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:
May. 23, 1989
Filed:
Sep. 14, 1988
George H Thompson, Sawbridgeworth, GB;
ITT Gallium Arsenide Technology Center, a Division of ITT Corporation, Roanoke, VA (US);
Abstract
A photo-detector in the form of an optical field effect transistor comprig a semi-insulating InP substrate (1), a p.sup.+InP gate region ( 2) an n.sup.- InGaAs channel region (3) and source and drain contacts (5,6). Light incident on the bottom face of the substrate is detected. The channel region is thicker and reduced in doping in comparison with a normal JFET in order to achieve efficient light absorption and low gate to source capacitance. The source and drain contacts are interdigitated to increase the area for optical absorption (FIG. 1). Alternatively, (FIG. 2), the channel region is a composite structure including a lowly doped layer (11) for directing photogenerated carriers to a more highly doped layer (12) (active channel layer) of reduced dimensions of reduced area and upon which strip-like source and drain contacts (9,10) are disposed. The optical FET structures proposed facilitate integration with other circuit elements.