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

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, 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 degrees 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 degrees C for a 100-mu m thick circular center boss diaphragm. (C) 1999 Elsevier Science S.A. All rights reserved.