Capacitive dynamic quantity sensor, method for manufacturing capacitive dynamic quantity sensor, and detector including capacitive dynamic quantity sensor

摘要

A capacitive dynamic quantity sensor includes a semiconductor substrate, a weight, a movable electrode, and two fixed electrodes. The weight is movably supported by the semiconductor substrate. The movable electrode is integrated with the weight. The fixed electrodes are stationarily supported by the semiconductor substrate. The fixed electrodes face the movable electrode to provide a narrow gap and a wide gap and form a detection part having a capacitance. The weight and the movable electrode are displaced relative to the fixed electrodes in response to a dynamic quantity to be detected such that one of the gaps increases while the other decreases. The dynamic quantity is detected on the basis of the variation in the capacitance. One of wide gap electrode surfaces, which define the wide gap, is smaller than narrow gap electrode surfaces, which define the narrow gap, to improve sensor sensitivity.