12017-12-8Relevant articles and documents
Silicide formation of polycrystalline silicon by direct metal implantation
Kozicki,Robertson
, p. 878 - 881 (1989)
This paper discusses an alternative method of silicide formation on poly-Si which allows a higher degree of control than conventional polycide formation methods. The technique involves the direct implantation of high doses of transition metal ions into the poly-Si layer, followed by a transient annealing step.
Growth kinetics of Mo, W, Ti, and Co silicides formed by infrared laser heating
Lee,Wolga
, p. 684 - 690 (1990)
The growth kinetics of four metal silicides formed by infrared laser heating, MoSi2, WSi2, TiSi2, and CoSi2, were studied. Unfocused (1.4-2.5 mm radii) beams were scanned over thin metal films on Si substrates a
A comparative infrared study of H2O reactivity on Si(100)-(2×1), (2×1)-H, (1×1)-H and (3×1)-H surfaces
Ranga Rao,Wang, Zhi-Hong,Watanabe, Hidekazu,Aoyagi, Mutsumi,Urisu, Tsuneo
, p. 178 - 188 (2004)
The water adsorption on the bare and H-terminated Si(1 0 0) surfaces has been studied by the BML-IRRAS technique. It is found that H-terminated surfaces are much less reactive compared to the bare silicon surfaces. The (1×1)-H and (3×1)-H surfaces show similar and less reactivity pattern compared to the (2×1)-H surface. At higher exposures, the water reaction with coupled monohydride species provides an effective channel for oxygen insertion into the back bonds of dihydride species. It is not attributed to the H-Si-Si-H + H 2O → H-S-Si-OH + H2, which could give rise to the characteristic Si-H and Si-OH modes, respectively at 2081 and 921 cm -1. A more suitable reaction mechanism involving a metastable species, H-Si-Si-H + H2O → H2Si ? HO-Si-H (metastable) explains well the bending modes of oxygen inserted silicon dihydride species which are observed relatively strongly in the reaction of water with H-terminated Si(1 0 0) surfaces.
The growth of CoSi2 thin film in Co/W/Si(100) multilayer structures
Moshfegh,Hashemifar,Akhavan
, p. 239 - 244 (2003)
The growth of a CoSi2 thin film has been studied for the Co/W/Si(100) system. The Co film with a thickness of about 30 nm was grown over 12 nm sputtered W interlayer using the evaporation technique. The deposited multilayer structure was annealed in an N2 (80%)+H2 (20%) environment in a temperature range from 400 to 1000 °C for 60 min. The samples were characterized by X-ray diffraction (XRD), four point probe sheet resistance (RS) measurement and scanning electron microscopy (SEM). Using the deposited Co/Si(100) system as a reference point, a CoSi2 layer was formed at 800 °C with undesirable crystalline structure and the RS value of about 1.6Ω/□. Instead, for the Co/W/Si(100) system, it has been observed that CoSi2 layer grown at about 900 °C has a nearly single crystalline structure with a dominant (200) texture and the RS value of about 1.0Ω/□. The presence of a W interlayer between Co and Si causes the CoSi2 layer to be thermally stable at high temperatures (900-1000 °C).
Polycrystalline silicon/CoSi2 Schottky diode with integrated SiO2 antifuse: A nonvolatile memory cell
Herner,Mahajani,Konevecki,Kuang,Radigan,Dunton
, p. 4163 - 4165 (2003)
The development of a low-cost, field-programmable memory cell device based on CoSi2/polysilicon Schottky diodes with integrated SiO2 antifuses was discussed. An SiO2 antifuse thin film was also grown in between the polysilicon and CoSi2. The ability to grow thin, high quality SiO2 films directly on CoSi2 allowed cells to be formed using a polysilicon deposition doped with a single dopant type.
X-ray-absorption spectroscopy of CoSi2
Pong,Chang,Mayanovic,Ho,Lin,Ko,Tseng,Chen,Hiraya,Watanabe
, p. 16510 - 16515 (1996)
X-ray-absorption near-edge structure (XANES) spectra of thin-film CoSi2 were measured at the Si K edge and Co L3 edge using the total electron yield mode. The Si K-edge results for CoSi2 showed a dramatic reduction of intensity in the first broad feature accompanied by a rise in a relatively strong and sharp feature at higher binding energies when compared to XANES spectra for crystalline Si. We attribute these two features to the Si 1s photoelectron excitations to a broad Si 3p nonbonding band and a relatively narrow band of hybridized Si p-Co 3d antibonding states, respectively. Analysis of the Co L3-edge white line spectra for CoSi2 reveals the appearance of a triple structure, which can be attributed to excitations to the unoccupied Co 3d nonbonding states and hybridized antibonding Co (3d,4s)-Si p states.
Interaction of cobalt with the Si(1 0 0)2 × 1 surface studied by photoelectron spectroscopy
Gomoyunova,Pronin,Gall,Vyalikh,Molodtsov
, p. 174 - 182 (2005)
Cobalt adsorption and condensation on the Si(1 0 0)2 × 1 surface as well as solid-phase reaction of CoSi2 formation have been studied by high-resolution photoelectron spectroscopy with synchrotron radiation. We have measured the Si 2p and valence-band spectra after the Co deposition from a submonolayer coverage to 6 ML thickness and a subsequent annealing to 600 °C. Room temperature Co adsorption results in the loss of the initial surface reconstruction, and the chemisorbed Co atoms appear to be embedded into the upper layer of Si(1 0 0); however, no stable CoSi2 was observed. With further metal deposition, a discontinuous solid solution CoSi film was formed and the dissolved Si concentration decreased with the distance from the crystal surface. The formation of cobalt disilicide was found to occur in the range of 250-400 °C.
Influence of annealing ambience on the formation of cobalt silicides
Liu, Feng-Ming,Ren, Bin,Jiang, Yu-Xiong,Ye, Jian-Hui,Tian, Zhong-Qun
, p. 15 - 21 (2003)
By using two sets of Raman systems with excitation lines of 514.5 and 632.8 nm, the influence of annealing ambience was investigated on the formation of cobalt silicides. The results show that a more uniform, compact and thermal stable cobalt silicide film can be formed in the hydrogen annealing ambience than that in the Ar annealing ambience. Two characteristic bands located at 305 and 325 cm-1, which may be assigned to the CoSi and CoSi2, respectively, were found during the phase transition processes. The strong band which appeared at 325 cm-1 that can only be detected with the excitation line of 632.8 nm was found to be due to the resonant Raman effect.
Formation of CoSi2 on various polycrystalline silicon structures and its effects on thermal stability
Bae, Jong-Uk,Sohn, Dong Kyun,Park, Ji-Soo,Han, Chang Hee,Park, Jin Won
, p. 1551 - 1554 (2000)
We have investigated formation of CoSi2 on various grain sizes of polycrystalline Si (poly-Si) with emphasis on its thermal stability. As the grain size of poly-Si decreases, CoSi2 phase is formed at lower temperature because of the diffusion of Co atoms along grain boundaries of poly-Si during the rapid thermal annealing process. The enhanced reaction of cobalt with silicon on small-grain-sized poly-Si creates a rough CoSi2/poly-Si interface, which becomes thermally unstable. CoSi2 formed on amorphous Si showed less thermal stability than that found on medium and large grain sized poly-Si.
A combined Moessbauer and Rutherford backscattering spectroscopy analysis of the influence of nanosized cavities on CoSi2 formation
Deweerd,Moons,Verheyden,Milants,Langouche,Pattyn
, p. 3584 - 3586 (1996)
For Co in Si, the competition between CoSi2 formation and cavity trapping is studied by Rutherford backscattering and Moessbauer spectroscopy. The presence of nanosized voids hampers the formation of a buried epitaxial silicide layer in its initial phase, preventing the small CoSi2 particles from forming a bulk layer. The Moessbauer spectra show that a pre-existing silicide phase can be partially dissolved in favor of cavity trapping. In addition, channeling measurements provide qualitative information about the voids, showing that the thermal stability of the voids is much higher than for defects resulting from self-implantation.
