The effect of low temperature AlN interlayers on the growth of GaN epilayer on Si (111) by MOCVD

Low temperature (LT) AlN interlayers were used to effectively reduce the tension stress and micro-cracks on the surface of the GaN epilayer grown on Si (111) substrate. Optical Microscopy (OM), Atomic Force Microscopy (AFM), Surface Electron Microscopy (SEM) and X-Ray Diffraction (XRD) were employed to characterize these samples grown by metal-organic chemical vapor deposition (MOCVD). In addition, wet etching method was used to evaluate the defect of the GaN epilayer. The results demonstrate that the morphology and crystalline properties of the GaN epilayer strongly depend on the thickness, interlayer number and growth temperature of the LT AlN interlayer. With the optimized LT AlN interlayer structures, high quality GaN epilayers with a low crack density can be obtained. (C) 2008 Elsevier Ltd. All rights reserved.

Key Innovation Program of Chinese Academy of Sciences KGCX2-SW-107-1 National Natural Science Foundation of China 60606002 Major State Basic Research Projects 2002CB311903 2006CB604905 513270605This work has been supported by Key Innovation Program of Chinese Academy of Sciences (No. KGCX2-SW-107-1), National Natural Science Foundation of China (No. 60606002); Special Funds for Major State Basic Research Projects (No. 2002CB311903, 2006CB604905 and 513270605).