High-Quality GaN Epilayers Achieved by Facet-Controlled Epitaxial Lateral Overgrowth on Sputtered AIN/PSS Templates
High-Quality GaN Epilayers Achieved by Facet-Controlled Epitaxial Lateral Overgrowth on Sputtered AIN/PSS Templates
复制标题
通过溅射 AlNPSS 模板上的面控制外延横向过度生长实现高质量 GaN 外延层
DOI：
10.1021/acsami.7b14801
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发表时间：
2017-12-13
影响因子：
9.5
通讯作者：
Chen, Zhitao
中科院分区：
文献类型：
--
作者：
He, Chenguang;Zhao, Wei;Chen, Zhitao
人们普遍认为，缺乏高质量的GaN晶圆严重阻碍了GaN基器件的发展，特别是缺陷敏感器件。在这里，低成本的氮化镓缓冲层被溅射到锥形图案蓝宝石衬底（pss）上，以获得高质量的氮化镓涂层。采用金属有机化学气相沉积的方法实现了面控外延横向过度生长。溅射AIN缓冲层的均匀涂层和优化的多重调制保证了GaN涂层的高生长选择性和均匀性。结果，获得了非常光滑的表面，平均粗糙度为0.17 nm / 3 × 3 μ m(2)。发现溅射AIN缓冲层能明显抑制锥体上的位错。优化后的三维生长工艺能有效促进位错弯曲。因此，GaN脱膜的螺纹位错密度（TDD）降低到4.6 x 10(7) cm(-2)，比PSS上的两步GaN低一个数量级。此外，利用溅射AIN缓冲层可以有效地抑制在所制备的GaN上制备的发光二极管中的污染和裂纹。所有这些优点导致在500毫安时的高输出功率为116毫瓦，发射波长为375纳米。这种简单而有效的生长技术在高性能tdd敏感光电和电子器件中具有很大的应用前景。
It is widely believed that the lack of high-quality GaN wafers severely hinders the progress in GaN-based devices, especially for defect-sensitive devices. Here, low-cost AIN buffer layers were sputtered on cone-shaped patterned sapphire substrates (PSSs) to obtain high-quality GaN epilayers. Without any mask or regrowth, facet-controlled epitaxial lateral overgrowth was realized by metal-organic chemical vapor deposition. The uniform coating of the sputtered AIN buffer layer and the optimized multiple modulation guaranteed high growth selectivity and uniformity of the GaN epilayer. As a result, an extremely smooth surface was achieved with an average roughness of 0.17 nm over 3 X 3 mu m(2). It was found that the sputtered AIN buffer layer could significantly suppress dislocations on the cones. Moreover, the optimized three-dimensional growth process could effectively promote dislocation bending. Therefore, the threading dislocation density (TDD) of the GaN epilayer was reduced to 4.6 x 10(7) cm(-2), which is about an order of magnitude lower than the case of two-step GaN on the PSS. In addition, contamination and crack in the light-emitting diode fabricated on the obtained GaN were also effectively suppressed by using the sputtered AIN buffer layer. All of these advantages led to a high output power of 116 mW at 500 mA with an emission wavelength of 375 nm. This simple, yet effective growth technique is believed to have great application prospects in high-performance TDD-sensitive optoelectronic and electronic devices.