HVPE 법을 통한 GaN 성장 시 기판 종류 및 V/III 비에 따른 잔류 stress 특성 연구
Study on residual stress characteristics according to the substrate type and V/III ratio during GaN growth by HVPE
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본 연구에서는 HVPE 성장법으로 GaN 성장 시 GaN 내에 잔류하는 stress로 인한 crack 현상을 감소시키고자기판 종류 및 V/III 비를 조절하여 잔류 stress 특성을 알아보고자 하였다. Sapphire, GaN template 위에 각각 V/III 비 5, 10,15의 조건으로 GaN을 성장시켜 형성된 hexagonal pit의 분포 및 깊이를 분석하였다. 이를 통해 G aN on GaN t emplate 성장에서 V/III 비가 높을수록 hexagonal pit의 분포 영역 및 깊이가 증가하는 것을 확인하였다. Raman 측정을 통해 hexagonalpit 영역 및 깊이가 컸던 GaN on GaN template 성장에서 V/III 비가 높을수록 stress가 감소하는 것을 확인하였다. 이를 통해 hexagonal pit의 분포 및 깊이가 증가할수록 잔류 stress가 낮아짐을 확인할 수 있었으며, 향후 후막 GaN 성장 시 stress감소 가능성에 대해 확인하였다.
Abstract
The characteristics of the residual stress on the types of the substrate was investigated with adjusting the V/IIIratio during GaN growth via the HVPE method. GaN single crystal layers were grown on a sapphire substrate and a GaNtemplate under the conditions of V/III ratio 5, 10, and 15, respectively. During GaN growth, multiple hexagonal pits inGaN single crystal were differently revealed in accordance with growth condition and substrate type, and their distributionand depth were measured via optical microscopy(OM) and white light interferometry(WLI). As a result, it was confirmedthat the distribution area and depth of hexagonal pit tended to increase as the V/III ratio increased. Moreover, it was foundthat the residual stress in GaN single crystal decreased as the distribution area and depth of the pit increased throughmeasuring micro Raman spectrophotometer. In the case of GaN growth according to substrate type, the GaN on GaNtemplate showed lower residual stress than the GaN grown on sapphire substrate.
참고문헌 (13)
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