Individual interface traps at the Si-SiO2 interface

In submicrometre-sized metal-oxide-semiconductor field-effect transistors, MOSFETs, the alternate capture and emission of carriers at individual Si-SiO₂ interface defects generates discrete switching in the source-drain resistance. The resistance changes are observed in the drain current as random telegraph signals (RTSs) or as stepped transients after a strong perturbation of the trap occupation. The study of individual defects in MOSFETs has provided a powerful means of investigating the capture and emission kinetics of interface traps, it has demonstrated the defect origins of low-frequency (1/f) noise in MOSFETs, and it has provided new insight into the nature of defects at the Si-SiO₂ interface. The analysis of individual interface defects has shown that a Coulomb energy of several hundred millivolts is involved in the transfer and localization of the single charge carrier into the interface trap.     

Al-V-graphite interface reactions: an XAFS study of the reactions in a composite interface system

The high temperature reaction properties of a metal matrix composite interface have been observed in this research by X-ray reflectivity and X-ray absorption fine structure (XAFS) coupled to Auger electron spectroscopy (AES). This study was taken from the vantage point of the vanadium diffusion barrier interfacial layer in a model aluminum-graphite metal-matrix laminate composite. The interfacial couple of aluminum and vanadium was analysed to ascertain the reaction species at temperatures between 200 and 350 °C. X-ray reflectivity and glancing angle XAFS showed that the initial Al-V reaction occurred at 325 °C where the aluminum-rich intermetallic Al₃V formed. Small angle XAFS was used to analyse the higher temperature interfacial changes in the temperature range of 300–500 °C. Further interactions occurred at 500 °C, where interdiffusion of Al, C and O occurred leading to phase formation of the vanadium, dependent on the graphite basal plane orientation. AES, used to determine the initial compositions and those resulting from the high temperature heat treatments, complemented the XAFS results.     

Individual interface traps at the Si—SiO2 interface

In submicrometre-sized metal-oxide-semiconductor field-effect transistors, MOSFETs, the alternate capture and emission of carriers at individual Si—SiO₂ interface defects generates discrete switching in the source-drain resistance. The resistance changes are observed in the drain current as random telegraph signals (RTSs) or as stepped transients after a strong perturbation of the trap occupation. The study of individual defects in MOSFETs has provided a powerful means of investigating the capture and emission kinetics of interface traps, it has demonstrated the defect origins of low-frequency (1/f) noise in MOSFETs, and it has provided new insight into the nature of defects at the Si—SiO₂ interface. The analysis of individual interface defects has shown that a Coulomb energy of several hundred millivolts is involved in the transfer and localization of the single charge carrier into the interface trap.     

Clinorotation Affects the Ultrastructure of Pea Root Mitochondria

Effects of clinorotation on the mitochondrial ultrastructure in cells of meristem, distal and central elongation zones of 3- and 5-day-old etiolated roots of pea seedling roots were studied. It was shown that mitochondria in cells of examined root growth zones revealed a different sensitivity to clinorotation. The ultrastructure of mitochondria in the meristem and central elongation zone cells did not substantially change in comparison with stationary control. At the same time, changes in the mitochondrial ultrastructure in cells of the distal elongation zone under clinorotation were observed, namely: decrease in the size of mitochondria, as well as increase in both matrix electron density and crista volume. Such changes in the mitochondrial ultrastructure under clinorotation are supposed to display the rearrangements of energy metabolism in cells of the distal elongation zone in these conditions.     

Atomic origin of the traps in memristive interface

In recent years,trap-related interfacial transport phenomena have received great attention owing to their potential applications in resistive switching devices and photo detectors.Not long ago,one new type of memristive interface that is composed of F-doped SnO2 and Bi2S3 nano-network layers has demonstrated a bivariate-continuous-tunable resistance with a swift response comparable to the one in neuron synapses and with a brain-like memorizing capability.However,the resistive mechanism is still not clearly understood because of lack of evidence,and the limited improvement in the development of the interfacial device.By combining I-V characterization,electron energy-loss spectroscopy,and firstprinciple calculation,we studied in detail the macro/micro features of the memristive interface using experimental and theoretical methods,and confirmed that its atomic origin is attributed to the traps induced by O-doping.This implies that impurity-doping might be an effective strategy for improving switching features and building new interfacial memristors.     

Instabilities of the liquid solid interface

Bodensohn et al.¹ observed that a sudden temperature change of the liquid above 1.1 K caused the interface between solid and liquid⁴He to become corrugated; they proposed that the instability of the interface was caused by the introduction of a heat current induced by the temperature gradient. Subsequently Grinfeld² showed that a non hydrostatic stress of the crystal could cause an instability; this idea was put forward by Balibar, Edwards and Saam³ to explain the observation of Bodensohn et al. A more detailed analysis has been given recently by Bowley and Nozières⁴. The two causes of instability are analyzed in the present paper for both normal³He and superfluid⁴He. The phase diagram and critical heat current for normal³He are presented. The corrugations will appear most rapidly near the minimum of the melting curve at 0.32 K and need a temperature gradient of order a few µK/cm. For superfluid⁴He the inability of the liquid to support thermal conduction (heat is transported by second sound) changes the nature of the instability, with the result that dissipation at the interface becomes important. As a consequence only the Grinfeld instability is observable in practice so that corrugations appear with wavelength between 6 and 8 mm.     

The competition between the crack kinking away from the interface and crack propagation along the interface in elastic bicrystals

The problem analyzed is of the crack kinking away from the interface between the two different anisotropic materials. The attention is concentrated on the initiation of the crack kinking and the condition that the length of the crack segment that is leaving the interface is small in comparison to the crack segment that remains along the interface. The emphasis is placed to the application of the fracture mechanics concept for the interfacial crack that propagates dynamically between the two orthotropic materials. The simulations and calculations were done by application of the Mathematica ^® programming routine. The stress intensity factors and the energy release rate are obtained for the kinked crack, as functions of the corresponding values for the interfacial crack prior to kinking. The analysis was performed of the influence of anisotropy on the crack kinking versus crack propagating along the interface competition. Due to anisotropy the kinking is easier, i.e., it is easier for the crack to kink away from the interface into the “softer” of the two materials. The oscillatory index for the case of the dynamic crack growth along the interface between the two orthotropic materials increases with crack tip speed v and with increase of the difference in stiffnesses. The practical application of this analysis could be for the interface in the glued joints and protective coatings.     

Fingering of the solid-liquid4He interface in two-dimensions

A novel Hele-Shaw experiment is described in which the two fluids are superfluid and solid⁴He. A thin cell in which solid and liquid⁴He initial occupy the lower and upper halves, respectively, is inverted. The growth of solid⁴He by simultaneous melting and freezing of different parts of the interface is monitored. Qualitative results on the shape of the interface and the growth rate are presented.     

Fracture toughness of the fibre-matrix interface in glass-epoxy composites

The failure process arising at a broken fibre end in polymer matrix composite materials has been studied experimentally and analytically using the finite element method. A series of experiments were carried out using S-glass and E-glass single filaments, with different sizings and/or coupling agents, embedded in epoxy matrices with different moduli. A finite element analysis was used to simulate the experiments and calculate the change in strain energy accompanying the observed fracture mode. The strain energy release rate upon arrest of the crack, G _arrest, was then calculated. The measured interface debonding energies varied from G _arrest=57–342 J m^–2, depending primarily on the nature of the fibre sizing and the ratio of moduli of the fibre and matrix. Transverse and shear matrix cracks were characterized by G _arrest values of 58–103 J m^–2. Subtle changes in the constituent properties or fibre surface treatment resulted in a change in the fracture mode. This measurement and analysis technique may suggest reasons for the variability of previous measurements of interfacial adhesion, and provide a standard method for characterizing fracture modes at broken fibre ends.     

Formation of a film-substrate interface in the silicon-diamond system

The paper presents results of research on the forces of interaction of a pair of isolated carbon atoms and of a carbon atom in the gas phase with diamond and silicon substrates in relation to the distance between them. Based on the results obtained, the conclusion is drawn that the transition of atoms to an ordered array in formation of a single-crystal film is caused by the forces of interaction between atoms of the precipitate whose electronic structure can change with a change in the energy of interaction. Belarusian State University, Minsk, Belarus. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 72, No. 1, pp. 138–140, January–February, 1999.     

Study of the diamond-matrix interface in hot-pressed cobalt-based tools

The interface between the constituents of a tool material produced by hot pressing of diamond particles and a metallic powder was studied. Morphological, structural and chemical analyses by scanning electron microscopy, X-ray diffraction and Auger electron spectroscopy were performed in order to characterize the interaction between diamond and cobalt powder during the consolidation. They revealed that graphite, cobalt carbide and a Co---C solid solution do form and are linked to the action of strong bonding between the constituents, but that diamond deterioration is also induced. To avoid graphitization of the diamond, and to improve the technological properties of the composite material, low percentages of tin were added to the metallic matrix; this proved to be effective.     

Variable power singular interface elements for a crack normal to the bimaterial interface

Zero thickness crack tip interface elements for a crack normal to the interface between two materials are presented. The elements are shown to have the desired r^λ−1 (0 < λ < 1) singularity in the stress field at the crack tip and are compatible with other singular elements. The stiffness matrices of the quadratic and cubic interface element are derived. Numerical examples are given to demonstrate the applicability of the proposed interface elements for a crack perpendicular to the bimaterial interface.