A CMOS compatible polycrystalline silicon-germanium based piezoresistive pressure sensor

Abstract

This paper presents for the first time a piezoresistive poly-SiGe pressure sensor processed at temperatures compatible with above-CMOS integration. Despite the low processing temperature (max. 455°C), a sensitivity of 5.8mV/V/bar for a membrane of 200×200 μm ² is reached by piezoresistor design optimization. The possibility of further enhancing the piezoresistive properties of SiGe by tuning annealing time is investigated, leading to a 30% improvement in gauge factor.