The aim of this paper is to analyze and evaluate the sensitivity and non-linearity of graphene piezoresistive MEMS force sensor by optimizing its geometrical parameters. In this work, important factors affecting sensitivity and non-linearity were identified such as geometrical dimensions of microcantilever, modulus of elasticity of material, shape, placement, doping concentration, and dimensions of piezoresistors. Based on the selection of factors, Taguchi optimization method was employed for finding an optimal combination of microcantilever and piezoresistor dimensions. The optimized model of force sensor was designed with the aid of obtained dimensions of microcantilever and piezoresistors. For designing and simulation, COMSOL Multiphysics® 5.3a software is used. The major findings revealed that the designed sensor possess a high sensitivity of 3.93 mV/µN in an operating range from 0 to 106 µN with 0.0092% of non-linearity. An important feature of flexibility is introduced in the sensor by incorporating the novel combination of Polydimethylsiloxane (PDMS) as a flexible substrate and graphene as a flexible piezoresistor. The originality also lies in the area of the cumulative analysis of various input factors which are listed above altogether in one platform.

本文的目的是通过优化其几何参数来分析和评估石墨烯压阻式MEMS力传感器的灵敏度和非线性。在这项工作中，确定了影响灵敏度和非线性的重要因素，例如微悬臂梁的几何尺寸、材料的弹性模量、形状、位置、掺杂浓度和压敏电阻器的尺寸。在选择因素的基础上，采用田口优化方法寻找微悬臂梁和压敏电阻器尺寸的最佳组合。借助获得的微悬臂梁和压敏电阻器的尺寸，设计了力传感器的优化模型。COMSOL Multiphysics® 5.3a 软件用于设计和仿真。主要发现表明，所设计的传感器在 0 至 106 µN 的工作范围内具有 3.93 mV/µN 的高灵敏度，非线性度为 0.0092%。通过将聚二甲基硅氧烷 (PDMS) 作为柔性基板和石墨烯作为柔性压敏电阻的新型组合，在传感器中引入了柔性的一个重要特征。独创性还在于将以上所列的各种输入因素综合在一个平台上进行累积分析。