Patent ID: 8413507

Claim:
A semiconductor dynamic quantity sensor comprising: a substrate having a thickness direction and a planar direction perpendicular to the thickness direction, the substrate comprising: a monocrystalline silicon semiconductor substrate having a main surface, the main surface including a recess and a projection adjacent to the recess, the projection being trapezoidal or triangular in cross section; an insulation layer on a main surface of the semiconductor substrate and defining a first through hole extending in the thickness direction and communicating the recess of the semiconductor substrate, and a P-type silicon semiconductor layer on a surface of the insulation layer, the semiconductor layer defining a second through hole extending in the thickness direction, the second through hole communicating with the first through hole and dividing the semiconductor layer into a movable portion that is configured to move upon application of a dynamic quantity, wherein the main surface of the semiconductor substrate is different from a (111) plane, an impurity concentration of the P-type semiconductor layer is greater than an impurity concentration of the semiconductor substrate, a tip of the projection of the semiconductor substrate is located directly below the movable portion and spaced from the movable portion by a predetermined distance in the thickness direction, a width of the tip of the projection is less than a width of the movable portion in the planar direction, and the distance between the tip of the projection and the movable portion is equal to a thickness of the insulation layer.