Abstract: An angular rate sensor made from a structural wafer of single crystal silicon has a pair of proof masses lying in an X-Y plane and supported by a circular frame. The masses are driven into oscillation in the X-direction using an interdigitated comb drive. Rotation of the sensor about the Z-axis induces Coriolis forces which cause the frame to rotate, the rotation of the frame being indicative of the angular rate of the sensor. A parallel plate sensor located outside of the circular frame senses rotation of the frame.

Abstract: A silicon monolithic miniature intra-ocular pressure sensing probe utilizes pressure sensing piezoresistors attached to a silicon pressure sensing membrane which is directly exposed to the irrigating fluid used during an eye operation, for example. From a silicon fabrication point of view, this is a micro electromechanical (MEM) device and the integration of the piezoresistive pressure sensor directly into the cannula which is inserted into the eye is partially made possible by providing p++ etch stops to gain access for electrical connection to the piezoresistive elements arranged in a Wheatstone bridge configuration. The silicon sensing membrane forms a smooth surface to avoid turbulence and is close to the eye to minimize error.

Abstract: Methods for surface micro-machining silicon wafers, including coating cavity sidewalls with oxidation-resistant material to prevent lateral oxidation. This in turn prevents "bird's beak" during formation of a diaphragm. The methods are useful for, among other things, the manufacture of absolute-type pressure sensors. Along with bulk micro-machining techniques, the methods can be used to produce gauge- and differential-type pressure sensors, as well.