Browse Prior Art Database

CMOS Junction Construction Process

IP.com Disclosure Number: IPCOM000038679D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Davari, BB: AUTHOR [+2]

Abstract

This article relates generally to integrated circuit devices and, more particularly, to a process for constructing source/drain junctions in CMOS technology. Shallow source/drain junctions in submicron device technology can be readily constructed having low resistance by using selective tungsten deposition. Referring to Fig. 1, after the active device area is defined by processes such as trench or silo formation, gate oxide layer 1 is grown on substrate 2 over the entire source/drain area and channel implantation 3 performed. Gate material 4 of tungsten or tungsten silicide is deposited on oxide layer 1 followed by nitride layer 5. The gate is patterned, and the source/drain reoxidized, if necessary. In Fig. 2, nitride is deposited and selectively removed by reactive ion etching to form sidewalls 6.

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CMOS Junction Construction Process

This article relates generally to integrated circuit devices and, more particularly, to a process for constructing source/drain junctions in CMOS technology. Shallow source/drain junctions in submicron device technology can be readily constructed having low resistance by using selective tungsten deposition. Referring to Fig. 1, after the active device area is defined by processes such as trench or silo formation, gate oxide layer 1 is grown on substrate 2 over the entire source/drain area and channel implantation 3 performed. Gate material 4 of tungsten or tungsten silicide is deposited on oxide layer 1 followed by nitride layer 5. The gate is patterned, and the source/drain reoxidized, if necessary. In Fig. 2, nitride is deposited and selectively removed by reactive ion etching to form sidewalls 6. Source/drain oxide 1 is etched to expose the implanted silicon and tungsten 7 is selectively deposited on the bare silicon by chemical vapor deposition. Tungsten does not form on silicon dioxide or silicon nitride at the top and sidewalls of gate 4. Source and drain are formed by either diffusion or ion implantation. When using diffusion, undoped polysilicon 8 is deposited, as in

(Image Omitted)

Fig. 3. P-channel regions 9 are implanted with boron and the n-channel regions 10 with phosphorus or arsenic through photoresist 11 or a combination of photoresist and aluminum lift-off masks. The dopants are easily diffused through the tungs...