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1.
P.J. Simpson A.P. Knights K. Dudeck S. Ruffell B. Terreault 《Applied Surface Science》2008,255(1):63-67
Despite decades of study, voids in silicon produced by implantation of H or He followed by annealing continue to be a topic of interest. There are two key applications: gettering of heavy metal impurities, and “ion cutting” used in silicon-on-insulator fabrication. Positron annihilation is one of the few techniques that can probe the vacancies and vacancy clusters that are the precursors to void formation. Data from recent studies will be discussed, including (I) isotopic substitution, in which comparisons of H vs. D implantation permit examination of the impact of primary point defects vs. chemical effects. Remarkable differences exist between H and D in blistering of silicon - ion doses 2-3 times higher are required for blistering with D than with H, despite a higher rate of primary defect production for D; (II) the effect of annealing temperature ramp-rate, in which we show that ramp-rate has a significant impact on residual defects, despite which it is so disregarded as to often be omitted from published reports; and (III) comparisons with electron microscopy which suggest that positron annihilation can be insensitive to large voids. In these studies, positron annihilation augments data from techniques including ion channelling, Raman scattering and electron microscopy; the suite of techniques allows elucidation of the interplay between implanted impurities and the vacancies and interstitials created by implantation. 相似文献
2.
S. Milita Y. Le Tiec E. Pernot L. Di Cioccio J. Härtwig J. Baruchel M. Servidori F. Letertre 《Applied Physics A: Materials Science & Processing》2002,75(5):621-627
A new process was recently developed to manufacture silicon carbide on insulator structures (SiCOI). The process consists
of several steps: (i) hydrogen implantation into an oxidised SiC wafer, (ii) bonding the oxidised surface of this wafer to
an oxidised silicon substrate and (iii) high temperature splitting of a thin SiC film from the SiC wafer at the depth of the
maximum hydrogen concentration and further annealing of the splitted film. The defect generation occurring during this process
was investigated by synchrotron radiation X-ray diffraction topography, with special emphasis on to the last two steps. Various
X-ray topographic techniques were used to characterise the lattice defects inside the SiC wafer, to quantify the strong lattice
distortion near the edges of the splitted SiC film and to reveal SiC film regions lost during the splitting process. Moreover,
we show that the strain fields of dislocations, observed in the silicon substrate after high temperature splitting and annealing
of the splitted structure, induce a corresponding deformation in the thin SiC overlayer, despite the presence of the sandwiched
oxide film. The defect density is much lower in the central region of the SiCOI structure.
Received: 29 June 2001 / Accepted: 8 November 2001 / Published online: 20 March 2002 相似文献
3.
Kögler R. Eichhorn F. Kaschny J.R. Mücklich A. Reuther H. Skorupa W. Serre C. Perez-Rodriguez A. 《Applied Physics A: Materials Science & Processing》2003,76(5):827-835
Nanometer-sized SiC precipitates were synthesized in situ in Si by simultaneous implantation of two ion beams of C+ and Si+ ions. The results of simultaneous dual-beam implantation are compared with those of sequential dual-beam ion implantation
and of single-beam C+ ion implantation. Remarkable differences are observed regarding the content and the crystal quality of SiC precipitates as
well as the defect structure of the Si substrate. The SiC precipitation during dual-beam synthesis is found to depend on the
ion energy of the second beam and on the implantation mode, simultaneous or sequential. For suitable implantation conditions,
simultaneous dual-beam synthesis can improve the in situ SiC formation in comparison to the single-beam synthesis. A higher
density of SiC precipitates with better crystal quality was observed, whereas their size was not changed. The second ion beam
enables a shift in the dynamic equilibrium of constructive and destructive processes for SiC formation. A model is proposed
assuming that SiC precipitation preferentially proceeds in regions with vacancy defects. The implantation process itself creates
vacancy-dominated and also interstitial-dominated regions. The balance of the local point-defect composition is shifted under
the second ion beam. In this way, the conditions for SiC precipitation can be modified.
Received: 18 February 2002 / Accepted: 17 May 2002 / Published online: 17 December 2002
RID="*"
ID="*"Corresponding author. Fax: +49-351/260-3411, E-mail: koegler@fz-rossendorf.de 相似文献
4.
Lei Wang 《Physica B: Condensed Matter》2009,404(1):58-60
The structures of Ge-O complexes in germanium-doped Czochralski (CZ) silicon wafers have been investigated by means of density functional theory (DFT). The calculations present the fact that the Ge-O complexes can be formed with the absence of vacancy during low-temperature thermal cycles so that they can enhance oxygen precipitation. Furthermore, the total energy of different Ge-O complexes is calculated, and then optimized and stable structure of Ge-O complexes is suggested. 相似文献
5.
Likhachev K. V. Breev I. D. Kidalov S. V. Baranov P. G. Nagalyuk S. S. Ankudinov A. V. Anisimov A. N. 《JETP Letters》2022,116(11):840-845
JETP Letters - We fabricate a quantum magnetic field sensor based on the silicon vacancy centers in 6H–SiC using atomic force microscopy technique. The quantum sensing is based on optically... 相似文献
6.
Depending on the implantation temperature, the implantation of carbon ions into silicon at high doses results in the formation
of either amorphous SiCx or crystalline 3C-SiC precipitates. Various aspects of the precipitation behaviour observed, such as the impeded nucleation,
the limited growth and the resulting sensitivity to ballistic destruction are attributed to the large interfacial energy between
crystalline silicon and 3C-SiC. Periodically arranged amorphous SiCx nanoclusters, which are formed at lower temperatures, are shown to promote amorphisation by their surrounding stress field
and to represent sinks for silicon self-interstitials, which can be activated by annealing at 900 °C. By control of the depth
distribution of equally sized, oriented 3C-SiC precipitates formed at higher implantation temperatures, it is possible to
establish suitable starting conditions for the formation of buried homogeneous, single-crystalline 3C-SiC layers during a
post-implantation anneal. The properties of these ion-beam-synthesised SiC layers are described and attempts to combine them
with insulating and metallic layers are reviewed. A survey is given of the emerging applications of ion-beam-synthesised buried
SiC layers and microstructures in electronic, optical and micromechanical devices and as large-area SiC pseudosubstrates.
Received: 11 November 2002 / Accepted: 12 November 2002 / Published online: 4 April 2003
RID="*"
ID="*"Corresponding author. Fax: +49-821/598-3425, E-mail: lindner@physik.uni-augsburg.de 相似文献
7.
S. A. Ahmad Razia Ramzan 《中国物理快报》2007,24(9):2631-2634
The interaction between small vacancy clusters and twin boundaries in copper is studied by using many-body potential developed by Ackland et aL for fcc metals. The interaction energies of single-, di- and tri-vacancy clusters with (111) and (112) twin boundaries are computed using well established simulation techniques. For (111) twins the vacancy clusters are highly repelled when they are on the adjacent planes, and are attracted when they are away from the boundary. In the case of (112) twins, vacancy clusters are more attracted to the boundary when they are near the boundary as compared to away from it. Vacancy clusters on both the sides of the boundary are also investigated, and it is observed that the clusters energetically prefer to lie on the off-mirror sites as compared to the mirror position across the twin. 相似文献
8.
Jiahe Chen Deren Yang Xiangyang Ma Duanlin Que 《Applied Physics A: Materials Science & Processing》2009,94(4):905-910
The internal gettering (IG) effects involved with a rapid thermal anneal (RTA) in germanium-doped Czochralski silicon (GCz-Si)
wafer have been investigated. It was found that germanium doping could enhance the oxygen precipitation in bulk while shrinking
the denuded zone width near the surface through pre-RTA at high temperature plus low–high temperature conventional furnace
anneals. Rapid cooling rate after RTA was clarified to be beneficial for oxygen precipitation for GCz-Si wafer. It was suggested
that the germanium doping could increase the vacancy concentration in Cz-Si during RTA by forming the germanium–vacancy complexes.
In contrast to that in Cz-Si wafer, the smaller-sized higher-density oxygen precipitates were presented in the nucleation
anneals, then followed RTA pretreatment while more oxygen precipitates survived during ramping processes after nucleation
anneals in the GCz-Si wafer. Enhanced heterogeneous nucleation and reduced critical radius of precipitates associated with
the germanium–vacancy complexes have been proposed for the oxygen precipitation enhancement. 相似文献
9.
S. Dannefaer 《Applied Physics A: Materials Science & Processing》1995,61(1):59-63
Recent positron lifetime and doppler broadening results on silicon, diamond and silicon carbide are presented in this contribution. In as-grown Czochralski Si ingols vacancies are found to be retained after growth at concentrations typically around 3×1016/cm3. 10 MeV eleciron irradiation of variously doped Si wafers shows that only high doping concentrations well in excess of the interstitial oxygen concentration causes an increase in the amount of monovacancies retained.In porous silicon very long-lived positronium lifetimes in the range 40–90 ns are found. Polycrystalline diamond films contain various types of vacancy agglomerates but these are found to be inhomogeneously distributed from crystallite to crystallite. Electron irradiation of silicon carbide results in two vacancy-related lifetimes which are interpreted as resulting from carbon and silicon vacancies.Paper presented at the 132nd WE-Heraeus-Seminar on Positron Studies of Semiconductor Defects, Halle, Germany, 29 August to 2 September 1994 相似文献
10.
P. Carlsson N.T. Son F. C. Beyer H. Pedersen J. Isoya N. Morishita T. Ohshima E. Janzén 《固体物理学:研究快报》2009,3(4):121-123
Deep levels introduced by low‐energy (200 keV) electron irradiation in n‐type 4H‐SiC epitaxial layers grown by chemical vapour deposition were studied by deep level transient spectroscopy (DLTS) and photoexcitation electron paramagnetic resonance (photo‐EPR). After irradiation, several DLTS levels, EH1, EH3, Z1/2, EH5 and EH6/7, often reported in irradiated 4H‐SiC, were observed. In irradiated freestanding films from the same wafer, the EPR signals of the carbon vacancy in the positive and negative charge states, VC+ and VC‐, respectively, can be observed simultaneously under illumination with light of certain photon energies. Comparing the ionization energies obtained from DLTS and photo‐EPR, we suggest that the EH6/7 (at ~EC – 1.6 eV) and EH5 (at ~EC – 1.0 eV) electron traps may be related to the single donor (+ | 0) and the double acceptor (1– | 2–) level of VC, respectively. Judging from the relative intensity of the DLTS signals, the EH6/7 level may also be contributed to by other unidentified defects. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
11.
In SiC epilayers sp
3 C-H bond vibration bands were detected by infrared transmittance measurements. The absorption constants of the transmission peaks are related to the temperature at which the layers were grown and decrease with increasing growth temperature. The absorption centers vanish when the epilayer is removed or after annealing the sample at temperatures very much lower than the growth temperatures in a hydrogen-free atmosphere. These absorption centers are connected to hydrogen on silicon lattice sites. 相似文献
12.
Microcrystalline silicon‐carbide (μc‐SiC:H) films were prepared using hot wire chemical vapor deposition at low substrate temperature. The μc‐SiC:H films were employed as window layers in microcrystalline silicon (μc‐Si:H) solar cells. The short‐circuit current density (JSC) in these n‐side illuminated n–i–p cells increases with increasing the deposition time tW of the μc‐SiC:H window layer from 5 min to 60 min. The enhanced JSC is attributed to both the high transparency and an anti‐reflection effect of the μc‐SiC:H window layer. Using these favourable optical properties of the μc‐SiC:H window layer in μc‐Si:H solar cells, a JSC value of 23.8 mA/cm2 and cell efficiencies above 8.0% were achieved with an absorber layer thickness of 1 μm and a Ag back reflector. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
13.
By means of low-temperature (10 K) Fourier transform infrared absorption spectroscopy, the kinetics of nitrogen indiffusion in Czochralski (CZ) silicon annealed at 1150-1250℃ in nitrogen ambient is investigated. Moreover, the nitrogen diffusivities in CZ silicon at elevated temperatures deduced herein are in good agreement with those previously obtained in float-zone silicon, thus leading to the conclusion that the nitrogen indiffusion in CZ silicon at elevated temperatures is via nitrogen pairs. 相似文献
14.
S. Intarasiri A. Hallén J. Jensen K. Bertilsson S. Singkarat 《Applied Surface Science》2007,253(11):4836-4842
Carbon ions at 40 keV were implanted into (1 0 0) high-purity p-type silicon wafers at 400 °C to a fluence of 6.5 × 1017 ions/cm2. Subsequent thermal annealing of the implanted samples was performed in a diffusion furnace at atmospheric pressure with inert nitrogen ambient at 1100 °C. Time-of-flight energy elastic recoil detection analysis (ToF-E ERDA) was used to investigate depth distributions of the implanted ions. Infrared transmittance (IR) and Raman scattering measurements were used to characterize the formation of SiC in the implanted Si substrate. X-ray diffraction analysis (XRD) was used to characterize the crystalline quality in the surface layer of the sample. The formation of 3C-SiC and its crystalline structure obtained from the above mentioned techniques was finally confirmed by transmission electron microscopy (TEM). The results show that 3C-SiC is directly formed during implantation, and that the subsequent high-temperature annealing enhances the quality of the poly-crystalline SiC. 相似文献
15.
The behavior of vacancies in selected coherent grain boundaries (GBs) in Fe and Ni is studied by means of molecular dynamics simulations. Corresponding positron lifetimes are calculated using the atomic superposition method. There is a difference between the vacancy behavior in Fe and Ni in dependence on temperature. In Ni, vacancies at GBs appear to diminish substantially their free volume (and lifetime) with the increasing temperature, which can be attributed to ‘vacancy delocalization’. Contrary, GB vacancies remain stable up to apparently higher temperatures in Fe. 相似文献
16.
A.A. Shiryaev M. Wiedenbeck V.B. Polyakov A.A. Lebedev 《Journal of Physics and Chemistry of Solids》2008,69(10):2492-2498
The distribution of both carbon and silicon isotopes in synthetic sublimation growth SiC wafers and in natural SiC grains was studied using secondary ion mass-spectrometry (SIMS). Significant variations in both isotopic ratios were observed which were broadly correlated with the crystalline perfection as documented by Raman microspectroscopy. Domains consisting of 15R (or with its admixture) are, on average, enriched in 12C isotope relative to 6H domains, and they also show larger scatter in their observed silicon isotope ratios. We ascribe such heterogeneity to fluctuations of Si/C ratio in the growth medium and it is possible to model the spatial extent of such fluctuations. For the natural SiC grains the isotopic data suggest that they grew under relatively stable conditions, although some of them show significant isotopic zoning. 相似文献
17.
R. Hoelzl K.-J. Range L. Fabry 《Applied Physics A: Materials Science & Processing》2002,75(4):525-534
Based on experimental findings we set up calculations of numerical modeling of gettering efficiencies for Cu in various silicon
wafers. Gettering efficiencies for Cu were measured by applying a reproducible spin-on contamination in the 1012 atoms/cm2 range, followed by a thermal treatment to redistribute the metallic impurity. Subsequently, the wafers were analyzed by a
novel wet chemical layer-by-layer etching technique in combination with inductively coupled plasma mass spectrometry. We investigated
p/p+ and n/n+ epitaxial wafers with different doping levels and different substrate-doping species. We have also investigated
gettering efficiencies of phosphorus-diffused p- and n-type wafers. Heavilyboron doped silicon exhibited a gettering efficiency
of ∼100%, while gettering by n+ silicon occurred for doping levels >3×1019 atoms/cm3 only. In another set of experiments we investigated the dependence of the gettering efficiency of p-type wafers with poly-silicon
back sides for different cooling rates and Cu spiking levels. A strong dependence on both parameters was found. Cu gettering
in p/p+ epitaxial wafers was modeled by calculating the increased solubility of Cu in p+ silicon compared to non-doped silicon
taking into account the Fermi-level effect, which stabilizes donors in p+ silicon, and the pairing reaction between Cu and
B. Calculated gettering efficiencies were in very good agreement with experimental results. Gettering in n+ silicon was similarly
modeled in terms of pairing reactions and the Fermi-level effect. But, for n-type silicon, many experimental uncertainties
existed; thus, we applied our expressions to solubility data of Hall and Racette to obtain the unknown parameters. The empirical
calculations were in good agreement even with results on n/n+ wafers. For phosphorus-diffused wafers we had to consider an
excess vacancy concentration of 1.2–5.5 times the equilibrium concentration to explain the experimental findings by the model.
Gettering by poly-silicon back sides was simulated by solving the time-dependent diffusion equation with boundary conditions
that take into account different surface reaction rates of silicon point defects. Using this advanced model, the experimentally
measured gettering efficiencies were reproduced within the uncertainty of the measurement.
Received: 3 September 2001 / Accepted: 4 September 2001 / Published online: 20 December 2001 相似文献
18.
L. Rebohle J. von Borany H. Fröb W. Skorupa 《Applied physics. B, Lasers and optics》2000,71(2):131-151
The microstructural, optical and electrical properties of Si-, Ge- and Sn-implanted silicon dioxide layers were investigated.
It was found, that these layers exhibit strong photoluminescence (PL) around 2.7 eV (Si) and between 3 and 3.2 eV (Ge, Sn)
at room temperature (RT), which is accompanied by an UV emission around 4.3 eV. This PL is compared with that of Ar-implanted
silicon dioxide and that of Si- and Ge-rich oxide made by rf magnetron sputtering. Based on PL and PL excitation (PLE) spectra
we tentatively interpret the blue–violet PL as due to a T1→S0 transition of the neutral oxygen vacancy typical for Si-rich SiO2 and similar Ge- or Sn-related defects in Ge- and Sn-implanted silicon dioxide. The differences between Si, Ge and Sn will
be explained by means of the heavy atom effect. For Ge-implanted silicon dioxide layers a strong electroluminescence (EL)
well visible with the naked eye and with a power efficiency up to 5×10-4 was achieved. The EL spectrum correlates very well with the PL one. Whereas the EL intensity shows a linear dependence on
the injection current over three orders of magnitude, the shape of the EL spectrum remains unchanged. The I-V dependence exhibiting
the typical behavior of Fowler–Nordheim tunneling shows an increase of the breakdown voltage and the tunnel current in comparison
to the unimplanted material. Finally, the suitability of Ge-implanted silicon dioxide layers for optoelectronic applications
is briefly discussed.
Received: 9 March 2000 / Published online: 30 June 2000 相似文献
19.
The defect evolution as a function of the annealing temperature has been studied in monocrystalline silicon grown in a hydrogen atmosphere and irradiated with 3.6×1017 neutrons/cm2. Positron lifetime spectroscopy has been used and the results compared with infrated absorption measurements. Vacancy-H, vacancy-2H, vacancy-O–H and divacancy complexes withm hydrogen atoms (m<6) have been identified for the first time as possible positron traps. 相似文献
20.
H. Bhuyan M. Favre G. Avaria H. Chuaqui E. Wyndham M. Paulraj 《Applied Surface Science》2007,254(1):197-200
We have performed an experimental analysis on the investigation of high energy ion beam irradiation on Si(1 0 0) substrates at room temperature using a low energy plasma focus (PF) device operating in methane gas. The surface modifications induced by the ion beams are characterized using standard surface science diagnostic tools, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), photothermal beam deflection, energy-dispersive X-ray (EDX) analysis and atomic force microscope (AFM) and the results are reported. In particular, it has been found that with silicon targets, the application of PF carbon ion beams results in the formation of a surface layer of hexagonal (6H) silicon carbide, with embedded self-organized step/terrace structures. 相似文献