Effect of electrostatic bonding on the characteristics of silicon diaphragm pressure transducer

Abstract

The effect of electrostatic bonding on the resistance and its temperature coefficient of the polysilicon highly doped piezoresistors is considered. The resistors are on the surface of anisotropically etched silicon diaphragms of different thickness. It is shown that changes of the resistance and temperature coefficient of the resistance cannot be accounted for solely by the mechanical stresses/strains at the silicon-glass interface. The residual thermo-mechanical stresses at the silicon-silicon thermal oxide interface are, probably, an issue. The effects of bonding on the R and TCR decreases as the thickness of diaphragm is increased.