Epitaxial Growth of AIGaN Using Selective Area Gmwth Technique

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It is extremely difficult to grow high-quality, thick A1GaN with a high AIN molar fraction on GaN, because the AIGaN cracks under the large in-plane tensile stress induced. In this study, crack-free high Al-content AIGaN with low dislocation density was grown on (SAG) GaN without coalescence of the wing GaN, which was firstly deposited on an AIN/sapphire template and the structural property of A1GaN was also investigated.SAG-GaN grown on AIN/sapphire template by metal-organic vapor phase epitaxy(MOVPE) was used as a substrate. Crack-free A1GaN with an Al content of 0.51 was successfully fabricated on selective-area-growth (SAG) GaN. lb avoid coalescence of the wing GaN, the growth process of SAG GaN was accurately controlled by in-situ monitoring. TEM measurement demonstrated that the threading dislocations(TDs) were disappeared in SAG GaN layer and appeared in the interface of SAG GaN and AIGaN. Furthermore, TDs in A1GaN layer are mainly pure edge-type dislocation and the TDs density of A1GaN layer was about 1-3×108 cm^<-2>