MEMS Capacitance Diaphragm Gauge With Two Sealed Reference Cavities

A capacitance diaphragm gauge based on a glass-silicon-glass structure was designed to possessed two sealed reference cavities. Square pressure-sensing diaphragm with four corners chamfered was used as the sensitive element, and non-evaporation getter film was utilized to maintain the vacuum pressure in the reference cavities. The gauge with the size of 13×8×1.4 mm³ was manufactured by micromachining technology and its performance was studied systematically. Measurement rang, sensitivity and long-term stability of the gauge were tested and analyzed. The experimental results indicated that the gauge had an operating range of 1 to 8.5×10⁵ Pa, and it can be used to measure accurate vacuum pressure ranging from 1 to 1000 Pa with a high sensitivity. Moreover, the long-term tests demonstrated that the gauge was stable enough for absolute vacuum pressure measurement.