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:
Dec. 14, 2004
Filed:
Jul. 17, 2002
Kozo Kinoshita, Kanagawa-ken, JP;
Tetsuo Hatakeyama, Kanagawa-ken, JP;
Takashi Shinohe, Kanagawa-ken, JP;
Kabushiki Kaisha Toshiba, Tokyo, JP;
Abstract
A high withstand voltage semicnductor device does not show any significant fall of its withstand voltage if the impurity concentration of the RESURF layer of a low impurity concentration semiconductor region thereof varies from the optimal level and/or influenced by the fixed electric charge. The device is produced by forming a ring-shaped high impurity concentration edge termination layer of a second conductivity type and a ring-shaped low impurity concentration RESURF layer of the second conductivity type on the front surface of a semiconductor layer of a first conductivity type carrying electrodes respectively on the opposite surfaces thereof along the outer edge of one of the electrodes, then forming an outer ring layer with an impurity concentration substantially as low as the RESURF layer concentrically outside the RESURF layer with a gap separating therebetween and subsequently forming an inner ring layer with an impurity concentration substantially as high as the edge termination layer concentrically inside the RESURF layer.