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)

An atomistic simulation of the threading (a+c)-mixed dislocation core in wurtzite GaN has been carried out. Starting from models generated in the framework of continuum elasticity theory, two core configurations are obtained independently by using an empirical potential and a... (Read more)

Realistic carbon nanotubes (CNTs) contain various structural defects by which the physical and chemical properties of the CNTs are significantly influenced. So, lowering the defect densities is of importance for the potential application of the CNTs. By performing tight-binding molecular dynamics... (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)

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)

Complexes formed by H and the isoelectronic impurity N in GaAs_1-yN_y alloys have been widely investigated because the significant effects of N on the GaAs properties and their passivation by H represent a unique tool for a defect engineering of semiconductors.... (Read more)

We report an ab initio study of the electronic properties of surface dangling-bond (SDB) states in hydrogen-terminated Si and Ge nanowires with diameters between 1 and 2 nm, Ge/Si nanowire heterostructures, and Si and Ge (111) surfaces. We find that the charge transition levels ε(+/-)... (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)

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)

The effect of forming gas and vacuum annealing on the concentration of carbon dangling bond (P_bC) centers at 3C- and 4H-SiC/SiO₂ interfaces has been studied by electron paramagnetic resonance (EPR) spectroscopy. Our results show efficient passivation at 400 °C and... (Read more)

Hydrogenated amorphous silicon carbide (a-SiC:H) films have been deposited using magnetron sputtering technique. An integrated investigation of the effect of vacuum annealing temperature on photoluminescence properties and paramagnetic defects and its correlation with structural... (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)

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)

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)

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)

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 identification of the vacancy-hydrogen complex in single crystal diamond synthesized by chemical vapor deposition. The S = 1 defect is observed by electron paramagnetic resonance in the negative charge state. The hydrogen atom is bonded to one of the carbon atoms neighboring the... (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)

We report the observation of a paramagnetic interface defect in thermally oxidized porous n-type doped 4H–SiC/SiO₂. Based on its axial symmetry and resolved hyperfine interactions it is attributed to an sp³ carbon dangling bond center situated... (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)

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 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)

We used a density functional method to investigate the mechanism of negative-bias temperature instability (NBTI) and resultant structural changes of Si/SiO₂ and Si/SiO_xN_y interfaces. The reaction energies for the water- and hydrogen-originated... (Read more)

The structural degradation of thermal SiO₂ on (100)Si under isochronal vacuum annealing in the range T_an = 950 °C–1250 °C was monitored by electron spin resonance (ESR) in terms of point defect creation, including... (Read more)

The electronic properties of the (100) Si/SiO₂ interfacial defect called P_b1 are quite controversial. We present electron spin resonance measurements that demonstrate: (1) that the P_b1 defects have levels in the silicon band gap, (2) that... (Read more)

The diffusion and reactions of hydrogenous species generated by single-pulsed F₂ laser photolysis of SiO-H bond in SiO₂ glass were studied in situ between 10 and 330 K. Experimental evidence indicates that atomic hydrogen (H⁰) becomes mobile even at temperatures as... (Read more)

We 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)

We have characterized the leakage current paths of ultra-thin gate dielectrics using spin-dependent tunneling (SDT) spectroscopy. A spin-dependent current was detected in metal-oxide-semiconductor diodes with chemical-vapor-deposition SiN gate films with thickness less than 3 nm. We examined the nature of the trap sites in terms of g-value, bias-dependent signal intensity, and magnetic-field orientation dependence. The main feature of the observed spectrum is attributed to a paramagnetic Si site in the SiN films. By using a quantitative model of electron spin-polarization, we were able to estimate the ratio of trap-assisted current to the total leakage current. (Read more)

We 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)

We show that Cat-CVD silicon nitride films contain more than 1019 cm−3 nitrogen-bonded Si dangling bonds, similarly to the case for conventional CVD films. However, the charge-trapping behavior of the Cat-CVD films is found to be quite different, in spite of the same origin for the dominant... (Read more)

We have previously concluded that the oxygen-precipitate-associated defects that we identified by the deep levels at E_v + 0.30 eV and E_c–0.25 eV were the P_b centers generated in the interface between the oxygen... (Read more)

Electron paramagnetic resonance has been used to study the influence of thermal treatments on defect evolution in helium-implanted Czochralski single-crystal silicon. It is shown that the thermal treatment induces helium migration and capturing by vacancy clusters that transform into pressurized... (Read more)

Electron paramagnetic resonance spectra of S2 paramagnetic center in Float zone silicon (FZ-Si) and Czochralski silicon (CZ-Si) produced by H+2 ion-implantation and by subsequent annealing have been studied. At room temperature the spectrum exhibits an isotropic line g=2.0066±0.0002, which,... (Read more)

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 HP_b) of paramagnetic P_b centers (Si₃?Si^?) at the (111)Si/SiO₂... (Read more)

Float-zone and Czochralski-grown silicon crystals have been implanted with protons or deuterons at ?50 K. Electron paramagnetic resonance measurements reveal a new signal in the spectrum of the Czochralski-grown (oxygen-rich) material. This signal is strongly temperature dependent, displaying a... (Read more)

n- and p-type float-zone silicon containing 10¹⁸-cm^-3 tin were irradiated with 2 MeV electrons to a dose of 10¹⁸ cm^-2 and subsequently examined by electron paramagnetic resonance (EPR). The p-type material yields only the well-known Si-G29 signal due to... (Read more)

An electron spin resonance (ESR) study has been carried out on the P_b centers (interfacial ?Si?Si₃) in standard thermal (111)Si/SiO₂, of which, in the as-grown state, a density 4.9?10¹² cm^-2 is inherently incorporated. The P_b density... (Read more)

The 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)

Ab 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)

The thermal interaction kinetics of interfacial Si dangling bond Pb defects (Si3≡Si·) in (1 1 1)Si/SiO2, including passivation in molecular hydrogen (pictured as PbH formation) and dissociation in vacuum, is readdressed. An initial simple thermal model had concluded simple exponential... (Read more)

Electron spin resonance (ESR) on thermal (100)Si/SiO₂ predominantly exhibiting either the P_b0 or P_b1 interface defect confirms the P_b1 point symmetry as monoclinic-I with g₁ = 2.0058,... (Read more)

The spectroscopic properties, structure and interconversions of optically active oxygen-deficiency-related point defects in vitreous silica are reviewed. These defects, the E′-centers (oxygen vacancies with a trapped hole or 3-fold-coordinated silicons), different variants of diamagnetic... (Read more)

Electron paramagnetic resonance (EPR) measurements of Si/SiO₂ systems began over 30 years ago. Most EPR studies of Si/SiO₂ systems have dealt with two families of defects: P_b centers and E centers. Several variants from each group have... (Read more)

Four sets of ESR doublets with splittings of 9, 23, 26 or 44 mT were observed in dry a-SiO2 (Type IV, OH concentrations1017 cm−3) implanted with 29Si+ to a fluence of 6×1016 cm−2 at 160 keV. These doublets were attributed to the hyperfine structures due to a 29Si nucleus of... (Read more)

An optimized electron spin resonance study has resulted in the observation of the full angular dependence of the hyperfine interaction spectrum associated with the unpaired electron of the P_b1 point defect at the thermal (100)Si/SiO₂ interface, showing that the dominant... (Read more)

In situ electron-spin-resonance (ESR) measurements of film growth of hydrogenated amorphous silicon (a-Si:H) using a remote hydrogen plasma technique have been performed. The Si dangling-bond signal in a-Si:H during and after deposition has been detected, in addition to the... (Read more)

Electron paramagnetic resonance spectra were measured on SiO2 glasses implanted with Si ions to a fluence of 6 × 1016 cm−2 at an acceleration voltage of 160 kV. Three sets of doublets with different separation were observed in Si29-implanted substrates and were ascribed to primary... (Read more)

Three varieties of E′ centers with a spin state, S = 1/2, and with a G-tensor, Gx Gy 2.0003, Gz 2.0018, were identified in the early reports on paramagnetic states in irradiated α-quartz. The atomic structure of two of these had an hydrogen ion (proton) in nearby sites and hence... (Read more)

Electron-spin-resonance (ESR) studies of intrinsic P_b defects at the (111)Si/SiO₂ interface have been carried out as a function of oxidation temperature T_ox for the range 22<T_oxT_ox and high-T_ox... (Read more)

The observation of optically detected magnetic resonance (ODMR) signals directly correlated with dislocations in silicon is reported. The ODMR signals are identified as resonances from free electrons, dangling bonds, and quasifree holes bound to a one-dimensional potential in straight dislocations.... (Read more)

The observation of (111) Si/SiO₂ interface P_b0 defects (modeled as ⁰SiSi₃) with dangling bonds positioned along [11], [11], and [11] from low-temperature (T30 K) electron spin resonance measurements is reported. This is connected with... (Read more)

In 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 (P_b... (Read more)

It is observed that the linewidth and line shape of the Zeeman resonance associated with dangling bonds at the (111)Si-SiO₂ interface (P_b centers) vary with the direction of the applied magnetic field. An analysis of the line shape of this resonance indicates that it can be... (Read more)

Electron spin resonance (ESR) experiments have been carried out at cryogenic temperatures (4.2 T 35 K) and room temperatures at 9.0 and 20.9 GHz on the Pb0 and Pb1 (commonly referred to as Pb) spin-active defects residing at the Si/SiO2 interface. The ESR lineshapes were shown to display gaussian... (Read more)

The hyperfine spectrum associated with unpaired electrons at the (111) Si/SiO₂ interface (P_b centers) is reported for the first time. Electron paramagnetic resonance measurements indicate that the hyperfine interaction S··I arises from the... (Read more)

Interface states and electron spin resonance centers have been observed and compared in thermally oxidized (111) and (100) silicon wafers subjected to various processing treatments. The ESR P_b signal, previously assigned to interface ·SiSi₃ defects on (111)... (Read more)

Magnetic properties of the dislocation dangling bond (DDB) spin system in silicon crystals are investigated by means of the EPR technique at T = (1.3 to 150) K. Experimental results are obtained which enable one to develop a one-dimensional model of the spin system according to which the DDB chains... (Read more)

Amorphous SiOx-layers with O < x < 2 have been prepared by evaporation of Si at oxygen pressures of 10−6 … 10−3 mbar. The composition of the samples was determined by proton backscattering. The band gap, derived from optical measurements, increases with rising oxygen... (Read more)

Three kinds of paramagnetic centers named P_A, P_B and P_C have been found in a silicon-silicon dioxide structure at liquid nitrogen temperature. P_A (g=∼2.000, ΔH=∼4 Oe), and P_B having anisotropic g-value... (Read more)

EPR measurements have been made on aligned cleavage faces of Si, prepared and studied in high vacuum (<10^-9 Torr). The signal, observable after accumulation, is a single line at g=2.0055 with width 6 G, similar to that from vacuum-crushed powders. It is unaffected by oxygen exposures... (Read more)