JPH05226685A - Manufacture of photodetector - Google Patents
Manufacture of photodetectorInfo
- Publication number
- JPH05226685A JPH05226685A JP4027698A JP2769892A JPH05226685A JP H05226685 A JPH05226685 A JP H05226685A JP 4027698 A JP4027698 A JP 4027698A JP 2769892 A JP2769892 A JP 2769892A JP H05226685 A JPH05226685 A JP H05226685A
- Authority
- JP
- Japan
- Prior art keywords
- recess
- layer
- substrate
- insulating film
- type
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Light Receiving Elements (AREA)
- Solid State Image Pick-Up Elements (AREA)
- Element Separation (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は光検知素子の製造方法に
係り、特に素子分離を確実に行うことができ、かつ電極
形成が高精度に形成可能な光検知素子の製造方法に関す
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a photo-sensing element, and more particularly to a method for manufacturing a photo-sensing element capable of reliably separating elements and forming electrodes with high precision.
【０００２】赤外線検知素子のような光検知素子は、高
感度化、高解像度化を図ることが要求され、そのため、
一枚の化合物半導体基板に高密度に光検知素子を形成す
ることが望まれ、かつその光検知素子の受光部の面積も
大面積のものが要求されている。A photo-sensing element such as an infrared sensing element is required to have high sensitivity and high resolution.
It is desired to form a high-density photodetection element on a single compound semiconductor substrate, and a large area is required for the light-receiving portion of the photodetection element.
【０００３】ところで、このように光検知素子を高密度
に配設すると、素子間で検知信号がクロストークする現
象が発生し易く、そのため、素子分離の方法が種々提案
されている。By the way, when the photo-sensing elements are arranged at a high density as described above, a phenomenon in which a detection signal cross-talks between the elements is likely to occur. Therefore, various methods for element isolation have been proposed.
【０００４】[0004]
【従来の技術】従来の光検知素子の製造方法に付いて説
明すると、図3(a)に示すようにCdTe基板１上にＭＯＣＶ
Ｄ(Metal Organic Chemical Vapor Deposition、有機金
属気相成長方法) によりｎ型HgCdTe層２とｐ型HgCdTe層
３を順次積層形成する。2. Description of the Related Art A conventional method for manufacturing a photodetector will be described. As shown in FIG. 3 (a), MOCV is formed on a CdTe substrate 1.
An n-type HgCdTe layer 2 and a p-type HgCdTe layer 3 are sequentially laminated by D (Metal Organic Chemical Vapor Deposition).
【０００５】次いで図3(b)に示すように、レジスト膜(
図示せず) をマスクとして用い、ブロム(Br2) とメタノ
ール(CH3OH) の混合液より成るメサエッチング液を用
い、CdTe基板１に到る迄エッチングする。このCdTe基板
１は高抵抗であるのでCdTe基板１上に形成されたｎ型Hg
CdTe層２とｐ型HgCdTe層３よりなるホトダイオード４は
素子間分離される。Next, as shown in FIG. 3B, a resist film (
Etching is performed until the CdTe substrate 1 is reached by using a mesa etching solution composed of a mixed solution of bromine (Br 2 ) and methanol (CH 3 OH) using a mask (not shown) as a mask. Since this CdTe substrate 1 has high resistance, n-type Hg formed on the CdTe substrate 1
The photodiode 4 composed of the CdTe layer 2 and the p-type HgCdTe layer 3 is separated between elements.
【０００６】そして前記したレジスト膜を除去した後、
図3(c)に示すようにそのｐ型HgCdTe層３とｎ型HgCdTe層
２に金より成る電極５を形成してメサ型の光起電力型の
光検知素子を形成している。After removing the resist film described above,
As shown in FIG. 3 (c), an electrode 5 made of gold is formed on the p-type HgCdTe layer 3 and the n-type HgCdTe layer 2 to form a mesa type photovoltaic photodetecting element.
【０００７】このような方法により、従来より用いられ
ているイオン注入法では、形成が困難な低濃度のｎ型Hg
CdTe層２よりなる活性層の上に、高濃度のｐ型HgCdTe層
３を持つｐｎ接合の形成が可能となり、移動度の低い正
孔の注入型のホトダイオードアレイの製造が可能であ
り、ゼロバイアス特性が改善された光検知素子の製造が
可能となる。With such a method, a low concentration of n-type Hg, which is difficult to form by the conventionally used ion implantation method, is used.
It is possible to form a pn junction having a high concentration p-type HgCdTe layer 3 on the active layer composed of the CdTe layer 2, and it is possible to manufacture a hole-injection type photodiode array with low mobility and to achieve zero bias. It is possible to manufacture a photo-sensing element with improved characteristics.
【０００８】[0008]
【発明が解決しようとする課題】ところで、上記したよ
うにメサエッチングで素子分離すると、基板１の表面が
平坦に成らず、電極５を形成する場合には、メサ型にエ
ッチングされたｎ型HgCdTe層２とｐ型HgCdTe層３上に電
極形成用の金を蒸着等で形成後、該金の電極膜を所定パ
ターンに形成するために、その上にレジスト膜を形成し
て、該レジスト膜をホトマスクを用いて所定パターンに
露光後、該レジスト膜を現像する工程がある。By the way, when the elements are separated by the mesa etching as described above, the surface of the substrate 1 is not flat, and when the electrode 5 is formed, the n-type HgCdTe etched in the mesa type is formed. After gold for electrode formation is formed on the layer 2 and the p-type HgCdTe layer 3 by vapor deposition or the like, a resist film is formed thereon to form an electrode film of the gold in a predetermined pattern. There is a step of developing the resist film after exposing to a predetermined pattern using a photomask.
【０００９】この工程に於いて、図3(c)のように基板１
表面が平坦に形成されていないと、基板上に形成される
レジスト膜に段差を生じるようになり、ホトマスクがレ
ジスト膜に密着した状態で設置できず、密着露光できな
いため、露光の精度が悪くなり、そのため、電極５が所
定のパターンに高精度に形成できない問題がある。In this process, as shown in FIG. 3 (c), the substrate 1
If the surface is not flat, a step will be created in the resist film formed on the substrate, and the photomask cannot be installed in close contact with the resist film, and contact exposure cannot be performed, resulting in poor exposure accuracy. Therefore, there is a problem that the electrode 5 cannot be formed in a predetermined pattern with high accuracy.
【００１０】本発明は上記した問題点を解決し、電極形
成を高精度に行うことができ、かつ素子分離が確実に行
い得るような光検知素子の製造方法の提供を目的とす
る。SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and provide a method for manufacturing a photo-sensing element which can form electrodes with high precision and can ensure element isolation.
【００１１】[0011]
【課題を解決するための手段】本発明の光検知素子の製
造方法は、請求項１に示すように半導体基板上に所定の
パターンの絶縁膜を形成し、該絶縁膜をマスクとして前
記基板に凹部を形成し、該凹部内に一導電型の半導体層
と、該半導体層の逆導電型層を順次積層して埋設形成す
ることを特徴とする。According to a method of manufacturing a photo-sensing element of the present invention, an insulating film having a predetermined pattern is formed on a semiconductor substrate, and the insulating film is used as a mask on the substrate. A recess is formed, and a semiconductor layer of one conductivity type and a layer of the opposite conductivity type of the semiconductor layer are sequentially stacked and embedded in the recess.
【００１２】また請求項２に示すように、請求項１記載
の凹部を等方性エッチング液でエッチングして絶縁膜を
オーバーハング構造とし、該凹部内に積層形成する半導
体層を気相成長方法で形成した化合物半導体層とするこ
とを特徴とする。According to a second aspect of the present invention, the recess according to the first aspect is etched with an isotropic etching solution to form an overhang structure in the insulating film, and a semiconductor layer laminated in the recess is formed by a vapor phase growth method. The compound semiconductor layer formed in 1.
【００１３】[0013]
【作用】本発明の光検知素子の製造方法によれば、光検
知素子を形成すべき凹部上に絶縁膜がオーバーハング構
造に張り出して形成しているので、この絶縁膜を除去し
た後、オーバーハング構造に張り出した絶縁膜の下部に
平坦な状態でｎ型層が露出するので、電極パターン形成
の際に用いてるレジスト膜にホトマスクが密着して露光
できるので、露光精度が向上し、電極パターンが高精度
の寸法で形成できる。According to the method of manufacturing a photodetecting element of the present invention, the insulating film is formed so as to overhang the concave portion where the photodetecting element is to be formed so as to overhang the structure. Since the n-type layer is exposed in a flat state below the insulating film overhanging the hang structure, the photomask can be brought into close contact with the resist film used when forming the electrode pattern, so that the exposure accuracy is improved and the electrode pattern is improved. Can be formed with high precision.
【００１４】また高抵抗の半導体基板に設けた凹部内
に、ホトダイオード形成用のHgCdTe結晶が気相成長され
て埋設形成されているので、素子分離が確実に実施でき
る。Further, since the HgCdTe crystal for forming the photodiode is vapor-phase-grown and buried in the recess formed in the high-resistance semiconductor substrate, element isolation can be surely performed.
【００１５】[0015]
【実施例】以下、図面を用いて本発明の一実施例につき
詳細に説明する。図1(a)に示すようにCdTe基板１上にSi
O2膜より成る絶縁膜11を蒸着等の方法を用いて形成す
る。An embodiment of the present invention will be described in detail below with reference to the drawings. As shown in Fig. 1 (a), Si is formed on the CdTe substrate 1.
The insulating film 11 made of an O 2 film is formed by a method such as vapor deposition.
【００１６】次いで図1(b)に示すように、該基板11上に
レジスト膜12を形成し、このレジスト膜12をマスクとし
て弗化水素酸と弗化アンモニウムの混合液のエッチング
液を用いて絶縁膜11を所定のパターンにエッチングす
る。Next, as shown in FIG. 1 (b), a resist film 12 is formed on the substrate 11, and using the resist film 12 as a mask, an etching solution of a mixed solution of hydrofluoric acid and ammonium fluoride is used. The insulating film 11 is etched into a predetermined pattern.
【００１７】次いで図1(c)に示すように、前記パターン
形成された絶縁膜11をマスクとしてイオンビームエッチ
ングにより、例えば深さが12μm で、20μm ×20μm の
面積の凹部13を形成する。Then, as shown in FIG. 1C, a recess 13 having a depth of 12 μm and an area of 20 μm × 20 μm is formed by ion beam etching using the patterned insulating film 11 as a mask.
【００１８】次いで図1(d)に示すように、ブロム(Br2)
とメタノール(CH3OH) の混合液より成る等方性エッチン
グ液を用いて基板１をエッチングすることで、横方向に
拡がった凹部15を形成する。このようにすると絶縁膜11
が凹部14上に張り出した構造となり、オーバーハング構
造が形成できる。Then, as shown in FIG. 1 (d), bromine (Br 2 )
By etching the substrate 1 using an isotropic etching solution composed of a mixed solution of methanol and CH 3 OH, a concave portion 15 that extends in the lateral direction is formed. In this way, the insulating film 11
Has a structure overhanging above the concave portion 14, and an overhang structure can be formed.
【００１９】次いで図2(a)に示すように、ジメチルカド
ミウム〔Cd(CH3)2〕、ジイソプロピルテルル〔Te(C3H5)
2 〕、水銀（Hg）、トリメチルインジウム〔(CH3)3In〕
を原料ガスとして用いて、厚さが10μm で、キャリア濃
度が1 〜5 ×1015 /cm3 の低濃度のｎ型HgCdTe層2 をＭ
ＯＣＶＤ法にて形成する。このｎ型HgCdTe層２は、SiO2
の絶縁膜11の上には成長しない。Then, as shown in FIG. 2 (a), dimethylcadmium [Cd (CH 3 ) 2 ] and diisopropyl tellurium [Te (C 3 H 5 )]
2 ], mercury (Hg), trimethylindium [(CH 3 ) 3 In]
Is used as a source gas, and a low-concentration n-type HgCdTe layer 2 having a thickness of 10 μm and a carrier concentration of 1 to 5 × 10 15 / cm 3 is formed as M
It is formed by the OCVD method. This n-type HgCdTe layer 2 is made of SiO 2
Does not grow on the insulating film 11.
【００２０】次いで図2(b)に示すように、ジメチルカド
ミウム〔(CH3)2Cd〕、ジイソプロピルテルル〔Te(C3H7)
2 〕、水銀（Hg）、ブチルアルシン (C4H9)As H2を原料
ガスとして用いて、厚さが２μm で、キャリア濃度が10
16〜1017 /cm3 の高濃度のｐ型HgCdTe層３をＭＯＣＶＤ
法にて形成する。この高濃度のｐ型HgCdTe層３は、上記
したＭＯＣＶＤ法によると容易に形成できる。Then, as shown in FIG. 2 (b), dimethylcadmium [(CH 3 ) 2 Cd] and diisopropyl tellurium [Te (C 3 H 7 )]
2 ], mercury (Hg), and butylarsine (C 4 H 9 ) As H 2 as source gases, the thickness is 2 μm and the carrier concentration is 10 μm.
MOCVD of highly concentrated p-type HgCdTe layer 3 of 16 to 10 17 / cm 3
Form by method. The high-concentration p-type HgCdTe layer 3 can be easily formed by the MOCVD method described above.
【００２１】このようにＭＯＣＶＤ法を用いることで、
イオン注入法では制御して形成し難い低濃度のｎ型HgCd
Te層２の上に高濃度のｐ型HgCdTe層３が、確実に容易に
形成できる。By using the MOCVD method in this way,
Low-concentration n-type HgCd that is difficult to control and form by ion implantation
The high-concentration p-type HgCdTe layer 3 can be reliably and easily formed on the Te layer 2.
【００２２】次いで図2(c)に示すように、前記形成した
絶縁膜11をエッチングして除去し、CdTe基板１表面を露
出する。するとｎ型HgCdTe層２、ｐ型HgCdTe層３が平坦
な状態で表面に露出しているので、電極５の形成の際
に、該基板上に金の電極膜形成用金属膜を形成後、その
上にレジスト膜を形成してもレジスト膜が平坦な状態で
形成できる。そのため、このレジスト膜上にレジスト膜
の露光用のホトマスクが密着して設置でき、密着露光が
可能となるので、レジスト膜の露光精度が向上し、レジ
ストパターンが高精度に形成でき、このレジストパター
ンをマスクとして用い前記した電極膜形成用金属膜をエ
ッチングすると、電極５が所定のパターンで高精度に形
成できるようになる。Next, as shown in FIG. 2 (c), the insulating film 11 thus formed is removed by etching to expose the surface of the CdTe substrate 1. Then, the n-type HgCdTe layer 2 and the p-type HgCdTe layer 3 are exposed on the surface in a flat state. Therefore, when the electrode 5 is formed, after forming a gold electrode film forming metal film on the substrate, Even if a resist film is formed thereon, the resist film can be formed in a flat state. Therefore, a photomask for exposure of the resist film can be closely attached to the resist film, and contact exposure can be performed, so that the exposure accuracy of the resist film is improved and the resist pattern can be formed with high accuracy. By etching the above-mentioned metal film for forming an electrode film using as a mask, the electrode 5 can be formed with a predetermined pattern with high precision.
【００２３】またホトダイオードを形成するｐｎ接合部
分は、確実に高抵抗のCdTe基板１の凹部14内に埋設形成
されているので、素子分離も確実に実施できる。Since the pn junction portion forming the photodiode is surely buried in the recess 14 of the high resistance CdTe substrate 1, element isolation can be surely performed.
【００２４】[0024]
【発明の効果】以上述べたように、本発明の光検知素子
の製造方法によれば、素子分離を確実に行うことがで
き、また電極形成面が平坦に形成されるので、電極形成
用のレジスト膜の露光精度が向上し、電極が所定パター
ンに高精度に形成でき、素子の信頼度が向上する効果が
ある。As described above, according to the method for manufacturing a photodetecting element of the present invention, element separation can be reliably performed, and the electrode forming surface is formed flat, so that the electrode forming surface can be formed. The exposure accuracy of the resist film is improved, the electrodes can be formed in a predetermined pattern with high accuracy, and the reliability of the device is improved.
【図１】 本発明の製造方法の工程を示す断面図であ
る。FIG. 1 is a cross-sectional view showing steps of a manufacturing method of the present invention.
【図２】 本発明の製造方法の工程を示す断面図であ
る。FIG. 2 is a cross-sectional view showing steps of the manufacturing method of the present invention.
【図３】 従来の製造方法を示す断面図である。FIG. 3 is a cross-sectional view showing a conventional manufacturing method.
1 CdTe基板 2 ｎ型HgCdTe層 3 ｐ型HgCdTe層 4 ホトダイード 5 電極 11 絶縁膜( SiO2) 12 レジスト膜 13,14 凹部1 CdTe substrate 2 n-type HgCdTe layer 3 p-type HgCdTe layer 4 photodide 5 electrode 11 insulating film (SiO 2 ) 12 resist film 13,14 recess
───────────────────────────────────────────────────── フロントページの続き (72)発明者 ▲齊▼藤 哲男 神奈川県川崎市中原区上小田中1015番地 富士通株式会社内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Sai Tetsuo Fuji, Tetsuo 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited
Claims (2)
縁膜(11)を形成し、該絶縁膜(11)をマスクとして前記基
板(1) に凹部(14)を形成し、該凹部(14)内に一導電型の
半導体層(2) と、該半導体層の逆導電型層(3) を順次積
層して埋設形成することを特徴とする光検知素子の製造
方法。An insulating film (11) having a predetermined pattern is formed on a semiconductor substrate (1), and a recess (14) is formed in the substrate (1) using the insulating film (11) as a mask. A method of manufacturing a photo-detecting element, characterized in that a semiconductor layer (2) of one conductivity type and a layer (3) of the opposite conductivity type of the semiconductor layer are sequentially laminated and embedded in (14).
ング液でエッチングして絶縁膜(11)の端部が、凹部(14)
上を覆うオーバーハング構造とし、該凹部(14)内に積層
形成する前記２つの半導体層(2,3) を気相成長方法で形
成した化合物半導体層とすることを特徴とする光検知素
子の製造方法。2. The recess (14) according to claim 1 is etched with an isotropic etching solution so that the end of the insulating film (11) has a recess (14).
A photo-sensing device having an overhang structure for covering the above, wherein the two semiconductor layers (2, 3) laminated in the recess (14) are compound semiconductor layers formed by a vapor phase growth method. Production method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4027698A JPH05226685A (en) | 1992-02-14 | 1992-02-14 | Manufacture of photodetector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4027698A JPH05226685A (en) | 1992-02-14 | 1992-02-14 | Manufacture of photodetector |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05226685A true JPH05226685A (en) | 1993-09-03 |
Family
ID=12228205
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4027698A Withdrawn JPH05226685A (en) | 1992-02-14 | 1992-02-14 | Manufacture of photodetector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05226685A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007532007A (en) * | 2004-04-06 | 2007-11-08 | キネテイツク・リミテツド | Production of cadmium mercury telluride |
-
1992
- 1992-02-14 JP JP4027698A patent/JPH05226685A/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007532007A (en) * | 2004-04-06 | 2007-11-08 | キネテイツク・リミテツド | Production of cadmium mercury telluride |
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