The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 14, 1992
Filed:
Sep. 23, 1991
John R Troxell, Sterling Heights, MI (US);
Marie I Harrington, Troy, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A thin film field effect transistor has an island of polysilicon on the surface of a substrate, preferably of an insulating material. A layer of silicon dioxide is on the surface of the substrate and surrounds the polysilicon island. The silicon dioxide layer is of substantially uniform thickness and contacts the edge of the polysilicon island. A gate insulator layer, preferably of silicon dioxide, of substantially uniform thickness is on the surface of the polysilicon island. A conductive gate, preferably of doped polysilicon, is on the gate insulator layer and extends across a portion of the polysilicon island. The portions of the polysilicon island at opposite sides of the gate are doped to form the source and drain of the transistor. The transistor is formed by applying a layer of polysilicon on the surface of a substrate and applying a mask over the portion of the polysilicon layer which is to form the island. The uncovered portion of the polysilicon layer is converted to silicon dioxide, such as by heating in an atmosphere containing oxygen. After removing the mask, the gate insulator layer is formed over the surface of the polysilicon island, and the gate is formed over the gate insulator.