Nanomechanical characterizations of InGaN thin films

摘要

In_xGa_(1-x)N 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, In_(0.25)Ga_(0.75)N film exhibits a larger grain size and a higher surface roughness. Results indicate that hardness decreases slightly with increasing In concentration in the In_xGa_(1-x)N films ranged from 16.6 ± 1.1 to 16.1 ± 0.7 GPa and, Young's modulus for the In_(0.25)Ga_(0.75)N, In_(0.3)Ga_(0.7)N and In_(0.34)Ga_(0.66)N 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.