The patented Si-Glas technology combines the high sensitivity of a variable capacitance transducer with the repeatability of a micro machined, ultra-thin single crystal silicon diaphragm. The Ashcroft Si-Glas sensor enables precise measurement and control of very low pressure. Although the diaphragm deflects only a micron, the sensor is 100 times more sensitive to pressure than available silicon piezo-resistive pressure sensors. The Si-Glas sensor is composed of sputtered metals and glass molecularly bonded to silicon. There are no epoxies or other organics in the sensor to contribute to drift or mechanical degradation over time.