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:
Jan. 22, 2008
Filed:
Dec. 15, 2004
Yutaka Nabeshima, Osaka, JP;
Yutaka Nabeshima, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In a method of manufacturing a variable capacitance diode according to the present invention, a mask is formed on a semiconductor substrate of a first conductive type having a low impurity concentration, a semiconductor region of the first conductive type having an intermediate impurity concentration is formed on the semiconductor substrate by means of ion implantation via an opening portion of the mask, a semiconductor region of a second conductive type having a high impurity concentration is formed in the semiconductor substrate on a surface side thereof relative to the semiconductor region of the first conductive type having the intermediate impurity concentration via the same opening portion of the mask, and the semiconductor region of the first conductive type having the intermediate impurity concentration and the semiconductor region of the second conductive type having the high impurity concentration are activated by applying a heat treatment to the semiconductor substrate. In a variable capacitance diode according to the present invention, a structure in which an annular contact layer of a first conductive type is formed in a periphery of a semiconductor region of a second conductive type having a high impurity concentration constitutes each of a plurality of units and the plurality of units is disposed in an array.