Method to form thermally stable nickel germanosilicide on SiGe

Details Method to form thermally stable nickel germanosilicide on SiGe Method to form thermally stable nickel germanosilicide on SiGe

2001-04-12

2003-01-14

Nelms, David (Department: 2818)

Semiconductor device manufacturing: process

Making field effect device having pair of active regions...

On insulating substrate or layer

C438S149000, C438S259000, C438S294000, C438S299000

Reexamination Certificate

active

06506637

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a nickel germanosilicide on SiGe integrated circuit device, and a method of making the same and, more particularly, to a thermally stable nickel germanosilicide on SiGe integrated circuit device, and a method of making the same, wherein during fabrication iridium or cobalt is added at the Ni/SiGe interface to decrease the sheet resistance of the device.
BACKGROUND OF THE INVENTION
The development of Si—Ge based integrated circuit devices has created the need for stable, low thermal budget, low resistivity metal-silicide contacts to SiGe alloys. Metal/SiGe systems based on titanium, cobalt, zirconium, nickel, palladium and platinum have been studied. However, these systems show poor phase segregation. In particular, during the thermal anneal, in the Ti/SiGe system, excess germanium combines with silicon and nucleates as SiGe precipitates along the grain boundaries. In the Co/SiGe system, excess Ge diffuses to the grain boundary to form Ge-enriched clusters. Due to this multi-phase formation, application of these materials to devices with small feature sizes is difficult unless a silicon buffer layer is used.
Recently, nickel has been applied to poly-silicon germanium (poly-SiGe) to form nickel germanosilicide poly-silicon germanium (Ni(Si
x
Ge
1-x
)/poly-Si
0.8
Ge
0.2
) gate structures without a polysilicon buffer layer. Use of this structure has been demonstrated to result in a ten percent increase of the saturated drain current (Idsat) in 0.15 &mgr;m pMOSFET. However, the thermal stability of this nickel germanosilicide is very poor. A sharp increase in the sheet resistance is observed at about 600° C. Accordingly, there is a need to improve the thermal stability of nickel germanosilicides.
SUMMARY OF THE INVENTION
The system of the present invention provides a thermally stable nickel germanosilicide on SiGe integrated circuit device, and a method of making the same, wherein during fabrication iridium or cobalt is added at the Ni/SiGe interface to decrease the sheet resistance of the device. The device comprising nickel silicide with iridium on SiGe shows thermal stability at temperatures up to 800° C. The device comprising nickel silicide with cobalt on SiGe shows a decrease in the sheet resistance with temperature, i.e., the resistance remains low when annealing temperatures extend up to and beyond 800° C.
Accordingly, an object of the invention is to provide a thermally stable nickel germanosilicide on SiGe integrated circuit device, and a method of making the same.
Another object of the invention is to provide a thermally stable nickel germanosilicide on SiGe integrated circuit device, and a method of making the same, wherein during fabrication iridium or cobalt is added at the Ni/SiGe interface.
Still another object of the invention is to provide a thermally stable nickel germanosilicide on SiGe integrated circuit device that has a low sheet resistance at temperatures up to 800° C. or more.


REFERENCES:
patent: 6214679 (2001-04-01), Murthy et al.
patent: 6225197 (2001-05-01), Maekawa
Donaton, R. A., Co Silicide Formation on SiGeC/Si and SiGe/Si Layers, Appl. Phys. Lett. 70, 1997, 1266.
Goeller, P.T., Co-deposition of Cobalt Disilicide on Silicon-Germanium Thin Films, Thin Solid Films, 320, 1998, 206.
Wang, Z., Silicide Formaton and Stability of Ti/SiGe and Co/SiGe, Thin Solid Films, 270, 1995, 555.
Wang, Z., EXAFS and XRD Studies of Phase Formations of Co in Reactions With Si-Ge Alloys, Physica B, 208 & 209, 1995, 567.
Goeller, P.T., Structure and Stability of Cobalt-Silicon-Germanium Thin Films, Nuclear Instruments and Methods in Physics Research, 133, 1997, 84.
Aldrich, D.B., Stability of C54 Titanium Germanosilicide on a Silicon-Germanium Alloy Substrate, J. Appl. Phys., 77, 1995, 5107.
Ku, J., High Performance pMOSFETs with Ni(SixGe1-x)/Poly-Si0.8Ge0.2Gate, 2000 Symposium on VLSI Technology Digest of Technical Papers, 2000.

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