Patent ID: 7531880
Filing Date: 2009-05-12
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor layer on an insulating layer, the semiconductor layer surrounded by a device isolating layer; a gate insulating film on the semiconductor layer; a gate electrode having comb-like shape on the gate insulating film, the gate electrode including a base portion extending in a first direction and a plurality of tooth portions extending in a second direction from one side surface of the base portion; a diffusion layer of first conductivity type having comb-like shape in the semiconductor layer under the gate electrode, the gate insulating film sandwiched between the diffusion layer and the gate electrode; a source layer of second conductivity type and having high impurity concentration in the semiconductor layer on a tooth portion side of the base portion of the gate electrode, the second conductivity type opposite the first conductivity type; a drain layer of the second conductivity type and having high impurity concentration in the semiconductor layer on a side of the base portion of the gate electrode opposite the tooth portion side, the first and second directions respectively corresponding to a gate width direction and a gate length direction of the gate electrode; and an extraction layer of the first conductivity type in the semiconductor layer between the source layer and the device isolating layer, the extraction layer having a high impurity concentration greater than an impurity concentration of the diffusion layer and connected with the diffusion layer below the tooth portions of the gate electrode.