SEMICONDUCTOR PRESSURE SENSOR AND ITS FABRICATION METHOD

A semiconductor pressure sensor comprises a silicon support substrate (1), an insulating layer (2) formed on the silicon support substrate (1), and a silicon thin plate (3) formed on the insulating layer (2). A through-hole (1a) extending in the thickness direction of the silicon support substrate (1) is formed in the silicon support substrate (1). The silicon thin plate (3) located on an extension of the through-hole (1a) functions as a diaphragm (23) that is deformed by an external pressure. The insulating layer (2) remains over the entire lower surface of the diaphragm (23). The thickness of the insulating layer (2) decreases from the peripheral portion toward the central portion of the diaphragm (23). This provides the semiconductor pressure sensor capable of reducing both the offset voltage and the variation of output voltage caused by the variation of temperature and its fabrication method.