Influence of Hydrogen On The Solid Phase Epitaxial Regrowth of Strained Layer Silicon Germanium Alloys

1995 ◽  
Vol 379 ◽  
Author(s):  
D. Love ◽  
D. Endisch ◽  
T.W. Simpson ◽  
T.D. Lowes ◽  
I.V. Mitchell ◽  
...  

ABSTRACTStrained layer Si/Si0.79Ge0.21 superlattices consisting of 16 alternating 19.0 nm Si0.79Ge0.21 / 18.5 nm Si layers have been amorphized by Si ion irradiation, then implanted with H ions to nominal atomic concentrations of 1%, 0.1% and 0.05% within the amorphized region. Subsequent solid phase epitaxy (SPE) at a regrowth temperature of 575°C was monitored in situ by time resolved reflectivity (TRR) measurements, while changes in the H distribution were measured by elastic recoil detection analysis (ERDA). Analysis was supplemented by Rutherford backscattering spectrometry (RBS), x-ray double crystal diffraction and reflectivity (DCD/XRF) and transmission electron microscopy (TEM). TRR data reveals a decrease in the initial SPE rate in the Si substrate from 4.9 Å/sec (no H) to 2Å/sec for 1% H concentration as well as a rate decrease as the interface enters the Si/SiGe layers. TRR also indicates an increased roughness in the crystal/amorphous interface with increasing H concentration. ERDA reveals that a significant fraction of the implanted H is stable in the amorphous region for the anneal times (10-30 min) at 575°C, while in the regrown lattice the H concentration has dropped below 20 ppm, near the detection limit of the ERDA. DCD shows almost no strain in the regrown structures. TEM and RBS channeling techniques reveal degradation in the crystal quality of epitaxially regrown structures and a large concentration of strain relieving defects originating near the second deepest of eight SiGe layers in all regrown structures. XRF indicates decreasing sharpness of the regrown Si/SiGe interfaces with increasing H concentration.

1995 ◽  
Vol 378 ◽  
Author(s):  
K. B. Belay ◽  
D. L. Llewellyn ◽  
M. C. Ridgway

AbstractNon-stoichiometric GaAs layers with semi-insulating properties can be produced by low-temperature molecular beam epitaxy or ion implantation. The latter is the subject of the present report wherein the solid-phase epitaxial growth of amorphized, non-stoichiometric GaAs layers has been investigated with time-resolved reflectivity, Rutherford backscattering spectrometry and transmission electron microscopy. GaAs substrates were implanted with Ga and/or As ions and annealed in air at a temperature of 260°C. The recrystallized material was composed of a thin, crystalline layer bordered by a thick, twinned layer. Non-stoichiometry results in a roughening of the amorphous/crystalline interface and the transformation from planar to non-planar regrowth. The onset of the transformation and the rate thereof can increase with an increase in non-stoichiometry. Non-stoichiometry can be achieved on a macroscopic scale via Ga or As implants or on a microscopic scale via Ga and As implants. The influence of the latter is greatest at low doses whilst the former dominates at high doses.


2002 ◽  
Vol 17 (2) ◽  
pp. 271-274 ◽  
Author(s):  
W. Jiang ◽  
W. J. Weber ◽  
C. M. Wang ◽  
Y. Zhang

Single-crystal 6H–SiC wafers were irradiated at 300 K with 50 keV He+ ions to fluences ranging from 7.5 to 250 He+/nm2. Ion-channeling experiments with 2.0 MeV He+ Rutherford backscattering spectrometry were performed to determine the depth profile of Si disorder. The measured profiles are consistent with SRIM-97 simulations at and below 45 He+/nm2 but higher than the SRIM-97 prediction at both 100 and 150 He+/nm2. Cross-sectional transmission electron microscopy study indicated that the volume expansion of the material is not significant at intermediate damage levels. Results from elastic recoil detection analysis suggested that the implanted He atoms diffuse in a high-damage regime toward the surface.


2003 ◽  
Vol 792 ◽  
Author(s):  
C.S. Camacho ◽  
P.F.P. Fichtner ◽  
F.C. Zawislak ◽  
G. Feldmann

ABSTRACTThe effects of film morphology (mosaic- or bamboo-like grain structures) and of He bubbles on the redistribution of Cu, as well as on the formation of Al-Cu precipitates in 200 nm thick Al/SiO2 films similar to microelectronic device interconnects, are investigated using Rutherford backscattering spectrometry, elastic recoil detection analysis and transmission electron microscopy. As-deposited and pre-annealed Al films were implanted with Cu and/or He ions forming concentration profiles located 100 nm below the surface and with peak concentrations of about 3 at.%. It is shown that grain boundaries and/or He bubbles can affect the vacancy fluxes inside the grains and reduce or even inhibit the Cu redistribution as well as the nucleation and growth of θ and θ′ Al-Cu precipitates during post-implantation annealings at temperatures from 473 to 553 K. It is also shown that mosaic-like grain structures allow the control of grain size distribution within the 25 to 1500 nm size range, thus providing an additional microstructure engineering tool to improve device reliability against electromigration failures.


1994 ◽  
Vol 357 ◽  
Author(s):  
Todd W. Simpson ◽  
Ian V. Mitchell ◽  
Ning Yu ◽  
Michael Nastasi ◽  
Paul C. Mcintyre

AbstractTime resolved optical reflectivity (TRR) and Rutherford backscattering spectrometry (RBS) and ion channelling methods have been applied to determine the crystallization kinetics of Fe-doped A1203 in the temperature range of 900-1050°C. Amorphous A1203 films, approximately 250 nm thick and with Fe cation concentrations of 0, 1.85, 2.2 and 4.5%, were formed by e-beam deposition on single crystal, [0001] oriented, A1203 substrates. Annealing was performed under an oxygen ambient in a conventional tube furnace, and the optical changes which accompany crystallization were monitored, in situ, by TRR with a 633nm wavelength laser.Crystallization is observed to proceed via solid phase epitaxy. An intermediate, epitaxial phase of -γ-Al203 is formed before the samples reach the ultimate annealing temperature. The 5% Fe-doped film transforms from γ to α-A1203 at a rate approximately 10 times that of the pure A1203 film and the 1.85% and 2.2% Fe-doped films transform at rates between these two extremes. The Fe-dopants occupy substitional lattice sites in the epilayer. Each of the four sets of specimens displays an activation energy in the range 5.0±0.2eV for the γ,α phase transition.


1993 ◽  
Vol 320 ◽  
Author(s):  
M.C. Ridgway ◽  
A. Vantomme ◽  
A.-M. Van Bavel ◽  
G. Langouche

ABSTRACTEpitaxial CoSi2 layers on Si substrates have been amorphized with Co and/or Si ion implantation. The influence of nonstoichiometry on the rate of solid-phase epitaxial growth (SPEG) of amorphized CoSi2 has been investigated with time-resolved reflectivity, Rutherford backscattering spectrometry and Mossbauer spectrometry, the latter with radioactive 57Co probes. A decrease in SPEG rate was apparent with an increase in nonstoichiometry. For a given ion dose, the decrease was greater following Co implantation. The means by which non-stoichiometry is accommodated in a crystalline CoSi2 lattice - either through phase separation or defect formation - has been considered. SPEG rate retardation was also evident in samples implanted with both Si and Co ions with a Si:Co dose ratio of 2:1. Additional mechanisms may thus also contribute to the observed SPEG rate reduction.


2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Sarayut Tunmee ◽  
Ratchadaporn Supruangnet ◽  
Hideki Nakajima ◽  
XiaoLong Zhou ◽  
Satoru Arakawa ◽  
...  

The compositions and bonding states of the amorphous hydrogenated carbon films at various thicknesses were evaluated via near-edge X-ray absorption fine-structure (NEXAFS) and elastic recoil detection analysis combined with Rutherford backscattering spectrometry. The absolute carbonsp2contents were determined to decrease to 65% from 73%, while the hydrogen contents increase from 26 to 33 at.% as the film thickness increases. In addition, as the film thickness increases, theπ⁎(C=C),σ⁎(C–H),σ⁎(C=C), andσ⁎(C≡C) bonding states were found to increase, whereas theπ⁎(C≡C) andσ⁎(C–C) bonding states were observed to decrease in the NEXAFS spectra. Consequently, the film thickness is a key factor to evaluate the composition and bonding state of the films.


2016 ◽  
Vol 49 (5) ◽  
pp. 1704-1712 ◽  
Author(s):  
Marko Karlušić ◽  
Sigrid Bernstorff ◽  
Zdravko Siketić ◽  
Branko Šantić ◽  
Ivančica Bogdanović-Radović ◽  
...  

Nanostructuring of surfaces and two-dimensional materials using swift heavy ions offers some unique possibilities owing to the deposition of a large amount of energy localized within a nanoscale volume surrounding the ion trajectory. To fully exploit this feature, the morphology of nanostructures formed after ion impact has to be known in detail. In the present work the response of a rutile TiO2 (001) surface to grazing-incidence swift heavy ion irradiation is investigated. Surface ion tracks with the well known intermittent inner structure were successfully produced using 23 MeV I ions. Samples irradiated with different ion fluences were investigated using atomic force microscopy and grazing-incidence small-angle X-ray scattering. With these two complementary approaches, a detailed description of the swift heavy ion impact sites, i.e. the ion tracks on the surface, can be obtained even for the case of multiple ion track overlap. In addition to the structural investigation of surface ion tracks, the change in stoichiometry of the rutile TiO2 (001) surface during swift heavy ion irradiation was monitored using in situ time-of-flight elastic recoil detection analysis, and a preferential loss of oxygen was found.


2010 ◽  
Vol 638-642 ◽  
pp. 2962-2969
Author(s):  
Mihail Ionescu ◽  
P. Photongkam ◽  
D. Yu ◽  
R. Siegele ◽  
S. Li ◽  
...  

Modification of electric and magnetic properties of ZnO thin films was achieved by low energy Eu ion irradiation. The desired doping levels as well as the depth distribution of the dopant was controlled by the ion energy and the ion flux, following a simulated interaction between the doping ion and the host ZnO matrix of epitaxial ZnO (0001) films of approximatelly 200nm, grown on c-Al2O3 by PLD. The properties of the doped ZnO film depend in a critical way on the homogeneity of the doped ions throughout the entire film. The doping levels and the depth distribution of dopants were measured by elastic recoil detection analysis (ERDA). The results show a uniform depth distribution of Eu, as well as some level of Al diffusion from the substrate and the presence of some low levels of H, N and O. PACS code: 68.49Sf; 74.78Bz


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.


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