| 摘要 |
A pressure sensor includes a SOI substrate that includes a Si substrate, a SiO2 layer, and a surface Si film. An opening portion is formed in the Si substrate through etching, and a displacement portion having a membrane structure is defined by the surface Si film and the SiO2 layer in this area. A piezoresistive element is provided in the displacement portion. The displacement portion bends in response to a pressure to be detected and a resistance value of the piezoresistive element changes in response thereto. A thickness of the membrane-structure displacement portion is not less than about 1 μm and not greater than about 10 μm, and a depth of a peak of an impurity concentration of the piezoresistive element is greater than about 0.5 μm and at a position less than about ½ of the depth of the thickness of the displacement portion. |
