Epitaxial Growth of AIGaN Using Selective Area Gmwth Technique

在GaN上生长高AlN摩尔分数的高质量、厚的AlGaN是非常困难的，因为AlGaN在大的面内拉应力下产生裂纹。本文采用金属-有机气相外延(MOVPE)方法在AlN/蓝宝石衬底上生长了无裂纹、高Al含量、低位错密度的(SAG)GaN，并研究了AlGaN的结构特性。在选区区域生长(SAG)GaN衬底上成功制备了Al含量为0.51的无裂纹AlGaN。Lb避免了翼型GaN的合并，通过现场监测精确地控制了SAG GaN的生长过程。电子显微镜测量表明，SAG GaN层中的穿线位错(TD)消失，而SAG GaN与AlGaN的界面上出现了穿线位错。AlGaN层中的TDS主要为纯刃型位错，密度约为1~3×108 cm~(-2)；

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>