Abstract: An integrated circuit device comprises a layer of semiconductor material on an insulating substrate. At least two spaced-apart circuit components, such as field-effect transistors, are formed in the layer of semiconductor material. The circuit components are electrically isolated from each other by a method of (1) forming a layer of insulating material over the layer of semiconductor material and between the circuit components, (2) forming a layer of electrically conductive material over the layer of insulating material, and (3) providing bias means between the layer of conductive material and the layer of semiconductor material so as to deplete completely a region in the layer of semiconductor material opposite to the layer of conductive material and between the circuit components.

Abstract: The breakdown voltage of a novel insulated gate field effect transistor (IGFET), comprising silicon on sapphire (SOS), is substantially doubled by a novel structure wherein a dielectric layer, formed over a channel region of the IGFET, also extends continuously over the surface of the sapphire on opposite sides of the channel region. A polysilicon gate electrode is disposed over the dielectric layer, the gate electrode extending beyond the channel region and being separated from the sapphire substrate by the dielectric layer. The novel method of making the IGFET comprises providing an island of epitaxially deposited doped silicon on the sapphire substrate, and dielectric layer extending continuously over both the island and over portions of the substrate on opposite sides of the island.