An optimized fabrication of high yield CMOS-compatible silicon carbide capacitive pressure sensors

Abstract

Using anodic bonding, we fabricated a silicon carbide absolute capacitive pressure sensor. Low process temperature below 430°C made the whole fabrication process CMOS compatible. Choosing gold as electrodes, good bonding between gold bottom electrode and SiC layer was available, which made the testing results agree well with the finite element method (FEM) simulations, i.e. the sensor with a square sensing membrane of 200 × 200 μm ² shows a sensitivity of 0.09494 pF/bar over a pressure range of 5 bars, while the simulation result is 0.1035pF/bar. The use of gold increased the yield of devices, for its lower strain, compared to tungsten. Additionally, owing to PECVD carbon silicon and gold's excellent corrosion resistance, this device could be used in harsh environment.