FU Runding 1，ZHUANG Dejin 2，XIU Xiangqian 1，XIE Zili 1，CHEN Peng 1，ZHANG Rong 1，ZHENG Youdou 1
(1. School of Electronic Science and Engineering, Nanjing University, Nanjing 210093, Jiangsu, China; 2. Qingdao Al-Ga
Photoelectric Semiconductor Co., Ltd., Qingdao 266105, Shandong, China)
Abstract: The structural and optical properties of single-crystal AlN prepared by physical vapor transport (PVT) method were studied. The results show that PVT-AlN single crystal has high quality. AlN samples with the uniform thickness and device-quality surfaces have been obtained by a sapphire-aided CMP method. AlGaN epi-layers with the Al content of 18.2% have been grown on CMP-AlN substrates by metal-organic chemical vapor deposition (MOCVD). The tensile stress in nominally compressed AlGaN layer and the formation mechanism of surface cracks are explained by strain gradients model.
Key words: single-crystal AlN; CMP; AlGaN; strain gradients model