Abstract: A silicon capacitive pressure sensor is disclosed that has a glass dielectric material sputter-deposited onto a silicon substrate of the sensor. After deposition of the bulk dielectric material, the glass is patterned and etched to form a pair of concentric rings. An inner ring is of a circular shape, while the outer ring is of an octagonal shape. As compared to prior art dielectric spacers which are of a single ring of relatively wide thickness, the pair of concentric rings disclosed herein significantly reduce the parasitic capacitance of the glass dielectric material, thereby increasing the sensitivity of the sensor.

Abstract: A silicon capacitive pressure sensor is disclosed having a silicon substrate and a silicon diaphragm separated by a glass dielectric spacer. The substrate has an upper surface formed as a mesa which is generally curved in shape, the curvature being concave. Due to manufacturing constraints the mesa upper surface comprises a series of concentric rings that approximate the desired concave shape. The step height and diameter of the rings are such that, at full deflection of the diaphragm, the diaphragm touches the center of the mesa, but not the edges of the individual steps. That is, letting the edges or corners of the steps define a curve, the radius of curvature of the diaphragm is smaller than the radius of curvature of the locus of the step corners.

Abstract: A silicon capacitive pressure sensor is disclosed having a silicon diaphragm and a silicon substrate arranged in parallel and separated by a glass dielectric spacer. The glass is deposited onto a surface of the substrate using an ion milling machine. The sensor further includes a transition piece attached to a second layer of glass insulator disposed between the silicon diaphragm and the transition piece. The transition piece has a throughbore formed therein for applying a fluid to a surface of the silicon diaphragm, the fluid having a pressure desired to be measured by the sensor. The glass disposed between the diaphragm and the transition piece is deposited onto the transition piece using the ion milling process.