Patent attributes
A pressure sensor die especially suitable for high-temperature, high-pressure operating environment and delivering accurate and reliable pressure measurement at low cost. A single crystalline silicon includes a cap, a substrate and a base connected together. A recess formed on the cap creates an upper sealed cavity with the substrate. A silicon oxide layer is formed between the substrate and the cap. A recess formed on the base creates a lower sealed cavity with the substrate. The upper sealed cavity and the lower sealed cavity overlap in their projections. The substrate includes at least two sets of piezoresistive sensing elements located within the overlapping projections, perpendicular to each other, and oriented in different crystallographic directions.
