Patent ID: 7859017

Claim:
A normally-off field-effect semiconductor device utilizing a two-dimensional carrier gas layer created by a heterojunction, comprising: (a) a first semiconductor layer of a first semiconducting material, the first semiconductor layer comprising a first and a second flat-surfaced section and, therebetween, a slant-surfaced section; (b) a second semiconductor layer formed on the first semiconductor layer by epitaxially growing a second semiconducting material thereon, the second semiconductor layer having a first and a second flat-surfaced section and, therebetween, a slant-surfaced section, the first and the second flat-surfaced section of the second semiconductor layer being sufficiently thick to normally generate two-dimensional carrier gas layers due to heterojunctions thereof with the first and the second flat-surfaced section of the first semiconductor layer, at least part of the slant-surfaced section of the second semiconductor layer being thinner than the first and the second flat-surfaced section of the second semiconductor layer and being too thin to normally generate a two-dimensional carrier gas layer due to a heterojunction thereof with the slant-surfaced section of the first semiconductor layer; (c) a first major electrode electrically coupled to the two-dimensional carrier gas layer due to the heterojunction between the first flat-surfaced sections of the first and the second semiconductor layer; (d) a second major electrode electrically coupled to the two-dimensional carrier gas layer due to the heterojunction between the second flat-surfaced sections of the first and the second semiconductor layer; and (e) gating means on the slant-surfaced section of the second semiconductor layer for control of conduction between the first and the second major electrode.