Micro-machined accelerometer with composite material springs

摘要

A transducer fabricated by micro-machining includes E-shaped leaf springs suspending a mass from a support. The transducer is formed by chemical etching through openings of opposite faces of a silicon wafer on which etch stop layer patterns are diffused. Sense and force conductive patterns are diffused onto opposite faces of the suspended mass. The legs of the E-shaped leaf springs are formed of a composite of a polysilicon base layer, a silicon dioxide insulating layer and a gold conducting layer. The thickness of such layers are selected to minimize bowing effects of the spring legs due to materials of different coefficients of thermal expansion. The spring-mass-support structure is sandwiched between opposite plates having corresponding force and conductive patterns which face such patterns on the suspended mass.