유기 금속 화학 증착법(MOCVD)으로 4H-SiC 기판에 성장한 Ga2O3 박막과 결정 상에 따른 특성
Growth of Ga2O3 films on 4H-SiC substrates by metal organic chemical vapor deposition and their characteristics depend on crystal phase
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ε-Ga2O3 박막은 금속 유기 화학 기상 증착법(MOCVD)에 의해 4H-SiC 기판에 성장되었으며, 결정성은 성장 조건에 따라 평가되었다. ε-Ga2O3의 최적 조건은 665°C의 성장 온도와 200 sccm의 산소 유량에서 성장한 것으로 나타났다.hexagonal 핵이 합쳐지면서 2차원으로 성장되었고, hexagonal 핵의 배열 방향은 기판의 결정 방향과 밀접한 관련이 있었다. 그러나 ε-Ga2O3의 결정 구조는 hexagonal이 아닌 orthorhombic 구조를 가짐을 확인하였다. 결정상 전이는 열처리에 의해 수행되었다. 그리고 상 전이된 β-Ga2O3 박막과 비교하기 위해 4H-SiC에서 β-Ga2O3 박막을 바로 성장하였다. 상 전이된 β-Ga2O3 박막은 바로 성장한 것보다 더 나은 결정성을 보여주었다.
Abstract
ε-Ga2O3 thin films were grown on 4H-SiC substrates by metal organic chemical vapor deposition (MOCVD) and crystalline quality were evaluated depend on growth conditions. It was found that the best conditions of the ε-Ga2O3 were grown at a growth temperature of 665°C and an oxygen flow rate of 200 sccm. Two-dimensional growth was completed after the merge of hexagonal nuclei, and the arrangement direction of hexagonal nuclei was closely related to the crystal direction of the substrate. However, it was confirmed that crystal structure of the ε-Ga2O3 had an orthorhombic rather than hexagonal. Crystal phase transformation was performed by thermal treatment. And a β-Ga2O3 thin film was grown directly on 4H-SiC for the comparison to the phase transformed β-Ga2O3 thin film. The phase transformed β-Ga2O3 film showed better crystal quality than directly grown one.
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