZrO 2 : SiO 2 of 38:62, an average coefficient of thermal expansion α S of 7.25 × 10 −6 / ° C., and α S / α GaAs. The ratio was 1.241. The ZrO 2 —SiO 2 based sintered body M has a molar ratio ZrO 2 : SiO 2 of 35:65, an average thermal expansion coefficient α S of 7.50 × 10 −6 / ° C., and α S / α GaAs. The ratio was 1.284.

上記のＺｒＯ2−ＳｉＯ2系焼結体Ａ〜Ｍから、直径４インチ（１０１．６ｍｍ）で厚さ１ｍｍの支持基板をそれぞれ切り出して、それぞれの支持基板の両主面を鏡面に研磨して、支持基板Ａ〜Ｍとした。すなわち、支持基板Ａ〜Ｍの２５℃から１０００℃までにおける平均熱膨張係数は、それぞれＺｒＯ2−ＳｉＯ2系焼結体Ａ〜Ｍの２５℃から１０００℃までにおける平均熱膨張係数に等しい。結果を表１にまとめた。 From the ZrO 2 —SiO 2 based sintered bodies A to M, a support substrate having a diameter of 4 inches (101.6 mm) and a thickness of 1 mm was cut out, and both main surfaces of each support substrate were polished into mirror surfaces. The supporting substrates A to M were used. That is, the average thermal expansion coefficients of the support substrates A to M from 25 ° C. to 1000 ° C. are equal to the average thermal expansion coefficients of the ZrO 2 —SiO 2 based sintered bodies A to M from 25 ° C. to 1000 ° C., respectively. The results are summarized in Table 1.

（２）下地基板上に単結晶膜を成膜するサブ工程
図３（Ｂ）を参照して、下地基板３０として、鏡面に研磨された（００１）面の主面３０ｎを有する直径５インチ（１２７ｍｍ）で厚さ０．５ｍｍのＳｉ基板を準備した。 (2) Sub-Process for Forming Single Crystal Film on Base Substrate With reference to FIG. 3B, the base substrate 30 has a main surface 30n of (001) surface polished to a mirror surface and has a diameter of 5 inches ( 127 mm) and a 0.5 mm thick Si substrate was prepared.

上記のＳｉ基板（下地基板３０）の主面３０ｎ上に、単結晶膜１３として厚さ０．４μｍのＧａＡｓ膜をＭＯＣＶＤ法により成膜した。成膜条件は、原料ガスとしてＴＭＧ（トリメチルガリウム）ガスおよびＡｓＨ3（アルシン）ガスを使用し、キャリアガスとしてＨ2ガスを使用し、成膜温度（基板温度）６２０℃、成膜圧力は１気圧とした。なお、こうして得られたＧａＡｓ膜（単結晶膜１３）の主面１３ｍは、（００１）面からのオフ角が±１°以内の面方位を有し、ＡＦＭ（原子間力顕微鏡）を用いて測定した１０μｍ×１０μｍの正方形領域におけるＲＭＳ（二乗平均平方根）粗さ（ＪＩＳ Ｂ０６０１：２００１に規定する二乗平均平方根粗さＲｑをいう。以下同じ）が１ｎｍ以下の鏡面であった。 A GaAs film having a thickness of 0.4 μm was formed as the single crystal film 13 on the main surface 30n of the Si substrate (underlying substrate 30) by the MOCVD method. The film formation conditions are as follows: TMG (trimethylgallium) gas and AsH 3 (arsine) gas are used as the source gas, H 2 gas is used as the carrier gas, the film formation temperature (substrate temperature) is 620 ° C., and the film formation pressure is 1 Atmospheric pressure. The main surface 13m of the GaAs film (single crystal film 13) obtained in this way has a plane orientation whose off angle from the (001) plane is within ± 1 °, and using an AFM (atomic force microscope). The RMS (root mean square) roughness (referred to the root mean square roughness Rq defined in JIS B0601: 2001, hereinafter the same) in a 10 μm × 10 μm square area was a mirror surface of 1 nm or less.

（３）支持基板と単結晶膜とを貼り合わせるサブ工程
図３（Ｃ）中の（Ｃ１）を参照して、図３（Ａ）の支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍ上に厚さ２μｍのＳｉＯ2膜をＣＶＤ（化学気相堆積）法により成膜した。次いで、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍ上の厚さ２μｍのＳｉＯ2膜を、ＣｅＯ2スラリーを用いて研磨することにより、厚さ０．２μｍのＳｉＯ2層だけ残存させて、接着層１２ａとした。これにより、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍの空隙が埋められ、平坦な主面１２ａｍを有する厚さ０．２μｍのＳｉＯ2層（接着層１２ａ）が得られた。 (3) Sub-process for bonding support substrate and single crystal film Referring to (C1) in FIG. 3 (C), each of the main substrates A to M (support substrate 11) in FIG. 3 (A) A SiO 2 film having a thickness of 2 μm was formed on the surface 11 m by a CVD (chemical vapor deposition) method. Next, the SiO 2 film having a thickness of 2 μm on each main surface 11m of the support substrates A to M (support substrate 11) is polished by using CeO 2 slurry, so that only the SiO 2 layer having a thickness of 0.2 μm is obtained. The adhesive layer 12a was made to remain. Thus, the gap is filled in each of the main surfaces 11m of the supporting substrate A to M (support substrate 11), SiO 2 layer having a thickness of 0.2μm having a flat main surface 12am (adhesive layer 12a) was obtained .

また、図３（Ｃ）中の（Ｃ２）を参照して、図３（Ｂ）のＳｉ基板（下地基板３０）上に成膜されたＧａＡｓ膜（単結晶膜１３）の主面１３ｎ上に厚さ２μｍのＳｉＯ2膜をＣＶＤ法により成膜した。次いで、この厚さ２μｍのＳｉＯ2膜を、ＣｅＯ2スラリーを用いて研磨することにより、厚さ０．２μｍのＳｉＯ2層だけ残存させて、接着層１２ｂとした。 Further, referring to (C2) in FIG. 3C, on the main surface 13n of the GaAs film (single crystal film 13) formed on the Si substrate (underlying substrate 30) in FIG. 3B. A SiO 2 film having a thickness of 2 μm was formed by a CVD method. Next, this SiO 2 film having a thickness of 2 μm was polished using a CeO 2 slurry, so that only the SiO 2 layer having a thickness of 0.2 μm was left to form an adhesive layer 12b.

次いで、図３（Ｃ）中の（Ｃ３）を参照して、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれに形成されたＳｉＯ2層（接着層１２ａ）の主面１２ａｍおよびＳｉ基板（下地基板３０）上に成膜されたＧａＡｓ膜（単結晶膜１３）上に形成されたＳｉＯ2層（接着層１２ｂ）の主面１２ｂｎをアルゴンプラズマにより清浄化および活性化させた後、ＳｉＯ2層（接着層１２ａ）の主面１２ａｍとＳｉＯ2層（接着層１２ｂ）の主面１２ｂｎとを貼り合わせて、窒素雰囲気下３００℃で２時間熱処理した。 Next, referring to (C3) in FIG. 3C, the main surface 12am of the SiO 2 layer (adhesive layer 12a) and the Si substrate (underlayer) formed on each of the support substrates A to M (support substrate 11). The main surface 12bn of the SiO 2 layer (adhesive layer 12b) formed on the GaAs film (single crystal film 13) formed on the substrate 30) is cleaned and activated by argon plasma, and then the SiO 2 layer The main surface 12am of the (adhesive layer 12a) and the main surface 12bn of the SiO 2 layer (adhesive layer 12b) were bonded together and heat-treated at 300 ° C. for 2 hours in a nitrogen atmosphere.

（４）下地基板を除去するサブ工程
図３（Ｄ）を参照して、支持基板Ａ〜Ｍ（支持基板１１）の裏側（単結晶膜１３が貼り合わされていない側）の主面および側面をワックス４０で覆って保護した後、１０質量％のフッ化水素酸および３質量％の硝酸を含む混酸水溶液を用いて、エッチングによりＳｉ基板（下地基板３０）を除去した。こうして、図２（Ａ）に示すように、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍ側にＧａＡｓ膜（単結晶膜１３）が配置された複合基板Ａ〜Ｍ（複合基板１０）が得られた。 (4) Sub-process for removing base substrate Referring to FIG. 3D, the main surface and side surfaces of the back side (side on which single crystal film 13 is not bonded) of support substrates A to M (support substrate 11) are After covering and protecting with wax 40, the Si substrate (underlying substrate 30) was removed by etching using a mixed acid aqueous solution containing 10% by mass of hydrofluoric acid and 3% by mass of nitric acid. Thus, as shown in FIG. 2A, composite substrates A to M (composite substrates) in which GaAs films (single crystal films 13) are arranged on the main surfaces 11m side of the support substrates A to M (support substrate 11). 10) was obtained.

３．ＧａＡｓ系膜の成膜工程
図２（Ｂ）を参照して、複合基板Ａ〜Ｍ（複合基板１０）のＧａＡｓ膜（単結晶膜１３）の主面１３ｍ（かかる主面は（００１）面である。）上に、それぞれＭＯＣＶＤ法によりＧａＡｓ膜（ＧａＡｓ系膜２０）を成膜した。ＧａＡｓ膜（ＧａＡｓ系膜２０）の成膜においては、成膜条件は、原料ガスとしてＴＭＧ（トリメチルガリウム）ガスおよびＡｓＨ3（アルシン）ガスを使用し、キャリアガスとしてＨ2ガスを使用し、成膜温度（基板温度）６８０℃で厚さ５μｍのＧａＡｓ単結晶層（ＧａＡｓ系単結晶層２３）を成長させた。ここで、ＧａＡｓ単結晶層の成長速度は１μｍ／ｈｒであった。その後、複合基板Ａ〜ＭのそれぞれにＧａＡｓ膜が成膜されたウエハＡ〜Ｍを１０℃／ｍｉｎの速度で室温（２５℃）まで冷却した。 3. GaAs film formation process Referring to FIG. 2B, the main surface 13m of the GaAs film (single crystal film 13) of the composite substrate A to M (composite substrate 10) (the main surface is the (001) surface). A GaAs film (GaAs-based film 20) was formed on each of them by MOCVD. In the formation of a GaAs film (GaAs-based film 20), the film formation conditions are as follows: TMG (trimethylgallium) gas and AsH 3 (arsine) gas are used as the source gas, and H 2 gas is used as the carrier gas. A GaAs single crystal layer (GaAs single crystal layer 23) having a thickness of 5 μm was grown at a film temperature (substrate temperature) of 680 ° C. Here, the growth rate of the GaAs single crystal layer was 1 μm / hr. Thereafter, the wafers A to M each having a GaAs film formed on each of the composite substrates A to M were cooled to room temperature (25 ° C.) at a rate of 10 ° C./min.

室温まで冷却後に成膜装置から取り出されたウエハＡ〜Ｍについて、ウエハの反り、ＧａＡｓ膜のクラック本数密度および転位密度を測定した。ここで、ウエハの反りの形状および反り量は、ＧａＡｓ膜の主面をＣｏｒｎｉｎｇ Ｔｒｏｐｅｌ社のＦＭ２００ＥＷａｆｅｒを用いて観察される光干渉縞により測定した。ＧａＡｓＮ膜のクラック本数密度は、ノマルスキー顕微鏡を用いて単位長さ当りのクラック本数を測定し、１本／ｍｍ未満を「極少」、１本／ｍｍ以上５本／ｍｍ未満を「少」、５本／ｍｍ以上１０本／ｍｍ未満を「多」、１０本／ｍｍ以上を「極多」と評価した。ＧａＡｓ膜の転位密度は、Ｌ（カソードルミネッセンス）による暗点の単位面積当たりの個数を測定した。なお、本実施例においてＧａＡｓ膜に発生したクラックは、膜を貫通しない微小なものであった。   For wafers A to M taken out from the film forming apparatus after cooling to room temperature, the warpage of the wafer, the number of cracks in the GaAs film and the dislocation density were measured. Here, the shape and amount of warpage of the wafer were measured by optical interference fringes observed on the main surface of the GaAs film using a Corning Tropel FM200EWafer. The number of cracks in the GaAsN film is determined by measuring the number of cracks per unit length using a Nomarski microscope. “Less” is less than 1 / mm, “Less” is 5 or less than 5 / mm. The book / mm or more and less than 10 / mm was evaluated as “many”, and the book / mm or more was evaluated as “very many”. The dislocation density of the GaAs film was measured by the number of dark spots per unit area due to L (cathode luminescence). In this example, cracks generated in the GaAs film were minute ones that did not penetrate the film.

ウエハＡは、ＧａＡｓ膜側が凹状に反り、反り量が６８０μｍであり、ＧａＡｓ膜のクラック本数密度が極多であった。ウエハＢは、ＧａＡｓ膜側が凹状に反り、反り量が６３０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が４×１０4ｃｍ-2であった。ウエハＣは、ＧａＡｓ膜側が凹状に反り、反り量が５００μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が３×１０4ｃｍ-2であった。ウエハＤは、ＧａＡｓ膜側が凹状に反り、反り量が４００μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が２．５×１０4ｃｍ-2であった。ウエハＥは、ＧａＡｓ膜側が凹状に反り、反り量が３５０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が２×１０4ｃｍ-2であった。ウエハＦは、ＧａＡｓ膜側が凹状に反り、反り量が２３０μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＧは、ＧａＡｓ膜側が凹状に反り、反り量が１５０μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＨは、ＧａＡｓ膜側が凹状に反り、反り量が１０μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＩは、ＧａＡｓ膜側が凸状に反り、反り量が１５μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＪは、ＧａＡｓ膜側が凸状に反り、反り量が１２０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が２×１０4ｃｍ-2であった。ウエハＫは、ＧａＡｓ膜側が凸状に反り、反り量が２３０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が３×１０4ｃｍ-2であった。ウエハＬは、ＧａＡｓ膜側が凸状に反り、反り量が７４５μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が４×１０4ｃｍ-2であった。ウエハＭは、支持基板に割れが発生し、十分なＧａＡｓ膜が得られなかった。これらの結果を表１にまとめた。表１において、「−」は、その物性値が未測定であることを示す。 The wafer A warped in a concave shape on the GaAs film side, the amount of warpage was 680 μm, and the number of cracks in the GaAs film was extremely large. The wafer B warped in a concave shape on the GaAs film side, the warpage amount was 630 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 4 × 10 4 cm −2 . The wafer C warped in a concave shape on the GaAs film side, the warpage amount was 500 μm, the number of cracks in the GaAs film was small, and the dislocation density of the GaAs film was 3 × 10 4 cm −2 . The wafer D was warped concavely on the GaAs film side, the warpage amount was 400 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 2.5 × 10 4 cm −2 . The wafer E warped in a concave shape on the GaAs film side, the warpage amount was 350 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 2 × 10 4 cm −2 . The wafer F warped in a concave shape on the GaAs film side, the warpage amount was 230 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer G was warped concavely on the GaAs film side, the warpage amount was 150 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer H warped in a concave shape on the GaAs film side, the warpage amount was 10 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer I was warped convexly on the GaAs film side, the warpage amount was 15 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer J warped in a convex shape on the GaAs film side, the warpage amount was 120 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 2 × 10 4 cm −2 . The wafer K was warped convexly on the GaAs film side, the warpage amount was 230 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 3 × 10 4 cm −2 . The wafer L was warped convexly on the GaAs film side, the amount of warpage was 745 μm, the number of cracks in the GaAs film was small, and the dislocation density of the GaAs film was 4 × 10 4 cm −2 . The wafer M was cracked in the support substrate, and a sufficient GaAs film could not be obtained. These results are summarized in Table 1. In Table 1, “-” indicates that the physical property value is not measured.

４．支持基板の除去工程
図２（Ｃ）を参照して、上記で得られたウエハＡ〜Ｌを、１０質量％のフッ化水素酸水溶液に浸漬することにより、支持基板Ａ〜Ｌ（支持基板１１）およびＳｉＯ2層を溶解させることにより除去して、ＧａＡｓ単結晶膜（単結晶膜１３）の主面１３ｍ上に成膜されたＧａＡｓ膜Ａ〜Ｌ（ＧａＡｓ系膜２０）が得られた。なお、ウエハＡ〜Ｌから支持基板Ａ〜ＬおよびＳｉＯ2層が除去されたＧａＡｓ膜Ａ〜Ｌ（ＧａＡｓ系膜２０）においても反りがＣｏｒｎｉｎｇ Ｔｒｏｐｅｌ社のＦＭ２００ＥＷａｆｅｒを用いて観察される光干渉縞による測定により認められ、ＧａＡｓ膜Ａ〜Ｌの反りの大小関係には、ウエハＡ〜Ｌにおける反りの大小関係が維持されていた。 4). Step of removing support substrate Referring to FIG. 2C, wafers A to L obtained above are immersed in a 10% by mass hydrofluoric acid aqueous solution, thereby supporting substrates A to L (support substrate 11). ) And the SiO 2 layer were removed by dissolution to obtain GaAs films A to L (GaAs-based film 20) formed on the main surface 13m of the GaAs single crystal film (single crystal film 13). It should be noted that warpage is also observed in the GaAs films A to L (GaAs-based film 20) from which the supporting substrates A to L and the SiO 2 layer are removed from the wafers A to L due to optical interference fringes observed using the Corning Tropel FM200EWafer. The magnitude relation of the warpage of the GaAs films A to L was maintained by the measurement, and the magnitude relation of the warpage in the wafers A to L was maintained.

Figure 2013116848
Figure 2013116848

表１を参照して、主面内の熱膨張係数αSがＧａＡｓ結晶の熱膨張係数αGaAsの０．８倍より大きく１．２倍より小さい（すなわち、０．８＜（αS／αGaAs比）＜１．２）支持基板を有する複合基板を用いることにより（ウエハＢ〜Ｋ）、反り小さく転位密度が低く結晶性の良好なＧａＡｓ膜を成膜することができた。また、ＧａＡｓ膜の反りおよび転位密度をさらに低減する観点から、複合基板の支持基板の主面内の熱膨張係数αSは、ＧａＡｓ結晶の熱膨張係数αGaAsの０．９倍より大きく１．１５倍より小さいこと（すなわち、０．９＜（αS／αGaAs比）＜１．１５）（ウエハＥ〜Ｊ）が好ましく、ＧａＡｓ結晶の熱膨張係数αGaAsの０．９５倍より大きく１．１倍より小さいこと（すなわち、０．９５＜（αS／αGaAs比）＜１．１）（ウエハＦ〜Ｉ）がより好ましい。 Referring to Table 1, the thermal expansion coefficient α S in the main surface is larger than 0.8 times and smaller than 1.2 times the thermal expansion coefficient α GaAs of the GaAs crystal (that is, 0.8 <(α S / α GaAs ratio) <1.2) By using a composite substrate having a supporting substrate (wafers B to K), a GaAs film having low warpage, low dislocation density, and good crystallinity could be formed. Further, from the viewpoint of further reducing the warpage and dislocation density of the GaAs film, the thermal expansion coefficient alpha S in the main surface of the supporting substrate of the composite substrate is greater than 0.9 times the thermal expansion coefficient alpha GaAs of GaAs crystal 1. It is preferably less than 15 times (that is, 0.9 <(α S / α GaAs ratio) <1.15) (wafers E to J), and the thermal expansion coefficient of GaAs crystal is larger than 0.95 times that of α GaAs and is 1 It is more preferable that the ratio is smaller than 1 time (that is, 0.95 <(α S / α GaAs ratio) <1.1) (wafers F to I).

（実施例２）
１．ＧａＡｓ結晶の熱膨張係数の測定
実施例１と同様に測定したところ、ＧａＡｓ結晶の２５℃から１０００℃までにおける平均熱膨張係数αGaAsは、５．８４×１０-6／℃であった。 (Example 2)
1. Measurement of Thermal Expansion Coefficient of GaAs Crystal When measured in the same manner as in Example 1, the average thermal expansion coefficient α GaAs from 25 ° C. to 1000 ° C. of the GaAs crystal was 5.84 × 10 −6 / ° C.

２．複合基板の準備工程
（１）支持基板を準備するサブ工程
図３（Ａ）を参照して、支持基板１１の材料として、ムライトとＹＳＺ（ＹＳＺにおけるＹ2Ｏ3含有率は３０モル％）との所定のモル比の混合物をアルゴンガス雰囲気下一軸方向に５０ＭＰａの圧力をかけて１７００℃で１時間焼結させることにより、１３種類のムライト−ＹＳＺ系焼結体Ａ〜Ｍを準備した。また、上記１３種類のムライト−ＹＳＺ系焼結体のそれぞれからサイズが４×４×２０ｍｍ（長手方向は焼結体から切り出される支持基板の主面に実質的に平行な方向）の測定用サンプルを切り出した。ここで、ムライト−ＹＳＺ系焼結体は熱膨張係数に関して方向特異性がないため、切り出し方向は任意とした。それらの測定用サンプルについて、上記と同様にして、室温（２５℃）から１０００℃まで昇温下時の平均熱膨張係数αSを測定した。 2. Preparation Step of Composite Substrate (1) Sub-Step of Preparing Support Substrate Referring to FIG. 3 (A), as a material for the support substrate 11, mullite and YSZ (Y 2 O 3 content in YSZ is 30 mol%) 13 types of mullite-YSZ-based sintered bodies A to M were prepared by sintering a mixture having a predetermined molar ratio of 50 MPa in a uniaxial direction under an argon gas atmosphere at 1700 ° C. for 1 hour. Further, each of the 13 types of mullite-YSZ sintered bodies has a size of 4 × 4 × 20 mm (longitudinal direction is a direction substantially parallel to the main surface of the support substrate cut out from the sintered body). Was cut out. Here, since the mullite-YSZ sintered body has no direction specificity with respect to the thermal expansion coefficient, the cutting direction was arbitrary. With respect to these measurement samples, the average thermal expansion coefficient α S when the temperature was raised from room temperature (25 ° C.) to 1000 ° C. was measured in the same manner as described above.

ムライト−ＹＳＺ系焼結体Ａは、ムライトとＹＳＺとのモル比（以下、モル比ムライト：ＹＳＺという）が９９．９：０．１であり、２５℃から１０００℃までにおける平均熱膨張係数αS（以下、単に平均熱膨張係数αSという）は４．２５×１０-6／℃であり、ＧａＡｓ結晶の平均熱膨張係数αGaAsに対する焼結体の熱膨張係数αSの比（以下、αS／αGaAs比という）は０．７２８であった。ムライト−ＹＳＺ系焼結体Ｂは、モル比ムライト：ＹＳＺが９９．６：０．４であり、平均熱膨張係数αSが４．７５×１０-6／℃であり、αS／αGaAs比が０．８１３であった。ムライト−ＹＳＺ系焼結体Ｃは、モル比ムライト：ＹＳＺが９９．３：０．７であり、平均熱膨張係数αSが５．００×１０-6／℃であり、αS／αGaAs比が０．８５６であった。ムライト−ＹＳＺ系焼結体Ｄは、モル比ムライト：ＹＳＺは９９：１であり、平均熱膨張係数αSが５．２０×１０-6／℃であり、αS／αGaAs比が０．８９０であった。ムライト−ＹＳＺ系焼結体Ｅは、モル比ムライト：ＹＳＺが９８．７：１．３であり、平均熱膨張係数αSが５．４０×１０-6／℃であり、αS／αGaAs比が０．９２５であった。ムライト−ＹＳＺ系焼結体Ｆは、モル比ムライト：ＹＳＺが９８．４：１．６であり、平均熱膨張係数αSが５．６０×１０-6／℃であり、αS／αGaAs比が０．９５９であった。ムライト−ＹＳＺ系焼結体Ｇは、モル比ムライト：ＹＳＺが９８．２：１．８であり、平均熱膨張係数αSが５．８０×１０-6／℃であり、αS／αGaAs比が０．９９３であった。ムライト−ＹＳＺ系焼結体Ｈは、モル比ムライト：ＹＳＺが９８：２であり、平均熱膨張係数αSが６．００×１０-6／℃であり、αS／αGaAs比が１．０２７であった。ムライト−ＹＳＺ系焼結体Ｉは、モル比ムライト：ＹＳＺが９０：１０であり、平均熱膨張係数αSが６．３３×１０-6／℃であり、αS／αGaAs比が１．０８４であった。ムライト−ＹＳＺ系焼結体Ｊは、モル比ムライト：ＹＳＺが８２：１８であり、平均熱膨張係数αSが６．６７×１０-6／℃であり、αS／αGaAs比が１．１４２であった。ムライト−ＹＳＺ系焼結体Ｋは、モル比ムライト：ＹＳＺが７５：２５であり、平均熱膨張係数αSが７．００×１０-6／℃であり、αS／αGaAs比が１．１９９であった。ムライト−ＹＳＺ系焼結体Ｌは、モル比ムライト：ＹＳＺが６９：３１であり、平均熱膨張係数αSが７．２５×１０-6／℃であり、αS／αGaAs比が１．２４１であった。ムライト−ＹＳＺ系焼結体Ｍは、モル比ムライト：ＹＳＺが６３：３７であり、平均熱膨張係数αSが７．５０×１０-6／℃であり、αS／αGaAs比が１．２８４であった。 The mullite-YSZ sintered body A has a molar ratio of mullite to YSZ (hereinafter referred to as molar ratio mullite: YSZ) of 99.9: 0.1, and an average thermal expansion coefficient α from 25 ° C. to 1000 ° C. S (hereinafter simply referred to as the average thermal expansion coefficient α S ) is 4.25 × 10 −6 / ° C., and the ratio of the thermal expansion coefficient α S of the sintered body to the average thermal expansion coefficient α GaAs of the GaAs crystal (hereinafter referred to as the following) α S / α GaAs ratio) was 0.728. The mullite-YSZ sintered body B has a molar ratio of mullite: YSZ of 99.6: 0.4, an average thermal expansion coefficient α S of 4.75 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.813. The mullite-YSZ sintered body C has a molar ratio mullite: YSZ of 99.3: 0.7, an average thermal expansion coefficient α S of 5.00 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.856. The mullite-YSZ sintered body D has a molar ratio mullite: YSZ of 99: 1, an average thermal expansion coefficient α S of 5.20 × 10 −6 / ° C., and an α S / α GaAs ratio of 0.2. 890. The mullite-YSZ sintered body E has a molar ratio mullite: YSZ of 98.7: 1.3, an average thermal expansion coefficient α S of 5.40 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.925. The mullite-YSZ sintered body F has a molar ratio mullite: YSZ of 98.4: 1.6, an average thermal expansion coefficient α S of 5.60 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.959. The mullite-YSZ sintered body G has a molar ratio mullite: YSZ of 98.2: 1.8, an average thermal expansion coefficient α S of 5.80 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.993. The mullite-YSZ sintered body H has a molar ratio mullite: YSZ of 98: 2, an average coefficient of thermal expansion α S of 6.00 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 027. The mullite-YSZ sintered body I has a molar ratio mullite: YSZ of 90:10, an average thermal expansion coefficient α S of 6.33 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 084. The mullite-YSZ sintered body J has a molar ratio mullite: YSZ of 82:18, an average thermal expansion coefficient α S of 6.67 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 142. The mullite-YSZ sintered body K has a molar ratio mullite: YSZ of 75:25, an average thermal expansion coefficient α S of 7.00 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 199. The mullite-YSZ sintered body L has a molar ratio of mullite: YSZ of 69:31, an average thermal expansion coefficient α S of 7.25 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 241. The mullite-YSZ sintered body M has a molar ratio mullite: YSZ of 63:37, an average coefficient of thermal expansion α S of 7.50 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 284.

上記のムライト−ＹＳＺ系焼結体Ａ〜Ｍから、直径４インチ（１０１．６ｍｍ）で厚さ１ｍｍの支持基板をそれぞれ切り出して、それぞれの支持基板の両主面を鏡面に研磨して、支持基板Ａ〜Ｍとした。すなわち、支持基板Ａ〜Ｍの２５℃から１０００℃までにおける平均熱膨張係数は、それぞれムライト−ＹＳＺ系焼結体Ａ〜Ｍの２５℃から１０００℃までにおける平均熱膨張係数に等しい。結果を表２にまとめた。   From the above-mentioned mullite-YSZ sintered bodies A to M, a support substrate having a diameter of 4 inches (101.6 mm) and a thickness of 1 mm is cut out, and both main surfaces of each support substrate are polished to a mirror surface to be supported. Substrates A to M were used. That is, the average thermal expansion coefficients of the support substrates A to M from 25 ° C. to 1000 ° C. are equal to the average thermal expansion coefficients of the mullite-YSZ sintered bodies A to M from 25 ° C. to 1000 ° C., respectively. The results are summarized in Table 2.

（２）下地基板上に単結晶膜を成膜するサブ工程
図３（Ｂ）を参照して、下地基板３０として、鏡面に研磨された（００１）面の主面３０ｎを有する直径５インチ（１２７ｍｍ）で厚さ０．５ｍｍのＳｉ基板を準備した。 (2) Sub-Process for Forming Single Crystal Film on Base Substrate With reference to FIG. 3B, the base substrate 30 has a main surface 30n of (001) surface polished to a mirror surface and has a diameter of 5 inches ( 127 mm) and a 0.5 mm thick Si substrate was prepared.

上記のＳｉ基板（下地基板３０）の主面３０ｎ上に、単結晶膜１３として厚さ０．４μｍのＧａＡｓ膜をＭＯＣＶＤ法により成膜した。成膜条件は、原料ガスとしてＴＭＧ（トリメチルガリウム）ガスおよびＡｓＨ3（アルシン）ガスを使用し、キャリアガスとしてＨ2ガスを使用し、成膜温度（基板温度）６２０℃、成膜圧力は１気圧とした。なお、こうして得られたＧａＡｓ膜（単結晶膜１３）の主面１３ｍは、（００１）面からのオフ角が±１°以内の面方位を有し、ＡＦＭ（原子間力顕微鏡）を用いて測定した１０μｍ×１０μｍの正方形領域におけるＲＭＳ（二乗平均平方根）粗さ（ＪＩＳ Ｂ０６０１：２００１に規定する二乗平均平方根粗さＲｑをいう。以下同じ）が１ｎｍ以下の鏡面であった。 A GaAs film having a thickness of 0.4 μm was formed as the single crystal film 13 on the main surface 30n of the Si substrate (underlying substrate 30) by the MOCVD method. The film formation conditions are as follows: TMG (trimethylgallium) gas and AsH 3 (arsine) gas are used as the source gas, H 2 gas is used as the carrier gas, the film formation temperature (substrate temperature) is 620 ° C., and the film formation pressure is 1 Atmospheric pressure. The main surface 13m of the GaAs film (single crystal film 13) obtained in this way has a plane orientation whose off angle from the (001) plane is within ± 1 °, and using an AFM (atomic force microscope). The RMS (root mean square) roughness (referred to the root mean square roughness Rq defined in JIS B0601: 2001, hereinafter the same) in a 10 μm × 10 μm square area was a mirror surface of 1 nm or less.

（３）支持基板と単結晶膜とを貼り合わせるサブ工程
図３（Ｃ）中の（Ｃ１）を参照して、図３（Ａ）の支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍ上に厚さ２μｍのＳｉＯ2膜をＣＶＤ（化学気相堆積）法により成膜した。次いで、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍ上の厚さ２μｍのＳｉＯ2膜を、ＣｅＯ2スラリーを用いて研磨することにより、厚さ０．２μｍのＳｉＯ2層だけ残存させて、接着層１２ａとした。これにより、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍの空隙が埋められ、平坦な主面１２ａｍを有する厚さ０．２μｍのＳｉＯ2層（接着層１２ａ）が得られた。 (3) Sub-process for bonding support substrate and single crystal film Referring to (C1) in FIG. 3 (C), each of the main substrates A to M (support substrate 11) in FIG. 3 (A) A SiO 2 film having a thickness of 2 μm was formed on the surface 11 m by a CVD (chemical vapor deposition) method. Next, the SiO 2 film having a thickness of 2 μm on each main surface 11m of the support substrates A to M (support substrate 11) is polished by using CeO 2 slurry, so that only the SiO 2 layer having a thickness of 0.2 μm is obtained. The adhesive layer 12a was made to remain. Thus, the gap is filled in each of the main surfaces 11m of the supporting substrate A to M (support substrate 11), SiO 2 layer having a thickness of 0.2μm having a flat main surface 12am (adhesive layer 12a) was obtained .

また、図３（Ｃ）中の（Ｃ２）を参照して、図３（Ｂ）のＳｉ基板（下地基板３０）上に成膜されたＧａＡｓ膜（単結晶膜１３）の主面１３ｎ上に厚さ２μｍのＳｉＯ2膜をＣＶＤ法により成膜した。次いで、この厚さ２μｍのＳｉＯ2膜を、ＣｅＯ2スラリーを用いて研磨することにより、厚さ０．２μｍのＳｉＯ2層だけ残存させて、接着層１２ｂとした。 Further, referring to (C2) in FIG. 3C, on the main surface 13n of the GaAs film (single crystal film 13) formed on the Si substrate (underlying substrate 30) in FIG. 3B. A SiO 2 film having a thickness of 2 μm was formed by a CVD method. Next, this SiO 2 film having a thickness of 2 μm was polished using a CeO 2 slurry, so that only the SiO 2 layer having a thickness of 0.2 μm was left to form an adhesive layer 12b.

次いで、図３（Ｃ）中の（Ｃ３）を参照して、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれに形成されたＳｉＯ2層（接着層１２ａ）の主面１２ａｍおよびＳｉ基板（下地基板３０）上に成膜されたＧａＡｓ膜（単結晶膜１３）上に形成されたＳｉＯ2層（接着層１２ｂ）の主面１２ｂｎをアルゴンプラズマにより清浄化および活性化させた後、ＳｉＯ2層（接着層１２ａ）の主面１２ａｍとＳｉＯ2層（接着層１２ｂ）の主面１２ｂｎとを貼り合わせて、窒素雰囲気下３００℃で２時間熱処理した。 Next, referring to (C3) in FIG. 3C, the main surface 12am of the SiO 2 layer (adhesive layer 12a) and the Si substrate (underlayer) formed on each of the support substrates A to M (support substrate 11). The main surface 12bn of the SiO 2 layer (adhesive layer 12b) formed on the GaAs film (single crystal film 13) formed on the substrate 30) is cleaned and activated by argon plasma, and then the SiO 2 layer The main surface 12am of the (adhesive layer 12a) and the main surface 12bn of the SiO 2 layer (adhesive layer 12b) were bonded together and heat-treated at 300 ° C. for 2 hours in a nitrogen atmosphere.

（４）下地基板を除去するサブ工程
図３（Ｄ）を参照して、支持基板Ａ〜Ｍ（支持基板１１）の裏側（単結晶膜１３が貼り合わされていない側）の主面および側面をワックス４０で覆って保護した後、１０質量％のフッ化水素酸および３質量％の硝酸を含む混酸水溶液を用いて、エッチングによりＳｉ基板（下地基板３０）を除去した。こうして、図２（Ａ）に示すように、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍ側にＧａＡｓ膜（単結晶膜１３）が配置された複合基板Ａ〜Ｍ（複合基板１０）が得られた。 (4) Sub-process for removing base substrate Referring to FIG. 3D, the main surface and side surfaces of the back side (side on which single crystal film 13 is not bonded) of support substrates A to M (support substrate 11) are After covering and protecting with wax 40, the Si substrate (underlying substrate 30) was removed by etching using a mixed acid aqueous solution containing 10% by mass of hydrofluoric acid and 3% by mass of nitric acid. Thus, as shown in FIG. 2A, composite substrates A to M (composite substrates) in which GaAs films (single crystal films 13) are arranged on the main surfaces 11m side of the support substrates A to M (support substrate 11). 10) was obtained.

３．ＧａＡｓ系膜の成膜工程
図２（Ｂ）を参照して、複合基板Ａ〜Ｍ（複合基板１０）のＧａＡｓ膜（単結晶膜１３）の主面１３ｍ（かかる主面は（００１）面である。）上に、それぞれＭＯＣＶＤ法によりＧａＡｓ膜（ＧａＡｓ系膜２０）を成膜した。ＧａＡｓ膜（ＧａＡｓ系膜２０）の成膜においては、成膜条件は、原料ガスとしてＴＭＧ（トリメチルガリウム）ガスおよびＡｓＨ3（アルシン）ガスを使用し、キャリアガスとしてＨ2ガスを使用し、成膜温度（基板温度）６８０℃で厚さ５μｍのＧａＡｓ単結晶層（ＧａＡｓ系単結晶層２３）を成長させた。ここで、ＧａＡｓ単結晶層の成長速度は１μｍ／ｈｒであった。その後、複合基板Ａ〜ＭのそれぞれにＧａＡｓ膜が成膜されたウエハＡ〜Ｍを１０℃／ｍｉｎの速度で室温（２５℃）まで冷却した。 3. GaAs film formation process Referring to FIG. 2B, the main surface 13m of the GaAs film (single crystal film 13) of the composite substrate A to M (composite substrate 10) (the main surface is the (001) surface). A GaAs film (GaAs-based film 20) was formed on each of them by MOCVD. In the formation of a GaAs film (GaAs-based film 20), the film formation conditions are as follows: TMG (trimethylgallium) gas and AsH 3 (arsine) gas are used as the source gas, and H 2 gas is used as the carrier gas. A GaAs single crystal layer (GaAs single crystal layer 23) having a thickness of 5 μm was grown at a film temperature (substrate temperature) of 680 ° C. Here, the growth rate of the GaAs single crystal layer was 1 μm / hr. Thereafter, the wafers A to M each having a GaAs film formed on each of the composite substrates A to M were cooled to room temperature (25 ° C.) at a rate of 10 ° C./min.

室温まで冷却後に成膜装置から取り出されたウエハＡ〜Ｍについて、ウエハの反り、ＧａＡｓ膜のクラック本数密度および転位密度を測定した。ここで、ウエハの反りの形状および反り量は、ＧａＡｓ膜の主面をＣｏｒｎｉｎｇ Ｔｒｏｐｅｌ社のＦＭ２００ＥＷａｆｅｒを用いて観察される光干渉縞により測定した。ＧａＡｓＮ膜のクラック本数密度は、ノマルスキー顕微鏡を用いて単位長さ当りのクラック本数を測定し、１本／ｍｍ未満を「極少」、１本／ｍｍ以上５本／ｍｍ未満を「少」、５本／ｍｍ以上１０本／ｍｍ未満を「多」、１０本／ｍｍ以上を「極多」と評価した。ＧａＡｓ膜の転位密度は、Ｌ（カソードルミネッセンス）による暗点の単位面積当たりの個数を測定した。なお、本実施例においてＧａＡｓ膜に発生したクラックは、膜を貫通しない微小なものであった。   For wafers A to M taken out from the film forming apparatus after cooling to room temperature, the warpage of the wafer, the number of cracks in the GaAs film and the dislocation density were measured. Here, the shape and amount of warpage of the wafer were measured by optical interference fringes observed on the main surface of the GaAs film using a Corning Tropel FM200EWafer. The number of cracks in the GaAsN film is determined by measuring the number of cracks per unit length using a Nomarski microscope. “Less” is less than 1 / mm, “Less” is 5 or less than 5 / mm. The book / mm or more and less than 10 / mm was evaluated as “many”, and the book / mm or more was evaluated as “very many”. The dislocation density of the GaAs film was measured by the number of dark spots per unit area due to L (cathode luminescence). In this example, cracks generated in the GaAs film were minute ones that did not penetrate the film.

ウエハＡは、ＧａＡｓ膜側が凹状に反り、反り量が６８０μｍであり、ＧａＡｓ膜のクラック本数密度が極多であった。ウエハＢは、ＧａＡｓ膜側が凹状に反り、反り量が６３０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が４×１０4ｃｍ-2であった。ウエハＣは、ＧａＡｓ膜側が凹状に反り、反り量が５００μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が３×１０4ｃｍ-2であった。ウエハＤは、ＧａＡｓ膜側が凹状に反り、反り量が４００μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が２．５×１０4ｃｍ-2であった。ウエハＥは、ＧａＡｓ膜側が凹状に反り、反り量が３５０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が２×１０4ｃｍ-2であった。ウエハＦは、ＧａＡｓ膜側が凹状に反り、反り量が２３０μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＧは、ＧａＡｓ膜側が凹状に反り、反り量が１５０μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＨは、ＧａＡｓ膜側が凹状に反り、反り量が１０μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＩは、ＧａＡｓ膜側が凸状に反り、反り量が１５μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＪは、ＧａＡｓ膜側が凸状に反り、反り量が１２０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が２×１０4ｃｍ-2であった。ウエハＫは、ＧａＡｓ膜側が凸状に反り、反り量が２３０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が３×１０4ｃｍ-2であった。ウエハＬは、ＧａＡｓ膜側が凸状に反り、反り量が７４５μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が４×１０4ｃｍ-2であった。ウエハＭは、支持基板に割れが発生し、十分なＧａＡｓ膜が得られなかった。これらの結果を表２にまとめた。表２において、「−」は、その物性値が未測定であることを示す。 The wafer A warped in a concave shape on the GaAs film side, the amount of warpage was 680 μm, and the number of cracks in the GaAs film was extremely large. The wafer B warped in a concave shape on the GaAs film side, the warpage amount was 630 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 4 × 10 4 cm −2 . The wafer C warped in a concave shape on the GaAs film side, the warpage amount was 500 μm, the number of cracks in the GaAs film was small, and the dislocation density of the GaAs film was 3 × 10 4 cm −2 . The wafer D was warped concavely on the GaAs film side, the warpage amount was 400 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 2.5 × 10 4 cm −2 . The wafer E warped in a concave shape on the GaAs film side, the warpage amount was 350 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 2 × 10 4 cm −2 . The wafer F warped in a concave shape on the GaAs film side, the warpage amount was 230 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer G was warped concavely on the GaAs film side, the warpage amount was 150 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer H warped in a concave shape on the GaAs film side, the warpage amount was 10 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer I was warped convexly on the GaAs film side, the warpage amount was 15 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer J warped in a convex shape on the GaAs film side, the warpage amount was 120 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 2 × 10 4 cm −2 . The wafer K was warped convexly on the GaAs film side, the warpage amount was 230 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 3 × 10 4 cm −2 . The wafer L was warped convexly on the GaAs film side, the amount of warpage was 745 μm, the number of cracks in the GaAs film was small, and the dislocation density of the GaAs film was 4 × 10 4 cm −2 . The wafer M was cracked in the support substrate, and a sufficient GaAs film could not be obtained. These results are summarized in Table 2. In Table 2, “-” indicates that the physical property value is not measured.

４．支持基板の除去工程
図２（Ｃ）を参照して、上記で得られたウエハＡ〜Ｌを、１０質量％のフッ化水素酸水溶液に浸漬することにより、支持基板Ａ〜Ｌ（支持基板１１）およびＳｉＯ2層を溶解させることにより除去して、ＧａＡｓ単結晶膜（単結晶膜１３）の主面１３ｍ上に成膜されたＧａＡｓ膜Ａ〜Ｌ（ＧａＡｓ系膜２０）が得られた。なお、ウエハＡ〜Ｌから支持基板Ａ〜ＬおよびＳｉＯ2層が除去されたＧａＡｓ膜Ａ〜Ｌ（ＧａＡｓ系膜２０）においても反りがＣｏｒｎｉｎｇ Ｔｒｏｐｅｌ社のＦＭ２００ＥＷａｆｅｒを用いて観察される光干渉縞による測定により認められ、ＧａＡｓ膜Ａ〜Ｌの反りの大小関係には、ウエハＡ〜Ｌにおける反りの大小関係が維持されていた。 4). Step of removing support substrate Referring to FIG. 2C, wafers A to L obtained above are immersed in a 10% by mass hydrofluoric acid aqueous solution, thereby supporting substrates A to L (support substrate 11). ) And the SiO 2 layer were removed by dissolution to obtain GaAs films A to L (GaAs-based film 20) formed on the main surface 13m of the GaAs single crystal film (single crystal film 13). It should be noted that warpage is also observed in the GaAs films A to L (GaAs-based film 20) from which the supporting substrates A to L and the SiO 2 layer are removed from the wafers A to L due to optical interference fringes observed using the Corning Tropel FM200EWafer. The magnitude relation of the warpage of the GaAs films A to L was maintained by the measurement, and the magnitude relation of the warpage in the wafers A to L was maintained.

Figure 2013116848
Figure 2013116848

表２を参照して、主面内の熱膨張係数αSがＧａＡｓ結晶の熱膨張係数αGaAsの０．８倍より大きく１．２倍より小さい（すなわち、０．８＜（αS／αGaAs比）＜１．２）支持基板を有する複合基板を用いることにより（ウエハＢ〜Ｋ）、反り小さく転位密度が低く結晶性の良好なＧａＡｓ膜を成膜することができた。また、ＧａＡｓ膜の反りおよび転位密度をさらに低減する観点から、複合基板の支持基板の主面内の熱膨張係数αSは、ＧａＡｓ結晶の熱膨張係数αGaAsの０．９倍より大きく１．１５倍より小さいこと（すなわち、０．９＜（αS／αGaAs比）＜１．１５）（ウエハＥ〜Ｊ）が好ましく、ＧａＡｓ結晶の熱膨張係数αGaAsの０．９５倍より大きく１．１倍より小さいこと（すなわち、０．９５＜（αS／αGaAs比）＜１．１）（ウエハＦ〜Ｉ）がより好ましい。 Referring to Table 2, the thermal expansion coefficient α S in the main surface is larger than 0.8 times and smaller than 1.2 times the thermal expansion coefficient α GaAs of the GaAs crystal (that is, 0.8 <(α S / α GaAs ratio) <1.2) By using a composite substrate having a supporting substrate (wafers B to K), a GaAs film having low warpage, low dislocation density, and good crystallinity could be formed. Further, from the viewpoint of further reducing the warpage and dislocation density of the GaAs film, the thermal expansion coefficient alpha S in the main surface of the supporting substrate of the composite substrate is greater than 0.9 times the thermal expansion coefficient alpha GaAs of GaAs crystal 1. It is preferably less than 15 times (that is, 0.9 <(α S / α GaAs ratio) <1.15) (wafers E to J), and the thermal expansion coefficient of GaAs crystal is larger than 0.95 times that of α GaAs and is 1 It is more preferable that the ratio is smaller than 1 time (that is, 0.95 <(α S / α GaAs ratio) <1.1) (wafers F to I).

（実施例３）
１．ＧａＡｓ結晶の熱膨張係数の測定
実施例１と同様に測定したところ、ＧａＡｓ結晶の２５℃から１０００℃までにおける平均熱膨張係数αGaAsは、５．８４×１０-6／℃であった。 (Example 3)
1. Measurement of Thermal Expansion Coefficient of GaAs Crystal When measured in the same manner as in Example 1, the average thermal expansion coefficient α GaAs from 25 ° C. to 1000 ° C. of the GaAs crystal was 5.84 × 10 −6 / ° C.

２．複合基板の準備工程
（１）支持基板を準備するサブ工程
図３（Ａ）を参照して、支持基板１１の材料として、ムライトとＭｇＯとの所定のモル比の混合物をアルゴンガス雰囲気下一軸方向に５０ＭＰａの圧力をかけて１７００℃で１時間焼結させることにより、１３種類のムライト−ＭｇＯ系焼結体Ａ〜Ｍを準備した。また、上記１３種類のムライト−ＭｇＯ系焼結体のそれぞれからサイズが４×４×２０ｍｍ（長手方向は焼結体から切り出される支持基板の主面に実質的に平行な方向）の測定用サンプルを切り出した。ここで、ムライト−ＭｇＯ系焼結体は熱膨張係数に関して方向特異性がないため、切り出し方向は任意とした。それらの測定用サンプルについて、上記と同様にして、室温（２５℃）から１０００℃まで昇温下時の平均熱膨張係数αSを測定した。 2. Preparation Step of Composite Substrate (1) Sub-Step of Preparing Support Substrate Referring to FIG. 3A, a mixture of mullite and MgO having a predetermined molar ratio as a material of support substrate 11 is uniaxially arranged in an argon gas atmosphere. Then, 13 kinds of mullite-MgO-based sintered bodies A to M were prepared by sintering at 1700 ° C. for 1 hour under a pressure of 50 MPa. Each of the 13 types of mullite-MgO-based sintered bodies has a measurement size of 4 × 4 × 20 mm (the longitudinal direction is a direction substantially parallel to the main surface of the support substrate cut out from the sintered body). Was cut out. Here, since the mullite-MgO-based sintered body has no direction specificity with respect to the thermal expansion coefficient, the cutting direction was arbitrary. With respect to these measurement samples, the average thermal expansion coefficient α S when the temperature was raised from room temperature (25 ° C.) to 1000 ° C. was measured in the same manner as described above.

ムライト−ＭｇＯ系焼結体Ａは、ムライトとＭｇＯとのモル比（以下、モル比ムライト：ＭｇＯという）が９９．９：０．１であり、２５℃から１０００℃までにおける平均熱膨張係数αS（以下、単に平均熱膨張係数αSという）は４．２５×１０-6／℃であり、ＧａＡｓ結晶の平均熱膨張係数αGaAsに対する焼結体の熱膨張係数αSの比（以下、αS／αGaAs比という）は０．７２８であった。ムライト−ＭｇＯ系焼結体Ｂは、モル比ムライト：ＭｇＯが９９．８：０．２であり、平均熱膨張係数αSが４．７５×１０-6／℃であり、αS／αGaAs比が０．８１３であった。ムライト−ＭｇＯ系焼結体Ｃは、モル比ムライト：ＭｇＯが９９．４：０．６であり、平均熱膨張係数αSが５．００×１０-6／℃であり、αS／αGaAs比が０．８５６であった。ムライト−ＭｇＯ系焼結体Ｄは、モル比ムライト：ＭｇＯは９９．１：０．９であり、平均熱膨張係数αSが５．２０×１０-6／℃であり、αS／αGaAs比が０．８９０であった。ムライト−ＭｇＯ系焼結体Ｅは、モル比ムライト：ＭｇＯが９８．８：１．２であり、平均熱膨張係数αSが５．４０×１０-6／℃であり、αS／αGaAs比が０．９２５であった。ムライト−ＭｇＯ系焼結体Ｆは、モル比ムライト：ＭｇＯが９８．５：１．５であり、平均熱膨張係数αSが５．６０×１０-6／℃であり、αS／αGaAs比が０．９５９であった。ムライト−ＭｇＯ系焼結体Ｇは、モル比ムライト：ＭｇＯが９８．３：１．７であり、平均熱膨張係数αSが５．８０×１０-6／℃であり、αS／αGaAs比が０．９９３であった。ムライト−ＭｇＯ系焼結体Ｈは、モル比ムライト：ＭｇＯが９８：２であり、平均熱膨張係数αSが６．００×１０-6／℃であり、αS／αGaAs比が１．０２７であった。ムライト−ＭｇＯ系焼結体Ｉは、モル比ムライト：ＭｇＯが９４：６であり、平均熱膨張係数αSが６．３３×１０-6／℃であり、αS／αGaAs比が１．０８４であった。ムライト−ＭｇＯ系焼結体Ｊは、モル比ムライト：ＭｇＯが８９：１１であり、平均熱膨張係数αSが６．６７×１０-6／℃であり、αS／αGaAs比が１．１４２であった。ムライト−ＭｇＯ系焼結体Ｋは、モル比ムライト：ＭｇＯが８５：１５であり、平均熱膨張係数αSが７．００×１０-6／℃であり、αS／αGaAs比が１．１９９であった。ムライト−ＭｇＯ系焼結体Ｌは、モル比ムライト：ＭｇＯが８１：１９であり、平均熱膨張係数αSが７．２５×１０-6／℃であり、αS／αGaAs比が１．２４１であった。ムライト−ＭｇＯ系焼結体Ｍは、モル比ムライト：ＭｇＯが７８：２２であり、平均熱膨張係数αSが７．５０×１０-6／℃であり、αS／αGaAs比が１．２８４であった。 The mullite-MgO-based sintered body A has a molar ratio of mullite to MgO (hereinafter referred to as molar ratio mullite: MgO) of 99.9: 0.1, and an average thermal expansion coefficient α from 25 ° C. to 1000 ° C. S (hereinafter simply referred to as the average thermal expansion coefficient α S ) is 4.25 × 10 −6 / ° C., and the ratio of the thermal expansion coefficient α S of the sintered body to the average thermal expansion coefficient α GaAs of the GaAs crystal (hereinafter referred to as the following) α S / α GaAs ratio) was 0.728. The mullite-MgO-based sintered body B has a molar ratio of mullite: MgO of 99.8: 0.2, an average coefficient of thermal expansion α S of 4.75 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.813. The mullite-MgO-based sintered body C has a molar ratio of mullite: MgO of 99.4: 0.6, an average thermal expansion coefficient α S of 5.00 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.856. The mullite-MgO-based sintered body D has a molar ratio of mullite: MgO of 99.1: 0.9, an average thermal expansion coefficient α S of 5.20 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.890. The mullite-MgO-based sintered body E has a molar ratio of mullite: MgO of 98.8: 1.2, an average thermal expansion coefficient α S of 5.40 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.925. The mullite-MgO-based sintered body F has a molar ratio of mullite: MgO of 98.5: 1.5, an average coefficient of thermal expansion α S of 5.60 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.959. The mullite-MgO-based sintered body G has a molar ratio of mullite: MgO of 98.3: 1.7, an average thermal expansion coefficient α S of 5.80 × 10 −6 / ° C., and α S / α GaAs. The ratio was 0.993. The mullite-MgO-based sintered body H has a molar ratio of mullite: MgO of 98: 2, an average coefficient of thermal expansion α S of 6.00 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 027. The mullite-MgO-based sintered body I has a molar ratio of mullite: MgO of 94: 6, an average coefficient of thermal expansion α S of 6.33 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 084. The mullite-MgO-based sintered body J has a molar ratio of mullite: MgO of 89:11, an average thermal expansion coefficient α S of 6.67 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 142. The mullite-MgO-based sintered body K has a molar ratio of mullite: MgO of 85:15, an average thermal expansion coefficient α S of 7.00 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 199. The mullite-MgO-based sintered body L has a molar ratio of mullite: MgO of 81:19, an average coefficient of thermal expansion α S of 7.25 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 241. The mullite-MgO-based sintered body M has a molar ratio of mullite: MgO of 78:22, an average coefficient of thermal expansion α S of 7.50 × 10 −6 / ° C., and an α S / α GaAs ratio of 1. 284.

上記のムライト−ＭｇＯ系焼結体Ａ〜Ｍから、直径４インチ（１０１．６ｍｍ）で厚さ１ｍｍの支持基板をそれぞれ切り出して、それぞれの支持基板の両主面を鏡面に研磨して、支持基板Ａ〜Ｍとした。すなわち、支持基板Ａ〜Ｍの２５℃から１０００℃までにおける平均熱膨張係数は、それぞれムライト−ＭｇＯ系焼結体Ａ〜Ｍの２５℃から１０００℃までにおける平均熱膨張係数に等しい。結果を表３にまとめた。   From the mullite-MgO-based sintered bodies A to M, a support substrate having a diameter of 4 inches (101.6 mm) and a thickness of 1 mm is cut out, and both main surfaces of each support substrate are polished to a mirror surface to be supported. Substrates A to M were used. That is, the average thermal expansion coefficient of the support substrates A to M from 25 ° C. to 1000 ° C. is equal to the average thermal expansion coefficient of the mullite-MgO-based sintered bodies A to M from 25 ° C. to 1000 ° C., respectively. The results are summarized in Table 3.

（２）下地基板上に単結晶膜を成膜するサブ工程
図３（Ｂ）を参照して、下地基板３０として、鏡面に研磨された（００１）面の主面３０ｎを有する直径５インチ（１２７ｍｍ）で厚さ０．５ｍｍのＳｉ基板を準備した。 (2) Sub-Process for Forming Single Crystal Film on Base Substrate With reference to FIG. 3B, the base substrate 30 has a main surface 30n of (001) surface polished to a mirror surface and has a diameter of 5 inches ( 127 mm) and a 0.5 mm thick Si substrate was prepared.

上記のＳｉ基板（下地基板３０）の主面３０ｎ上に、単結晶膜１３として厚さ０．４μｍのＧａＡｓ膜をＭＯＣＶＤ法により成膜した。成膜条件は、原料ガスとしてＴＭＧ（トリメチルガリウム）ガスおよびＡｓＨ3（アルシン）ガスを使用し、キャリアガスとしてＨ2ガスを使用し、成膜温度（基板温度）６２０℃、成膜圧力は１気圧とした。なお、こうして得られたＧａＡｓ膜（単結晶膜１３）の主面１３ｍは、（００１）面からのオフ角が±１°以内の面方位を有し、ＡＦＭ（原子間力顕微鏡）を用いて測定した１０μｍ×１０μｍの正方形領域におけるＲＭＳ（二乗平均平方根）粗さ（ＪＩＳ Ｂ０６０１：２００１に規定する二乗平均平方根粗さＲｑをいう。以下同じ）が１ｎｍ以下の鏡面であった。 A GaAs film having a thickness of 0.4 μm was formed as the single crystal film 13 on the main surface 30n of the Si substrate (underlying substrate 30) by the MOCVD method. The film formation conditions are as follows: TMG (trimethylgallium) gas and AsH 3 (arsine) gas are used as the source gas, H 2 gas is used as the carrier gas, the film formation temperature (substrate temperature) is 620 ° C., and the film formation pressure is 1 Atmospheric pressure. The main surface 13m of the GaAs film (single crystal film 13) obtained in this way has a plane orientation whose off angle from the (001) plane is within ± 1 °, and using an AFM (atomic force microscope). The RMS (root mean square) roughness (referred to the root mean square roughness Rq defined in JIS B0601: 2001, hereinafter the same) in a 10 μm × 10 μm square area was a mirror surface of 1 nm or less.

（３）支持基板と単結晶膜とを貼り合わせるサブ工程
図３（Ｃ）中の（Ｃ１）を参照して、図３（Ａ）の支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍ上に厚さ２μｍのＳｉＯ2膜をＣＶＤ（化学気相堆積）法により成膜した。次いで、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍ上の厚さ２μｍのＳｉＯ2膜を、ＣｅＯ2スラリーを用いて研磨することにより、厚さ０．２μｍのＳｉＯ2層だけ残存させて、接着層１２ａとした。これにより、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍの空隙が埋められ、平坦な主面１２ａｍを有する厚さ０．２μｍのＳｉＯ2層（接着層１２ａ）が得られた。 (3) Sub-process for bonding support substrate and single crystal film Referring to (C1) in FIG. 3 (C), each of the main substrates A to M (support substrate 11) in FIG. 3 (A) A SiO 2 film having a thickness of 2 μm was formed on the surface 11 m by a CVD (chemical vapor deposition) method. Next, the SiO 2 film having a thickness of 2 μm on each main surface 11m of the support substrates A to M (support substrate 11) is polished by using CeO 2 slurry, so that only the SiO 2 layer having a thickness of 0.2 μm is obtained. The adhesive layer 12a was made to remain. Thus, the gap is filled in each of the main surfaces 11m of the supporting substrate A to M (support substrate 11), SiO 2 layer having a thickness of 0.2μm having a flat main surface 12am (adhesive layer 12a) was obtained .

また、図３（Ｃ）中の（Ｃ２）を参照して、図３（Ｂ）のＳｉ基板（下地基板３０）上に成膜されたＧａＡｓ膜（単結晶膜１３）の主面１３ｎ上に厚さ２μｍのＳｉＯ2膜をＣＶＤ法により成膜した。次いで、この厚さ２μｍのＳｉＯ2膜を、ＣｅＯ2スラリーを用いて研磨することにより、厚さ０．２μｍのＳｉＯ2層だけ残存させて、接着層１２ｂとした。 Further, referring to (C2) in FIG. 3C, on the main surface 13n of the GaAs film (single crystal film 13) formed on the Si substrate (underlying substrate 30) in FIG. 3B. A SiO 2 film having a thickness of 2 μm was formed by a CVD method. Next, this SiO 2 film having a thickness of 2 μm was polished using a CeO 2 slurry, so that only the SiO 2 layer having a thickness of 0.2 μm was left to form an adhesive layer 12b.

次いで、図３（Ｃ）中の（Ｃ３）を参照して、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれに形成されたＳｉＯ2層（接着層１２ａ）の主面１２ａｍおよびＳｉ基板（下地基板３０）上に成膜されたＧａＡｓ膜（単結晶膜１３）上に形成されたＳｉＯ2層（接着層１２ｂ）の主面１２ｂｎをアルゴンプラズマにより清浄化および活性化させた後、ＳｉＯ2層（接着層１２ａ）の主面１２ａｍとＳｉＯ2層（接着層１２ｂ）の主面１２ｂｎとを貼り合わせて、窒素雰囲気下３００℃で２時間熱処理した。 Next, referring to (C3) in FIG. 3C, the main surface 12am of the SiO 2 layer (adhesive layer 12a) and the Si substrate (underlayer) formed on each of the support substrates A to M (support substrate 11). The main surface 12bn of the SiO 2 layer (adhesive layer 12b) formed on the GaAs film (single crystal film 13) formed on the substrate 30) is cleaned and activated by argon plasma, and then the SiO 2 layer The main surface 12am of the (adhesive layer 12a) and the main surface 12bn of the SiO 2 layer (adhesive layer 12b) were bonded together and heat-treated at 300 ° C. for 2 hours in a nitrogen atmosphere.

（４）下地基板を除去するサブ工程
図３（Ｄ）を参照して、支持基板Ａ〜Ｍ（支持基板１１）の裏側（単結晶膜１３が貼り合わされていない側）の主面および側面をワックス４０で覆って保護した後、１０質量％のフッ化水素酸および３質量％の硝酸を含む混酸水溶液を用いて、エッチングによりＳｉ基板（下地基板３０）を除去した。こうして、図２（Ａ）に示すように、支持基板Ａ〜Ｍ（支持基板１１）のそれぞれの主面１１ｍ側にＧａＡｓ膜（単結晶膜１３）が配置された複合基板Ａ〜Ｍ（複合基板１０）が得られた。 (4) Sub-process for removing base substrate Referring to FIG. 3D, the main surface and side surfaces of the back side (side on which single crystal film 13 is not bonded) of support substrates A to M (support substrate 11) are After covering and protecting with wax 40, the Si substrate (underlying substrate 30) was removed by etching using a mixed acid aqueous solution containing 10% by mass of hydrofluoric acid and 3% by mass of nitric acid. Thus, as shown in FIG. 2A, composite substrates A to M (composite substrates) in which GaAs films (single crystal films 13) are arranged on the main surfaces 11m side of the support substrates A to M (support substrate 11). 10) was obtained.

３．ＧａＡｓ系膜の成膜工程
図２（Ｂ）を参照して、複合基板Ａ〜Ｍ（複合基板１０）のＧａＡｓ膜（単結晶膜１３）の主面１３ｍ（かかる主面は（００１）面である。）上に、それぞれＭＯＣＶＤ法によりＧａＡｓ膜（ＧａＡｓ系膜２０）を成膜した。ＧａＡｓ膜（ＧａＡｓ系膜２０）の成膜においては、成膜条件は、原料ガスとしてＴＭＧ（トリメチルガリウム）ガスおよびＡｓＨ3（アルシン）ガスを使用し、キャリアガスとしてＨ2ガスを使用し、成膜温度（基板温度）６８０℃で厚さ５μｍのＧａＡｓ単結晶層（ＧａＡｓ系単結晶層２３）を成長させた。ここで、ＧａＡｓ単結晶層の成長速度は１μｍ／ｈｒであった。その後、複合基板Ａ〜ＭのそれぞれにＧａＡｓ膜が成膜されたウエハＡ〜Ｍを１０℃／ｍｉｎの速度で室温（２５℃）まで冷却した。 3. GaAs film formation process Referring to FIG. 2B, the main surface 13m of the GaAs film (single crystal film 13) of the composite substrate A to M (composite substrate 10) (the main surface is the (001) surface). A GaAs film (GaAs-based film 20) was formed on each of them by MOCVD. In the formation of a GaAs film (GaAs-based film 20), the film formation conditions are as follows: TMG (trimethylgallium) gas and AsH 3 (arsine) gas are used as the source gas, and H 2 gas is used as the carrier gas. A GaAs single crystal layer (GaAs single crystal layer 23) having a thickness of 5 μm was grown at a film temperature (substrate temperature) of 680 ° C. Here, the growth rate of the GaAs single crystal layer was 1 μm / hr. Thereafter, the wafers A to M each having a GaAs film formed on each of the composite substrates A to M were cooled to room temperature (25 ° C.) at a rate of 10 ° C./min.

室温まで冷却後に成膜装置から取り出されたウエハＡ〜Ｍについて、ウエハの反り、ＧａＡｓ膜のクラック本数密度および転位密度を測定した。ここで、ウエハの反りの形状および反り量は、ＧａＡｓ膜の主面をＣｏｒｎｉｎｇ Ｔｒｏｐｅｌ社のＦＭ２００ＥＷａｆｅｒを用いて観察される光干渉縞により測定した。ＧａＡｓＮ膜のクラック本数密度は、ノマルスキー顕微鏡を用いて単位長さ当りのクラック本数を測定し、１本／ｍｍ未満を「極少」、１本／ｍｍ以上５本／ｍｍ未満を「少」、５本／ｍｍ以上１０本／ｍｍ未満を「多」、１０本／ｍｍ以上を「極多」と評価した。ＧａＡｓ膜の転位密度は、Ｌ（カソードルミネッセンス）による暗点の単位面積当たりの個数を測定した。なお、本実施例においてＧａＡｓ膜に発生したクラックは、膜を貫通しない微小なものであった。   For wafers A to M taken out from the film forming apparatus after cooling to room temperature, the warpage of the wafer, the number of cracks in the GaAs film and the dislocation density were measured. Here, the shape and amount of warpage of the wafer were measured by optical interference fringes observed on the main surface of the GaAs film using a Corning Tropel FM200EWafer. The number of cracks in the GaAsN film is determined by measuring the number of cracks per unit length using a Nomarski microscope. “Less” is less than 1 / mm, “Less” is 5 or less than 5 / mm. The book / mm or more and less than 10 / mm was evaluated as “many”, and the book / mm or more was evaluated as “very many”. The dislocation density of the GaAs film was measured by the number of dark spots per unit area due to L (cathode luminescence). In this example, cracks generated in the GaAs film were minute ones that did not penetrate the film.

ウエハＡは、ＧａＡｓ膜側が凹状に反り、反り量が６８０μｍであり、ＧａＡｓ膜のクラック本数密度が極多であった。ウエハＢは、ＧａＡｓ膜側が凹状に反り、反り量が６３０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が４×１０4ｃｍ-2であった。ウエハＣは、ＧａＡｓ膜側が凹状に反り、反り量が５００μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が３×１０4ｃｍ-2であった。ウエハＤは、ＧａＡｓ膜側が凹状に反り、反り量が４００μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が２．５×１０4ｃｍ-2であった。ウエハＥは、ＧａＡｓ膜側が凹状に反り、反り量が３５０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が２×１０4ｃｍ-2であった。ウエハＦは、ＧａＡｓ膜側が凹状に反り、反り量が２３０μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＧは、ＧａＡｓ膜側が凹状に反り、反り量が１５０μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＨは、ＧａＡｓ膜側が凹状に反り、反り量が１０μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＩは、ＧａＡｓ膜側が凸状に反り、反り量が１５μｍであり、ＧａＡｓ膜のクラック本数密度が極少であり、ＧａＡｓ膜の転位密度が１×１０4ｃｍ-2であった。ウエハＪは、ＧａＡｓ膜側が凸状に反り、反り量が１２０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が２×１０4ｃｍ-2であった。ウエハＫは、ＧａＡｓ膜側が凸状に反り、反り量が２３０μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が３×１０4ｃｍ-2であった。ウエハＬは、ＧａＡｓ膜側が凸状に反り、反り量が７４５μｍであり、ＧａＡｓ膜のクラック本数密度が少であり、ＧａＡｓ膜の転位密度が４×１０4ｃｍ-2であった。ウエハＭは、支持基板に割れが発生し、十分なＧａＡｓ膜が得られなかった。これらの結果を表３にまとめた。表３において、「−」は、その物性値が未測定であることを示す。 The wafer A warped in a concave shape on the GaAs film side, the amount of warpage was 680 μm, and the number of cracks in the GaAs film was extremely large. The wafer B warped in a concave shape on the GaAs film side, the warpage amount was 630 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 4 × 10 4 cm −2 . The wafer C warped in a concave shape on the GaAs film side, the warpage amount was 500 μm, the number of cracks in the GaAs film was small, and the dislocation density of the GaAs film was 3 × 10 4 cm −2 . The wafer D was warped concavely on the GaAs film side, the warpage amount was 400 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 2.5 × 10 4 cm −2 . The wafer E warped in a concave shape on the GaAs film side, the warpage amount was 350 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 2 × 10 4 cm −2 . The wafer F warped in a concave shape on the GaAs film side, the warpage amount was 230 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer G was warped concavely on the GaAs film side, the warpage amount was 150 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer H warped in a concave shape on the GaAs film side, the warpage amount was 10 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer I was warped convexly on the GaAs film side, the warpage amount was 15 μm, the crack number density of the GaAs film was extremely small, and the dislocation density of the GaAs film was 1 × 10 4 cm −2 . The wafer J warped in a convex shape on the GaAs film side, the warpage amount was 120 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 2 × 10 4 cm −2 . The wafer K was warped convexly on the GaAs film side, the warpage amount was 230 μm, the crack number density of the GaAs film was small, and the dislocation density of the GaAs film was 3 × 10 4 cm −2 . The wafer L was warped convexly on the GaAs film side, the amount of warpage was 745 μm, the number of cracks in the GaAs film was small, and the dislocation density of the GaAs film was 4 × 10 4 cm −2 . The wafer M was cracked in the support substrate, and a sufficient GaAs film could not be obtained. These results are summarized in Table 3. In Table 3, “-” indicates that the physical property value is not measured.

４．支持基板の除去工程
図２（Ｃ）を参照して、上記で得られたウエハＡ〜Ｌを、１０質量％のフッ化水素酸水溶液に浸漬することにより、支持基板Ａ〜Ｌ（支持基板１１）およびＳｉＯ2層を溶解させることにより除去して、ＧａＡｓ単結晶膜（単結晶膜１３）の主面１３ｍ上に成膜されたＧａＡｓ膜Ａ〜Ｌ（ＧａＡｓ系膜２０）が得られた。なお、ウエハＡ〜Ｌから支持基板Ａ〜ＬおよびＳｉＯ2層が除去されたＧａＡｓ膜Ａ〜Ｌ（ＧａＡｓ系膜２０）においても反りがＣｏｒｎｉｎｇ Ｔｒｏｐｅｌ社のＦＭ２００ＥＷａｆｅｒを用いて観察される光干渉縞による測定により認められ、ＧａＡｓ膜Ａ〜Ｌの反りの大小関係には、ウエハＡ〜Ｌにおける反りの大小関係が維持されていた。 4). Step of removing support substrate Referring to FIG. 2C, wafers A to L obtained above are immersed in a 10% by mass hydrofluoric acid aqueous solution, thereby supporting substrates A to L (support substrate 11). ) And the SiO 2 layer were removed by dissolution to obtain GaAs films A to L (GaAs-based film 20) formed on the main surface 13m of the GaAs single crystal film (single crystal film 13). It should be noted that warpage is also observed in the GaAs films A to L (GaAs-based film 20) from which the supporting substrates A to L and the SiO 2 layer are removed from the wafers A to L due to optical interference fringes observed using the Corning Tropel FM200EWafer. The magnitude relation of the warpage of the GaAs films A to L was maintained by the measurement, and the magnitude relation of the warpage in the wafers A to L was maintained.

Figure 2013116848
Figure 2013116848

表３を参照して、主面内の熱膨張係数αSがＧａＡｓ結晶の熱膨張係数αGaAsの０．８倍より大きく１．２倍より小さい（すなわち、０．８＜（αS／αGaAs比）＜１．２）支持基板を有する複合基板を用いることにより（ウエハＢ〜Ｋ）、反り小さく転位密度が低く結晶性の良好なＧａＡｓ膜を成膜することができた。また、ＧａＡｓ膜の反りおよび転位密度をさらに低減する観点から、複合基板の支持基板の主面内の熱膨張係数αSは、ＧａＡｓ結晶の熱膨張係数αGaAsの０．９倍より大きく１．１５倍より小さいこと（すなわち、０．９＜（αS／αGaAs比）＜１．１５）（ウエハＥ〜Ｊ）が好ましく、ＧａＡｓ結晶の熱膨張係数αGaAsの０．９５倍より大きく１．１倍より小さいこと（すなわち、０．９５＜（αS／αGaAs比）＜１．１）（ウエハＦ〜Ｉ）がより好ましい。 Referring to Table 3, the coefficient of thermal expansion α S in the main surface is larger than 0.8 times that of GaAs crystal α GaAs and smaller than 1.2 times (that is, 0.8 <(α S / α GaAs ratio) <1.2) By using a composite substrate having a supporting substrate (wafers B to K), a GaAs film having low warpage, low dislocation density, and good crystallinity could be formed. Further, from the viewpoint of further reducing the warpage and dislocation density of the GaAs film, the thermal expansion coefficient alpha S in the main surface of the supporting substrate of the composite substrate is greater than 0.9 times the thermal expansion coefficient alpha GaAs of GaAs crystal 1. It is preferably less than 15 times (that is, 0.9 <(α S / α GaAs ratio) <1.15) (wafers E to J), and the thermal expansion coefficient of GaAs crystal is larger than 0.95 times that of α GaAs and is 1 It is more preferable that the ratio is smaller than 1 time (that is, 0.95 <(α S / α GaAs ratio) <1.1) (wafers F to I).

なお、上記実施例においては、複合基板上に非ドーピングのＧａＡｓ膜を成膜した例を示したが、ドーピングによりｎ型またはｐ型の導電性が付与されたＧａＡｓ膜を成膜した場合、ドーピングにより比抵抗が高められたＧａＡｓ膜を成膜した場合にも、上記実施例とほぼ同一の結果が得られた。   In the above embodiment, an example is shown in which an undoped GaAs film is formed on a composite substrate. However, when an n-type or p-type conductivity imparted by doping is formed, doping is performed. Even when a GaAs film having a higher specific resistance was formed by the above method, almost the same result as in the above example was obtained.

また、ＧａＡｓ膜に替えてＧａxＩｎyＡｌ1-x-yＡｓ膜（０＜ｘ＜１、ｙ≧０、ｘ＋ｙ≦１）などのＧａＡｓ系膜を成膜した場合にも上記実施例と同様の結果が得られた。特に、ＧａＡｓ膜に替えてＧａxＩｎyＡｌ1-x-yＡｓ膜（０．５＜ｘ＜１、ｙ≧０、ｘ＋ｙ≦１）を成膜する場合には、上記実施例とほぼ同一の結果が得られた。 Further, when a GaAs-based film such as a Ga x In y Al 1-xy As film (0 <x <1, y ≧ 0, x + y ≦ 1) is formed instead of the GaAs film, the same as the above embodiment Results were obtained. In particular, when a Ga x In y Al 1-xy As film (0.5 <x <1, y ≧ 0, x + y ≦ 1) is formed in place of the GaAs film, the results are almost the same as in the above embodiment. was gotten.

また、ＧａＡｓ系膜（具体的にはＧａxＩｎyＡｌ1-x-yＡｓ膜（ｘ＞０、ｙ≧０、ｘ＋ｙ≦１）など）は、Ｇａ、Ｉｎ、ＡｌなどのＩＩＩ族元素の組成比を変えて複数成膜することもできる。すなわち、ＧａＡｓ膜に替えてＧａxＩｎyＡｌ1-x-yＡｓ膜（ｘ＞０、ｙ≧０、ｘ＋ｙ≦１）などのＧａＡｓ系膜を、Ｇａ、Ｉｎ、ＡｌなどのＩＩＩ族元素の組成比を変えて、複数成膜することができる。 A GaAs-based film (specifically, Ga x In y Al 1-xy As film (x> 0, y ≧ 0, x + y ≦ 1), etc.) is a composition ratio of group III elements such as Ga, In, and Al. It is also possible to form a plurality of films by changing. That is, a GaAs-based film such as a Ga x In y Al 1-xy As film (x> 0, y ≧ 0, x + y ≦ 1) is used instead of the GaAs film, and the composition ratio of group III elements such as Ga, In, and Al A plurality of films can be formed by changing the above.

本発明の実施においては、ＧａＡｓ系膜の成膜の際にＥＬＯ（Epitaxial Lateral Overgrowth；ラテラル成長）技術などの公知の転位低減技術を適用できる。   In the practice of the present invention, a known dislocation reduction technique such as an ELO (Epitaxial Lateral Overgrowth) technique can be applied when forming a GaAs-based film.

また、複合基板にＧａＡｓ系膜を成膜した後に、複合基板の支持基板などを除去する際には、ＧａＡｓ系膜を別の支持基板に転写してもよい。   Further, after removing the support substrate of the composite substrate after forming the GaAs film on the composite substrate, the GaAs film may be transferred to another support substrate.

今回開示された実施の形態および実施例はすべての点で例示であって制限的なものではないと考えられるべきである。本発明の範囲は上記した説明ではなくて特許請求の範囲によって示され、特許請求の範囲と均等の意味および範囲内でのすべての変更が含まれることが意図される。   It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

１０ 複合基板、１１ 支持基板、１１ｍ，１２ｍ，１２ａｍ，１２ｂｎ，１３ｍ，１３ｎ，２０ｍ，２１ｍ，２３ｍ，３０ｎ 主面、１２，１２ａ，１２ｂ 接着層、１３ 単結晶膜、２０ ＧａＡｓ系膜、２１ ＧａＡｓ系バッファ層、２３ ＧａＡｓ系単結晶層、３０ 下地基板、４０ ワックス。   DESCRIPTION OF SYMBOLS 10 Composite substrate, 11 Support substrate, 11m, 12m, 12am, 12bn, 13m, 13n, 20m, 21m, 23m, 30n Main surface, 12, 12a, 12b Adhesive layer, 13 Single crystal film, 20 GaAs system film, 21 GaAs Buffer layer, 23 GaAs single crystal layer, 30 base substrate, 40 wax.

Claims (11)

フッ化水素酸に溶解する支持基板と、前記支持基板の主面側に配置されている単結晶膜と、を含み、
前記支持基板の主面内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて、０．８倍より大きく１．２倍より小さい複合基板。 A support substrate that dissolves in hydrofluoric acid, and a single crystal film disposed on the main surface side of the support substrate,
A composite substrate having a thermal expansion coefficient in the main surface of the support substrate that is greater than 0.8 times and less than 1.2 times the thermal expansion coefficient of a GaAs crystal. 前記支持基板は、ジルコニアとシリカとで形成されるＺｒＯ2−ＳｉＯ2複合酸化物と、ジルコニアおよびシリカの少なくともいずれかと、を含む請求項１に記載の複合基板。 The composite substrate according to claim 1, wherein the support substrate includes a ZrO 2 —SiO 2 composite oxide formed of zirconia and silica, and at least one of zirconia and silica. 前記支持基板は、アルミナとシリカとで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、イットリア安定化ジルコニアと、を含む請求項１に記載の複合基板。 The composite substrate according to claim 1, wherein the support substrate includes an Al 2 O 3 —SiO 2 composite oxide formed of alumina and silica, and yttria-stabilized zirconia. 前記支持基板は、アルミナとシリカとで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、マグネシアと、を含む請求項１に記載の複合基板。 The composite substrate according to claim 1, wherein the support substrate includes Al 2 O 3 —SiO 2 composite oxide formed of alumina and silica, and magnesia. 前記複合基板における前記単結晶膜の主面の面積が４５ｃｍ2以上である請求項１から請求項４のいずれかに記載の複合基板。 5. The composite substrate according to claim 1, wherein an area of a main surface of the single crystal film in the composite substrate is 45 cm 2 or more. フッ化水素酸に溶解する支持基板と、前記支持基板の主面側に配置されている単結晶膜と、を含み、前記支持基板の主面内の熱膨張係数が、ＧａＡｓ結晶の熱膨張係数に比べて、０．８倍より大きく１．２倍より小さい複合基板を準備する工程と、
前記支持基板の主面側に配置されている前記単結晶膜の主面上にＧａＡｓ系膜を成膜する工程と、
前記支持基板を、フッ化水素酸に溶解することにより、除去する工程と、を含むＧａＡｓ系膜の製造方法。 A support substrate that dissolves in hydrofluoric acid, and a single crystal film disposed on a main surface side of the support substrate, wherein a thermal expansion coefficient in the main surface of the support substrate is a thermal expansion coefficient of a GaAs crystal A step of preparing a composite substrate larger than 0.8 times and smaller than 1.2 times;
Forming a GaAs-based film on the main surface of the single crystal film disposed on the main surface side of the support substrate;
A step of removing the support substrate by dissolving it in hydrofluoric acid. 前記支持基板は、ジルコニアとシリカとで形成されるＺｒＯ2−ＳｉＯ2複合酸化物と、ジルコニアおよびシリカの少なくともいずれかと、を含む請求項６に記載のＧａＡｓ系膜の製造方法。 The GaAs-based film manufacturing method according to claim 6, wherein the support substrate includes a ZrO 2 —SiO 2 composite oxide formed of zirconia and silica, and at least one of zirconia and silica. 前記支持基板は、アルミナとシリカとで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、イットリア安定化ジルコニアと、を含む請求項６に記載のＧａＡｓ系膜の製造方法。 The GaAs-based film manufacturing method according to claim 6, wherein the support substrate includes an Al 2 O 3 —SiO 2 composite oxide formed of alumina and silica and yttria-stabilized zirconia. 前記支持基板は、アルミナとシリカとで形成されるＡｌ2Ｏ3−ＳｉＯ2複合酸化物と、マグネシアと、を含む請求項６に記載のＧａＡｓ系膜の製造方法。 The method for producing a GaAs-based film according to claim 6, wherein the support substrate includes Al 2 O 3 —SiO 2 composite oxide formed of alumina and silica, and magnesia. 前記複合基板における前記単結晶膜の主面の面積が４５ｃｍ2以上である請求項６から請求項９のいずれかに記載のＧａＡｓ系膜の製造方法。 The method for producing a GaAs-based film according to any one of claims 6 to 9, wherein an area of a main surface of the single crystal film in the composite substrate is 45 cm 2 or more. 前記ＧａＡｓ系膜を成膜する工程は、前記単結晶膜の主面上にＧａＡｓ系バッファ層を形成するサブ工程と、前記ＧａＡｓ系バッファ層の主面上にＧａＡｓ系単結晶層を形成するサブ工程と、を含む請求項６から請求項１０のいずれかに記載のＧａＡｓ系膜の製造方法。   The step of forming the GaAs-based film includes a sub-step of forming a GaAs-based buffer layer on the main surface of the single-crystal film and a sub-step of forming a GaAs-based single crystal layer on the main surface of the GaAs-based buffer layer. A method for producing a GaAs-based film according to any one of claims 6 to 10, comprising a step.
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JP2017186203A (en) * 2016-04-07 2017-10-12 住友電気工業株式会社 Polycrystal ceramic substrate, polycrystal ceramic substrate with joint layer and laminate substrate

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JP2017186203A (en) * 2016-04-07 2017-10-12 住友電気工業株式会社 Polycrystal ceramic substrate, polycrystal ceramic substrate with joint layer and laminate substrate
WO2017175801A1 (en) * 2016-04-07 2017-10-12 住友電気工業株式会社 Polycrystalline ceramic substrate, polycrystalline ceramic substrate provided with bonding layer, and laminated substrate
TWI709672B (en) * 2016-04-07 2020-11-11 日商住友電氣工業股份有限公司 Polycrystalline ceramic substrate, polycrystalline ceramic substrate with bonding layer added, and multilayer substrate
US11545356B2 (en) 2016-04-07 2023-01-03 Sumitomo Electric Industries, Ltd. Polycrystalline ceramic substrate, bonding-layer-including polycrystalline ceramic substrate, and laminated substrate

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