A novel PRC signal drift reduction method for new developed SEM-based nanoindentation/nanoscratch instrument integrated with AFM

• DOI: 10.1016/j.precisioneng.2020.12.021
• Publication Date: 2021-01-04T07:27:23Z
• Authors: Sen Gu; Miao Hao; Peng Pan; Xin Li; Junhui Zhu; Yong Wang; Changhai Ru
• Keywords: Piezoresistive effect; SIGNAL (programming language); Nanomechanics

Abstract In-situ SEM nanoindentation and nanoscratch testing methods are commonly used for mechanical characterization and investigation of the deformation and failure mechanisms of coating materials with micro-to nano-scale thicknesses. However, existing SEM-based integrated nanoindentation and nanoscratch instruments have two main limitations. First, the measured mechanical properties of the coating materials at micro-to nano-scale thicknesses are highly sensitive to surface roughness. Second, the existing SEM-based instruments lack the capability to acquire the morphology of residual imprints in real-time after nanoindentation and nanoscratching. In this study, a novel SEM-based integrated nanoindentation, nanoscratch, and atomic force microscopy (AFM) instrument, namely, NMT-AFM was proposed, developed and fabricated. The self-sensing piezoresistive cantilever (PRC) was selected as the AFM force sensor owing to its miniaturization ability. However, the resistance of the PRC sensor fluctuated because of the electron irradiation from SEM, resulting in the continuous drift of the PRC signal during SEM imaging. To overcome this limitation, a mechanism of PRC signal drift inside SEM was analyzed for the first time, and a PRC signal drift reduction method was proposed based on the mechanism analysis. The experimental results indicated that the PRC signal drift was reduced to 2 nm in 2 min by applied external voltage value UA of 30 V to modified PRC, which proved the proposed mechanism of PRC signal drift during SEM imaging. Finally, the X–Y fine nanopositioner angle calibration test using AFM calibration chip VGRP-UM and the nanoindentation/nanoscratch characterizations of the TiAlSiN coating material were conducted.