The Influence of Graded AlGaN Buffer Thickness for Crack-Free GaN on Si(111) Substrates by using MOCVD

Pei-Qiang Xu, Yang Jiang, Zi-Guang Ma, Zhen Deng, Tai-Ping Lu, Chun-Hua Du, Yu-Tao Fang, Peng Zuo, Hong Chen
2013 Chinese Physics Letters  
GaN films with different thicknesses of Al composition graded AlGaN buffer are grown on substrates of Si(111) by metal-organic chemical vapor deposition (MOCVD). The thicknesses of graded AlGaN buffer are fixed at 200 nm, 300 nm, and 450 nm, respectively. Optical microscopy, atomic force microscopy, x-ray diffraction, and Raman spectroscopy are employed to characterize these samples. We find that the thickness of the graded AlGaN buffer layer plays a key role on the following growth of GaN
more » ... . The optimized thickness of the graded AlGaN buffer layer is 300 nm. Under such conditions, the GaN epitaxial film is crack-free, and its dislocation density is the lowest.
doi:10.1088/0256-307x/30/2/028101 fatcat:ggqgg5xtfvfmhiudo4tqdzsfom