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:
Nov. 29, 1994
Filed:
Dec. 06, 1993
Prashant Kenkare, Austin, TX (US);
James R Pfiester, Austin, TX (US);
Shih-Wei Sun, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
Dual field oxide isolation (34 & 42) is formed by oxidizing through a portion (44) of a silicon nitride layer (30), through an exposed portion (43) of a remaining portion (18) of a masking layer (16), and through an exposed portion (42) of a buffer layer (28), all of which overlie isolation regions (22) of the silicon substrate (12). The different portions vary the diffusion rate of oxygen so that different field oxide thicknesses are created in a single field oxidation cycle. Therefore, integrated circuits having both low voltage densely packed devices and high voltage devices can be fabricated on the same circuit.