Study on piezoresistive effect of pressure MOSFET formed by polysilicon films

The source and drain of pressure MOSFET formed by n⁺-type polysilicon film is placed over an oxide on p-type crystalline silicon were fabricated and the Piezoresistive Effect of pressure MOSFET was study. The polysilicon film layer was deposited in a plasma enhanced chemical vapor deposition system. Results shown, The new structure of pressure MOSFET can operate at higher temperature than can sensor fabricated in single-crystal silicon, and the polysilicon films deposited at 650degC, source region and drain region with doping concentration of 3.6times10²⁰ cm^-3, the best value of thickness should be around 3 mum. The results indicate that for pressure MOSFET shown high-temperature capability makes them especially attractive for automotive application.