Nanomechanical characterizations of InGaN thin films

Abstract

InxGa1-x thin films with In concentration ranging from 25 to 34 at.% were deposited on sapphire substrate by metal-organic chemical vapor deposition (MOCVD). Crystalline structure and surface morphology of the deposited films were studied by using X-ray diffraction (XRD) and atomic force microscopy (AFM). Hardness, Young's modulus and creep resistance were measured using a nanoindenter. Among the deposited films, In0.25Ga0.75N film exhibits a larger grain size and a higher surface roughness. Results indicate that hardness decreases slightly with increasing In concentration in the InxGa1-xN films ranged from 16.6 +/- 1.1 to 16.1 +/- 0.7 GPa and, Young's modulus for the In0.25Ga0.75N, In0.3Ga0.7N and In0.34Ga0.66N films are 375.8 +/- 23.1, 322.4 +/- 13.5 and 373.9 +/- 28.6 GPa, respectively. In addition, the time-dependent nanoindentation creep experiments are presented in this article. (c) 2005 Elsevier B.V. All rights reserved.