A high temperature pressure sensor prepared by selective deposition of cubic silicon carbide on SOI substrates

Abstract

A high temperature pressure sensor with 3C–SiC piezoresistors as sensing elements was prepared. For the first time the sensing elements were structured by selective deposition of 3C–SiC on a patterned Si/SiO 2 surface. To ensure dielectric isolation SOI substrates were used. The effectiveness of the selective deposition process is demonstrated by REM-photographs. Characterisation of the sensing elements shows the good crystal quality of the sensing elements as indicated by the gauge factor of −18 at room temperature which decreases to −10 at 200°C. As a benefit of the deep dry etching process the related sensitivity is 3.5 mV/V bar at room temperature decreasing to 2.1 mV/V bar at 200°C for a 100-μm thick circular center boss diaphragm.