[en] Charge trapping in HfO₂ films on Si(1 0 0) was studied using generation of electron-hole pairs in the oxide by 10 eV photons. The oxide deposition chemistry strongly influences the density and sign of the trapped charge: positive charge is observed in films obtained from HfCl₄ and metallo-organics, while negative charge is dominant in the films grown from Hf(NO₃)₄. The weak dependence of the trapped charge on the HfO₂ thickness suggests that charging is associated with a silicon oxide interlayer grown between the Si and HfO₂ during deposition. The latter is affirmed by enhancement of the charging after oxidation of the samples at 650 deg. C, indicating the interfacial silicon oxide as being the key factor determining the electrical stability of the HfO₂ insulating stacks

[en] Si-on-insulator structures formed by implantation of oxygen (SIMOX) in a single step to a dose approx = 1.8 x 10¹⁸ O⁺ cm^-2 into p-type (0 0 1) Si and high temperature annealing have been studied by K-band electron spin resonance (ESR) at 4.3-31 K. γ-irradiation to a dose of 1 Mrad (Si) is found to introduce a new anisotropic ESR signal originating from a shallow donor in Si. It is tentatively assigned to an oxygen-related double donor intrinsic to SIMOX, which ionization state is tuned by changes in Si band bending resulting from modification of the net charge in adjacent SiO₂ by γ-irradiation. Possibly, this centre relates to the new donors recently suggested from transport measurements. (author)

[en] The characteristic energy loss corresponding to band-to-band electron excitation at the SiC surface is observed in the internal photoemission (IPE) spectra of SiC-SiO₂ interfaces for three polytypes of SiC (4H, 6H, and 15R). From this feature the SiC bandgap width at the interface with thermal oxide was found to be the same as in the bulk of SiC. This importantly indicates that oxidation in dry O₂ at temperatures as high as 1300 deg. C does not lead to polytypic transition in SiC

[en] Published in summary form only

[en] The electron-electron cross-relaxation rate has the right order of magnitude to explain the variation of linewidth and g factor against temperature of Conduction Electron Spin Resonance in Aluminium at low temperatures. (orig.)

[en] Optical absorption (OA) and electron spin resonance measurements have been performed on IIa, Ib, IaA and IaB type diamonds irradiated by 3 MeV electrons. OA reveals that the GR1 system in diamond is usually accompanied by an underlying broad background band, which is tentatively attributed to strained neutral vacancies (V deg. ). The photochromic changes in OA suggest that the concentration calibration constants for the V deg. , H3 and H4 defects should be halved, that the 3H and 5RL centres could be different charge states of a di-interstitial related defect and that the di-interstitial R1, 3H and 5RL centres in diamond are stable to annealing temperatures up to at least 800 deg. C. The generation and annealing of interstitials and vacancies have been studied as a function of the nitrogen concentration and aggregation state. The results suggest that single substitutional nitrogen (N_S) efficiently traps carbon interstitials, but releases them upon annealing at 400 deg. C. Defects related to nitrogen aggregation in IaB diamond also trap interstitials, but do not release them upon annealing. Carbon interstitials are not trapped by N_S-N_S pairs. Instead, an increase in the concentration of N_S-N_S centres enhances the production rates of vacancies and interstitials, reduces their annealing temperatures and favours formation of the 3H over R1 di-interstitials

[en] The generation of interface defects during the injection of electrons in metal-oxide-semiconductor (MOS) structures with thin SiO₂ gate layers and SiO₂/ZrO₂ gate stacks is investigated. A model is proposed to explain the kinetics of interface defect generation, based on the depassivation of trivalent silicon dangling bonds at the (1 0 0)Si/SiO₂ interface by the injected electrons. A gaussian spread for the activation energy E_d related to the dissociation of the Si-H bond is included in this model. Comparison with experimental results reveals that the mean value of the activation energy E_di decreases linearly with the electric field E_ox across the SiO₂ layer. This behaviour is attributed to the alignment of the Si-H dipole moment with respect to E_ox, which favours the dissociation of the Si-H bond

[en] In view of its application as an intensity marker in electron spin resonance, the conduction electron spin resonance signal of Li particles in neutron-irradiated LiF has been analysed regarding its lineshape, linewidth, intensity and spectral composition in the temperature range 4.2 ≤ T ≤ 300 K at the X and K bands. (author)

[en] The influence of ion implantation of ⁵⁶Fe and ⁶³Cu on the bulk properties of the conduction electrons in aluminium has been investigated with the reflection conduction electron spin resonance (CESR) technique at 21 GHz. The doses were kep low and varied from 3 x 10¹³ to 5.4 x 10¹⁴ atoms cm^-2. Below 25 K, large line broadening and an unexpected g rise has been found in the nonannealed Fe implanted samples, which indicate the existence of surface spins. From the similarity between pure and ion implanted Al it is concluded that surface spins may be important in the so called pure Al too. (author)

[en] The small width (∼ 0.02 mT for T < 150 K) and low g value (∼ 1.9800) of the ESR signal observed from low concentrations (<∼ 1 ppm) of ⁵²Cr³⁺ ions embedded in MgO suggests that this material may be very useful as a general ESR intensity and g marker. The 9.55% naturally abundant ⁵³Cr (I = 3/2) isotope, however, complicates the former single-line spectrum with a hyperfine (HF) quartet. The low-field HF components often hinder (frequent) measurements of weak spectra in the near-g 2.0023 region. Based on ⁵²Cr ion implantation in 6 N pure Mg foil a method is presented which eliminates the HF spectrum. The resulting MgO:⁵²Cr³⁺ powder only exhibits one narrow line of which ESR analysis shows it to be a very convenient marker. Regarding the physical properties of the ⁵²Cr³⁺ ions, weakly asymmetric line shapes emerge, being more pronounced the higher the observational frequency and/or the lower T. From this, the existence of a non-negligible uβS³B term in the effective spin Hamiltonian of cubic-site Cr³⁺ impurities im MgO is inferred. Independent measurements of u(T) and g(T) (g being the isotropic Zeeman-term spectroscopic splitting factor) reveal both quantities to exhibit an identical T dependence arising from the implicit thermal lattice expansion (i.e., u and g ∝ d⁵; d is the Cr³⁺ site-to-nearest-neighbor-oxygen distance). This finding, which disagrees with former results, is in accordance with the simple crystal field model. Also in accordance with this model, no g anisotropies are observed. (author)