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Recessed Oxidation Process to Reduce Boron Concentration Around Perimeter of Active Device Regions

IP.com Disclosure Number: IPCOM000051088D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-10

Publishing Venue

IBM

Related People

Authors:
De La Moneda, FH Kotecha, HN [+details]

Abstract

Thick seki-recessed silicon dioxide 10 used to isolate MOSFETs and n+ diffusions has a p+ layer 9 implanted thereunder to obtain high thick oxide threshold voltage. This boron implantation is done at the beginning of the fabrication process and consequently is driven in by subsequent heat cycles. That portion of the boron which spreads laterally significantly increases the p-type doping concentration around the perimeter of the active device regions containing MOSFETs and n+ diffused inter-connections, as illustrated in the Fig. 1 cross-section.