Abstract: The integrated circuit is manufactured upside down relative to conventional silicon-on-sapphire (SOS) processing techniques for manufacturing field effect transistors. First a conductive pattern, typically of a refractory metal, is deposited and defined on an insulating substrate, such as sapphire, and then silicon transistors are formed over the conductive pattern. Using the process, a masking step, namely the contact definition mask, used in conventional SOS manufacture, is eliminated.

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.