Abstract: A SOI integrated circuit includes a plurality of islands of single crystalline silicon on a surface of a substrate of an insulating material. Each of the silicon islands contains an electrical component, such as a MOS transistor. A layer of silicon oxide is on the surface of the substrate between the islands and is slightly spaced, at least about 0.1 micrometers, from each of the silicon islands. A line of a conductive material, such as conductive polycrystalline silicon, extends over the silicon islands and between the silicon islands over the silicon oxide layer. The silicon oxide layer isolates the conductive line from the substrate so that any photocurrent generated in the substrate as a result of the integrated circuit being exposed to radiation will not flow through the conductive line to disrupt the circuit.

Abstract: An SOS integrated circuit includes a plurality of spaced islands of single-crystalline silicon on a surface of a sapphire substrate. A conformal layer of silicon oxide is on the surface of the sapphire substrate between the islands and extends along a portion of the side surfaces of the islands. A layer of polycrystalline silicon is over the silicon oxide layer and extends over the side surface and at least a portion of the top surface of the islands. A separate field-effect transistor is on each island and includes source and drain regions spaced by a channel region and a channel dielectric layer over the channel region. The polycrystalline silicon layer may extend over the channel dielectric to serve as the gate of the transistor. The method of making the circuit includes depositing the silicon oxide layer over the sapphire substrate surface and the islands, and applying a layer of a negative photoresist over the silicon oxide layer.

Abstract: A process for forming a silicon-on-sapphire integrated circuit comprises forming a layer of a conformal dielectric material, such as silicon dioxide, over a sapphire substrate having at least one island of silicon on a major surface thereof; forming a layer of a planarizing material over the dielectric layer, anisotropically etching the planarizing material for a time sufficient to expose the surface of the dielectric layer overlying the island; etching the dielectric layer for a time sufficient to expose at least the top surface of the island; removing the remaining planarizing material, growing a thin layer of gate oxide on the exposed surface of the island and providing a patterned layer of conductive polycrystalline silicon thereover. The etching of the dielectric layer can be continued to at least partially expose the sidewall surface of the islands.

Abstract: A method of forming a resistor comprises forming a conducting layer on a substrate. An area of the layer is removed such as by etching. A resistor portion is formed in the area. The conducting layer including the resistor portion can be p-Si. The substrate can comprise an insulator such as Al.sub.2 O.sub.3 and a barrier layer can be formed on the substrate to achieve improved radiation hardening.