A Novel Combined Pressure/Temperature Microsensor

A novel microsensor combining piezoresistive and thermal resistive components is designed and fabricated. A 50mum thick silicon diaphragm (500mumtimes500mum) is used, thicker than that of the conventional piezoresistive pressure sensor, which extends the high stress distribution in the bulk silicon, and increases the operating range as well as the burst pressure. Novel meander shape piezoresistors are designed with optimized structure parameters, parts of which are fabricated on the high stress bulk silicon to obtain high sensitivity. Effects of different fabrication parameters on bulk silicon thermistor performances are compared, and the same implantation process with piezoresistors is chosen. Good temperature linearity and sensitivity are obtained, and the fabrication is simplified. The whole fabrication is low-cost and compatible with standard IC process, which tolerates large process variations. Primary measured results are presented