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. 21, 1997
Filed:
Sep. 23, 1996
Jengping Lin, Tao-Yuan, TW;
Sun-Chieh Chien, Hsin-Chu City, TW;
United Microelectronics Corporation, Hsin-Chu City, TW;
Abstract
Device isolation is provided for a MOSFET circuit by providing channel stop regions comprising a distribution of dopants localized beneath and adjacent to corresponding field oxide regions. Channel stop regions are not formed under the channel regions of the MOSFETs and are selectively formed under the narrower field oxide regions which are most likely to provide inadequate device isolation. The channel stop regions are formed subsequent to the formation of field oxide regions, beginning by forming polysilicon spacers so that the polysilicon spacers extend over the bird's beak regions of the field oxide regions. Next, a channel stop mask having openings over selected field oxide regions is formed. Trenches are etched near the center of the exposed field oxide regions, leaving approximately 500 .ANG. of oxide on the bottom of the trench. Ions are implanted through the bottom of the trenches to form channel stop regions beneath the field oxide regions.