Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Berkovich Nanoindentation on AlN Thin Films | Nanoscale Res Lett 2010 5 935-940 DOI s11671-010-9582-5 NANO EXPRESS Berkovich Nanoindentation on AlN Thin Films Sheng-Rui Jian Guo-Ju Chen Ting-Chun Lin Received 6 January 2010 Accepted 16 March 2010 Published online 31 March 2010 The Author s 2010. This article is published with open access at Abstract Berkovich nanoindentation-induced mechanical deformation mechanisms of AlN thin films have been investigated by using atomic force microscopy AFM and cross-sectional transmission electron microscopy XTEM techniques. AlN thin films are deposited on the metalorganic chemical-vapor deposition MOCVD derived Si-doped 2 X 1017 cm 3 GaN template by using the helicon sputtering system. The XTEM samples were prepared by means of focused ion beam FIB milling to accurately position the cross-section of the nanoindented area. The hardness and Young s modulus of AlN thin films were measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements CSM option. The obtained values of the hardness and Young s modulus are 22 and 332 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 in the unloading segments of load-displacement curve suggests that no pressure-induced phase transition was involved. Results obtained in this study may also have technological implications for estimating possible mechanical damages induced by the fabrication processes of making the AlN-based devices. Keywords AlN Nanoindentation Focused ion beam Transmission electron microscopy . Jian . Chen . Lin Department of Materials Science and Engineering I-Shou University Kaohsiung 840 Taiwan ROC e-mail srjian@ Introduction The advent and development of microsystems and nanotechnology has its .
