Semiconductor physical quantity sensor

摘要

A semiconductor acceleration sensor, which prevents an adhesion of a movable electrode to a first or second fixed electrode due to an electrostatic attracting force generated therebetween. The sensor has a weight portion and movable electrodes formed on both sides of which, and first and second fixed electrodes each engaging with the each of the movable electrodes. Each of the first and second fixed electrodes is disposed in parallel with each of the movable electrodes so that side faces thereof determine a detection interval and non-detection interval larger than the detection interval with side faces of adjoining two of the movable electrodes. Protrusions are formed on both of the side faces of each of the first and second fixed electrodes. These protrusions prevent the movable electrodes from adhering to the first or second fixed electrode in both of the detection interval and non-detection interval.