Comparison Between Ion-Beam and Thermal-Annealing Induced Solid Phase Epitaxy in Fe-Implanted Si

1993 ◽  
Vol 320 ◽  
Author(s):  
X.W. Lin ◽  
J. Desimoni ◽  
H. Bernas ◽  
Z. Liliental-Weber ◽  
J. Washburn

Rutherford backscattering spectrometry and transmission electron microscopy were used to compare thermally induced solid phase epitaxy (SPE) with ion-beam induced epitaxial crystallization (IBIEC) of Fe-implanted Si (001). It was found that thermal annealing leads to both Si SPE and β-FeSi2 precipitation at 520°C, but has no visible effect at 320°C. In contrast, Si SPE and FeSi2 precipitation occur at both 320 and 520°C, when ion irradiation is introduced. The precipitates grow epitaxially as γ-FeSi2 at 320°C, but consist of both β-FeSi2 and γ-FeSi2 at 520°C. It was also found that thermal annealing at 520°C results in Fe segregation toward the surface, while IBIEC basically retains the as-implanted Fe profile.

1995 ◽  
Vol 379 ◽  
Author(s):  
N.D. Theodore ◽  
W.S. Liu ◽  
D.Y.C. Lie ◽  
T.K. Cams ◽  
K.L. Wang

ABSTRACTTransmission electron microscopy, conventional and high-resolution, is used to characterize the microstructural behavior of oxidized Ge0.78Si0.12 layers annealed in a reducing 95% N2+ 5% H2 ambient. An epitaxial Ge layer grows by solid-phase epitaxy on an underlying Ge0.78Si0.12 seeding layer with a Ge-Sio2 matrix positioned between them. Defect densities in the epitaxial Ge are significantly lower than in the underlying Ge0.78Si0.12. Microstructural details of this behavior are investigated.


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.


1989 ◽  
Vol 157 ◽  
Author(s):  
S. P. Withrow ◽  
O. W. Holland ◽  
S. J. Pennycook ◽  
J. Pankove ◽  
A. Mascarenhas

ABSTRACTIon beam annealing of amorphous Si(100) layers formed by co-implantation of overlapping Ga and As distributions is studied. Annealing was done using 750 keV Si+ ions with the Si substrate held at 300°C. The samples were characterized using 2.0 and 5.0 MeV He+ backscattering/channeling as well as by transmission electron microscopy (TEM). Crystallization of the amorphous Si layer occurs during irradiation via solid-phase-epitaxial growth without impurity precipitation or segregation. Both the Ga and As are mainly substitutional in the Si lattice, even at concentrations in excess of 7 at. % for each species. These results are attributed to compensation effects, most likely through ion pairing of the dopants.


1993 ◽  
Vol 311 ◽  
Author(s):  
X.X. Lin ◽  
J. Desimoni ◽  
H. Bemas ◽  
Z. Liliental-Weber ◽  
J. Washburn

ABSTRACTCubic FeSi2 precipitates were produced in Si (001) wafers by Fe implantation at room temperature, followed by ion beam-induced crystallization at 320°C, and their stability upon thermal annealing was examined by transmission electron microscopy. We found that the cubic phase remains relatively stable for a 650°C anneal, but the precipitates tend to change from an aligned to a twinned orientation with respect to the Si matrix. For higher temperature (800 and 900°C) anneals, most of the precipitates are transformed into β-FeSi2, accompanied by substantial precipitate coarsening. For platelet-shaped precipitates, the coarsening activation energy was determined to be 3.48 eV.


1996 ◽  
Vol 439 ◽  
Author(s):  
S. X. Wang ◽  
L. M. Wang ◽  
R. C. Ewing

AbstractThe ion beam-induced crystalline-to-amorphous transition was studied for crystalline phases in the MgO-A12O3-SiO 2 system. Samples were irradiated with 1.5 MeV Xe+ at temperatures from 15 to 1023 K, and the dose required for amorphization was determined by in situ transmission electron microscopy. Based on a cascade quenching model, we propose that irradiation-induced amorphization is closely related to glass formation. The rate of crystallization from a melt is the controlling factor in determining the susceptibility to amorphization and glass formation. From the analysis of cascade quenching evolution, we have derived a simple relation between amorphization dose and temperature. A quantitative parameter, S0, that describes the susceptibility to amorphization is derived that considers the crystalline structure, field strength, and phase transition temperature.


1989 ◽  
Vol 160 ◽  
Author(s):  
B.J. Robinson ◽  
B.T. Chilton ◽  
P. Ferret ◽  
D.A. Thompson

AbstractSingle strained layer structures of up to 30 nm of Si1-xGex. on (100) Si and capped with 30-36 nm of Si have been amorphized by implantation with 120 keV As . The amorphized region, extending to a depth of 130 nm, has been regrown by solid phase epitaxy (SPE) at 600°C. Characterization of the regrown structure by Rutherford backscattering/channeling techniques and transmission electron microscopy indicates that for x < 0.18 the SPE process results in the recovery of strain, while for x > 0.18 there is increasing strain relaxation and a deterioration of crystal quality.


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.


1991 ◽  
Vol 235 ◽  
Author(s):  
L. M. Wang ◽  
R. C. Ewing

ABSTRACTEffects of ion beam irradiation of five members of the (Mg, Fe)2SiO4 olivine series, from synthetic pure fayalite (Fe2SiO4) to naturally occurring (Mg0.88Fe0.12)2SiO4, have been studied by in situ transmission electron microscopy (TEM). Under 1.5 MeV Kr+ ion room temperature irradiations, all of the samples have been amorphized. The critical amorphization dose or the total collision energy loss required for amorphization increased rapidly with the increasing Mg:Fe ratio which coincides with an increasing melting temperature (bond strength) and an increasing average bond ionicity. A 400 keV He+ ion irradiation of (Mg0.88Fe0.12)2-SiO4, which mainly results in ionization energy loss in the sample, did not cause amorphization even at a much higher dose rate and a much higher final dose. This indicates nuclear interactions (collisions) are primarily responsible for ion beam induced amorphization. Also, high resolution electron microscopy (HREM) images of the defect structure at a low ion dose have been obtained and compared with the displacement cascade structure generated by computer modelling.


1985 ◽  
Vol 54 ◽  
Author(s):  
G. J. Campisi ◽  
H. B. DIETRICH ◽  
M. Delfino ◽  
D. K. Sadana

ABSTRACTSeveral silicon wafers were implanted with 58Ni+ at an energy of 170 keV and a current density of 12 μA cm-2 to doses between 5 × 1015 and 1.8 × 1018 ions cm-2. The substrates were phosphorus doped n-type <100> Czochralski grown silicon wafers. The wafers were water cooled during implantation and the surface temperatures was monitored with an infrared pyrometer and controlled to < 70°C. Samples were subsequently furnace annealed at 900°C for 30 min in nitrogen. The as-implanted and annealed samples were analyzed using cross-sectional transmission electron microscopy (XTEM), Rutherford backscattering (RBS) spectroscopy, spreading resistance depth profiling (SRP), and scanning electron microscopy (SEM). Micro-crystallites of NiSi2 (2–5nm) buried within an amorphous matrix formed during the 1.5 × 1017 ions cm-2 dose implantation. For higher doses above 3 × 1017 Ni+ cm-2, ion beam sputtering occurred. After annealing, rapid diffusion of nickel and solid-phase recrystallization of the amorphous regions occurred.


1997 ◽  
Vol 480 ◽  
Author(s):  
K. B. Belay ◽  
M. C. Ridgway ◽  
D. J. Llewellyn

AbstractIn-situ transmission electron microscopy (TEM) has been used to characterize the solidphase epitaxial growth of amorphized GaAs at a temperature of 260°C. To maximize heat transfer from the heated holder to the sample and minimize electron-irradiation induced artifacts, non-conventional methodologies were utilized for the preparation of cross-sectional samples. GaAs (3xI) mm rectangular slabs were cut then glued face-to-face to a size of (6x3) mm stack by maintaining the TEM region at the center. This stack was subsequently polished to a thickness of ~ 200 ýtm. A 3 mm disc was then cut from it using a Gatan ultrasonic cutter. The disc was polished and dimpled on both sides to a thickness of ~15 mimT.h is was ion-beam milled at liquid nitrogen temperature to an electron-transparent layer. From a comparison of in-situ and ex-situ measurements of the recrystallization rate, the actual sample temperature during in-situ characterization was estimated to deviate by ≤ 20°C from that of the heated holder. The influence of electron-irradiated was found to be negligible by comparing the recrystallization rate and microstructure of irradiated and unirradiated regions of comparable thickness. Similarly, the influence of “thin-foil effect” was found to be negligible by comparing the recrystallization rate and microstructure of thick and thin regions, the former determined after the removal of the sample from the microscope and further ion-beam milling of tens of microns of material. In conclusion, the potential influence of artifacts during in-situ TEM can be eliminated by the appropriate choice of sample preparation procedures.


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