Patent ID: 7622760
Filing Date: 2009-11-24
Classification: H01L

Abstract:
1. A MOS type variable capacitance device, comprising: at least one first semiconductor layer constituted with a first conduction type; at least one second semiconductor layer in adjacent to the first semiconductor layer at the surface of a semiconductor substrate and constituted with a second conduction type that is different from the first conduction type; at least one first gate insulating layer disposed on the first semiconductor layer; at least one second gate insulating layer disposed on the second semiconductor layer; at least one gate layer arranged on the first gate insulating layer and the second gate insulating layer; and at least one first conduction type or at least one second conduction type source layer which is arranged adjacent to the first and second gate insulating layers, wherein the impurity concentration of the first or second semiconductor layer is lower than the impurity concentration of a source layer of an identical conduction type; when a number of the at least one gate layer is two or more, two of the gate layers are connected to each other; when a number of the at least one first conduction type or at least one second conduction type source layer is two or more, two of the first conduction type or the second conduction type source layers are connected to each other; and the gate layer and the source layer are used as electrodes.