Epitaxial Growth of AIGaN Using Selective Area Gmwth Technique

在GaN上生长高AIN摩尔分数的高质量、厚的A1GaN是极其困难的，因为A1GaN在较大的面内拉伸应力诱导下会产生裂纹。在本研究中，在（SAG） GaN上生长出无裂纹、低位错密度的高al含量A1GaN，而不存在翼状GaN的聚结，并将其沉积在AIN/蓝宝石模板上，并对A1GaN的结构性能进行了研究。采用金属有机气相外延（MOVPE）在AIN/蓝宝石模板上生长sagg - gan作为衬底。在选择性面积生长（SAG） GaN上成功制备了Al含量为0.51的无裂纹A1GaN。为了避免翼状氮化镓的聚结，通过现场监测精确控制了SAG氮化镓的生长过程。透射电镜（TEM）测量结果表明，在SAG GaN层中，螺纹位错（TDs）消失，并出现在SAG GaN与AIGaN的界面上。此外，A1GaN层中的TDs主要是纯边型位错，A1GaN层的TDs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>