Synthesis of Transition Metal Epitaxial Silicides on Silicon (100), (111)
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SYNTHESIS OF TRANSITION METAL EPITAXIAL SILICIDES
ON SILICON (100), (111)
V.V. Tokarev*,
V.E. Borisenko**,
and T.M.
Pyatkova***
*Institute of Solid State and Semiconductor Physics, the BSSR Academy of Sciences, P. Browka 17, 220726 Minsk, USSR
**Minsk Radioengineering Institute, P. Browka 6, 220600 Minsk, USSR ***the Ural Polytechnical Institute, 620002 Sverdlovsk, USSR
1. INTRODUCTION Epitaxial silicide growth is of great interest to many researchers and process engineers working in the field of microelectronics. The interest towards epitaxial silicides is due,
firstly to the fact that these structures are suitable for
systematic investigation of physics of a metal-semiconductor interface, and secondly that epitaxial intermetallic structures on silicon allow development of new devices such as threedimensional ones. At present, however, one can successfully form layers with epitaxial structure with thickness of no more than 150 nm using solid-state reaction in the metal layersilicon substrate system. Such values satisfy researchers dealing with problems of epitaxial growth because main processes occur in the range of 10-20 lj]lFrom a technological point of view, however, it is desirable to form layers with thickness up to 1 pm.
2. EXPERIMENTAL Polished phosphorus-doped,
20 Ohm cm,
(100) and
(111)
si-
licon wafers were used as original substrates. Thin cobalt and nickel films were deposited using elpctron-beam evaporation in 0 vacuum at residual pressure of 5xlO -Torr. They had thickness between 60 and 100 nm. The prepared structures were implanted with 50-150 keV argon ions having penetration depth of 0.25, 0.65 and 1.0 of film thickness. Integrated current was 300jAA and beam size wag 1 cm . Implantation doses were in the range of 1E15-5E16 cm-'. The temperature of the samples during implantation was kept at 70 0 C. Implanted and unimplanted samples were subjected to rapid thermal annealing (RTA) in vacuum at residual pressure of 6xlO-Torr. The exposure time was 10-40 s and radiation powers from halogen lamps provided induced temperature variation in the range of 450-1050 0 C and the temperature was determined with accuracy of 5 0 C. 3.
RESULTS AND DISCUSSION
Nickel and silicon layer interactions stimulated by argon implantation and pulse heat treatment were analysed using four-point measurements of sheet resistance, x-ray diffraction, and Rutherford backscattering of 1 MeV H+ and He+ ions. The structure of silicide layers was determined using channeling and shade effects during interaction of energetic ions with solid atoms and Auger electron spectroscopy. Electrophysical and phase properties of synthesized siliMat. Res. Soc. Symp. Proc. Vol. 128.
1989 Materials Research Society
660
cides are treated below. Fig. 1 and 2 show anneal temperature dependence of sheet resistance and reflection intensities for Ni-Si and Co-Si systems.
ON5i ,I iSi 2 -Vf
2P-Co-S&
50
-Z
M
CCoSL'-
- Vu o COaS LICoS •LZ
0
400
6_0
TrC
Fig. 1. Temperature dependence of nickel and cobalt disilicide layers (100
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