JP2019121625A - Cleaning method of vapor growth device - Google Patents

Cleaning method of vapor growth device Download PDF

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JP2019121625A
JP2019121625A JP2017253342A JP2017253342A JP2019121625A JP 2019121625 A JP2019121625 A JP 2019121625A JP 2017253342 A JP2017253342 A JP 2017253342A JP 2017253342 A JP2017253342 A JP 2017253342A JP 2019121625 A JP2019121625 A JP 2019121625A
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vapor phase
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phase growth
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達矢 人見
Tatsuya Hitomi
達矢 人見
徹 永島
Toru Nagashima
徹 永島
玲子 岡山
Reiko Okayama
玲子 岡山
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Tokuyama Corp
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Abstract

To provide a cleaning method of vapor growth device which allows for stable production of high quality single crystal laminate, where occurrence of polycrystalline section in a single crystal layer is restrained, by preventing contamination of foreign matter during crystal growth.SOLUTION: In the manufacturing process of single crystal laminate using a vapor growth device for growing a single crystal layer on a base substrate by reaction of multiple material gases, after manufacturing the single crystal laminate by growing a single crystal layer on the base substrate, the substrate is removed from the growth part, and then the precipitated foreign matter is removed by cleaning the member composing the growth part by solution.SELECTED DRAWING: None

Description

本発明は、気相成長装置の洗浄方法に関する。詳しくは、複数のガスの反応によりベース基板上に単結晶層を積層させる気相成長装置において、結晶成長面への異物等の付着による結晶品質の低下を防止する気相成長装置の洗浄方法に関する。   The present invention relates to a method of cleaning a vapor phase growth apparatus. More specifically, the present invention relates to a method of cleaning a vapor phase growth apparatus that prevents deterioration of crystal quality due to adhesion of foreign matter and the like to a crystal growth surface in a vapor phase growth apparatus in which a single crystal layer is laminated on a base substrate .

気相成長装置は、反応炉内で気相成長反応により結晶成長を行う装置であり、例えば、原料となるガスを供給する原料ガス供給口、気相成長を行うベースとなる基板を載置する基板保持台、該基板保持台を加熱することにより基板を加熱する加熱手段、及び原料ガス供給口、基板保持台及び加熱手段等を収容する成長部等で構成されている。このような気相成長装置を用いて、昇華(PVT:Physical Vapor Transport)法やハイドライド気相エピタキシー(HVPE:Hydride Vapor Phase Epitaxy)法等の結晶成長が行われる。このような気相成長を行う材料としては、発光素子材料として用いられる窒化アルミニウム、窒化ガリウム、窒化インジウムといったIII族窒化物単結晶が知られている。特に近年では、紫外光の発光素子として、アルミニウム系III族窒化物半導体(主に窒化アルミニウムガリウム混晶)を用いた発光素子の開発が精力的に進められている。   The vapor phase growth apparatus is an apparatus that performs crystal growth by vapor phase growth reaction in a reaction furnace, and for example, mounts a raw material gas supply port for supplying a raw material gas and a substrate serving as a base for vapor phase growth. A substrate holder, heating means for heating the substrate by heating the substrate holder, a raw material gas supply port, a growth portion for containing the substrate holder, heating means and the like are included. Crystal growth such as sublimation (PVT: Physical Vapor Transport) method or hydride vapor phase epitaxy (HVPE) method is performed using such a vapor phase growth apparatus. As a material for performing such vapor phase growth, group III nitride single crystals such as aluminum nitride, gallium nitride and indium nitride which are used as light emitting device materials are known. In particular, in recent years, development of a light emitting element using an aluminum-based group III nitride semiconductor (mainly an aluminum gallium nitride mixed crystal) as an ultraviolet light emitting element has been vigorously promoted.

現在、III族窒化物半導体発光素子の製造にあたっては、基板としての結晶品質、紫外光透過性、量産性やコストの観点から、ベース基板にはサファイア基板が一般的に採用されている。しかし、サファイア基板上にIII族窒化物を成長させた場合、サファイア基板と半導体積層膜を形成するIII族窒化物(例えば窒化アルミニウムガリウム等)との間の格子定数や熱膨張係数等の違いに起因して、結晶欠陥(ミスフィット転位)やクラック等が生じ、素子の発光性能を低下させる原因になるため、ベース基板としては、格子定数がより半導体積層膜の格子定数に近く、かつ熱膨張係数がより半導体積層膜の熱膨張係数に近い基板であることが望ましい。そのため、上記アルミニウム系III族窒化物半導体発光素子を形成するベース基板には、窒化アルミニウムや窒化アルミニウムガリウム等のIII族窒化物単結晶基板が好適に用いられている。   At present, a sapphire substrate is generally employed as a base substrate in view of crystal quality as a substrate, ultraviolet light transparency, mass productivity, and cost when manufacturing a group III nitride semiconductor light emitting device. However, when a group III nitride is grown on a sapphire substrate, differences in lattice constant, thermal expansion coefficient, etc. between the sapphire substrate and a group III nitride (for example, aluminum gallium nitride etc.) forming the semiconductor laminated film As a result, crystal defects (misfit dislocations), cracks, etc. occur, which causes the light emission performance of the device to deteriorate. Therefore, as a base substrate, the lattice constant is closer to the lattice constant of the semiconductor laminated film and the thermal expansion It is desirable that the substrate has a coefficient closer to the thermal expansion coefficient of the semiconductor laminated film. Therefore, a group III nitride single crystal substrate such as aluminum nitride or aluminum gallium nitride is suitably used as a base substrate for forming the aluminum-based group III nitride semiconductor light emitting device.

上記III族窒化物単結晶基板の製造方法としては、前記のPVT法や、MOCVD法、HVPE法等の気相成長法が知られている。PVT法とは、固体のIII族窒化物を高温で昇華させ、低温のベース基板上に析出させることで単結晶層を成長させ、単結晶積層体を製造する方法である。高い成長速度で厚膜を成長することが可能であるというメリットがある。一方、MOCVD法や、HVPE法は、ベース基板上で、III族源ガスと窒素源ガス(例えば、アンモニアガス)とを反応させて、単結晶層を成長させ、単結晶積層体を製造する方法である。   As a manufacturing method of the said group III nitride single crystal substrate, vapor phase growth methods, such as said PVT method, MOCVD method, and HVPE method, are known. The PVT method is a method of producing a single crystal laminate by growing a single crystal layer by sublimating solid Group III nitride at a high temperature and depositing it on a low temperature base substrate. There is an advantage that it is possible to grow a thick film at a high growth rate. On the other hand, MOCVD or HVPE is a method in which a group III source gas and a nitrogen source gas (for example, ammonia gas) are reacted on a base substrate to grow a single crystal layer to manufacture a single crystal laminate. It is.

上記気相成長法において、III族窒化物単結晶積層体は、複数の原料ガスを供給する原料ガス供給口、基板を載置する基板保持台、該基板保持台を加熱することにより基板を加熱する加熱手段、及びこれらを収容する成長部を有する気相成長装置を用いて製造されている。   In the above-mentioned vapor phase growth method, the group III nitride single crystal laminate heats the substrate by heating a source gas supply port for supplying a plurality of source gases, a substrate holder on which the substrate is placed, and the substrate holder. It manufactures using the vapor phase growth apparatus which has the heating part which carries out, and the growth part which accommodates these.

ここで、これら気相成長法の課題として、該単結晶層中への異物の混入がある。異物が結晶成長面に付着した状態で結晶成長を行うと、付着した異物周辺における結晶成長異常による結晶欠陥の発生の要因となる。このような結晶成長異常による結晶欠陥は、具体的には、ノマルスキー微分干渉顕微鏡観察において比較的大きな凸部(以下、ヒロックと称す)として観察されたり、反射X線トポグラフ評価によって、他の領域の画像よりも明るい点(以下、明点と称す)として観察されるものである。上記結晶欠陥の発生は、III族窒化物単結晶層上に積層される発光素子において発光効率の低下等の性能低下の要因となる。また、異物が付着した箇所は他の領域と比べて機械強度が著しく低下し、研磨加工時にピット(窪み)を形成するばかりでなく、発光素子層を積層させた後にチップ形状に切断加工する際には加工割れの起点となりやすく、該基板を用いて製造される発光素子の歩留まりを大きく低下させる要因となるため、III族窒化物単結晶積層体の製造時における結晶成長面への異物の付着は可能な限り低減させることが必要である。   Here, as a problem of these vapor phase growth methods, there is contamination of foreign matter in the single crystal layer. If crystal growth is performed in the state where foreign matter adheres to the crystal growth surface, it causes generation of crystal defects due to crystal growth abnormality around the adhered foreign matter. Specifically, crystal defects due to such crystal growth abnormalities are observed as relatively large convex portions (hereinafter referred to as hillocks) in Nomarski differential interference microscopy, or in other regions by reflection X-ray topographical evaluation. It is observed as a point brighter than the image (hereinafter referred to as a bright point). The occurrence of the crystal defects causes the performance deterioration such as the reduction of the light emission efficiency in the light emitting element stacked on the group III nitride single crystal layer. Further, the mechanical strength of the portion where foreign matter adheres is significantly reduced compared to other regions, and not only pits (dents) are formed at the time of polishing, but also when the light emitting element layer is laminated and cut into chips Adhesion to foreign matter on the crystal growth surface during manufacture of the group III nitride single crystal laminate, because it tends to be a starting point of processing cracking and to significantly reduce the yield of light emitting devices manufactured using the substrate. Needs to be reduced as much as possible.

前述した結晶成長面への異物の付着は、気相成長装置がIII族源ガス等の雰囲気ガスに侵され、該装置部材材質が剥離等する場合や、反応中にIII族化合物の粒子等が副生することが原因であると考えられており、これらの異物の付着を防ぎながら、結晶成長を行う方法が種々提案されている。例えば、結晶成長装置部材として耐腐食性材料を使用することによる装置部材の腐食の抑制(特許文献1参照)が行われている。   The adhesion of foreign matter to the crystal growth surface described above is caused by attack of the vapor growth apparatus by the atmosphere gas such as a group III source gas and the material of the apparatus member is peeled off or particles of group III compound during reaction. It is believed that by-production is the cause, and various methods for crystal growth have been proposed while preventing adhesion of these foreign substances. For example, suppression of corrosion of a device member by using a corrosion resistant material as a crystal growth device member has been performed (see Patent Document 1).

さらに近年、より高品質な単結晶が望まれており、気相成長中の副生成物を抑制する方法が種々検討されている。例えば、反応器内のガスの流れを調整することにより、気相反応で生じた粒子(付着粒子:ノマルスキー微分干渉顕微鏡(100〜500倍で観察)で観察される粒子)が結晶成長面に付着するのを防止し、高品質な単結晶を製造する方法が知られている(特許文献2参照)。   Furthermore, in recent years, higher quality single crystals are desired, and various methods for suppressing by-products during vapor phase growth have been studied. For example, by adjusting the flow of gas in the reactor, particles generated in the gas phase reaction (adhered particles: particles observed with Nomarski differential interference microscope (observed at 100 to 500 times)) adhere to the crystal growth surface There is known a method of preventing the problem and producing a high quality single crystal (see Patent Document 2).

特表2009−536605号JP 2009-536605 No. 国際公開WO2014/031119号International Publication WO2014 / 031119

上記の方法により気相成長法における結晶成長面への異物の付着がある程度低減され、高品質なIII族窒化物単結晶積層体が製造できるようになってきているが、本発明者らの検討により、上記対策を講じてもなお、結晶成長面への異物の付着が完全には抑制できないことが判明した。特に、同じ気相成長装置を用いて繰り返しIII族窒化物単結晶層の成長を行った際には、繰り返す回数が増加するにつれて結晶成長面への異物の付着によるものと推測される単結晶層上のヒロックや明点の発生数が増加し、さらには異物を起点に多結晶として成長するものも観られた。このような異物起点の多結晶が成長すると、得られたIII族窒化物単結晶積層体の表面を平坦化し、最終的に化学的機械的研磨(CMP)を実施した際に、前記多結晶部分が凹部となって残り、場合によってはIII族窒化物単結晶層を貫通するような孔が形成される。   By the above-mentioned method, adhesion of foreign matter to the crystal growth surface in the vapor phase growth method is reduced to some extent, and high quality group III nitride single crystal laminate can be manufactured, but the inventors examined Thus, it has been found that, even if the above measures are taken, adhesion of foreign matter to the crystal growth surface can not be completely suppressed. In particular, when the group III nitride single crystal layer is repeatedly grown using the same vapor phase growth apparatus, the single crystal layer is presumed to be due to the adhesion of foreign matter to the crystal growth surface as the number of repetitions increases. The number of occurrences of hillocks and bright spots on the top was increased, and those growing as polycrystals from foreign substances were also observed. When such foreign matter origin polycrystal grows, the surface of the obtained group III nitride single crystal laminate is planarized, and when the chemical mechanical polishing (CMP) is finally performed, the polycrystalline portion Remain as recesses, and in some cases, holes are formed so as to penetrate the group III nitride single crystal layer.

通常、同じ気相成長装置を用いて繰り返しIII族窒化物単結晶層の成長を行う際には、直前の成長バッチにおいて該装置部材表面に析出した析出物を除去するため、キャリアガス、或いは塩化水素ガスや塩素ガス等の酸性ガス等のクリーニングガス雰囲気下で加熱クリーニング処理を行った後に次の成長バッチを行う。この加熱クリーニング処理の目的は、直前の成長バッチにおいて結晶成長の副反応等により該装置部材表面に析出した析出物等を完全に除去し、系内をパーティクル等のないクリーンな状態にした上で次の成長バッチを行うことにあるが、かかる加熱クリーニング処理によっても析出物が完全には除去できずに残留してしまい、次の成長バッチにおいて残留した析出物が該装置部材表面より脱離して結晶成長面に付着し、単結晶層中の異物の原因となることが判明した。すなわち本発明の目的は、複数のガスの反応によりベース基板上に単結晶層を成長させる気相成長装置において、結晶成長面への異物の付着による結晶品質の低下を防止する気相成長装置の洗浄方法を提供することにある。   Usually, when growing the group III nitride single crystal layer repeatedly using the same vapor phase growth apparatus, the carrier gas or chloride is used to remove the precipitate deposited on the surface of the device member in the previous growth batch. After the heating and cleaning process is performed in a cleaning gas atmosphere such as hydrogen gas or acid gas such as chlorine gas, the next growth batch is performed. The purpose of this heating and cleaning treatment is to completely remove precipitates and the like deposited on the surface of the device member by side reactions and the like of crystal growth in the previous growth batch, and to make the inside of the system clean without particles and the like. Although the next growth batch is to be carried out, the deposit can not be completely removed even by the heating cleaning process, and the deposit remaining in the next growth batch is detached from the surface of the device member. It has been found that it adheres to the crystal growth surface and causes foreign matter in the single crystal layer. That is, an object of the present invention is to provide a vapor phase growth apparatus for growing a single crystal layer on a base substrate by reaction of a plurality of gases, which prevents deterioration of crystal quality due to adhesion of foreign matter to crystal growth surface. It is to provide a cleaning method.

本発明者等は、上記課題を解決するため、気相成長装置の洗浄方法について鋭意検討を行った。その結果、気相成長後の装置から成長部を構成する部材を取り外し、取り外した各部材を水溶液により洗浄することによって、前記加熱クリーニング処理では除去しきれずに残留してしまう析出物を除去できるという知見を得た。そこで洗浄後の部材を使用して気相成長装置を組み再度気相成長を行うことで、結晶成長面への異物の付着に起因する多結晶の発生が抑制できることを見出し本発明を完成させるに至った。   The present inventors diligently studied the cleaning method of the vapor phase growth apparatus in order to solve the above-mentioned problems. As a result, by removing the members constituting the growth part from the apparatus after the vapor phase growth, and washing the removed members with an aqueous solution, it is possible to remove the deposits that can not be completely removed by the heating and cleaning process. I got the knowledge. Therefore, it is found that the occurrence of polycrystals caused by the adhesion of foreign matter to the crystal growth surface can be suppressed by recombining vapor phase growth using a member after cleaning and performing vapor phase growth again to complete the present invention. It reached.

すなわち、第1の本発明は原料ガスを供給する原料ガス供給口、基板を載置する基板保持台、該基板保持台を加熱することにより基板を加熱する加熱手段、及び原料ガス供給口、基板保持台及び加熱手段を収容する成長部を有する気相成長装置において、気相成長装置にて気相成長を行った後、該成長部を構成する部材を取り外し、取り外した部材を水溶液により洗浄することを特徴とする気相成長装置の洗浄方法である。上記気相成長装置の洗浄方法において、以下の態様が好適に採り得る。
1)前記水溶液が酸性又はアルカリ性であること。
2)前記水溶液が酸化剤を含有すること。
3)前記酸化剤が過酸化水素であること。
4)さらに硫酸を含有すること。
That is, according to the first aspect of the present invention, a raw material gas supply port for supplying a raw material gas, a substrate holder on which the substrate is placed, a heating unit for heating the substrate by heating the substrate holder, a raw material gas supply port, a substrate In a vapor phase growth apparatus having a growth section containing a holding table and a heating means, after vapor phase growth is performed in the vapor phase growth apparatus, members constituting the growth portion are removed, and the removed members are washed with an aqueous solution It is a cleaning method of the vapor phase growth apparatus characterized by the above. In the method of cleaning the vapor phase growth apparatus, the following aspect can be suitably employed.
1) The aqueous solution is acidic or alkaline.
2) The aqueous solution contains an oxidizing agent.
3) The oxidizing agent is hydrogen peroxide.
4) Further contain sulfuric acid.

本発明の気相成長装置の洗浄方法によれば、単結晶層成長時における結晶成長面への異物の付着を防止することができる。このため、異物の付着に由来する多結晶部の発生が非常に少ない単結晶積層体を製造することができる。特に同じ気相成長装置を用いて繰り返し単結晶積層体を製造する際においても製造回数を重ねても安定的に異物の付着を防止することができるため、安定的に多結晶部が非常に少ない単結晶積層体を製造することができる。   According to the cleaning method of the vapor phase growth apparatus of the present invention, it is possible to prevent the adhesion of foreign matter to the crystal growth surface at the time of single crystal layer growth. For this reason, it is possible to manufacture a single crystal laminate in which the generation of a polycrystalline portion derived from the adhesion of foreign matter is extremely small. In particular, even when the single-crystal laminate is repeatedly manufactured using the same vapor phase growth apparatus, the adhesion of foreign matter can be stably prevented even if the number of times of manufacturing is increased, so that the number of polycrystalline portions is very small stably. Single crystal laminates can be manufactured.

一般的な気相成長装置成長部の概略図である。It is the schematic of a general vapor phase growth apparatus growth part. 気相成長装置におけるサセプタ及び加熱部材周辺の構造の一例を示す概略図である。It is the schematic in the vapor phase growth apparatus which shows an example of the structure of the susceptor and heating member periphery. 気相成長装置におけるサセプタ及び加熱部材周辺の構造の他の一例を示す概略図である。It is the schematic in the vapor phase growth apparatus which shows another example of the structure of the susceptor and heating member periphery.

本発明の洗浄方法は、原料ガスを供給する原料ガス供給口、基板を載置する基板保持台、該基板保持台を加熱することにより基板を加熱する加熱手段、及び原料ガス供給口、基板保持台及び加熱手段を収容する成長部を有する気相成長装置において、気相成長装置にて気相成長を行った後、該成長部を構成する部材を取り外し、取り外した部材を水溶液により洗浄することが特徴である。   The cleaning method of the present invention comprises a source gas supply port for supplying a source gas, a substrate holder on which the substrate is placed, a heating unit for heating the substrate by heating the substrate holder, a source gas supply port, and a substrate holder. In a vapor phase growth apparatus having a growth portion containing a pedestal and a heating means, after vapor phase growth is performed in the vapor phase growth device, a member constituting the growth portion is removed, and the removed member is washed with an aqueous solution. Is a feature.

前述のとおり、例えば、III族源ガスと窒素源ガスとを反応させてベース基板上にIII族窒化物単結晶層を成長させIII族窒化物単結晶積層体を得るまでのサイクルを同一の気相成長装置にて繰り返し行う際には、通常、反応の副生物である塩化アルミニウムや塩化ガリウム等のIII族金属由来の析出物およびベース基板外に析出したIII族窒化物等を成長部内より除去するため、キャリアガス、或いは塩化水素や塩素ガス等の酸性ガス等の雰囲気下で加熱クリーニング処理を行った後に結晶成長を行うが、かかる加熱クリーニングによっても塩化アルミニウムや塩化ガリウム等のIII族金属由来の副生物およびベース基板外に析出したIII族窒化物等は完全には除去できず、成長部内に残留する。成長部内に残留した該析出物が単結晶層の成長前又は成長中に脱離し結晶成長面に異物として付着した場合、付着した箇所およびその周辺において結晶成長異常による結晶欠陥および多結晶の発生等を引き起こし、結晶品質の低下の要因となる。特に、該析出物の脱離は窒化アルミニウム単結晶や窒化アルミニウムガリウム等アルミニウムを含む窒化物単結晶等のアルミニウム系III族窒化物単結晶のような高温下で気相成長を行う場合に顕著に生じる傾向がある。従って、本発明の洗浄方法を用いて成長部内に析出したIII族金属由来成分を除去した後にベース基板上にIII族窒化物単結晶層を成長させることで成長時における単結晶層中への異物の混入を防止し、結晶成長面への異物の付着に起因する多結晶の発生や、最終的に成長後の基板を研磨した際には凹部の発生が抑制された高品質のIII族窒化物単結晶積層体を得ることができるものと推測される。以下、本発明の洗浄方法について詳述する。   As described above, for example, the cycle from the reaction of the group III source gas and the nitrogen source gas to grow the group III nitride single crystal layer on the base substrate to obtain the group III nitride single crystal laminate is the same When repeated in a phase growth apparatus, generally, precipitates derived from group III metals such as aluminum chloride and gallium chloride, which are by-products of the reaction, and group III nitrides and the like deposited outside the base substrate are removed from the growth portion. In order to perform this, crystal growth is performed after performing heating and cleaning processing in an atmosphere of a carrier gas or an acidic gas such as hydrogen chloride or chlorine gas, but such heating and cleaning also derives from Group III metals such as aluminum chloride and gallium chloride. And by-products such as Group III nitrides deposited outside the base substrate can not be completely removed and remain in the growth portion. When the precipitate remaining in the growth portion is detached before or during the growth of the single crystal layer and adheres to the crystal growth surface as foreign matter, generation of crystal defects and polycrystals due to crystal growth abnormality in the adhered portion and its periphery, etc. Cause the deterioration of crystal quality. In particular, desorption of the precipitates is remarkable when vapor phase growth is performed at high temperatures such as aluminum group III nitride single crystals such as aluminum nitride single crystals and aluminum nitride single crystals such as aluminum gallium nitride. There is a tendency to occur. Therefore, foreign matter introduced into the single crystal layer during growth is obtained by growing the group III nitride single crystal layer on the base substrate after removing the group III metal-derived component deposited in the growth portion using the cleaning method of the present invention. High quality group III nitride which prevents the generation of polycrystals due to the adhesion of foreign matter to the crystal growth surface and the generation of recesses when the substrate after the final growth is polished. It is presumed that a single crystal laminate can be obtained. Hereinafter, the cleaning method of the present invention will be described in detail.

(気相成長装置)
図1に本発明の一実施形態に係る気相成長装置成長部の概略図を示す。図1に示す気相成長装置成長部99は、気相成長を行う反応管30、該反応管30内部を反応管外部より加熱する加熱手段36、結晶成長となるベース基板10を戴置する基板支持台(サセプタ)32、基板支持台32の下部に位置し、該支持台を加熱することによってベース基板10を加熱するための加熱手段37、反応管30内部に原料ガスを供給するために原料ガス供給口42、及び45、反応管30内部のガスを排気するための排気部34から構成されている。ここで、気相成長を行う際に複数の原料ガスを用いる場合には、図1に示す様に用いるガスの種類に応じて複数の原料ガス供給口を有することも可能である。また、原料ガスの流れを制御するため、或いは複数の原料ガスがベース基板に達する前に混合されることを防ぐためにキャリアガスを用いることがあり、かかる場合には、上記気相成長装置においてキャリアガスの供給口を有してもよい。また、ベース基板10上に均一に単結晶層を積層させるためにサセプタ32を回転可能としても良い。さらに図1では、サセプタ32を加熱する加熱手段として高周波加熱コイルを用いているが、他の加熱手段(例えばヒータコイルが埋設されているサセプタ等を用いた電気抵抗加熱など)を用いても良い。また、原料ガスが接触することによる加熱手段の劣化や、成長部反応域31以外の領域を必要以上に加熱することを抑制するため、図2及び図3に示すように加熱手段を覆うように保護部材33を用いてもよい。また、成長部を構成する部材の材質としては、かかる気相成長反応での反応中の温度に耐え得るものであれば限定せずに使用できるが、加熱手段に高周波加熱を用いる場合には、石英、アルミナ、サファイア、窒化ホウ素、窒化ケイ素、炭化ケイ素等の絶縁体を使用することが好ましい。また特に、サセプタやベース基板周辺の部材のように加熱手段と近く高温となる部材は、反応中に成長部内を流通する原料ガス等による腐食が起こりやすいため、使用する原料ガス等に対する腐食耐性が高い材質を使用することが好ましく、例えば原料ガスに塩化アルミニウムを使用する場合には窒化ホウ素、窒化ケイ素が好ましい。
(Gas vapor deposition system)
FIG. 1 is a schematic view of a vapor phase growth apparatus growth unit according to an embodiment of the present invention. A vapor phase growth apparatus growth unit 99 shown in FIG. 1 includes a reaction tube 30 for vapor phase growth, a heating means 36 for heating the inside of the reaction tube 30 from the outside of the reaction tube, and a substrate on which a base substrate 10 for crystal growth is placed. A supporting table (susceptor) 32, a heating unit 37 located under the substrate supporting table 32 for heating the base substrate 10 by heating the supporting table, a raw material for supplying a source gas into the reaction tube 30. The gas supply ports 42 and 45, and an exhaust unit 34 for exhausting the gas in the reaction tube 30 are provided. Here, when using a plurality of source gases when performing vapor phase growth, it is also possible to have a plurality of source gas supply ports according to the type of gas used as shown in FIG. In addition, a carrier gas may be used to control the flow of the source gas or to prevent a plurality of source gases from being mixed before reaching the base substrate. In such a case, the carrier in the vapor phase growth apparatus is used. It may have a gas supply port. In addition, the susceptor 32 may be rotatable in order to laminate the single crystal layer uniformly on the base substrate 10. Furthermore, although a high frequency heating coil is used as a heating means for heating the susceptor 32 in FIG. 1, other heating means (for example, electrical resistance heating using a susceptor or the like in which a heater coil is embedded) may be used. . In addition, as shown in FIG. 2 and FIG. 3, the heating means is covered in order to suppress deterioration of the heating means due to the contact of the raw material gas and heating the region other than the growth portion reaction zone 31 more than necessary. The protective member 33 may be used. Moreover, as a material of the member which comprises a growth part, although it can use without limitation if it can endure the temperature in reaction in this vapor-phase growth reaction, when using high frequency heating as a heating means, It is preferable to use an insulator such as quartz, alumina, sapphire, boron nitride, silicon nitride or silicon carbide. In particular, a member such as a susceptor or a member around the base substrate, which has a high temperature close to the heating means, is likely to be corroded by the source gas or the like flowing through the growth portion during the reaction. It is preferable to use a high material, for example, when using aluminum chloride as a source gas, boron nitride and silicon nitride are preferable.

(気相成長方法)
上記気相成長装置を用いた気相成長法による単結晶層の一般的な成長手順としては、反応管30内にベース基板10を設置した後、反応管30内を原料ガスを含まないキャリアガスを流通した状態で、反応管30とベース基板10をそれぞれ所定の温度に加熱する。次いで第一の原料ガス供給ノズル42および第二の原料ガス供給ノズル45より原料ガスの供給を開始してベース基板10上に単結晶層の成長を開始し、所望の膜厚が得られるまで前記原料ガスの供給を継続する。所望の膜厚に到達後、原料ガスの供給を停止し、単結晶積層体を冷却後に反応管30から取り出す。その後、反応管30内部のベース基板10以外に析出した析出物を除去するために、反応管30内部のクリーニング処理を行う。反応管30内部に析出物を分解することのできるクリーニングガス(例えば塩素ガスや塩化水素ガスなど)を供給して反応管30内部の析出部分を加熱状態に保持することで、析出物を除去することもできる。クリーニング終了後は、必要に応じて反応管30内部にキャリアガスを流通した状態で空焼処理する。クリーニング処理と空焼を兼ねる場合は、空焼処理は省略される。このような手順を一つのサイクルとして、サセプタ32上に次のサイクルのベース基板を設置して単結晶層の成長を行い、その後もサイクルを繰り返し行う。
(Gas phase growth method)
As a general growth procedure of the single crystal layer by the vapor phase growth method using the above-mentioned vapor phase growth apparatus, after installing the base substrate 10 in the reaction tube 30, a carrier gas containing no source gas in the reaction tube 30 The reaction tube 30 and the base substrate 10 are heated to predetermined temperatures, respectively. Subsequently, the supply of the source gas is started from the first source gas supply nozzle 42 and the second source gas supply nozzle 45 to start the growth of the single crystal layer on the base substrate 10 until the desired film thickness is obtained. Continue the supply of source gas. After reaching the desired film thickness, the supply of the source gas is stopped, and the single crystal laminate is taken out of the reaction tube 30 after cooling. Thereafter, the inside of the reaction tube 30 is subjected to a cleaning process in order to remove the precipitate deposited on other than the base substrate 10 inside the reaction tube 30. The deposit is removed by supplying a cleaning gas (for example, chlorine gas or hydrogen chloride gas) capable of decomposing the precipitate into the inside of the reaction tube 30 to keep the deposition part in the reaction tube 30 in a heated state. It can also be done. After completion of the cleaning, the carrier gas is circulated in the reaction tube 30 if necessary, and the air is burned out. In the case of combining the cleaning process and the firing, the firing process is omitted. With such a procedure as one cycle, the base substrate of the next cycle is placed on the susceptor 32 to grow a single crystal layer, and the cycle is repeated thereafter.

(本発明の気相成長装置の洗浄方法)
本発明の気相成長装置の洗浄方法は、気相成長装置にて気相成長を行った後、上記クリーニングガスによるクリーニング処理の代わりに、成長部を構成する部材を取り外し、取り外した部材を水溶液により洗浄することが特徴である。上記図1の気相成長装置の場合を例示すると、単結晶積層体を反応管30から取り出した後にサセプタ32やベース基板10周辺の部材、第一の原料ガス供給ノズル42、第二の原料ガス供給ノズル45、反応管30等の成長部を構成する各部材を取り外し、各部材を水溶液で洗浄する。このような水溶液による洗浄を行うことにより、該成長部の各部材の表面に析出した析出物を除去することができる。特に、サセプタ32および保護部材33はその他の成長部部材よりも高温になることから析出物の析出量が多く、クリーニングガスによる一般的なクリーニング処理を行った際には析出物が残留しやすい傾向にある。従って、上記部材に対して、本発明の気相成長装置の洗浄方法を実施することが好ましい。またIII族窒化物単結晶、特に、窒化アルミニウム単結晶や窒化アルミニウムガリウム等、のアルミニウム系III族窒化物単結晶を気相成長法により製造する場合には、気相成長時の反応温度が比較的高いため成長部部材表面に析出物が残留していると、結晶成長時にかかる残留した析出物の脱離が起きやすい傾向にある。従って、かかる単結晶成長の際に本発明の気相成長装置の洗浄方法を実施することが好ましい。本発明の気相成長装置の洗浄方法は、単結晶成長を行った後に毎回行ってもよいし、成長させた単結晶層に含有する異物の個数についての閾値を設定し閾値を越えた場合に洗浄を行い、次の結晶成長を行ってもよい。
(Method for cleaning vapor phase growth apparatus of the present invention)
According to the cleaning method of the vapor phase growth apparatus of the present invention, after vapor phase growth is performed by the vapor phase growth apparatus, the member constituting the growth portion is removed instead of the cleaning process by the cleaning gas, and the removed member is an aqueous solution It is a feature to wash by. If the case of the vapor phase growth apparatus of the said FIG. 1 is illustrated, after taking out a single crystal laminated body from the reaction tube 30, the member of susceptor 32 or base substrate 10 periphery, 1st source gas supply nozzle 42, 2nd source gas The respective members constituting the growing portion such as the supply nozzle 45 and the reaction tube 30 are removed, and the respective members are washed with an aqueous solution. By performing such cleaning with an aqueous solution, the precipitate deposited on the surface of each member of the growth portion can be removed. In particular, since the susceptor 32 and the protective member 33 have a higher temperature than other growth part members, the amount of precipitates deposited is large, and the precipitates tend to remain easily when the general cleaning treatment with a cleaning gas is performed. It is in. Therefore, it is preferable to carry out the cleaning method of the vapor phase growth apparatus of the present invention on the above-mentioned member. In the case of producing a group III nitride single crystal, particularly an aluminum group III nitride single crystal such as aluminum nitride single crystal or aluminum gallium nitride by a vapor phase growth method, the reaction temperature at the time of vapor phase growth is compared If deposits remain on the surface of the growth member, the deposits tend to be detached during crystal growth. Therefore, it is preferable to carry out the cleaning method of the vapor phase growth apparatus of the present invention during such single crystal growth. The cleaning method of the vapor phase growth apparatus according to the present invention may be performed every time after single crystal growth is performed, or when the threshold for the number of foreign substances contained in the grown single crystal layer is set and exceeds the threshold. After washing, crystal growth may be performed.

(水溶液による洗浄)
本発明の気相成長装置の洗浄方法に用いる水溶液としては、析出物の除去効果が高い点で、水溶液を酸性、又はアルカリ性とすることが好ましい。酸性の水溶液として具体的には、硝酸、塩酸、硫酸、りん酸、フッ化水素酸等の酸溶液を原液もしくは希釈水溶液を使用することができる。一方、アルカリ性の水溶液として具体的には、アンモニア、水酸化ナトリウム、水酸化カリウム、水酸化カルシウム等の一般的な無機アルカリを水溶液化したものや、テトラメチルアンモニウムハイドロオキサイドやテトラエチルアンモニウムハイドロオキサイドのような有機アルカリ水溶液を適宜希釈して使用することができる。酸またはアルカリの濃度は、濃い方が洗浄効果は高まるため、酸性、或いはアルカリ性の水溶液を用いる際の水溶液のpHとしては、3以下もしくは10以上が好ましく、2以下もしくは12以上がより好ましく、特に1以下もしくは13以上であることが最も好ましい。
(Washing with aqueous solution)
As an aqueous solution used for the cleaning method of the vapor phase growth apparatus of the present invention, it is preferable to make the aqueous solution acidic or alkaline from the viewpoint that the removal effect of the precipitate is high. As an acidic aqueous solution, specifically, an acid solution of nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, hydrofluoric acid or the like can be used as a stock solution or diluted aqueous solution. On the other hand, specific examples of the alkaline aqueous solution include aqueous solutions of general inorganic alkali such as ammonia, sodium hydroxide, potassium hydroxide and calcium hydroxide, tetramethyl ammonium hydroxide and tetra ethyl ammonium hydroxide. The organic alkaline aqueous solution can be appropriately diluted and used. As the concentration of the acid or alkali is higher, the washing effect is enhanced. Therefore, the pH of the aqueous solution when using an acidic or alkaline aqueous solution is preferably 3 or less or 10 or more, more preferably 2 or less or 12 or more, particularly Most preferably, it is 1 or less or 13 or more.

さらに、酸性もしくはアルカリ性水溶液による洗浄を行う際に酸化剤を添加することで標準酸化還元電位を高め、析出物の除去効果を高めることができるため、酸化剤を添加することが特に好ましい。酸化剤として具体的には、過酸化水素、二クロム酸塩、過マンガン酸塩等が上げられる。これらの中でも過酸化水素水が金属元素を含まないため金属汚染の原因とならず、かつ取扱いが比較的容易である点から、過酸化水素を用いることが好ましい。過酸化水素は、上記酸性もしくはアルカリ性水溶液に過酸化水素水を混合することで用いることができる。過酸化水素を用いる場合の濃度としては、0.1〜30質量%の範囲で適宜用いれば良い。   Furthermore, it is particularly preferable to add an oxidizing agent, since the standard oxidation-reduction potential can be increased and the effect of removing precipitates can be enhanced by adding an oxidizing agent when washing with an acidic or alkaline aqueous solution. Specific examples of the oxidizing agent include hydrogen peroxide, dichromate, permanganate and the like. Among them, hydrogen peroxide is preferably used because hydrogen peroxide solution does not contain a metal element and does not cause metal contamination and is relatively easy to handle. Hydrogen peroxide can be used by mixing hydrogen peroxide solution with the above-mentioned acidic or alkaline aqueous solution. As a density | concentration in the case of using hydrogen peroxide, it may use suitably in the range of 0.1-30 mass%.

上記洗浄に用いる水溶液の中でも、特に硫酸と過酸化水素の混合液や、塩酸と過酸化水素の混合液、或いはアンモニアと過酸化水素の混合液は、前記の好ましいpHと高い標準酸化還元電位を兼備えるため特に洗浄効果が高く好ましい。上記混合液の混合比としては、上記のpHの範囲且つ過酸化水素の濃度の範囲で適宜混合すれば良い。   Among the aqueous solutions used for the above-mentioned washing, particularly, a mixture of sulfuric acid and hydrogen peroxide, a mixture of hydrochloric acid and hydrogen peroxide, or a mixture of ammonia and hydrogen peroxide preferably has the above-mentioned preferable pH and a high standard redox potential. In particular, the cleaning effect is high because it is provided. The mixing ratio of the mixed solution may be properly mixed in the above pH range and the concentration range of hydrogen peroxide.

上記部材を洗浄する方法としては、洗浄する部材の形状等を勘案して適宜行えば良く、水溶液中に部材を浸漬させる浸漬洗浄、或いは、部材に水溶液を流す流水洗浄等いずれも洗浄方法を用いても良い。また洗浄する際の温度としては、表面に析出した析出物が除去できる温度で適宜設定すれば良い。通常20℃以上200℃以下好ましくは60℃以上180℃以下、特に好ましくは90℃以上150℃以下の範囲で適宜選択すれば良い。さらに洗浄時間についても表面に析出した析出物が除去できる温度で適宜設定すれば良く、通常1分から300分の範囲から適宜選択すれば良い。   As a method of cleaning the above-mentioned member, it may be appropriately performed in consideration of the shape of the member to be cleaned, etc. Immersion cleaning in which the member is immersed in an aqueous solution or running water cleaning in which the aqueous solution is flowed to the member It is good. Further, the temperature at the time of cleaning may be appropriately set at a temperature at which the precipitate deposited on the surface can be removed. The temperature may be appropriately selected in the range of usually 20 ° C. to 200 ° C., preferably 60 ° C. to 180 ° C., particularly preferably 90 ° C. to 150 ° C. Further, the cleaning time may be appropriately set at a temperature at which the precipitate deposited on the surface can be removed, and may be properly selected usually in the range of 1 minute to 300 minutes.

上記本発明の気相成長装置の洗浄方法を行った後は、洗浄した部材表面の水を乾燥させた後に、気相成長装置に用いれば良い。水溶液として、酸性又はアルカリ性の水溶液を用いた場合、或いはさらに酸化剤を用い場合には、純水で洗浄後、乾燥しても良い。使用する純水としては、部材表面の汚染を低減させる観点から、金属イオン不純物や総有機炭素量(Total Organic Carbon:TOC)が低減された超純水を使用することが好ましく、特に、比抵抗が18MΩ・cm(25℃)以上を有し、かつ総有機炭素量が50ppb以下に管理された超純水を使用することが好ましい。   After the cleaning method of the vapor deposition apparatus of the present invention is performed, the water on the surface of the cleaned member may be dried and then used in the vapor deposition apparatus. When an acidic or alkaline aqueous solution is used as the aqueous solution, or in the case where an oxidizing agent is further used, it may be dried after washing with pure water. As pure water to be used, it is preferable to use ultrapure water with reduced metal ion impurities and total organic carbon (TOC) from the viewpoint of reducing the contamination of the member surface, and in particular, the specific resistance It is preferable to use ultrapure water having an M. of at least 18 M.OMEGA.cm (25.degree. C.) and a total organic carbon content of 50 ppb or less.

上記、本発明の気相成長装置の洗浄方法を行った部材は、再度気相成長装置の部材として組み立てた後、上記方法によって結晶成長を行えば良い。   The member subjected to the cleaning method of the vapor phase growth apparatus of the present invention may be assembled as a member of the vapor phase growth apparatus again, and then crystal growth may be performed by the above method.

以下、実施例を挙げて本発明を詳細に説明するが、本発明は以下の実施例に限定されるものではない。なお、窒化アルミニウム単結晶層中の多結晶部の測定は、以下の方法により行った。   EXAMPLES Hereinafter, the present invention will be described in detail by way of examples, but the present invention is not limited to the following examples. The measurement of the polycrystalline portion in the aluminum nitride single crystal layer was performed by the following method.

(窒化アルミニウム単結晶積層体中の多結晶部の測定方法)
窒化アルミニウム単結晶積層体の単結晶層表面をノマルスキー微分干渉顕微鏡(ニコン社製LV150)により、観察倍率50倍〜1000倍で観察した。単結晶層体表面に露出した不定形な凸部の個数を多結晶部の個数としてカウントした。なお、不定形な凸部が多結晶であることはラマン分光分析により窒化アルミニウム単結晶をc軸方向以外から分析した際や、窒化アルミニウム多結晶を分析した際に観測されるラマンシフト670cm−1付近のE(TO)モードのラマン散乱に由来するピークおよびラマンシフト610cm−1付近に観測されるA(TO)モードのラマン散乱に由来するピークの有無により確認した。
(Method of measuring polycrystalline part in aluminum nitride single crystal laminate)
The surface of the single crystal layer of the aluminum nitride single crystal laminate was observed with a Nomarski differential interference microscope (LV 150 manufactured by Nikon Corporation) at an observation magnification of 50 times to 1000 times. The number of indeterminate convex portions exposed on the surface of the single crystal layer body was counted as the number of polycrystalline portions. In addition, the Raman shift of 670 cm −1 observed when analyzing an aluminum nitride single crystal from other than the c-axis direction by Raman spectroscopic analysis or when analyzing an aluminum nitride polycrystal that the indeterminate convex portion is polycrystal It confirmed by the presence or absence of the peak derived from the Raman scattering of nearby E 1 (TO) mode and the peak derived from the Raman scattering of A 1 (TO) mode observed near a Raman shift of 610 cm −1 .

実施例1
図1に示す成長部を有する気相成長装置を使用し、ベース基板上に窒化アルミニウム単結晶層を成長させた。結晶成長中に特に高温となるサセプタ32および保護部材33の材質としては窒化ホウ素を採用し、反応管30および反応管30内部のその他の部材の材質としては石英を採用した。本実施例の実施前の成長バッチにおいて、後述する本実施例と同様の成長条件で窒化アルミニウム単結晶層の成長を予め行い、窒化アルミニウム単結晶積層体をを取り出した。
Example 1
An aluminum nitride single crystal layer was grown on a base substrate using a vapor deposition apparatus having a growth portion shown in FIG. Boron nitride was adopted as a material of the susceptor 32 and the protective member 33 which become particularly high temperature during crystal growth, and quartz was adopted as a material of the reaction tube 30 and other members inside the reaction tube 30. In the growth batch before implementation of the present example, the growth of the aluminum nitride single crystal layer was performed in advance under the same growth conditions as the present example described later, and the aluminum nitride single crystal laminate was taken out.

(成長部部材に析出した析出物の除去)
次いで、気相成長装置から図1に示す成長部を取り外し、96%濃硫酸400ml、30%過酸化水素水100mlを混合した水溶液(洗浄媒体)に90℃で10分間浸漬した後、比抵抗が18.2MΩ・cm、総有機炭素量(TOC)が5ppbの超純水流水中(2L/min)にて7分間流水洗浄し、洗浄媒体成分を除去した。洗浄後、クリーンベンチ内において成長部部材を60分間静置乾燥した。
(Removal of precipitates deposited on growth member)
Next, the growth section shown in FIG. 1 is removed from the vapor phase growth apparatus and immersed in an aqueous solution (washing medium) mixed with 400 ml of 96% concentrated sulfuric acid and 100 ml of 30% hydrogen peroxide water for 10 minutes at 90 ° C. 18.2 M.OMEGA.cm, and the total organic carbon content (TOC) was washed with flowing ultrapure water (2 L / min) of 5 ppb for 7 minutes for 7 minutes to remove the cleaning medium components. After washing, the growth member was allowed to stand still for 60 minutes in a clean bench.

(成長部の再設置)
成長部部材が乾燥した後、成長部取り外し前と同じように各部材を設置し、次の窒化アルミニウム単結晶の成長の準備を行った。その後、気相成長装置内部に侵入した大気成分を除去するために、減圧とキャリアガスの充填を複数回繰り返して、気相成長装置内をパージした。
(Replacement of growth department)
After the growth member was dried, each member was placed in the same manner as before removal of the growth member, and preparation for the next aluminum nitride single crystal growth was performed. Thereafter, in order to remove the atmospheric component that has entered the inside of the vapor phase growth apparatus, the inside of the vapor phase growth apparatus was purged by repeating decompression and filling of the carrier gas a plurality of times.

(気相成長装置の空焼)
次に、成長部部材や気相成長装置内部に吸着した水分を除去するために空焼を行った。空焼では、気相成長装置内の各ガス供給管からキャリアガスを供給しながら高周波加熱コイルに電力を印加してサセプタを1500℃まで加熱し、成長部部材を前記サセプタからの輻射熱により加熱した。最高温度に達した状態で30分間保持した後、室温まで冷却した。
(Steaming of vapor deposition equipment)
Next, in order to remove the moisture adsorbed in the growth part member and the inside of the vapor growth apparatus, calcination was performed. In the case of the firing, while supplying the carrier gas from each gas supply pipe in the vapor phase growth apparatus, the power is applied to the high frequency heating coil to heat the susceptor to 1500 ° C. and the growth member is heated by the radiant heat from the susceptor . It was cooled to room temperature after holding for 30 minutes while reaching the maximum temperature.

(III族窒化物単結晶層の成長)
冷却後、次の窒化アルミニウム単結晶層を成長するための新たなベース基板をサセプタ上に設置した。ベース基板には直径25.4mmで厚さ500μmの昇華法で製造したc面窒化アルミニウム単結晶を使用した。次いで、気相成長装置内の各ガス供給管からキャリアガスを流通した状態で、サセプタおよび基板温度を1500℃に加熱した。到達後に、塩化アルミニウムガスと塩化水素ガスの混合ガスとをIII族源ガス供給ノズル(第一の原料ガス供給ノズル)を通じてベース基板上に供給した。さらに、窒素源ガス供給ノズル(第二の原料ガス供給ノズル)を通してアンモニアガスおよび塩化水素ガスを供給して、ベース基板上に窒化アルミニウム単結晶層の成長を開始した。所定時間を経過後、塩化アルミニウムガス、塩化水素ガス、アンモニアガスの供給を停止し、室温まで冷却した。ベース基板中心位置における成長速度は55μm/hであり、6時間成長することによって膜厚330μmの窒化アルミニウム単結晶層を得た。
(Growth of group III nitride single crystal layer)
After cooling, a new base substrate for growing the next aluminum nitride single crystal layer was placed on the susceptor. As a base substrate, a c-plane aluminum nitride single crystal manufactured by a sublimation method with a diameter of 25.4 mm and a thickness of 500 μm was used. Next, the susceptor and the substrate were heated to 1500 ° C. while the carrier gas was circulated from each gas supply pipe in the vapor phase growth apparatus. After reaching, a mixed gas of aluminum chloride gas and hydrogen chloride gas was supplied onto the base substrate through a group III source gas supply nozzle (first source gas supply nozzle). Furthermore, ammonia gas and hydrogen chloride gas were supplied through the nitrogen source gas supply nozzle (second source gas supply nozzle) to start the growth of the aluminum nitride single crystal layer on the base substrate. After a predetermined time elapsed, the supply of aluminum chloride gas, hydrogen chloride gas, and ammonia gas was stopped, and cooled to room temperature. The growth rate at the center position of the base substrate is 55 μm / h, and by growing for 6 hours, an aluminum nitride single crystal layer with a thickness of 330 μm was obtained.

冷却後、得られた窒化アルミニウム単結晶積層体を気相成長装置内より取り出しノマルスキー微分干渉顕微鏡により50倍〜1000倍の範囲で観察したところ、多結晶部は0個であった。   After cooling, the obtained aluminum nitride single crystal laminate was taken out of the vapor phase growth apparatus and observed with a Nomarski differential interference microscope in a range of 50 times to 1000 times. As a result, the number of polycrystalline parts was zero.

以降、窒化アルミニウム単結晶積層体を取り出した後は、再び成長部を構成する部材の取り外しおよび水溶液による洗浄の工程に移行し、次のバッチの窒化アルミニウム単結晶層の成長を繰り返し行った。成長バッチを30回繰り返した結果、1基板あたりの多結晶の最大発生数は1個、平均の発生数は0.1個、発生数の標準偏差は0.35であり、成長部部材に析出した析出物の除去工程を含まない場合やクリーニングガスによる一般的なクリーニングを実施した場合と比較して多結晶の発生が低減した。   Thereafter, after taking out the aluminum nitride single crystal laminate, the process again proceeds to the steps of removing the members constituting the growth portion and cleaning with an aqueous solution, and the next batch of aluminum nitride single crystal layer growth is repeated. As a result of repeating the growth batch 30 times, the maximum number of occurrences of polycrystals per substrate is 1, the average number of occurrences is 0.1, the standard deviation of the number of occurrences is 0.35, and precipitation occurs in the growth member The generation of polycrystals was reduced as compared with the case where the process of removing the deposited material was not included or the case where the general cleaning with a cleaning gas was performed.

実施例2〜4、比較例1〜3
表1に示す洗浄媒体および洗浄方法で成長部部材のクリーニングを行った以外は、実施例1と同様にIII族窒化物単結晶層の成長を行った。
結果を表2に示す。
Examples 2 to 4 and Comparative Examples 1 to 3
The growth of the group III nitride single crystal layer was performed in the same manner as in Example 1 except that the growth member was cleaned by the cleaning medium and cleaning method shown in Table 1.
The results are shown in Table 2.

Figure 2019121625
Figure 2019121625

Figure 2019121625
Figure 2019121625

99 気相成長装置
10 ベース基板
30 反応管
31 反応部反応域
32 サセプタ
33 保護部材
34 排気部
36 加熱手段
37 加熱手段
42 第一の原料ガス供給ノズル
45 第二の原料ガス供給ノズル
99 vapor phase growth apparatus 10 base substrate 30 reaction tube 31 reaction part reaction zone 32 susceptor 33 protection member 34 exhausting part 36 heating means 37 heating means 42 first source gas supply nozzle 45 second source gas supply nozzle

Claims (5)

原料ガスを供給する原料ガス供給口、基板を載置する基板保持台、該基板保持台を加熱することにより基板を加熱する加熱手段、及び原料ガス供給口、基板保持台及び加熱手段を収容する成長部を有する気相成長装置において、
気相成長装置にて気相成長を行った後、該成長部を構成する部材を取り外し、取り外した部材を水溶液により洗浄することを特徴とする気相成長装置の洗浄方法。
A raw material gas supply port for supplying a raw material gas, a substrate holder on which a substrate is placed, a heating unit for heating the substrate by heating the substrate holder, a raw material gas supply port, a substrate holder and a heating unit are accommodated. In a vapor phase growth apparatus having a growth portion,
A method of cleaning a vapor phase growth apparatus, comprising performing vapor phase growth in the vapor phase growth apparatus, removing members constituting the growth portion, and cleaning the removed members with an aqueous solution.
前記水溶液が酸性又はアルカリ性である請求項1記載の気相成長装置の洗浄方法。   The method for cleaning a vapor phase growth apparatus according to claim 1, wherein the aqueous solution is acidic or alkaline. 前記水溶液が酸化剤を含有する請求項1または2記載の気相成長装置の洗浄方法。   The method for cleaning a vapor deposition apparatus according to claim 1, wherein the aqueous solution contains an oxidizing agent. 前記酸化剤が過酸化水素である請求項3記載の気相成長装置の洗浄方法。   The method for cleaning a vapor phase growth apparatus according to claim 3, wherein the oxidizing agent is hydrogen peroxide. 前記水溶液が硫酸を含有する請求項4記載の気相成長装置の洗浄方法。   The method for cleaning a vapor phase growth apparatus according to claim 4, wherein the aqueous solution contains sulfuric acid.
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