We utilize a very sensitive electron spin resonance technique called spin-dependent tunneling to identify defect centers involved in the negative bias temperature instability in plasma-nitrided p-channel metal-oxide-silicon field-effect transistors. The defect's ²⁹Si hyperfine... (Read more)

The authors combine metal oxide semiconductor (MOS) gated diode measurements and very sensitive electrically detected electron spin resonance measurements to detect and identify negative bias temperature instability (NBTI) generated defect centers in fully processed HfO₂ pMOS field effect... (Read more)

Fluorine-vacancy (FV) complexes have been directly observed in the Si_0.94Ge_0.06 layer in a Si-SiGe-Si structure, using variable-energy positron annihilation spectroscopy (VEPAS). These complexes are linked to the significant reduction of boron diffusion in the SiGe layer via... (Read more)

Recent work has suggested that prior determinations of diffusion mechanism and point defect thermodynamics in silicon have been affected by nonequilibrium effects stemming from uncontrolled adsorption-induced suppression of a pathway for defect creation at the surface. Through silicon self-diffusion... (Read more)

A computationally efficient hybrid Green's function (GF) technique is developed for multiscale modeling of point defects in a trilayer lattice system that links seamlessly the length scales from lattice (subnanometers) to continuum (bulk). The model accounts for the discrete structure of the lattice... (Read more)

²⁹Si NMR spectra and nuclear spin-lattice relaxation rate measurements in MnSi paramagnetic phase are presented. The experimental results are analyzed in the framework of the self-consistent renormalization theory for spin fluctuations, and detailed estimates of microscopic parameters... (Read more)

The rearrangement of silicon dangling bonds induced by pulsed laser heating of monohydride-covered Si(001) surfaces has been studied by means of scanning tunneling microscopy (STM). The initial configurations, which were created by laser-induced thermal desorption, consist of isolated pairs of... (Read more)

The effect of HF etching of the silicon oxide shell covering the surface of Si nanocrystals (NCs) on the subsequent room-temperature atmospheric oxidation of Si-NCs has been investigated by means of photoluminescence measurements, Fourier transform infrared spectroscopy, and electron paramagnetic... (Read more)

The annealing of damage generated by low-energy ion implantation in polycrystalline silicon (poly-Si) and amorphous silicon (a-Si) is compared. The rate of heat release between implantation temperature and 350–500 °C for Si implanted in both materials and for different ions implanted in... (Read more)

The vibrational lifetimes of a range of H-related defects and interstitial O (O_i) in Si, including isotopic substitutions, are calculated from first principles as a function of temperature. The theoretical approach is explained in detail. The vibrational lifetimes of... (Read more)

We present a detailed study of the comparative thermal evolutions of H- and D-related defects in silicon implanted with 2×10¹⁶ H or D/cm², or coimplanted with 0.25×10¹⁶ He/cm² and 0.7×10¹⁶ H/cm², in both orders.... (Read more)

In a recent experiment, Derycke et al. have made the exciting observation that H₂ molecules readily adsorb dissociatively on the c(4×2) but not on the 3×2 surface of SiC(001) at room temperature. To unravel this spectacular reactivity difference, we have investigated a... (Read more)

We report the diffusion of boron, arsenic, and phosphorus in silicon isotope multilayer structures at temperatures between 850 °C and 1100 °C. The diffusion of all dopants and self-atoms at a given temperature is modeled with the same setting of all native-point-defect-related parameters.... (Read more)

Contrary to ordinary solids, which are normally known to harden by compression, the compressibility of SiO₂ (silica) glass has a maximum at about 2–4 GPa and its mechanical strength shows a minimum around 10 GPa. At this pressure, the compression of silica glass undergoes a change... (Read more)

We have studied the structure and spectroscopic properties of the paramagnetic nonbridging oxygen hole center and of the Egamma^[prime]" align="middle"> center at the hydroxylated silica surfaces using density functional theory and an embedded-cluster model. To investigate the... (Read more)

The migration of monovacancies (V⁰) and self-interstitials (I) has been observed in ion-implanted low-doped float-zone silicon by variable-energy positron annihilation spectroscopy. V⁰ and I were created by the in situ implantation of ~20 keV... (Read more)

White electroluminescence from carbon- and silicon-rich silicon oxide layers is reported. The films were fabricated by Si and C ion implantation at low energy in 40 nm thick SiO₂, followed by annealing at 1100 °C. Structural and optical studies allow assigning the... (Read more)

The density and spatial distribution of oxide precipitates within a crystalline silicon wafer is of paramount importance for microelectronic device yield. In this letter, the authors show how the formation of previously unconsidered, very small vacancy aggregates can explain macroscopic spatial... (Read more)

The beneficial effects of F implantation on the modification of extended defects in Si have been studied. Preamorphized Si samples were implanted with F (75 keV, 6×10¹⁵ F/cm²) and regrown by solid phase epitaxy (SPE) at 700 °C. The formation, just after SPE, of a... (Read more)

The effects of dislocations and Si doping on the electrical properties of n-type GaN grown by metal organic chemical vapor deposition (MOCVD) are investigated. It is found that both electron mobility and carrier concentration are strongly influenced by edge dislocations. A moderate Si doping... (Read more)

Low pressure chemical vapor deposition of Si₃N₄ on oxidized Si (111) surfaces causes a change in the properties of the dominant interface defect, the P_b center, observed by electron paramagnetic resonance. The change in the signature of the... (Read more)

Based on ab initio density-functional energetics for saturated (n=2m+2) fluorine-vacancy clusters F_nV_m for m up to 4, the authors set up a model showing that (a) fluorine-vacancy (F–V) aggregates in Si can form in any... (Read more)

The authors modified the charge decay model of silicon-oxide-nitride-oxide-silicon-type memory at the temperatures above 150 °C. The modified model includes the effect of the internal electric field induced by the charges trapped in silicon nitride layer. The authors extracted the trap density... (Read more)

Using density functional theory, the interaction of hydrogen with a nitrogen vacancy in -Si₃N₄ is investigated. A single H atom was found to be energetically favorable over non- and doubly protonated vacancies. The traps composed of excess silicon and hydrogen have negative... (Read more)

Based on theoretical calculations, we find that at p+ polycrystalline silicon (poly-Si)/HfO₂ gates, Si interstitials are easily migrated from the electrode, forming Hf–Si bonds with a charge transfer to the electrode, and the resulting interface dipole raises the Fermi level... (Read more)

We developed a tapping-mode-scanning near-field optical microscope to measure near-field photoluminescence (SNOM-PL) with nanometer spatial resolution using an ultraviolet laser, and we measured the defect distribution of a Si-doped GaN film. The obtained result was compared with one measured by... (Read more)

The role of dimerization of atomic hydrogen to give molecular hydrogen in determining negative bias temperature instability (NBTI) kinetics is explored analytically. The time dependency of NBTI involving molecular hydrogen was found to obey a power law with a slope of 1/6, as opposed to the 1/4... (Read more)

Infrared absorption spectroscopy and ab initio density functional modeling are used to investigate hydrogen defects that are stable at and above room temperature in proton-implanted Ge-rich SiGe alloys. We find that Si atoms are effective nucleation sites for hydrogen, leading to the... (Read more)

Changing the ratio of carbon to silicon during the epitaxial 4H–SiC growth is expected to alter the dominant deep level trap, which has been attributed to a native defect. The C/Si ratio was changed from one to six during epitaxial growth of SiC. Diodes fabricated on the epitaxial layer were... (Read more)

The structure of the interface between SiO₂ and Si(100) is investigated using the replica-exchange method driven by classical molecular dynamics simulations based on ab initio-derived interatomic potentials. Abrupt interfaces are shown to be unstable, whereas a substoichiometric... (Read more)

The influence of Hf-based dielectrics on the underlying SiO₂ interfacial layer (IL) in high-k gate stacks is investigated. An increase in the IL dielectric constant, which correlates to an increase of the positive fixed charge density in the IL, is found to depend on the starting,... (Read more)

The effects of 2 MeV Si⁺ implantation on silicon-on-insulator layers uniformly doped with B at concentrations 1.0 and 1.8×10²⁰ cm^–3, and the kinetics of damage recovery were investigated by carrier density, mobility measurements, and transmission... (Read more)

Infrared (IR) spectroscopy was employed for a thorough study of the C_iC_s(Si_I) defect formed in neutron-irradiated carbon-doped Czochralski silicon material. Its IR signals at 987 and 993 cm^–1, as well as the thermal evolution of the... (Read more)

To determine if the only source of optical absorption between 5.8 and 5.9 eV is the E center (absorbing at 5.85 eV) two separate suites of type III silica samples were implanted, one with Si and one with O. Several ion energies were used for implantation to produce layers 600 and... (Read more)

In this paper, the formation and evolution of defects induced by ion irradiation with 1 MeV Si⁺ ions in Ni₂Si/4H–SiC Schottky diodes were studied and correlated with the electrical properties of the contacts. The current-voltage characteristics of the contacts... (Read more)

An overview of the evolution of transistor parameters under negative bias temperature instability stress conditions commonly observed in p-MOSFETs in recent technologies is presented. The physical mechanisms of the degradation as well as the different defects involved have been discussed according to a systematic set of experiments with different stress conditions. According to our findings, a physical model is proposed which could be used to more accurately predict the transistor degradation. Finally, based on our new present understanding, a new characterization methodology is proposed, which would open the way to a more accurate determination of parameter shifts and thus allowing implementing the degradation into design rules. (Read more)

In the same way that gases react with surfaces from above, solid-state point defects such as interstitial atoms can react from below. Little attention has been paid to this form of surface chemistry. Recent bulk self-diffusion measurements near the Si(100) surface have quantified Si interstitial... (Read more)

Density-functional-theory calculations were performed for the unrelaxed +2 Si vacancy and +2 self-interstitial utilizing periodic boundary conditions and two different methods—the uniform background charge method and the local moment counter charge method—for circumventing the divergence... (Read more)

We present a detailed analysis of the fundamental atomic-scale processes that determine the surface smoothness of hydrogenated amorphous silicon (a-Si:H) thin films. The analysis is based on a synergistic combination of molecular-dynamics (MD) simulations of radical precursor migration on surfaces... (Read more)

Atomic configurations, formation energies, electronic transition energies, and binding energies of the silicon divacancy in the +1, 0, −1, and −2 charge states were obtained from density functional theory calculations. The calculations were performed using the local density approximation... (Read more)

We present a model of amorphous silicon generated by extensive annealing of a continuous random network structure using a molecular dynamics simulation with forces computed by a tight-binding total energy method. We also produce a refined model by relaxing the annealed model using density functional... (Read more)

Gradient-corrected density-functional calculations are used to determine the structure, stability, and diffusion of arsenic-interstitial and phosphorus-interstitial pairs in the positive, neutral, and negative charge states. For both cases, our calculations show that the neutral pair will be... (Read more)

We have used molecular dynamics simulation techniques to study the generation of damage in Si within the low-energy deposition regime. We have demonstrated that energy transfers below the displacement threshold can produce a significant amount of damage, usually neglected in traditional radiation... (Read more)

The role of various types of defects in establishing the magnetic properties of the C₆₀-based polymers and the single-wall carbon nanotubes is investigated. Comparing the role of carbon vacancies, and that of substitutional impurity atoms X (X=N, B, O, Si, P, and S) in... (Read more)

We investigate the hole trapping process of a neutral oxygen vacancy in amorphous silicon dioxide (a-SiO₂) using cluster calculations based on the density functional theory (DFT) method. We show that trapping a hole at a neutral oxygen vacancy leads to the formation of several... (Read more)

We propose a diffusion pathway for a fluorine-silicon interstitial pair (F-Si_i) in silicon based on extensive first-principles density functional calculations. We find the F-Si_i pair to be most stable in the singly positive charge state under intrinsic conditions and can exist... (Read more)

Using ab initio calculations on clusters, we have identified a new reaction path between the dicoordinated silicon atom defect and the paramagnetic Egamma^[prime]" align="middle"> center in amorphous silica. Under ionizing irradiation, the dicoordinated silicon atom... (Read more)

Based on first-principles calculations, we studied the generation behavior of P_b centers at SiO₂/Si interfaces, especially for P_b1 centers, under oxidation of Si(100) surfaces. P_b1 centers were found to be formed... (Read more)

First-principles calculations carried out in 3C- and 4H-SiC show that small metastable carbon clusters can be created in irradiated SiC. The metastable carbon clusters possess occupation levels in the p-type as well as in the n-type 4H-SiC. Depending on the... (Read more)

The structure of the SiO₂/4H-SiC interface produced by dry oxidation has been studied using positron annihilation spectroscopy using energy-variable slow positron beams. Based on the Doppler broadening shape and wing parameter (S-W) correlation, the interface layer was... (Read more)

We report a study by electron paramagnetic resonance on the E_α point defect in amorphous silicon dioxide (a-SiO₂). Our experiments were performed on γ-ray irradiated oxygen-deficient materials and pointed out that the ²⁹Si... (Read more)

Electron paramagnetic resonance and ab initio supercell calculations suggest that the P6/P7 centers, which were previously assigned to the photoexcited triplet states of the carbon vacancy-antisite pairs in the double positive charge state, are related to the triplet ground... (Read more)

Silicon oxynitride films were deposited using a plasma-enhanced chemical vapor deposition process. The bond configurations of the constituent atoms in the deposited film were analyzed using x-ray photoelectron spectroscopy. Analysis of the Si 2p spectra showed the presence of... (Read more)

Recent experimental studies [A. Ural, P. B. Griffin, and J. D. Plummer, J. Appl. Phys. 85, 6440 (1999); R. Kim, T. Hirose, T. Shano, H. Tsuji, and K. Taniguchi, Jpn. J. Appl. Phys. 41, 227 (2002); S. Solmi, M. Ferri, M. Bersani, D. Giubertoni, and V. Soncini, J. Appl. Phys. 94,... (Read more)

We utilize a very sensitive electron paramagnetic resonance technique called spin-dependent recombination to observe and identify defect centers generated by modest negative bias and moderately elevated temperatures in fully processed p-channel metal-oxide-silicon field-effect transistors.... (Read more)

Negative bias temperature instability has become an important reliability concern for ultra-scaled Silicon IC technology with significant implications for both analog and digital circuit design. In this paper, we construct a comprehensive model for NBTI phenomena within the framework of the standard reaction–diffusion model. We demonstrate how to solve the reaction–diffusion equations in a way that emphasizes the physical aspects of the degradation process and allows easy generalization of the existing work. We also augment this basic reaction–diffusion model by including the temperature and field-dependence of the NBTI phenomena so that reliability projections can be made under arbitrary circuit operating conditions. (Read more)

Interface defects related to negative-bias temperature instability (NBTI) in an ultrathin plasma-nitrided SiON/ Si<100> system were characterized by using conductance–frequency measurements, electron-spin resonance measure- ments, and synchrotron radiation X-ray photoelectron spectroscopy. It was confirmed that NBTI is reduced by using D₂-annealing instead of the usual H₂-annealing. Interfacial Si dangling bonds (P_b1 and P_b0 centers) were detected in a sample subjected to negative-bias temperature stress (NBTS). Although we suggest that NBTS also generates non-Pb defects, it does not seem to generate nitrogen dangling bonds. These results show that NBTI of the plasma-nitrided SiON/Si system is predominantly due to P_b depassivation. Plasma nitridation was also found to increase the P_b1/P_b0 density ratio, modify the P_b1 defect structure, and increase the latent interface trap density by generating Si suboxides at the interface. These changes are likely to be the causes of NBTI in ultrathin plasma-nitrided SiON/Si systems. (Read more)

The transient enhanced diffusion of acceptor impurities severely affects the realization of ultrahigh doping regions in miniaturized Si-based devices. Fluorine codoping has been found to suppress this transient diffusion, but the mechanism underlying this effect is not understood. It has been proposed that fluorine-impurity or fluorine–native-defect interactions may be responsible. Here we clarify this mechanism combining first-principles theoretical studies of fluorine in Si and purposely designed experiments on Si structures containing boron and fluorine. The central interaction mechanism is the preferential binding of fluorine to Si-vacancy dangling bonds and the consequent formation of vacancy-fluorine complexes. The latter effectively act as traps for the excess self-interstitials that would normally cause boron transient enhanced diffusion. Instead, fluorine-boron interactions are marginal and do not play any significant role. Our results are also consistent with other observations such as native-defect trapping and bubble formation. (Read more)

Spin-polarized density functional calculations are carried out on Er and Er-oxygen defects in crystalline Si. We find that the interstitial site is favored but the diffusion barrier of Er_i is only 1.9 eV, and inevitably Er_i forms complexes with impurities and... (Read more)

Electron-positron momentum distributions associated with vacancy defects in 6H-SiC after irradiation with 2-MeV electrons and annealing at 1000 °C have been studied using angular correlation of annihilation radiation measurements. It was confirmed that the above vacancy defects have... (Read more)

Electron spin resonance (ESR) was used to study neutron-induced defects in silicon as functions of anneal temperature T_an. For T_an below 200 °C, the ESR response is dominated by the Si-P3 and Si-P6 spectra, as observed before. At T_an=200 ... (Read more)

We show direct evidence, obtained by positron annihilation spectroscopy, for the complexing of fluorine with vacancies in silicon. Both float zone and Czochralski silicon wafers were implanted with 30 keV fluorine ions to a fluence of 2×10¹⁴ ions/cm², and studied in the... (Read more)

We utilize spin-dependent recombination (SDR) to observe deep level trap defects at or very near the interface of 6H silicon carbide and the SiO₂ gate dielectric in SiC metal-oxide-semiconductor field effect transistors. The SDR response is strongly correlated to SiC/SiO₂... (Read more)

Process-induced defects are a serious issue for modern sub-micron Si LSIs. To characterize such defects, two different techniques are useful: electrically detected magnetic resonance (EDMR) and transmission electron microscope (TEM), which can detect small (point) and extended defects, respectively. We applied EDMR and TEM to the issue of defect-induced leakage currents in dynamic-random-access memory (DRAM) cells. For our DRAM samples (a 0.25- μm-rule series), although TEM showed no extended defects, EDMR successfully detected two types of point defects: V₂+O x (Si divacancy-oxygen complexes) and larger Si vacancies (at least larger than V₆). We confirmed that these defects are the source of DRAM leakage currents. The observed defects were formed by ion implantation processes, but were more thermally stable than those in bulk Si crystals. The origins of this enhanced stability are attributed to the presence of oxygen atoms and a strong mechanical strain in LSIs. To clarify the origin of the complicated strain in LSI structures, we can directly measure the local-strain distribution in DRAM samples by means of convergent-beam electron diffraction (CBED) using TEM, which provides us with a valuable hint for understanding the formation mechanism of process-induced defects. (Read more)

Interfacial defect structures of NO-nitride oxide on Si(100) were characterized by electron spin resonance spectroscopy. We confirmed that the effective g values of the P_b1 center are affected by interfacial nitridation even at a small nitrogen concentration of 5 at. %, while those of the P_b0 center proved to be unchanged. We observed that the shifted P_b1 line appeared gradually with interfacial nitrogen concentration, which suggests that the nitrogen-induced modified structure substitutes for the original P_b1 structure. Angular variations of the shifted P_b1 lines were also significantly different from those of pure oxide. Based on our analysis, we attributed the g value shift of the P_b1 center to dangling bond tilting, caused by the displacement of nearest-neighbor Si atoms. (Read more)

Combining electron paramagnetic resonance measurements with ab initio calculations, we identify the V_CC_Si(Si_CC_Si) complex as a second annealing product of the silicon vacancy via an analysis of resolved carbon hyperfine interactions and of... (Read more)

The electronic, structural, and vibrational properties of small carbon interstitial and antisite clusters are investigated by ab initio methods in 3C- and 4H-SiC. The defects possess sizable dissociation energies and may be formed via condensation of carbon interstitials, e.g.,... (Read more)

The annealing of P6/P7 centers (V_CC_Si pairs) in the presence of carbon vacancies in high concentrations typical for semi-insulating (SI) silicon carbide (SiC) is studied theoretically. The calculated hyperfine parameters support the suggestion of a negatively... (Read more)

We present ab initio calculations for internal interfaces in Si and SiC. Density-functional calculations within the local-density approximation and the pseudopotential-plane-wave approach are performed to understand the effect of such two-dimensional defects on the electronic properties. We... (Read more)

Shallow N donors in n-type 4H-SiC were studied by electron paramagnetic resonance (EPR) and electron nuclear double resonance (ENDOR). For the N donor at the cubic site (N_k) in 4H-SiC, the hyperfine (hf) constants of the interaction with the nearest-neighbor... (Read more)

The interstitial and vacancy mediated boron diffusion in silicon carbide is investigated with an ab initio method. The boron interstitials in p-type and n-type materials are found to be far more mobile than the boron-vacancy complexes. A kick-out mechanism and an interstitialcy... (Read more)

Atomic-scale computer simulations, both molecular dynamics (MD) and the nudged-elastic band methods, have been applied to investigate long-range migration of point defects in cubic SiC (3C-SiC) over the temperature range from 0.36T_m to 0.95T_m (melting... (Read more)

The diffusion of interstitial atomic hydrogen in 4H-SiC was investigated theoretically, using the local density approximation of density functional theory. We have found that the diffusion barrier in the perfect crystal is 0.6 eV. Comparing this value with the calculated zero point vibration... (Read more)

In this paper we analyze, by means of first-principles electronic structure calculations, the structural, energetic, and diffusive properties of B impurities in SiC as well as of vacancies. We focus our study on (i) determining the equilibrium structures of the impurity in the lattice by means of... (Read more)

The nontrivial recombination-induced behavior of the well-known low-temperature photoluminescence of the hydrogen complex with a silicon vacancy (V_Si-H) has been previously reported by different authors. It was known to be limited to the metastable quenching and/or growth. In this... (Read more)

mplanted fluorine is observed to behave unusually in silicon, manifesting apparent uphill diffusion and reducing diffusion and enhancing activation of boron. In order to investigate fluorine behavior, we calculate the energy of fluorine defect structures in the framework of density functional theory. In addition to identifying the ground-state configuration and diffusion migration barrier of a single fluorine atom in silicon, a set of energetically favorable fluorine defect structures were found (F_nV_m). The decoration of vacancies and dangling silicon bonds by fluorine suggests that fluorine accumulates in vacancy-rich regions, which explains the fluorine redistribution behavior reported experimentally. (Read more)

We report the formation processes of interface dangling bonds (P_b centers) during initial oxidation of a clean Si(111) surface using an ultrahigh-vacuum electron-spin-resonance technique. At the oxidation of one or two Si layer(s), the P_b center... (Read more)

An unexpected physical phenomenon—dynamic recovery of negative bias temperature instability (NBTI)—is reported. NBTI degradation in p-type metal–oxide–semiconductor field-effect transistors is significantly (by ~40%) reduced after stress interruption. NBTI recovery... (Read more)

Interface defects generated by negative-bias temperature stress (NBTS) in an ultrathin plasma- nitrided SiON/Si(100) system were characterized by using D₂ annealing, conductance-frequency measurements, and electron-spin resonance measurements. D₂ annealing was shown to lower... (Read more)

The influence of nitrogen concentration at a nitrided oxide/silicon interface on the activation energies of both near-interface fixed-charge trapping and interface state generation caused by negative bias temperature instability stress has been studied quantitatively. It is observed that the charge... (Read more)

We used electrically detected magnetic resonance to study the microscopic structure of ion-implantation-induced point defects that remained in large-scale Si integrated circuits (Si LSIs). Two types of defects were detected in the source/drain (n⁺-type) region of... (Read more)

We present an overview of negative bias temperature instability (NBTI) commonly observed in p-channel metal–oxide–semiconductor field-effect transistors when stressed with negative gate voltages at elevated temperatures. We discuss the results of such stress on device and circuit... (Read more)

The oxidation states of Mn in epitaxial GaN films grown by plasma induced molecular beam epitaxy were investigated by electron spin resonance (ESR), elastic recoil detection, superconducting quantum interference device magnetization, and photothermal deflection spectroscopy measurements. Comparison... (Read more)

The diffusion of intrinsic defects in 3C-SiC is studied using an ab initio method based on density functional theory. The vacancies are shown to migrate on their own sublattice. The carbon split-interstitials and the two relevant silicon interstitials, namely the tetrahedrally... (Read more)

Using the self-consistent-charge density-functional-based tight-binding (SCC-DFTB) method, we have investigated the migration of vacancies at high temperatures, taking into account the entropy contribution to the Gibbs free energy. We have found that the energy barrier for sublattice migration of... (Read more)

We propose a mechanism for the annealing of vacancy-related defects in SiC, based on ab initio total energy calculations. Our mechanism is based on the formation and migration of carbon and nitrogen split interstitials resulting in C_Si(N_C)_n or... (Read more)

To reveal the microscopic origin of the spin-resonance centers in 3C- and 4H-SiC, we perform first-principles calculations of the hyperfine tensors for vacancy-related defects and interstitials. The calculations for the silicon vacancy corroborates the earlier experimental identification. The... (Read more)

The D_I low temperature photoluminescence center is a well-known defect stable up to 1700 °C annealing in SiC, still its structure is not yet known. Combining experimental and theoretical studies, in this paper we will show that the properties of an antisite pair can reproduce... (Read more)

Electron-paramagnetic-resonance (EPR) and electron-spin-echo (ESE) studies have been performed that show that isolated V_Si^-, V_Si⁰, and V_C vacancies are the dominant intrinsic paramagnetic defects in SiC treated by room-temperature neutron... (Read more)

We present first-principle calculations on the initial stages of SiC homoepitaxial growth on the –SiC(111)–(×) surface. We show that the nonstoichiometric reconstruction plays a relevant role in favoring the attainment of high-quality films. The motivation is twofold: On one hand, we... (Read more)

A Comment on the Letter by A. A. Rempel et al., Phys. Rev. Lett. 89, 185501 (2002). The authors of the Letter offer a Reply.... (Read more)

The effect of vacancies on the behavior of F in crystalline Si has been elucidated experimentally for the first time. With positron annihilation spectroscopy and secondary ion mass spectroscopy, we find that F retards recombination between vacancies (V) and interstitials (I) because V and I trap F to form complexes. F diffuses in the V-rich region via a vacancy mechanism with an activation energy of 2.12±0.08 eV. After a long annealing time at 700ºC, F precipitates have been observed by cross-section transmission electron microscopy which are developed from the V-type defects around the implantation range and the I-type defects at the end of range. (Read more)

We have studied semi-insulating (SI) 4H SiC grown by physical vapor transport (PVT) and by high-temperature chemical vapor deposition (HTCVD) using electron paramagnetic resonance (EPR) and infrared photoluminescence (IR-PL) to better understand the defect(s) responsible for the SI behavior.... (Read more)