semiconductor pressure transducers with single crystal silicon membrane, and strain gauges and manufacturing process to result

摘要

A semiconductor pressure sensor (10) utilizes single-crystal silicon piezoresistive gage elements (18) dielectrically isolated by silicon oxide (17) from other such elements, and utilizes an etched silicon substrate with an etch stop (16). P-type implants form p-type piezoresistive gage elements (18) and form p+ interconnections (20) to connect the sensor to external electrical devices. The diaphragm (14) is made from epitaxially-grown single-crystal silicon. Passivation nitride (22) can be used for additional dielectric isolation. One practice of the invention provides over-range cavity protection, and thus increased robustness, by forming an over-range stop for the diaphragm (14) through localized oxygen ion implantation and etching. IMAGE