Patent ID: 8146426

Claim:
A physical sensor for detecting a physical quantity comprising: a substrate including a silicon layer, an oxide film and a support layer, which are stacked in this order; and a sensor portion includes a movable portion, a fixed portion and a lower electrode, wherein the movable portion and the fixed portion are disposed in the silicon layer, the movable portion includes a movable electrode, which is supported by a beam on the support layer, the fixed portion includes a fixed electrode facing the movable electrode, the lower electrode is disposed on the support layer, and the lower electrode faces the movable electrode via a space without the oxide film, wherein the physical sensor detects the physical quantity along with a first direction parallel to the substrate based on a capacitance between the movable electrode and the fixed electrode, wherein the physical sensor detects the physical quantity along with a second direction perpendicularly to the substrate based on a capacitance between the movable electrode and the lower electrode, wherein the beam includes a vertical beam displaceable along with the second direction and a horizontal beam displaceable along with the first direction, wherein the vertical beam has a thickness in the second direction, and the horizontal beam has a thickness in the second direction, and wherein the thickness of the vertical beam is smaller than the thickness of the horizontal beam.