Mechanical Characteristics of AlGaN Thin Films by Nanoindentation and Transmission Electron Microscopy

摘要

This article reports a nanomechanical response study of the contact-induced deformation behavior in Al_(0.16)Ga_(0.84)N thin film by means of a combination of nanoindentation and the cross-sectional transmission electron microscopy (XTEM) techniques. Al_(0.16)Ga_(0.84)N thin film is deposited by using the metal-organic chemical vapor deposition (MOCVD) method. Hardness and Young's modulus of the Al_(0.16)Ga_(0.84)N films were measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM) mode. The obtained values of the hardness and Young's modulus are 19.76 ± 0.15 GPa and 310.63 ± 9.41 GPa, respectively. The XTEM images taken in the vicinity regions just underneath the indenter tip revealed that the multiple "pop-ins" observed in the load-displacement curve during loading are due primarily to the activities of dislocation nucleation and propagation. The absence of discontinuities are in the unloading segments of load-displacement curve suggests that no pressure-induced phase transition was involved.