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- 1. phys. stat. sol. (b) 245, 1298-1314 (2008) , “EPR identification of intrinsic defects in SiC”, J. Isoya, T. Umeda, N. Mizuochi, N. T. Son, E. Janzen, T. OhshimaThe structure determination of intrinsic defects in 4H-SiC, 6H-SiC, and 3C-SiC by means of EPR is based on measuring the angular dependence of the 29Si/13C hyperfine (HF) satellite lines, from which spin densities, sp-hybrid ratio, and p-orbital direction can be determined over... (Read more)Si SiC diamond| EPR Theory electron-irradiation thermal-meas./anneal-exp.| +1 -1 0(neutral) 1.0eV~ 13C 29Si C1h C3v Carbon Csi D2d EI5/6 HEI1 HEI9/10 P6/7 Silicon T1 Td Tv2a V1/2/3 Vc Vsi antisite dangling-bond mono(=1) motional-effect n-type p-type pair(=2) quartet semi-insulating spin-relaxation triplet vacancy .inp files: SiC/Baranov/Baranov_g.inp SiC/EI5_C1h/5.inp SiC/EI5_C3v/5.inp SiC/EI6_RT/6.inp SiC/HEI10/HEI10a.inp SiC/HEI10/HEI10b.inp SiC/HEI1_C1h/1.inp SiC/HEI9/HEI9a.inp SiC/HEI9/HEI9b.inp SiC/SI5_C1h/4.inp SiC/Ky2/Ky2.inp SiC/Tv2a/Main.INP SiC/Vsi-_II_4H/Main.INP SiC/Vsi-_II_6H/Main.INP SiC/Vsi-_I_4H/Main.INP SiC/Vsi-_I_6H/Main.INP | last update: Takahide Umeda
- 2. Phys. Rev. B 75, 144103 (2007) , “Multiscale modeling of point defects in Si-Ge(001) quantum wells”, B. Yang and V. K. TewaryA 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)
- 3. Phys. Rev. B 75, 085439 (2007) , “Real-space investigation of fast diffusion of hydrogen on Si(001) by a combination of nanosecond laser heating and STM”, C. H. Schwalb, M. Lawrenz, M. Dürr,, and U. HöferThe 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)
- 4. Phys. Rev. B 75, 075206 (2007) , “Isotope dependence of the vibrational lifetimes of light impurities in Si from first principles”, D. West and S. K. EstreicherThe vibrational lifetimes of a range of H-related defects and interstitial O (Oi) 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)
- 5. Phys. Rev. B 75, 073409 (2007) , “Why thermal H2 molecules adsorb on SiC(001)-c(4×2) and not on SiC(001)-(3×2) at room temperature”, Xiangyang Peng, Peter Krüger, and Johannes PollmannIn 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)
- 6. Phys. Rev. B 75, 035211 (2007) , “Self- and foreign-atom diffusion in semiconductor isotope heterostructures. II. Experimental results for silicon”, H. Bracht, H. H. Silvestri, I. D. Sharp, and E. E. HallerWe 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)
- 7. Phys. Rev. B 75, 024205 (2007) , “Mechanical strength and coordination defects in compressed silica glass: Molecular dynamics simulations”, Yunfeng Liang, Caetano R. Miranda, and Sandro ScandoloContrary 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)
- 8. Phys. Rev. B 75, 024109 (2007) , “Optical and EPR properties of point defects at a crystalline silica surface: Ab initio embedded-cluster calculations”, L. Giordano, P. V. Sushko, G. Pacchioni, and A. L. ShlugerWe 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)
- 9. Appl. Phys. Lett. 89, 053511 (2006) , “Density functional theory study of deep traps in silicon nitride memories”, Max Petersen and Yakov RoizinUsing 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)
- 10. Appl. Phys. Lett. 88, 253504 (2006) , “Single silicon vacancy-oxygen complex defect and variable retention time phenomenon in dynamic random access memories”, T. Umeda, K. Okonogi, K. Ohyu, S. Tsukada, K. Hamada, S. Fujieda, and Y. MochizukiThe variable retention time phenomenon has recently been highlighted as an important issue in dynamic random access memory (DRAM) technology. Based on electrically detected magnetic resonance and simulation studies, we suggest that a single Si vacancy-oxygen complex defect is responsible for this... (Read more)
- 11. Appl. Phys. Lett. 88, 162107 (2006) , “Physical origin of threshold voltage problems in polycrystalline silicon/HfO2 gate stacks”, Dae Yeon Kim, Joongoo Kang, and K. J. ChangBased on theoretical calculations, we find that at p+ polycrystalline silicon (poly-Si)/HfO2 gates, Si interstitials are easily migrated from the electrode, forming HfSi bonds with a charge transfer to the electrode, and the resulting interface dipole raises the Fermi level... (Read more)
- 12. Appl. Phys. Lett. 88, 153518 (2006) , “Negative bias temperature instability mechanism: The role of molecular hydrogen”, Anand T. Krishnan, Srinivasan Chakravarthi, Paul Nicollian, Vijay Reddy, and Srikanth KrishnanThe 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)
- 13. Appl. Phys. Lett. 88, 012101 (2006) , “The structure of the SiO2/Si(100) interface from a restraint-free search using computer simulations”, Dominik Fischer, Alessandro Curioni, Salomon Billeter, and Wanda AndreoniThe 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)
- 14. Microelectron. Reliability 46, 1 (2006) , “NBTI degradation: From physical mechanisms to modelling”,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)
- 15. Phys. Rev. B 74, 235301 (2006) , “Precursor mechanism for interaction of bulk interstitial atoms with Si(100)”, Xiao Zhang, Min Yu, Charlotte T. M. Kwok, Ramakrishnan Vaidyanathan, Richard D. Braatz, and Edmund G. SeebauerIn 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)
- 16. Phys. Rev. B 74, 235209 (2006) , “Comparison of two methods for circumventing the Coulomb divergence in supercell calculations for charged point defects”, A. F. Wright and N. A. ModineDensity-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)
- 17. Phys. Rev. B 74, 205324 (2006) , “Surface smoothness of plasma-deposited amorphous silicon thin films: Surface diffusion of radical precursors and mechanism of Si incorporation”, Mayur S. Valipa, Tamas Bakos, and Dimitrios MaroudasWe 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)
- 18. Phys. Rev. B 74, 205208 (2006) , “Formation energies, binding energies, structure, and electronic transitions of Si divacancies studied by density functional calculations”, R. R. Wixom and A. F. WrightAtomic 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)
- 19. Phys. Rev. B 74, 205202 (2006) , “Structural model of amorphous silicon annealed with tight binding”, N. Bernstein, J. L. Feldman,, and M. FornariWe 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)
- 20. Phys. Rev. B 74, 195202 (2006) , “Interstitial-mediated mechanisms of As and P diffusion in Si: Gradient-corrected density-functional calculations”, Scott A. Harrison, Thomas F. Edgar, and Gyeong S. HwangGradient-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)
- 21. Phys. Rev. B 74, 174115 (2006) , “Modeling of damage generation mechanisms in silicon at energies below the displacement threshold”, Iván Santos, Luis A. Marqués, and Lourdes PelazWe 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)
- 22. Phys. Rev. B 74, 153403 (2006) , “Doping and the unique role of vacancies in promoting the magnetic ground state in carbon nanotubes and C60 polymers”, Antonis N. Andriotis, R. Michael Sheetz, and Madhu MenonThe 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)
- 23. Phys. Rev. B 74, 125203 (2006) , “Density functional theory of structural transformations of oxygen-deficient centers in amorphous silica during hole trapping: Structure and formation mechanism of the Egamma[prime]" align="middle"> center”, T. Uchino and T. YokoWe 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)
- 24. Phys. Rev. B 74, 121201 (2006) , “Prediction of the anomalous fluorine-silicon interstitial pair diffusion in crystalline silicon”, Scott A. Harrison, Thomas F. Edgar, and Gyeong S. HwangWe propose a diffusion pathway for a fluorine-silicon interstitial pair (F-Sii) in silicon based on extensive first-principles density functional calculations. We find the F-Sii pair to be most stable in the singly positive charge state under intrinsic conditions and can exist... (Read more)
- 25. Phys. Rev. B 73, 235211 (2006) , “Ab initio calculations for the interconversion of optically active defects in amorphous silica”, M. M. G. Alemany and James R. ChelikowskyUsing 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)
- 26. Phys. Rev. B 73, 073302 (2006) , “Origin of Pb1 center at SiO2/Si(100) interface: First-principles calculations”, K. Kato, T. Yamasaki, T. UdaBased on first-principles calculations, we studied the generation behavior of Pb centers at SiO2/Si interfaces, especially for Pb1 centers, under oxidation of Si(100) surfaces. Pb1 centers were found to be formed... (Read more)
- 27. Phys. Rev. B 73, 033204 (2006) , “Electrical characterization of metastable carbon clusters in SiC: A theoretical study”, A. Gali, N. T. Son, E. JanznFirst-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)
- 28. Phys. Rev. Lett. 96, 55501 (2006) , “Divacancy in 4H-SiC”, N. T. Son, P. Carlsson, J. ul Hassan, E. Janzén, T. Umeda, J. Isoya, A. Gali, M. Bockstedte, N. Morishita, T. Ohshima, H. ItohElectron 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)
- 29. Phys. Rev. Lett. 96, 145501 (2006) , “Identification of the Carbon Antisite-Vacancy Pair in 4H-SiC”, T. Umeda, N. T. Son, J. Isoya, E. Janzn, T. Ohshima, N. Morishita, H. Itoh, A. Gali, M. BockstedteThe metastability of vacancies was theoretically predicted for several compound semiconductors alongside their transformation into the antisite-vacancy pair counterpart; however, no experiment to date has unambiguously confirmed the existence of antisite-vacancy pairs. Using electron paramagnetic resonance and first principles calculations we identify the SI5 center as the carbon antisite-vacancy pair in the negative charge state (CSiVC-) in 4H-SiC. We suggest that this defect is a strong carrier-compensating center in n-type or high-purity semi-insulating SiC. (Read more)SiC| ENDOR EPR Theory electron-irradiation optical-spectroscopy thermal-meas./anneal-exp.| -1 -2 1.0eV~ 13C 29Si C1h C3v Carbon Csi EI5/6 HEI1 HEI5/6 Nitrogen P6/7 SI5 Silicon Vc antisite bistable/metastable dangling-bond n-type pair(=2) semi-insulating vacancy .inp files: SiC/SI5_C1h SiC/SI5_80K SiC/SI5_100K | last update: Takashi Fukushima
- 30. Microelectron. Reliability 45, 71 (2005) , “A comprehensive model of PMOS NBTI degradation ”,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)
- 31. Phys. Rev. B 72, 045219 (2005) , “Fluorine in Si: Native-defect complexes and the supression of impurity diffusion”, Giorgia M. Lopez, Vincenzo Fiorentini, Giuliana Impellizzeri, Salvatore Mirabella, Enrico NapolitaniThe 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)
- 32. Phys. Rev. B 71, 245203 (2005) , “Electrical Activity of Er and Er-O Centers in Silicon”, D. Prezzi, T. A. G. Eberlein, R. Jones, J. S. Filhol, J. Coutindo, M. J. Shaw, P. R. Briddon.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 Eri is only 1.9 eV, and inevitably Eri forms complexes with impurities and... (Read more)
- 33. Phys. Rev. B 71, 193204 (2005) , “Angular correlation of annihilation radiation associated with vacancy defects in electron-irradiated 6H-SiC”, A. Kawasuso, T. Chiba, T. HiguchiElectron-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)
- 34. Phys. Rev. B 70, 245204 (2004) , “Silicon vacancy annealing and DI luminescence in 6H-SiC”, M. V. B. Pinheiro, E. Rauls, U. Gerstmann, S. Greulich-Weber, H. Overhof, and J.-M. SpaethCombining electron paramagnetic resonance measurements with ab initio calculations, we identify the VCCSi(SiCCSi) complex as a second annealing product of the silicon vacancy via an analysis of resolved carbon hyperfine interactions and of... (Read more)
- 35. Phys. Rev. B 70, 235211 (2004) , “Structure and vibrational spectra of carbon clusters in SiC”, Alexander Mattausch, Michel Bockstedte, and Oleg PankratovThe 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)
- 36. Phys. Rev. B 70, 201204(R) (2004) , “Annealing of vacancy-related defects in semi-insulating SiC”, U. Gerstmann, E. Rauls, and H. OverhofThe annealing of P6/P7 centers (VCCSi 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)
- 37. Phys. Rev. B 70, 195344 (2004) , “Ab initio study of structural and electronic properties of planar defects in Si and SiC”, C. Raffy, J. Furthmüller, J.-M. Wagner, and F. BechstedtWe 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)
- 38. Phys. Rev. B 70, 115203 (2004) , “Different roles of carbon and silicon interstitials in the interstitial-mediated boron diffusion in SiC”, Michel Bockstedte, Alexander Mattausch, and Oleg PankratovThe 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)
- 39. Phys. Rev. B 69, 245205 (2004) , “Atomistic study of intrinsic defect migration in 3C-SiC”, Fei Gao, William J. Weber, M. Posselt, and V. BelkoAtomic-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 0.36Tm to 0.95Tm (melting... (Read more)
- 40. Phys. Rev. B 69, 233202 (2004) , “Diffusion of hydrogen in perfect, p-type doped, and radiation-damaged 4H-SiC”, B. Aradi, P. Deák, A. Gali, N. T. Son, E. JanzénThe 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)
- 41. Phys. Rev. B 69, 125203 (2004) , “First-principles studies of the diffusion of B impurities and vacancies in SiC”, R. Rurali, E. Hernández, P. Godignon, J. Rebollo, and P. OrdejónIn 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)
- 42. Phys. Rev. Lett. 93, 245901 (2004) , “Ab Initio Calculations to Model Anomalous Fluorine Behavior”, Milan Diebel, Scott T. Dunhammplanted 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 (FnVm). 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)
- 43. J. Appl. Phys. 94, 1 (2003) , “Negative bias temperature instability: Road to cross in deep submicron silicon semiconductor manufacturing”,We present an overview of negative bias temperature instability (NBTI) commonly observed in p-channel metaloxidesemiconductor 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)
- 44. Phys. Rev. B 68, 205201 (2003) , “Ab initio study of the migration of intrinsic defects in 3C-SiC”, Michel Bockstedte, Alexander Mattausch, and Oleg PankratovThe 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)
- 45. Phys. Rev. B 68, 155208 (2003) , “Theoretical study of vacancy diffusion and vacancy-assisted clustering of antisites in SiC”, E. Rauls, Th. Frauenheim, A. Gali, P. DeákUsing 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)
- 46. Phys. Rev. B 67, 205202 (2003) , “Formation and annealing of nitrogen-related complexes in SiC”, U. Gerstmann, E. Rauls, Th. Frauenheim, and H. OverhofWe 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 CSi(NC)n or... (Read more)
- 47. Phys. Rev. B 67, 193102 (2003) , “Signature of intrinsic defects in SiC: Ab initio calculations of hyperfine tensors”, Michel Bockstedte, Matthias Heid, and Oleg PankratovTo 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)
- 48. Phys. Rev. B 67, 155203 (2003) , “Correlation between the antisite pair and the DI center in SiC”, A. Gali, P. Deák, E. Rauls, N. T. Son, I. G. Ivanov, F. H. C. Carlsson, E. Janzén, and W. J. ChoykeThe DI 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)
- 49. Phys. Rev. Lett. 91, 136101 (2003) , “Ab initio Simulations of Homoepitaxial SiC Growth”, M. C. Righi, C. A. Pignedoli, R. Di Felice, C. M. Bertoni, A. CatellaniWe 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)
- 50. Physica B 340-342, 15-24 (2003) , “Defects in SiC”, E. Janzén, I. G. Ivanov, N. T. Son, B. Magnusson, Z. Zolnai, A. Henry, J. P. Bergman, L. Storasta, F. CarlssonRecent results from studies of shallow donors, pseudodonors, and deep level defects in SiC are presented. The selection rules for transitions between the electronic levels of shallow donors in 4H–SiC in the dipole approximation are derived and the ionization energy for the N donor at... (Read more)
- 51. J. Appl. Phys. 91, 8919-8941 (2002) , “Transient Enhanced Diffusion of Boron in Si”, S. C. Jain, W. Schoenmaker, R. Lindsay, P. A. Stolk, S. Decoutere, M. Willander, H. E. Maes.On annealing a boron implanted Si sample at ~800 °C, boron in the tail of the implanted profile diffuses very fast, faster than the normal thermal diffusion by a factor 100 or more. After annealing for a sufficiently long time, the enhanced diffusion saturates. The enhanced diffusion is... (Read more)
- 52. Phys. Rev. B 66, 024106 (2002) , “Cascade overlap and amorphization in 3C-SiC: Defect accumulation, topological features, and disordering”, F. Gao and W. J. WeberMolecular dynamics (MD) simulations with a modified Tersoff potential have been used to investigate cascade overlap, damage accumulation, and amorphization processes in 3C-SiC over dose levels comparable to experimental conditions. A large number of 10 keV displacement cascades were randomly... (Read more)
- 53. Phys. Rev. B 65, 184108 (2002) , “Alphabet luminescence lines in 4H-SiC”, T. A. G. Eberlein, C. J. Fall, R. Jones, P. R. Briddon, S. ÖbergFirst-principles density functional calculations are used to investigate antisite pairs in 4H-SiC. We show that they are likely to be formed in close proximity under ionizing conditions, and they possess a donor level and thermal stability consistent with the series of 40 photoluminescent lines... (Read more)
- 54. Phys. Rev. B 65, 085202 (2002) , “Divacancy in 3C- and 4H-SiC: An extremely stable defect”, L. Torpo, T. E. M. Staab, R. M. NieminenUsing first-principles calculations for divacancy defects in 3C- and 4H-SiC, we determine their formation energies and stability, their ionization levels, and relaxed geometries (symmetry point groups) for neutral as well as for charged states. For 4H-SiC all four possible nearest-neighbor divacancy... (Read more)
- 55. Phys. Rev. Lett. 88, 205502 (2002) , “Metastability of Amorphous Silicon from Silicon Network Rebonding”, R. Biswas, B. C. Pan, and Y. Y. YeWe propose a network rebonding model for light-induced metastability in amorphous silicon, involving bonding rearrangements of silicon and hydrogen atoms. Nonradiative recombination breaks weak silicon bonds and generates dangling bond–floating bond pairs, with very low activation energies. The... (Read more)
- 56. Appl. Phys. Lett. 78, 1571 (2001) , “Hydrogen Passivation and Activation of Oxygen Complexes in Silicon”, S. N. Rashkeev, M. Di Ventra, and S. T. PantelidesWe report first-principles calculations in terms of which we describe the role of hydrogen in passivating or activating oxygen complexes in Si. In particular we find that attaching H to a pre-existing oxygen cluster can change the electric activity of the cluster. Furthermore, the addition of a... (Read more)
- 57. J. Phys.: Condens. Matter 13, L1-L7 (2001) , “Identification of the Tetra-Interstitial in Silicon”, B. J. Coomer, J. P. Goss, R. Jones, S. Öberg, P. R. Briddon.First-principles computational methods are employed to investigate the structural, vibrational, optical and electronic properties of the self-interstitial aggregate, I4 in silicon. We find the defect to be electrically active and identify it with the B3 EPR centre. We... (Read more)
- 58. J. Phys.: Condens. Matter 13, 6203-6231 (2001) , “Comprehensive ab initio study of properties of monovacancies and antisites in 4H-SiC”, L. Torpo, M. Marlo, T. E. M. Staab, R. M. NieminenWe present results of ab initio calculations for the electronic and atomic structures of monovacancies and antisite defects in 4H-SiC in all possible charge states. The calculations make use of a plane-wave pseudopotential method based on density-functional theory and the local spin-density... (Read more)
- 59. Phys. Rev. B 64, 245212 (2001) , “Structure of the silicon vacancy in 6H-SiC after annealing identified as the carbon vacancy-carbon antisite pair”, Th. Lingner, S. Greulich-Weber, J.-M. Spaeth, U. Gerstmann, E. Rauls, Z. Hajnal, Th. Frauenheim, H. OverhofWe investigated radiation-induced defects in neutron-irradiated and subsequently annealed 6H-silicon carbide (SiC) with electron paramagnetic resonance (EPR), the magnetic circular dichroism of the absorption (MCDA), and MCDA-detected EPR (MCDA-EPR). In samples annealed beyond the annealing... (Read more)
- 60. Phys. Rev. B 64, 245208 (2001) , “Ab initio and empirical-potential studies of defect properties in 3C-SiC”, Fei Gao, Eric J. Bylaska, William J. Weber, L. René CorralesDensity functional theory (DFT) is used to study the formation and properties of native defects in 3C-SiC. Extensive calculations have been carried out to determine the formation of point defects and the stability of self-interstitials. Although there is good agreement in the formation of vacancies... (Read more)
- 61. Phys. Rev. B 63, 245202 (2001) , “Ab initio density-functional supercell calculations of hydrogen defects in cubic SiC”, B. Aradi, A. Gali, P. Deák, J. E. Lowther, N. T. Son, E. Janzén, W. J. ChoykeBased on ab initio density-functional calculations in supercells of 3C-SiC, the stable configurations of hydrogen and dihydrogen defects have been established. The calculated formation energies are used to give semiquantitative estimates for the concentration of hydrogen in SiC after chemical vapor... (Read more)
- 62. Phys. Rev. B 63, 165204 (2001) , “g values of effective mass donors in AlxGa1-xN alloys”, M. W. Bayerl, M. S. Brandt, T. Graf, O. Ambacher, J. A. Majewski, M. Stutzmann, D. J. As, K. LischkaElectron spin resonance experiments were performed on Si-doped wurtzite and zinc-blende GaN and Si-doped wurtzite AlxGa1-xN alloys with x=0.15, 0.32, 0.52, 0.75, and 1. For zinc-blende GaN, an isotropic g factor of 1.9475 is found. The g tensors of the silicon effective mass... (Read more)
- 63. Phys. Rev. Lett. 87, 235501 (2001) , “Thermal Double Donors and Quantum Dots”, J. Coutinho, R. Jones, L. I. Murin, V. P. Markevich, J. L. Lindström, S. Öberg, P. R. Briddon.Combined local mode spectroscopy and ab initio modeling are used to demonstrate for the first time that oxygen atoms in thermal double donors (TDD) in Si are in close proximity. The observed vibrational modes in 16O, 18O, and mixed isotopic samples are consistent with a model... (Read more)
- 64. Phys. Rev. Lett. 86, 5522-5525 (2001) , “E' Centers in Amorphous SiO2 Revisited: A New Look at an Old Problem”, T. Uchino, M. Takahashi, T. YokoWe present theoretical evidence that the paramagnetic E? defect centers in amorphous silicon dioxide ( a-SiO2) do not have the same microscopic structures as those well-defined in the corresponding crystalline counterparts such as ?-quartz. We then present alternative models of... (Read more)
- 65. Phys. Rev. Lett. 86, 4560-4563 (2001) , “Structure and Generation Mechanism of the Peroxy-Radiacal Defect in Amorphous Silica”, T. Uchino, M. Takahashi, and T. YokoWe provide a new model of the peroxy-radical defect in amorphous silica on the basis of quantum-chemical calculations applied to clusters of atoms to model the defect. In this model, the 29Si hyperfine splittings of the peroxy radical arise from a single silicon, in agreement with the... (Read more)
- 66. Physica B 308-310, 637 (2001) , “Calculation of hyperfine parameters of positively charged carbon vacancy in SiC”, T. T. Petrenko, T. L. Petrenko, V. Ya. Bratus and J. L. MongeTheoretical simulation of hyperfine parameters for the nearest and next-nearest neighbor atoms of VC+ in SiC has been performed for the cubic and hexagonal clusters. The gradient-corrected all-electron DFT calculations with Becke's three-parameter functional have been performed by the use of split... (Read more)
- 67. J. Phys.: Condens. Matter 12, 3369 (2000) , “Local electronic structure around vacancies and vacancy-antisite complexes in ?-SiC”, G. Cubiotti, Yu. Kucherenko, A. Yaresko, A. Perlov, V. AntonovThe local electronic structure around vacancies and vacancy-antisite complexes in cubic SiC has been calculated by means of the LMTO (linear muffin-tin orbital) method and the supercell approach. In order to improve the description of the electronic structure near the energy gap, the... (Read more)
- 68. Phys. Rev. B 62, 6854 (2000) , “Spin state of vacancies: From magnetic Jahn-Teller distortions to multiplets”, A. Zywietz, J. Furthmüller, and F. BechstedtThe spin configuration of isoelectronic vacancies surrounded by first-row atoms is studied within density-functional theory (DFT) using the local spin density approximation. Allowing for a symmetry break in the electronic system, a mixed-spin state is found to be lowest in energy. It is accompanied... (Read more)
- 69. Phys. Rev. B 61, 8393-8403 (2000) , “Dissociation Kinetics of Hydrogen-Passivated Pb Defects at the (111)Si/SiO2 Interface”, A. Stesmans.An electron-spin-resonance study has been carried out, both isothermally and isochronically, of the recovery under vacuum annealing from the hydrogen passivated state (symbolized as HPb) of paramagnetic Pb centers (Si3?Si•) at the (111)Si/SiO2... (Read more)
- 70. Phys. Rev. B 61, 13655 (2000) , “Intravacancy transition energies in 3C- and 4H-SiC”, A. Zywietz, J. Furthmüller, F. BechstedtSpin-polarized ab initio calculations are used to determine energy differences between ground and excited states of silicon and carbon vacancies in 3C- and 4H-SiC. The calculated transition energies are compared with recent findings from photoluminescence and magnetic-resonance experiments. (Read more)
- 71. Phys. Rev. B 61, 12602 (2000) , “Phosphorus-related deep donor in SiC”, A. Gali, P. Deák, P. R. Briddon, R. P. Devaty, W. J. ChoykeTwo phosphorus centers in SiC, an isolated P atom substituting for Si (PSi) and a Si-site P-atom adjacent to a carbon vacancy (PSi+VC) are investigated by first principle calculations. It is shown that PSi+VC produces a singly occupied donor... (Read more)
- 72. Phys. Rev. Lett. 85, 2773-2776 (2000) , “Dangling Bond Defects at Si-SiO2 Interfaces: Atomic Structure of the Pb1 Center”, A. Stirling, A. Pasquarello, J.-C. Charlier, R. CarUsing a first-principles approach, we characterize dangling bond defects at Si-SiO2 interfaces by calculating hyperfine parameters for several relaxed structures. Interface models, in which defect Si atoms remain close to crystalline sites of the substrate upon relaxation, successfully... (Read more)
- 73. Phys. Rev. Lett. 85, 2324-2327 (2000) , “Fast Diffusion of H and Creation of Dangling Bonds in Hydrogenated Amorphous Silicon Studied by in situ ESR”, U. K. Das, T. Yasuda, and S. YamasakiThe interaction of atomic hydrogen with a-Si:H films was studied by means of in situ ESR during H plasma treatment. H diffuses into the a-Si:H film and creates additional Si dangling bonds (∼1013 cm -2). We observed a high diffusion coefficient (>10-10  cm... (Read more)
- 74. Mater. Sci. Eng. B 61-62, 593 (1999) , “Electronic structure of the anti-structure pair in 3C–SiC”, L. Torpo and R. M. NieminenWe have studied the anti-structure pair (adjacent carbon CSi and silicon SiC antisites) in 3C–SiC using the plane–wave pseudopotential method. We report results for the formation energies, the ionization levels and the geometry of the relaxed structures of the defect in all its... (Read more)
- 75. Phys. Rev. B 59, 15166 (1999) , “Vacancies in SiC: Influence of Jahn-Teller distortions, spin effects, and crystal structure”, A. Zywietz, J. Furthmüller, and F. BechstedtWe present results of first-principles calculations for the neutral and charged Si and C monovacancies in cubic (3C) and hexagonal (4H) SiC. The calculations are based on the density functional theory in the local-density approximation as well as local spin density approximation. Explicitly a... (Read more)
- 76. Phys. Rev. Lett. 83, 372 (1999) , “Hydrogen Electrochemistry and Stress-Induced Leakage Current in Silica”, Peter E. Blöchl and James H. StathisHydrogen-related defects in oxygen-deficient silica, representing the material of a thermal gate oxide, are analyzed using first-principles calculations. Energetics and charge-state levels of oxygen vacancies, hydrogen, and their complexes in the silica framework are mapped out. The neutral hydrogen... (Read more)
- 77. phys. stat. sol. (b) 210, 13 (1999) , “Neutral Vacancies in Group-IV Semiconductors”, A. Zywietz, J. Furthmüller, F. BechstedtAb initio plane-wave-supercell calculations are performed for the neutral monovacancies in silicon, silicon carbide and diamond using ultrasoft non-normconserving Vanderbilt pseudopotentials. We study the structure, the energetics and the single-particle energy spectrum. The local symmetry, the... (Read more)
- 78. Nature 396, 58-60 (1998) , “Interface structure between silicon and its oxide by first-principles molecular dynamics”, A. Pasquarello, M. S. Hybertsen, R. CarThe requirement for increasingly thin (<50 Ã…) insulating oxide layers in silicon-based electronic devices highlights the importance of characterizing the Si–SiO2 interface structure at the atomic scale. Such a characterization relies to a large extent on an understanding of the atomic-scale mechanisms that govern the oxidation process. The widely used Deal–Grove model invokes a two-step process in which oxygen first diffuses through the amorphous oxide network before attacking the silicon substrate, resulting in the formation of new oxide at the buried interface1. But it remains unclear how such a process can yield the observed near-perfect interface2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. Here we use first-principles molecular dynamics13, 14, 15 to generate a model interface structure by simulating the oxidation of three silicon layers. The resulting structure reveals an unexpected excess of silicon atoms at the interface, yet shows no bonding defects. Changes in the bonding network near the interface occur during the simulation via transient exchange events wherein oxygen atoms are momentarily bonded to three silicon atoms — this mechanism enables the interface to evolve without leaving dangling bonds. (Read more)
- 79. Phys. Rev. B 58, 9845 (1998) , “Theory of Carbon-Carbon Pairs in Silicon”, R. B. Capaz, A. Dal Pino, Jr., J. D. Joannopoulos.Interstitial-substitutional carbon pairs (CiCs) in silicon display interesting metastable behavior associated with two different structural configurations. In this work, we perform extensive ab initio calculations on this system. Our results show the following. (i) The... (Read more)
- 80. Phys. Rev. B 57, 6243 (1998) , “Antisites in silicon carbide”, L. Torpo, S. Pöykkö, and R. M. NieminenTen years ago, deep-level-transient-spectroscopy (DLTS) signals, assigned to centers labeled as H1, H2, H3, and E2, have been detected in neutron-irradiated 3C SiC. The H centers were believed to be the primary point defects and the E2 center a secondary defect, which forms after the H centers start... (Read more)
- 81. phys. stat. sol. (b) 210, 13 (1998) , “Neutral Vacancies in Group-IV Semiconductors”, A. Zywietz, J. Furthmüller, F. BechstedtAb initio plane-wave-supercell calculations are performed for the neutral monovacancies in silicon, silicon carbide and diamond using ultrasoft non-normconserving Vanderbilt pseudopotentials. We study the structure, the energetics and the single-particle energy spectrum. The local symmetry, the... (Read more)
- 82. Phys. Rev. B 56, 7384 (1997) , “Negatively charged Si vacancy in 4H SiC: A comparison between theory and experiment”, T. Wimbauer, B. K. Meyer, A. Hofstaetter, A. Scharmann, H. OverhofWe use electron paramagnetic resonance and electron nuclear double resonance to identify the negatively charged Si vacancy in neutron-irradiated 4H SiC. The identification is based on resolved ligand hyperfine interactions with carbon and silicon nearest and next nearest neighbors and on the... (Read more)
- 83. phys. stat. sol. (a) 162, 95-151 (1997) , “EPR and ENDOR Investigations of Shallow Impurities in SiC Polytypes”, S. Greulich-WeberInvestigations of nitrogen donors in 6H-, 4H- and 3C-SiC using conventional electron paramagnetic resonance (EPR), electron nuclear double resonance (ENDOR) and optical detection of EPR and ENDOR as well as optical absorption and emission spectroscopy are reviewed and critically discussed. An... (Read more)
- 84. Phys. Rev. B 38, 9674-9685 (1988) , “Hyperfine interactions in cluster models of the Pb defect center”, M. Cook, C. T. WhiteHyperfine interactions in the Pb center (denoted schematically as Si3?Si?) at the Si(111)/SiO2 interface have been studied with use of spin-polarized self-consistent multiple-scattering X? calculations on Si22H21/Si6O18... (Read more)
- 85. Phys. Rev. B 38, 12752(R) (1988) , “Formation energies, abundances, and the electronic structure of native defects in cubic SiC”, C. Wang, J. Bernholc, R. F. DavisThe relative abundance of native point defects in cubic SiC has been studied via ab initio calculations as a function of composition and the Fermi-level position. For Si-rich cubic SiC, the SiC antisite is the dominant defect in n-type material, while the carbon vacancy, which is a double... (Read more)
- 86. Phys. Rev. B 36, 9638-9648 (1987) , “Theory of the Pb center at the <111> Si/SiO2 interface”, A. H. EdwardsWe present a series of semiempirical calculations on threefold-coordinated silicon at the ?111? Si/SiO2 interface. These were performed on finite clusters of atoms with use of hydrogen terminators in an unrestricted Hartree-Fock formalism wherein we include lattice relaxations. We have... (Read more)
- 87. Phys. Rev. B 34, 3610-3619 (1986) , “Dipolar interactions between dangling bonds at the (111) Si-SiO2 interface”, K. L. Brower, T. J. HeadleyIn this paper a computational model is developed which allows one to calculate the contribution to the Zeeman linewidth arising from magnetic dipole-dipole interactions between unpaired electrons in the dilute limit, which in our specific application correspond to dangling bonds (Pb... (Read more)
- 88. J. Appl. Phys. 54, 179-183 (1983) , “The Mechanism of the Enhancement of Divacancy Production by Oxygen During Electron Irradiation of Silicon. II. Computer Modeling”, G. S. Oehrlein, I. Krafcsik, J. L. Lindström, A. E. Jaworowski, and J. W. CorbettNumerical tests of possible models for the oxygen dependence of the divacancy introduction rate in silicon electron irradiated at room temperature were performed on a computer. Only the model in which oxygen traps Si self-interstitials can reproduce all the experimental data. Our modeling results... (Read more)
- 89. Sov. Phys. Solid State 23, 2126 (1981) , “Electron spin resonance of exchange-coupled vacancy pairs in hexagonal silicon carbide”, V. S. Va?ner, V. A. ll’in
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