Salient features of the electrical characteristics of oxygen-implanted gallium arsenide Schottky-barrier structures

We have studied the deep levels in gallium arsenide implanted with oxygen ions at a low dose of 2·10¹⁰ cm⁻² and the influence of those levels on the current-voltage characteristics of Ni/Pd/Ga Schottky-barrier structures. The deep levels were checked by the thermally-stimulated-current (TSC) method. The number of peaks on the TSC curves and their amplitudes are shown to depend on the oxygen-ion energy and the temperature of the post-implantation anneal. An important role in the formation of centers associated with oxygen is played by gallium diffusion into the protective SiO₂/Si₃N₄ insulator layer as well as by elastic and plastic strain phenomena that occur during deposition of the coating and post-implantation annealing of the specimens. The deep levels due to oxygen are responsible for the appearance of excess currents resulting from recombination as well as for ohmic leakages. V. D. Kuznetsov Siberian Physicotechnical Institute at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 30–36, May, 1996.     

Transport mechanism at a metal-gallium arsenide contact

A study was made of the temperature dependence of the current-voltage characteristics of surface-barrier metal-n-type gallium arsenide junctions with various doping levels. The transport mechanism is shown to be governed by the temperature and by the electric field in the space-charge layer; thermionic or thermionic-field emission occurs.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 82–87, January, 1971.     

Joint consistency in extensions of the minimal logic

Analogs of Robinson’s theorem on joint consistency are found which are equivalent to the weak interpolation property (WIP) in extensions of Johansson’s minimal logic J. Although all propositional superintuitionistic logics possess this property, there are J-logics without WIP. It is proved that the problem of the validity of WIP in J-logics can be reduced to the same problem over the logic Gl obtained from J by adding the tertium non datur. Some algebraic criteria for validity of WIP over J and Gl are found.     

The effect of water vapor on the electrical properties and sensitivity of thin-film gas sensors based on tin dioxide

The results of theoretical and experimental studies into the effect of water vapor on the electrical conductance of a gas sensor and the sensor response to hydrogen action are discussed. A relation describing the dependence of electrical conductance G₀ on absolute humidity in the pure air is derived using a hypothesis of the presence of space-charge regions depleted of electrons between the SnO ₂ grains in a polycrystalline tin dioxide film. Due to dissociative chemisorption of water molecules, the energy-band bending at the SnO ₂ grain interfaces decreases and the oxygen-vacancy concentration in the grains increases, resuling in an increase in G₀. An equation for the sensor response to hydrogen action is derived (the G₁/G₀, ratio, where G₁ is the sensor conductance in a gas mixture containing molecular hydrogen). The expression describes the dependence of G₁/G₀ on the hydrogen concentration in the interval 50–6·10³ ppm, band bending at the SnO ₂ grain interface, and sensor temperature. The dependences of the sensor conductance, highest possible conductance, and energy-band bending on temperature and absolute humidity resulting from processing of the experimental data are in good agreement with the theoretical predictions. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 50–56, August, 2008.