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:
Oct. 08, 1991
Filed:
Oct. 31, 1989
John M Beall, Dallas, TX (US);
Knauf Fiber Glass, GmbH, Shelbeyville, IN (US);
Abstract
A lateral varactor is fabricated with a recess structure that provides staggered punch-through points, enabling the varactor to be tuned through punch-through without significant non-linearities in either capacitance or Q. The lateral varactor (30) includes a cathode (32) and an anode (40) disposed on the surface of an active layer (12). The anode (40) includes a surface section (45), and a recess section (46) disposed within a recess area (50). This recess structure results in a greater active layer depth under the anode surface section (45) than under the anode recess section (46). As a result, as reverse-bias voltage on the anode increases, the depletion region (60) reaches punch-through under the anode recess section (46) prior to reaching punch-through under the anode surface section (45). As a result, varactor capacitance depends upon the contributions associated with each anode section and sidewall capacitance, so that the abrupt impedance changes caused by tuning the varactor through a punch-through point is reduced, and varactor tuning is made more continuous.