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: IThe Microscopic Origin of Residual Stress for Flat Self-Actuating Piezoelectric Cantilevers | Lee et al. Nanoscale Res Lett 2011 6 55 http content 6 1 55 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access The Microscopic Origin of Residual Stress for Flat Self-Actuating Piezoelectric Cantilevers Jeong Hoon l_eeH Kyo Seon Hwang2t Tae Song Kim 2 Abstract In this study flat piezoelectric microcantilevers were fabricated under low-stress Pb O3 PZT film conditions. They were analyzed using the Raman spectrum and wafer curvature methods. Based on the residual stress analysis we found that a thickness of 1 pm was critical since stress relaxation starts to occur at greater thicknesses due to surface roughening. The 111 preferred orientation started to decrease when the film thickness was greater than 1 pm. The d33 value was closely related to the stress relaxation associated with the preferred orientation changes. We examined the harmonic response at different PZT cantilever lengths and obtained a tip displacement at 3 Vp-p at 1 kHz. These analyses can provide a platform for the reliable operation of piezoelectric microdevices potentially nanodevice when one needs to have simultaneous control of the residual stress and the piezoelectric properties. Introduction There is strong interest in the use of piezoelectric films applied to micro nano-electro-mechanical systems MEMS NEMS for sensing actuating and energyharvesting applications 1-3 . Among the piezoelectric materials lead zirconate titanate PZT film especially with a morphotropic phase boundary MPB is one of the most promising candidates for MEMS and NEMS applications since it has high piezoelectric coefficients high electromechanical coupling coefficients and thermal stability. Residual stress affects the piezoelectrical characteristics and reliability in films. More importantly it plays key role in the reliability of the MEMS device structure. For example in comparison with an electronic application such as ferroelectric random access .
