Fabrication of anti-corrosive capacitive vacuum sensors with a silicon carbide/polysilicon bi-layer diaphragm and electrical through-hole connections on the opposite side

This paper reports a capacitive vacuum sensor with a bi-layer diaphragm made of silicon carbide (SiC) and polysilicon for uses in corrosive environments like etchers. The diaphragm side is completely covered with SiC to avoid corrosion, and electrical contacts are placed on the opposite side for easy packaging. This vacuum sensor design was realized with ]a sealing of the pressure reference room achieved by Au-Si eutectic bonding. In spite of incomplete sealing of the pressure reference room, the fabricated vacuum sensor was evaluated using a laser Doppler meter and an impedance analyzer.