Browse Prior Art Database

Field-Implant Spacer for Isolation Devices

IP.com Disclosure Number: IPCOM000044099D
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Warren, MJ: AUTHOR

Abstract

A chemical vapor deposition (CVD) spacer is designed to keep the field boron implant under the thick oxide of the isolation device, and away from the thin oxide taper and active region of the integrated circuit. This effect will enhance the transconductance of narrow devices as well as decrease several device-degrading perimeter capacitances. The traditional recessed oxide (ROX) structure (Fig. 1) is improved by introducing a spacer for the implant. This method is described as follows (Fig. 2). Before the photoresist patterning of the ROX level, a 4000 A CVD oxide 11 is deposited on the silicon nitride 12. The photoresist is then patterned in the standard fashion. Next, the CVD oxide 11 is directionally etched and then the nitride 12 is etched in the standard fashion along with the pad oxide 13.

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Field-Implant Spacer for Isolation Devices

A chemical vapor deposition (CVD) spacer is designed to keep the field boron implant under the thick oxide of the isolation device, and away from the thin oxide taper and active region of the integrated circuit. This effect will enhance the transconductance of narrow devices as well as decrease several device- degrading perimeter capacitances. The traditional recessed oxide (ROX) structure (Fig. 1) is improved by introducing a spacer for the implant. This method is described as follows (Fig. 2). Before the photoresist patterning of the ROX level, a 4000 A CVD oxide 11 is deposited on the silicon nitride 12. The photoresist is then patterned in the standard fashion. Next, the CVD oxide 11 is directionally etched and then the nitride 12 is etched in the standard fashion along with the pad oxide 13. A 3000 A CVD oxide 14 is added, and the field implant is done at an increased energy to penetrate the 3000 A CVD oxide 14. The entire 7000 A CVD oxide stack 11, 14 is wet etched, and the process proceeds in the standard fashion.

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