Smart Pressure Sensor on SOI optimized by Finite Element Analysis for Heatspreader Integration

摘要

In this contribution are presented the results concerning the optimization of a piezoresistive pressure sensor, integrated into a microheat-spreader entirely micromachined in silicon. The membrane limited area, imposed by the heat spreader geometry, requires the use of an ultra thin membrane. Results from FEA calculations are indicating a good sensitivity for 0.7μm membrane thickness, with a good linearity in the pressure domain of interest. The whole structure is micromachined in SOI wafers in order to provide a better sensor reproducibility across the wafer. Temperature and residual stress influences are also taken into account, a high doping level and a three-layered membrane being proposed in order to reduce the temperature dependence and the residual stress effects.