为了测量毫克级的微小力,设计并制造了一种硅基PZT薄膜悬臂式微力传感芯片。采用溶胶-凝胶(Sol-Gel)方法在Pt/Ti/SiO2/Si衬底上成功制备了厚度不同(300-800nm)的锆钛酸铅(Pb(ZrxTi1-x)O3)薄膜,薄膜表面均匀,无裂纹。通过测试和分析,研究了PZT薄膜的制备工艺参数和压电、铁电、阻抗特性。采用微机械加工手段制作了长度为1000μm、500μm、250μm的硅基PZT薄膜微型悬臂结构。当在悬臂的自由端沿着厚度方向施加毫克级的微小力时,微型悬臂就会在厚度方向发生弯曲和振动,通过测量在压电材料表面电极上的电荷量,并通过计算可得到微型悬臂所受的集中力的大小,实现微力的测量。该文还对微力传感芯片的工作方式进行了研究,初步设计了传感器系统模型。
In order to measure the micro-forces which are in the degree of milligrams, a novel micro-force sensor based on the Si-based lead zirconate titanate(PZT) piezoelectric micro-cantilever was designed and fabricated by MEMS technique. PZT piezoelectric thin films with various thicknesses (300-800 nm) were prepared by Sol-Gel method on Pt/Ti/SiO2/Si substrates. The films were well crystallized and had single perovskite phase structure. Preparation process, piezoelectric and ferroelectrics properties were studied. Three kinds of Si-based PZT film microcantilevers were fabricated by micromaching method. The cantilevers will bend when a force in milligrams degree is applied on the surface of the cantilevers. By measuring the charge of the electrodes, the microforce can be calculated. The work principle of the microforce sensor was studied and the systemic model was designed approximately.