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Title: Effects of Additive Elements on the Phase Formation and Morphological Stability of Nickel Monosilicide Films

Abstract

Alloying elements can substantially affect the formation and morphological stability of nickel monosilicide. A comprehensive study of phase formation was performed on 24 Ni alloys with varying concentrations of alloying elements. Silicide films have been used for more than 15 years to contact the source, drain and gate of state-of-the-art complementary-metal-oxide-semiconductor (CMOS) devices. In the past, the addition of alloying elements was shown to improve the transformation from the high resistivity C49 to the low resistivity C54-TiSi{sub 2} phase and to allow for the control of surface and interface roughness of CoSi{sub 2} films as well as produce significant improvements with respect to agglomeration of the films. Using simultaneous time-resolved X-ray diffraction (XRD), resistance and light scattering measurements, we follow the formation of the silicide phases in real time during rapid thermal annealing. Additions to the Ni-Si system lead to modifications in the phase formation sequence at low temperatures (metal-rich phases), to variations in the formation temperatures of NiSi and NiSi{sub 2}, and to changes in the agglomeration behavior of the films formed. Of the 24 elements studied, additions of Mo, Re, Ta and W are amongst the most efficient to retard agglomeration while elements such as Pd, Pt andmore » Rh are most efficient to retard the formation of NiSi{sub 2}.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930196
Report Number(s):
BNL-80859-2008-JA
TRN: US200822%%1225
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Microelectronic Engineering; Journal Volume: 83; Journal Issue: 39764
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; NICKEL ALLOYS; SILICON ALLOYS; MORPHOLOGY; PHASE STUDIES; MOLYBDENUM ADDITIONS; RHENIUM ADDITIONS; TANTALUM ADDITIONS; TUNGSTEN ADDITIONS; PALLADIUM ADDITIONS; PLATINUM ADDITIONS; RHODIUM ADDITIONS; national synchrotron light source

Citation Formats

Lavoie,C., Detavernier, C., Cabral, Jr. , C., d'Heurle, F., Kellock, A., Jordan-Sweet, J., and Harper, J.. Effects of Additive Elements on the Phase Formation and Morphological Stability of Nickel Monosilicide Films. United States: N. p., 2006. Web. doi:10.1016/j.mee.2006.09.006.
Lavoie,C., Detavernier, C., Cabral, Jr. , C., d'Heurle, F., Kellock, A., Jordan-Sweet, J., & Harper, J.. Effects of Additive Elements on the Phase Formation and Morphological Stability of Nickel Monosilicide Films. United States. doi:10.1016/j.mee.2006.09.006.
Lavoie,C., Detavernier, C., Cabral, Jr. , C., d'Heurle, F., Kellock, A., Jordan-Sweet, J., and Harper, J.. Sun . "Effects of Additive Elements on the Phase Formation and Morphological Stability of Nickel Monosilicide Films". United States. doi:10.1016/j.mee.2006.09.006.
@article{osti_930196,
title = {Effects of Additive Elements on the Phase Formation and Morphological Stability of Nickel Monosilicide Films},
author = {Lavoie,C. and Detavernier, C. and Cabral, Jr. , C. and d'Heurle, F. and Kellock, A. and Jordan-Sweet, J. and Harper, J.},
abstractNote = {Alloying elements can substantially affect the formation and morphological stability of nickel monosilicide. A comprehensive study of phase formation was performed on 24 Ni alloys with varying concentrations of alloying elements. Silicide films have been used for more than 15 years to contact the source, drain and gate of state-of-the-art complementary-metal-oxide-semiconductor (CMOS) devices. In the past, the addition of alloying elements was shown to improve the transformation from the high resistivity C49 to the low resistivity C54-TiSi{sub 2} phase and to allow for the control of surface and interface roughness of CoSi{sub 2} films as well as produce significant improvements with respect to agglomeration of the films. Using simultaneous time-resolved X-ray diffraction (XRD), resistance and light scattering measurements, we follow the formation of the silicide phases in real time during rapid thermal annealing. Additions to the Ni-Si system lead to modifications in the phase formation sequence at low temperatures (metal-rich phases), to variations in the formation temperatures of NiSi and NiSi{sub 2}, and to changes in the agglomeration behavior of the films formed. Of the 24 elements studied, additions of Mo, Re, Ta and W are amongst the most efficient to retard agglomeration while elements such as Pd, Pt and Rh are most efficient to retard the formation of NiSi{sub 2}.},
doi = {10.1016/j.mee.2006.09.006},
journal = {Microelectronic Engineering},
number = 39764,
volume = 83,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
  • Ultrathin Ni, Co, and Pt films, each no more than 4 nm in thickness, as well as their various combinations are employed to investigate the competing growth of epitaxial Co{sub 1-y}Ni{sub y}Si{sub 2} films against polycrystalline Pt{sub 1-z}Ni{sub z}Si. The phase formation critically affects the morphological stability of the resulting silicide films, with the epitaxial films being superior to the polycrystalline ones. Any combination of those metals improves the morphological stability with reference to their parent individual metal silicide films. When Ni, Co, and Pt are all included, the precise initial location of Pt does little to affect the final phasemore » formation in the silicide films and the epitaxial growth of Co{sub 1-x}Ni{sub x}Si{sub 2} films is always perturbed, in accordance to thermodynamics that shows a preferential formation of Pt{sub 1-z}Ni{sub z}Si over that of Co{sub 1-y}Ni{sub y}Si{sub 2}.« less
  • Lattice spacing measurements of the (211)/(202), (020)/(013), and (111)/(102) reflections were used to calculate the residual stresses in a Ni monosilicide film after cooling from its formation temperature. The ability to measure stresses in crystalline materials using x-ray diffraction requires the use of appropriate x-ray elastic constants, which link the measured strain to the stress tensor of the grains that satisfy the diffraction condition. X-ray elastic constants were calculated in the Neerfeld-Hill (NH) limit for a polycrystalline aggregate composed of orthorhombic crystals. The anisotropy in grains that possess orthorhombic elasticity introduces significant variation in the stresses determined among the threemore » sets of reflections. However, the in-plane stress calculated due to thermal expansion mismatch between NiSi and the underlying Si substrate shows a close correspondence to the average of x-ray measurements.« less
  • The formation and degradation of NiSi films has been studied when elements with a high melting point (W, Ta, and Ti) were added to pure Ni films as an alloying element. In situ techniques were used to characterize the phase stability and the morphological stability of the NiSi layers. Depending on the concentration of the alloying element, two distinct regimes could be distinguished. First, the addition of a small quantity of an alloying element (e.g., <10 vol % W) had little impact on the formation of NiSi, but significantly improved the morphological stability. In some cases, the agglomeration temperature wasmore » increased by 100 degree sign C. Second, for higher concentrations (e.g., <10 vol % W), no crystalline metal rich phases (Ni{sub x}Si{sub y}with x>y) could be observed prior to NiSi formation. Furthermore, a significant increase was observed of the apparent activation energy for NiSi formation.« less
  • The morphological stability of NiSi is investigated when 40% of Si is mixed into an as deposited 10 nm Ni film. When annealing at 3?C/s, scanning electron microscopy images and in situ sheet-resistance measurements show that NiSi agglomeration is delayed by more than 100?C. In situ x-ray diffraction reveals that NiSi grows from an unusual transient hexagonal ?-nickel-silicide phase. The significant improvement of the NiSi film's morphological stability can be related to its microstructure, with large grains and a strong texture. This peculiar microstructure is compared to the microstructure of the ?-nickel-silicide precursor by electron backscattering diffraction and pole figures.