Patent ID: 7859019
Filing Date: 2010-12-28
Classification: H01L

Abstract:
1. A field-effect semiconductor device capable of normally-off operation, comprising: (a) a main semiconductor region having a major surface; (b) a source on the major surface of the main semiconductor region; (c) a drain on the major surface of the main semiconductor region spaced from the source; (d) a first insulating film on the major surface of the main semiconductor region and between the source and the drain; (e) a carrier storage layer on the first insulating film, the carrier storage layer being capable of accepting and storing electrons, the carrier storage layer being made from a conductive material selected from the group comprising electroconductive polysilicon, metal, crystalline semiconductor and organic semiconductor; (f) a second insulating film on the carrier storage layer; (g) a gate on the second insulating film; and (h) a field plate formed on the second insulating film positioned between the carrier storage layer and the drain, the field plate being electrically coupled to the gate, wherein the carrier storage layer has electrons stored therein to such an extent that the source and the drain are held electrically disconnected from each other even without application of a bias voltage to the gate wherein the main semiconductor region comprises an electron transit layer and an electron supply layer disposed on the electron transit layer for generating a two-dimensional electron gas layer as a channel between the source and the drain, wherein the electron transit layer and the electron supply layer are both made from compound semiconductors, and wherein the electron supply layer has a flat major surface.