scholarly journals Thin Ni Silicide Formation by Low Temperature-Induced Metal Atom Reaction with Ion Implanted Amorphous Silicon

1992 ◽  
Vol 279 ◽  
Author(s):  
Yu.N. Erokhin ◽  
B. K. Patnaik ◽  
S. Pramanick ◽  
F. Hong ◽  
C. W. White ◽  
...  

ABSTRACTWe have extended our recent work [1,2] on buried suicide formation by Ni diffusion into a buried amorphous silicon layer to the case where silicide formation is at lower temperatures on silicon substrates which have been preamorphized. The reaction of metal atoms from a 12 nm Ni film evaporated on top of a 65 nm thick surface amorphous layer formed by 35 keV Si+ ion implantation has been investigated at temperature ≤400 °C. Rutherford Backscattering Spectrometry (RBS) with channeling, cross-sectional transmission electron microscopy (XTEM), X-ray diffraction and four-point-probe measurements were used to determine the structure, interfacial morphology, composition and resistivity of the silicide films. It has been found that an increased rate of silicidation occurs for amorphous silicon with respect to crystalline areas permitting a selective control of the silicon area to be contacted during silicide growth. Vacuum furnace annealing at 360 °C for 8 hours followed by an additional step at 400 °C for one hour produces a continuos NiSi2 layer with a resistivity 44 μΩ cm.

1986 ◽  
Vol 70 ◽  
Author(s):  
H. E. Rhodes ◽  
G. Apai ◽  
L. Rivaud ◽  
L. S. Hung ◽  
J. W. Mayer

ABSTRACTSilicide formation by reaction of palladium metal (Pd0) with hydrogenated amorphous silicon (a-Si:H) substrates was studied with Rutherford backscattering spectrometry (RBS), forward recoil spectrometry, x-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Upon low-temperature (200° C) annealing, RBS and TEM show a single-phase Pd2Si. This phase grows with the square root of time, and the activation energy is identical to that of the corresponding metal on single-crystal silicon substrates. The growth is slightly faster for hydrogenated amorphous silicon, which is attributed to its amorphous structure. During silicide formation, the hydrogen is released from silicides and presumably outdiffuses into a vacuum without interfacial accumulation. Thus, barrier formation does not occur, and the presence of hydrogen in the substrates has no effect on silicide growth.The silicide electronic structure (core level binding energies, lineshapes, and d-band filling) of Pd2 Si on a-Si:H is identical to that of Pd2 Si formed on cr stalline silicon. Binding energy and peak shape analysis show the Pd2Si/Pd0 interface to be composed of one additional phase, Pd4Si, which has a well-defined binding energy (335.8 eV) and a narrow (FWHM = 1.1 eV), symmetric line shape. It has long been postulated that interface phases may be important in determining the phase sequence in silicide growth and the dominant diffusing species. This Pd4 Si interface phase may be important in understanding palladium silicide growth.


2004 ◽  
Vol 810 ◽  
Author(s):  
J.M. Jacques ◽  
N. Burbure ◽  
K.S. Jones ◽  
M.E. Law ◽  
L.S. Robertson ◽  
...  

ABSTRACTIn prior works, we demonstrated the phenomenon of fluorine-enhanced boron diffusion within self-amorphized silicon. Present studies address the process dependencies of low temperature boron motion within ion implanted materials utilizing a germanium amorphization. Silicon wafers were preamorphized with either 60 keV or 80 keV Ge+ at a dose of 1×1015 atoms/cm2. Subsequent 500 eV, 1×1015 atoms/cm211B+ implants, as well as 6 keV F+ implants with doses ranging from 1×1014 atoms/cm2 to 5×1015 atoms/cm2 were also done. Furnace anneals were conducted at 550°C for 10 minutes under an inert N2 ambient. Secondary Ion Mass Spectroscopy (SIMS) was utilized to characterize the occurrence of boron diffusion within amorphous silicon at room temperature, as well as during the Solid Phase Epitaxial Regrowth (SPER) process. Amorphous layer depths were verified through Cross-Sectional Transmission Electron Microscopy (XTEM) and Variable Angle Spectroscopic Ellipsometry (VASE). Boron motion within as-implanted samples is observed at fluorine concentrations greater than 1×1020 atoms/cm3. The magnitude of the boron motion scales with increasing fluorine dose and concentration. During the initial stages of SPER, boron was observed to diffuse irrespective of the co-implanted fluorine dose. Fluorine enhanced diffusion at room temperature does not appear to follow the same process as the enhanced diffusion observed during the regrowth process.


1982 ◽  
Vol 18 ◽  
Author(s):  
L. J. Chen ◽  
C. Y. Hou

As+-ion-induced silicide formation in nickel thin films on silicon was investigated by Rutherford backscattering spectrometry and transmission electron microscopy. The emphasis was on the study of ion-beam-induced microstructural changes.For 160 keV As+ implantation, amorphization of the interface occurred at a dose of 5 × 1014 cm−2. Ni2Si was found together with an amorphous layer after a 1 × 1015 cm−2 bombardment. For Ni/Si(100) the surface layer became completely amorphous after implantation to 5×1015 cm−2. Silicides were found after a 1×1016 cm−2 irradiation. The amorphous layer was not stable enough to withstand the enormous chemical driving force causing the formation of crystalline silicides as the composition ratio Nsi/NNi reached a critical value. A similar trend for ion-beam-induced reactions was found for 190 keV As+ implantation on Ni/Si(111) as for 160 keV implantation.The results of post-implantation annealing showed major differences from those obtained for directly annealed samples.


1989 ◽  
Vol 147 ◽  
Author(s):  
G. Ottaviani ◽  
F. Nava ◽  
R. Tonini ◽  
S. Frabboni ◽  
G. F. Cerofolini ◽  
...  

AbstractWe have performed a systematic investigation of boron implantation at 30 keV into <100> n-type silicon in the 77 –300 K temperature range and mostly at 9×1015 cm−2 fluence. The analyses have been performed with ion channeling and cross sectional transmission electron microscopy both in as-implanted samples and in samples annealed in vacuum furnace at 500 °C and 850 °C for 30 min. We confirm the impossibility of amorphization at room temperature and the presence of residual damage mainly located at the boron projected range. On the contrary, a continuous amorphous layer can be obtained for implants at 77 K and 193 K; the thickness of the implanted layer is increased by lowering the temperature, at the same time the amorphous-crystalline interface becomes sharper. Sheet resistance measurements performed after isochronal annealing shows an apparent reverse annealing of the dopant only in the sample implanted at 273 K. The striking differences between light and heavy ions observed at room temperature implantation disappears at 77 K and full recovery with no residual damage of the amorphous layer is observed.


1991 ◽  
Vol 235 ◽  
Author(s):  
YU. N. Erokhin ◽  
R. Grotzschel ◽  
S. R. Oktyabrski ◽  
S. Roorda ◽  
W. Sinke ◽  
...  

ABSTRACTThe interaction during low temperature thermal annealing of metal atoms from a Ni film evaporated on top of Si structures with a buried amorphous layer formed by ion implantation has been investigated. Rutherford Backscattering Spectrometry (RBS)/channeling, cross-sectional transmission electron microscopy (XTEM) and X-ray microanalysis were used to determine structures and compositions. It is shown that the combination of such silicon properties as the increased rate of silicidation reaction for amorphous silicon with respect to the crystalline one in combination with high metal atom diffusivity leads to formation of buried epitaxial Ni silicide islands at the interface between the amorphous and the top crystalline silicon layers. During thermal annealing at temperatures as low as 350° C, these islands move through the a-Si layer leaving behind epitaxially recrystallized Si.


2007 ◽  
Vol 994 ◽  
Author(s):  
Douglas C. Thompson ◽  
T. L. Alford ◽  
J. W. Mayer ◽  
T. Hochbauer ◽  
J. K. Lee ◽  
...  

AbstractMicrowave heating is used to initiate the ion-cut process for transfer of coherent silicon-layers onto insulator substrates. Hydrogen and boron co-implanted silicon was bonded to an insulative substrate before processing inside a 2.45 GHz, 1300 W cavity applicator microwave system. Sample temperatures measured using a pyrometer were comparable to previous ion – cut studies. Selected samples were further annealed to repair any damage created in the ion implant process. Rutherford backscattering spectrometry and selective area electron diffraction patterns show high crystallinity in transferred layers. RUMP simulation of backscattering spectra and cross-sectional transmission electron microscopy demonstrate that thicknesses of the transferred layers are comparable to previous ion-cut exfoliation techniques. Surface quality as characterized by an atomic force microscope compares well with previous ion-cut studies. Hall measurements were used to characterize electrical properties of transferred layers. The mobility and carrier density of microwave activated ion – cut silicon on insulator processed samples compares well with previous annealing techniques.


1989 ◽  
Vol 148 ◽  
Author(s):  
L.A. Clevenger ◽  
C.V. Thompson ◽  
R.R. de Avillez ◽  
K.N. Tu

ABSTRACTCross-sectional transmission and scanning transmission electron microscopy and thermodynamic and kinetic analysis have been used to characterize amorphous and crystalline nickel silicide formation in nickel/amorphous-silicon multilayer thin films. An amorphous-nickelsilicide layer was formed between the nickel and amorphous-silicon layers during deposition. Heating caused crystalline Ni2Si to form at the nickel/amorphous-nickel-silicide interface. The composition of the amorphous-siicide was determined to be approximately 1 Ni atom to 1 Si atom. Thermodynamic analysis indicates that amorphous-nickel-silicide could be in equilibrium with nickel and amorphous-silicon if there were kinetic barriers to the formation of the crystalline silicides. Kinetic analysis indicates that the “nucleation surface energies” of the crystalline silicides, other than Ni3Si, must be 1.6 to 3.0 times larger than that of amorphous-nickel-silicide.


Author(s):  
H. Takaoka ◽  
M. Tomita ◽  
T. Hayashi

High resolution transmission electron microscopy (HRTEM) is the effective technique for characterization of detailed structure of semiconductor materials. Oxygen is one of the important impurities in semiconductors. Detailed structure of highly oxygen doped silicon has not clearly investigated yet. This report describes detailed structure of highly oxygen doped silicon observed by HRTEM. Both samples prepared by Molecular beam epitaxy (MBE) and ion implantation were observed to investigate effects of oxygen concentration and doping methods to the crystal structure.The observed oxygen doped samples were prepared by MBE method in oxygen environment on (111) substrates. Oxygen concentration was about 1021 atoms/cm3. Another sample was silicon of (100) orientation implanted with oxygen ions at an energy of 180 keV. Oxygen concentration of this sample was about 1020 atoms/cm3 Cross-sectional specimens of (011) orientation were prepared by argon ion thinning and were observed by TEM at an accelerating voltage of 400 kV.


1993 ◽  
Vol 311 ◽  
Author(s):  
Lin Zhang ◽  
Douglas G. Ivey

ABSTRACTSilicide formation through deposition of Ni onto hot Si substrates has been investigated. Ni was deposited onto <100> oriented Si wafers, which were heated up to 300°C, by e-beam evaporation under a vacuum of <2x10-6 Torr. The deposition rates were varied from 0.1 nm/s to 6 nm/s. The samples were then examined by both cross sectional and plan view transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy and electron diffraction. The experimental results are discussed in terms of a new kinetic model.


1992 ◽  
Vol 280 ◽  
Author(s):  
Z. Ma ◽  
L. H. Allen

ABSTRACTSolid phase epitaxial (SPE) growth of SixGei1-x alloys on Si (100) was achieved by thermal annealing a-Ge/Au bilayers deposited on single crystal Si substrate in the temperature range of 280°C to 310°C. Growth dynamics was investigated using X-ray diffraction, Rutherford backscattering spectrometry, and cross-sectional transmission electron microscopy. Upon annealing, Ge atoms migrate along the grain boundaries of polycrystalline Au and the epitaxial growth initiates at localized triple points between two Au grains and Si substrate, simultaneously incorporating a small amount of Si dissolved in Au. The Au is gradually displaced into the top Ge layer. Individual single crystal SixGei1-x islands then grow laterally as well as vertically. Finally, the islands coalesce to form a uniform layer of epitaxial SixGe1-x alloy on the Si substrate. The amount of Si incorporated in the final epitaxial film was found to be dependent upon the annealing temperature.


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