We carry out a comprehensive density-functional study of the vacancy-oxygen (VO) center in germanium using large H-terminated Ge clusters. The importance of a nonlinear core correction to account for the involvement of the 3d electrons in Ge-O bonds is discussed. We calculate the electrical... (Read more)

The authors have calculated that fluorine substituting for oxygen gives no gap states in HfO₂. This accounts for the good passivation of oxygen vacancies by F seen experimentally. Bonding arguments are used to account for why F may be the most effective passivant in ionic oxides such as... (Read more)

The optical excitation and thermal ionization energies of oxygen vacancies in m-HfO₂ are calculated using a non-local density functional theory with atomic basis sets and periodic supercell. The thermal ionization energies of negatively charged V^– and... (Read more)

The self-diffusion coefficient of zinc in ZnO is derived as a function of the chemical potential and Fermi level from first-principles calculations. Density functional calculations in combination with the climbing image-nudged elastic band method are used in order to determine migration barriers for... (Read more)

Two occupied native defect bands are experimentally detected in pure HfO₂. The density of states of band one in the middle of the band gap reduces drastically with the Al addition, while that of band two slightly above the valence-band maximum remains rather unaffected. We attribute the... (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)

Nitrogen is known to reduce leakage currents and charge trapping in high-dielectric-constant gate oxides such as HfO₂. We show that this occurs because nitrogen, substituting for oxygen atoms next to oxygen vacancy sites, repels the occupied gap states due to the neutral and positively... (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)

Oxygen vacancy in cubic HfO₂ was investigated using first-principles calculation based on density functional theory and generalized gradient approximation. Five different charge states (V⁺⁺, V⁺, V⁰, V^–, and... (Read more)

Using ab initio density-functional total energy and molecular-dynamics simulations, we study the effects of various forms of nitrogen postdeposition anneal (PDA) on the electric properties of hafnia in the context of its application as a gate dielectric in field-effect transistors. We... (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)

Using constrained ab initio molecular dynamics, we investigate the reaction of the O₂ molecule at the Si(100)–SiO₂ interface during Si oxidation. The reaction proceeds sequentially through the incorporation of the O₂ molecule in a Si-Si bond and the... (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 observed two paramagnetic defects in thin films of HfO₂ on silicon with electron spin resonance. Both appear after photoinjecting electrons into the dielectric. Strong spectroscopic evidence links one spectrum to an O2^-" align="middle"> defect. A second spectrum is... (Read more)

We report the identification of the nitrogen-vacancy-hydrogen complex in a freestanding nitrogen-doped isotopically engineered single crystal diamond synthesized by chemical vapor deposition. The hydrogen atom is located in the vacancy of a nearest-neighbor nitrogen-vacancy defect and appears to be... (Read more)

Previous calculations on n-type doping of diamond by P and S predicted that S has a shallower level and a higher solubility than P. Our first-principles calculations show that the opposite is true: Phosphorus impurity in diamond gives rise to a shallower donor level, and has a higher bulk solid... (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)

Hydrogen-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)

Deep levels in vanadium-doped n- and p-type silicon have been investigated using deep level transient spectroscopy (DLTS) and concentration profile measurements. The DLTS measurement reveals two electron traps of E_C−0.20 eV and... (Read more)

It is demonstrated that hydrogen can migrate in silicon as a negatively charged species (H^-). The evidence is the combined observation of a strong electric-field dependence in the rate of removal of PH complexes during bias-temperature stress of hydrogenated Schottky-barrier diodes and... (Read more)

Results are reported on the paramagnetic resonance spectrum recently identified with the negatively charged state of substitutional nickel in n-type silicon. Studies were made on the presence of the spectrum in silicon with different concentrations of phosphorus doping and under various conditions... (Read more)

The behavior of hydrogen in crystalline silicon is examined with state-of-the-art theoretical techniques, based on the pseudopotential-density-functional method in a supercell geometry. Stable sites, migration paths, and barriers for different charge states are explored and displayed in total-energy... (Read more)

A review is given on the diffusion, solubility and electrical activity of 3d transition metals in silicon. Transition elements (especially, Cr, Mn, Fe, Co, Ni, and Cu) diffuse interstitially and stay in the interstitial site in thermal equilibrium at the diffusion temperature. The parameters of the liquidus curves are identical for the Si:Ti — Si:Ni melts, indicating comparable silicon-metal interaction for all these elements. Only Cr, Mn, and Fe could be identified in undisturbed interstitial sites after quenching, the others precipitated or formed complexes. The 3d elements can be divided into two groups according to the respective enthalpy of formation of the solid solution. The distinction can arise from different charge states of these impurities at the diffusion temperature. For the interstitial 3d atoms remaining after quenching, reliable energy levels are established from the literature and compared with recent calculations. (Read more)

EPR studies of silicon irradiated at 20.4 K and 4.2 K by 1.5 MeV and 46 MeV electrons are described. In 46 MeV irradiations the dominant defects formed appear to be divavancies and other multiple defect aggregates which liberate vacancies throughout the anneal to room temperature as they reorder, recombine, etc. For 1.5 MeV irradiations group III atoms play a vital role in p- and n-type materials in trapping interstitials and stabilizing damage. Carbon and oxygen are not effective interstitial traps at these temperatures. Evidence of limited vacancy migration during irradiation is also cited. Two distinct excited configurations of vacancy-oxygen pairs are identified as precursors to A-centre formation in n-type silicon. The kinetics for their conversion to A-centres depends strongly upon the Fermi level as does the isolated vacancy migration energy whhich is measured to be 0.18 ± 0.02 eV for the V^＝ charge state. The vacancy has four charge states, V^＋, V⁰, V^－ and V^＝. Kinetics for hole release from V^＋ reveals an activation barrier of 0.057 eV. The concentration of V^＋ at 20.4 K in boron-doped material indicates the corresponding donor level even closer to the band edge, approximately E_V ＋ 0.039 eV. Jahn-Teller energies for V⁰, V^＋, and V^－ are estimated from stress-alignment studies and confirmed to be large. Kinetics studies for reorientation from one Jahn-Teller distortion to another are also described for each charge state.

We have observed ESR signals of negative ions in liquid helium. The linewidth and g value have been measured. Electrons injected into helium by field emission from ferromagnetic tips are shown to be polarized. We propose a new technique for the measurement of electron spin polarization. (Read more)