Mosfets With Force / Magnetic Sensor Integrated

Multi-sensor is largely used in many field for its excellet small size, light weight and power intelligent function. In this paper, the Multi-sensor made by MEMS technology has square silicon film with four parallel n type MOSFETs, which are in the stress field. 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. They make up of Wheatstone bridge.When the pressure applied, the carriers drift ratio change corresponding, two longitudinal P type equivalent channel resistances of MOSFET turn to bigger, the other two become smaller. Then there is the voltage output, which changes the pressure signal into the corresponding electric signal. Two HALL poles are placed beside the gate about scale 0.7, for single MOS Hall element, the conductive layer is the exhausted layer. When the vertical filed applied, the HALL output voltage VH is produced on the output poles. The output voltage changed as the intensity of magnetic filed changed.In this paper, the basic work theory of the MOSFETs pressure/magnetic sensor was discussed; the structure and the fabrication process of the MOSFETs pressure/magnetic sensor were discribled. In the experiment results, the I-V characteristic, temperature characteristic are tested. The experiment results indictate that the sensitivity of the pressure sensor is 11.5mV/100KPa, the magnetic sensitivity is 2.53mV/T; the pressure linearity is 1.36% F·S, the magnetic linearity is 0.02% F·S; the pressure lag is 0.68% F·S, the magnetic lag is 5.06% F·S; the pressure repeatability is 1.31% F·S, the magnetic repeatability is 1.48% F·S; the pressure precision is 3.5%F·S, the magetic precision is 1.8%F·S. The MOSFETs pressure/magnetic sensor meets the design demand.There is rarely report about the pressure/magnetic Multi-sensor abroad and internal. In this paper, the research of the pressure sensor and magnetic sensor intergrating is very meaningful in the field of the intergrating of sensors.