Semiconductor pressure sensor having strain gauge and circuit portion on semiconductor substrate

摘要

A semiconductor pressure sensor includes a SOI substrate composed of first and second silicon substrates. A diaphragm portion is formed by the first silicon substrate as a bottom of a recess portion formed in the second silicon substrate. Strain gauges are formed on the diaphragm portion, and a circuit portion is formed on the first silicon substrate at a region other than the diaphragm portion. ALOCOS film for isolating the strain gauges from the circuit portion is formed on the first silicon substrate outside the outermost peripheral portion of the diaphragm portion.