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:
Mar. 07, 2000
Filed:
Jul. 28, 1999
Chen-Bin Lin, Taipei, TW;
Feng-Ming Liu, Feng-Shan, TW;
James Ho, Taichung, TW;
Yu-Ju Liu, Hsinchu, TW;
Abstract
A process for fabricating a mixed signal integrated circuit on a substrate, wherein the substrate is partially covered with a field oxide layer. An oxide layer is formed over a portion of the substrate, wherein the portion of the substrate is not covered with the field oxide layer. First impurities are implanted into the substrate, wherein the first impurities damage the oxide layer. A buffer layer is formed over the oxide layer. A polysilicon layer is formed over the buffer layer. Second impurities are implanted into the polysilicon layer, wherein the buffer layer prevents the oxide layer form being damaged by the second impurities. The polysilicon layer is etched to remove the polysilicon layer, wherein the buffer layer prevents the oxide layer and the substrate from being etched. The portion of buffer layer and the damaged oxide layer over the substrate are removed. The gate oxide layer is formed over the substrate.