Patent ID: 7965017
Filing Date: 2011-06-21
Classification: H03H

Abstract:
1. A thin film piezoelectric resonator comprising: a semiconductor substrate; an insulating layer formed on the semiconductor substrate in contact with a surface of the semiconductor substrate; and a piezoelectric resonator stack formed above the insulating layer and having a lower electrode, a piezoelectric layer and an upper electrode in this order from the insulating layer side, wherein the electrical resistivity of the semiconductor substrate is 2000 Ω·cm or more, and a fixed charge density in the insulating layer is 1×10 wherein an oscillating space is formed as an enclosed cavity in one of the semiconductor substrate and the insulating layer, the oscillating space in communication with the outside air through a hole penetrating at least the layered structure of the upper electrode, the piezoelectric layer, and the lower electrode into the oscillating space.