Polar Dependence of Threading Dislocation Density in GaN Films Grown by Metal-Organic Chemical Vapor Deposition

• 来源期刊: 中国物理快报（英文版）
• 年，卷（期）: 2018,（2）
• 页码范围: 57-60
• 页数: 4页
• 语种: 英文
• DOI: 10.1088/0256-307X/35/2/026104

摘要

We investigate the threading dislocation (TD) density in N-polar and Ga-polar GaN films grown on sapphire substrates by metal-organic chemical vapor deposition.X-ray diffraction results reveal that the proportion of screw type TDs in N-polar GaN is much larger and the proportion of edge type TDs is much smaller than that in Ga-polar.Transmission electron microscope results show that the interface between the A1N nucleation layer and the GaN layer in N-polar films is smoother than that in Ga-polar films,which suggests different growth modes of GaN.This observation explains the encountered difference in screw and edge TD density.A model is proposed to explain this phenomenon.