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. 28, 2003
Filed:
Apr. 04, 2002
Applicant:
Inventors:
Assignee:
Bourns Limited, Bedford, GB;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01L 2/974 ; H01L 3/1111 ;
U.S. Cl.
CPC ...
H01L 2/974 ; H01L 3/1111 ;
Abstract
A semiconductor overvoltage protection device in the form of a four layer diode has first and third layers of a first conductivity semiconductor material, second and fourth layers of a second conductivity type semiconductor material and a first buried region of the first conductivity type in the third layer adjacent to the junction between the second and third layers. The buried region has a greater impurity concentration than the third layer. The first layer is penetrated by a plurality of dots of the second layer extending through the first layer and the first buried region lies wholly beneath the second layer and is laterally offset from the dots and the first layer.