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. 25, 1993
Filed:
Sep. 17, 1990
Earl D Fuchs, Phoenix, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An improved method and structure for high voltage semiconductor devices capable of blocking voltages of the order of 1000 volts and greater is described. In a preferred embodiment, a blanket P layer is formed in an N.sup.- epi-layer on an N.sup.+ substrate. An annular groove is etched through the blanket P layer into the N.sup.- epi-layer. The bottom of the groove is doped N.sup.+ using the same mask as for the first groove etch. A second groove is formed inside of and partly overlapping the first groove and extending to a greater depth than the first groove, but not through the epi-layer. The second groove is filled with passivating material, metal electrodes are applied to the P.sup.+ region and the N.sup.+ substrate, and the devices separated at the N.sup.+ region lying outside the second groove in the bottom of the first groove. Excellent high voltage blocking characteristics are obtained with the same or fewer process steps and better yield.