基于MEMS技术制作MOSFET压力传感器研究

【作者】 万灵；

【导师】 温殿忠；

【作者基本信息】 黑龙江大学 ， 微电子学与固体电子学， 2008， 硕士

【摘要】 压力传感器被广泛应用于医疗、工业过程监控、生物和航空等各个领域。据相关文献介绍,压力传感器种类繁多,其中多数都是采用硅材料制作的。扩散硅式压力传感器具有灵敏度高且可以小型化、集成化等许多优点,近些年有长足的发展。本文基于MEMS技术制作的MOSFETs压力传感器是在硅杯的方形硅膜上采用微机械加工工艺制作四个P沟道增强型场效应管(P-MOSFET),使硅膜上的四个P-MOSFETs组成惠斯通电桥。利用半导体压阻效应,令两个P-MOSFETs置于硅敏感膜的径向位置,而另外两个P-MOSFETs置于硅敏感膜的横向位置。传感器受电源激励时,对硅敏感膜施加压力,电桥中两个径向的P-MOSFETs沟道等效电阻阻值增大,两个横向P-MOSFETs沟道等效电阻阻值减小。因此使桥路失去平衡,产生端电压输出,从而实现了将力学量信号转化为与之有对应关系的电压信号。本文在综述了国内外压力传感器研究概况的基础上,阐述了MOSFETs压力传感器的结构设计、工作原理、制造工艺和该新结构传感器的计算机仿真,对实验研制的MOSFETs压力传感器I-V特性、压敏特性、温度特性进行了实验测试和静态特性分析。实验结果表明,研制的MOSFETs压力传感器灵敏度为8.9mV/100KPa,线性度为±1.651%F·S,迟滞为±0.529%F·S,重复性为±1.550%F·S,精度是2.326%F·S,零点输出的温度系数为1.32%/℃,灵敏度的温度系数为-0.33%/℃,符合设计要求。本文设计的MOSFETs压力传感器信号容易采集,测试系统简单;很好地克服了MOSFET电容式压力传感器的测试电路复杂且微小电容信号难以测量的缺点。同时,本文的MOSFETs压力传感器采用P-MOSFET沟道等效电阻做压敏电阻,代替了以往的扩散硅压敏电阻;不但增强了传感器的稳定性,降低了传感器的噪声,而且测量信号稳定,温度特性较好。基于MEMS技术制作的MOSFETs压力传感器的制作工艺与集成电路工艺相兼容,有广泛的应用前景。更多还原

【Abstract】 Pressure sensor is largely used in the fields such as medical treatment, industry process control, biology and aviation. As far as some literatures concerned, there are many types of pressure sensors, most of them are made from silicon. Silicon diffusion pressure sensor has high sensitivity and could realize miniaturization, integration and so on. So it has made great progress these years. In this paper, the pressure sensor made by MEMS technology has square silicon film with four P type MOSFETs. They make up of Wheatstone bridge. In terms of piezoresistance effect of semiconductor, the sensor has two P type equivalent channel resistances of MOSFET locate at the longitudinal orientation, and the other two locate at the transverse orientation. When the power is supplied and the pressure is applied, two longitudinal P type equivalent channel resistances of MOSFET turn to bigger, the other two become smaller. Then the bridge is out of balance, there is the voltage output, so we can change the pressure signal into the corresponding electric signal.Based on the related research of pressure sensor at home and abroad, this paper describes the structure design, work theory, fabrication process and the simulation of MOSFETs pressure sensor. During the experiment, the I-V characteristic, pressure sensitive characteristic and the temperature characteristic are tested; after that the static characteristic is analyzed. The experiment results indicate that the sensitivity of MOSFETs pressure sensor is 8.9mV/100KPa, the linearity is±1.651%F·S, the lag is±0.529%F·S, the repeatability is±1.550%F·S, the precision is2.326 % F·S, the temperature coefficient of null output is 1.32%/℃, the temperature coefficient of sensitivity is -0.33%/℃. The MOSFETs pressure sensor meets the design demand.The MOSFET pressure sensor this paper designed can easily get the useful information, and it has simple test system. It can get over the difficulties that MOSFET capacitance pressure sensor has, it avoid the complex test circuit and the trouble that tiny signal is hard to test. At the mean time, the MOSFETs pressure sensor use P-MOSFET channel as pressure sensitive resistance instead of using diffusion silicon as pressure sensitive resistance. So the stability of the sensor is enhanced, the disturbance of the sensor is minimized, the test signal is stabilized, the temperature characteristic is better. The process of MOSFETs pressure sensor based on MEMS technology is compatible with IC process, which has expensive application prospect.更多还原