Single Crystal SiC Capacitive pressure sensor design and analysis using MEMS Pro L-Edit and Samcef Field & Oofelie software

Abstract

Single crystal 3C-SiC capacitive pressure sensors are proposed for high-temperature sensing applications. SiC is an attractive material for harsh environment micromachined transducers due to its outstanding electrical, mechanical and chemical properties. The prototype device consists of an edge-clamped circular SiC diaphragm with a radius of 400 μm and a thickness of 0.5 μm suspended over a 2 μm sealed cavity on a silicon substrate. The fabricated sensor demonstrates a high temperature sensing capability up to 400oC, limited by the test setup. At 400oC, the device achieves a linear characteristic response between 1100 Torr and 1760 Torr with a sensitivity of 7.7 fF/Torr, a linearity of 2.1 %, a hysterisis of 3.7 %, and a sensing resolution of 9.1 Torr (12 mbar).