In the present work, we report fabrication and characterization of a low-cost MEMS based piezoresistive micro-force sensor with SU-8 tip using laboratory made silicon-on-insulator (SOI) substrate. To prepare SOI wafer, silicon film (0.8 µm thick) was deposited on an oxidized silicon wafer using RF magnetron sputtering technique. The films were deposited in Argon (Ar) ambient without external substrate heating. The material characteristics of the sputtered deposited silicon film and silicon film annealed at different temperatures (400-1050°C) were studied using atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The residual stress of the films was measured as a function of annealing temperature. The stress of the as-deposited films was observed to be compressive and annealing the film above 1050°C resulted in a tensile stress. The stress of the film decreased gradually with increase in annealing temperature. The fabricated cantilevers were 130 µm in length, 40 µm wide and 1.0 µm thick. A series of force-displacement curves were obtained using fabricated microcantilever with commercial AFM setup and the data were analyzed to get the spring constant and the sensitivity of the fabricated microcantilever. The measured spring constant and sensitivity of the sensor was 0.1488N/m and 2.7mV/N. The microcantilever force sensor was integrated with an electronic module that detects the change in resistance of the sensor with respect to the applied force and displays it on the computer screen.

中文翻译：

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基于MEMS的低成本压阻微悬臂力传感器和传感器模块

在目前的工作中，我们报告了使用实验室制造的绝缘体上硅 (SOI) 衬底制造和表征具有 SU-8 尖端的低成本基于 MEMS 的压阻微力传感器。为了制备 SOI 晶片，使用射频磁控溅射技术将硅膜（0.8 µm 厚）沉积在氧化硅晶片上。薄膜在没有外部基板加热的情况下在氩 (Ar) 环境中沉积。使用原子力显微镜 (AFM) 和 X 射线衍射 (XRD) 技术研究了溅射沉积硅膜和在不同温度 (400-1050°C) 下退火的硅膜的材料特性。测量薄膜的残余应力作为退火温度的函数。观察到沉积后薄膜的应力是压缩的，在 1050°C 以上对薄膜进行退火会产生拉伸应力。随着退火温度的升高，薄膜的应力逐渐降低。制造的悬臂长 130 µm，宽 40 µm，厚 1.0 µm。使用具有商业 AFM 设置的制造微悬臂梁获得一系列力-位移曲线，并分析数据以获得制造的微悬臂梁的弹簧常数和灵敏度。测得的传感器弹簧常数和灵敏度分别为 0.1488N/m 和 2.7mV/N。微悬臂力传感器与一个电子模块集成在一起，该模块检测传感器相对于施加的力的电阻变化，并将其显示在计算机屏幕上。使用具有商业 AFM 设置的制造微悬臂梁获得一系列力-位移曲线，并分析数据以获得制造的微悬臂梁的弹簧常数和灵敏度。测得的传感器弹簧常数和灵敏度分别为 0.1488N/m 和 2.7mV/N。微悬臂力传感器与一个电子模块集成在一起，该模块检测传感器相对于施加的力的电阻变化，并将其显示在计算机屏幕上。使用具有商业 AFM 设置的制造微悬臂梁获得一系列力-位移曲线，并分析数据以获得制造的微悬臂梁的弹簧常数和灵敏度。测得的传感器弹簧常数和灵敏度分别为 0.1488N/m 和 2.7mV/N。微悬臂力传感器与一个电子模块集成在一起，该模块检测传感器相对于施加的力的电阻变化，并将其显示在计算机屏幕上。