Effect of hydrogen on the current-voltage characteristics of tunneling mis diodes based on gallium arsenide

Results are presented for experimental studies of the static current-voltage characteristics of tunneling MIS diodes based on n-type gallium arsenide. It is shown that the forward branch of the current-voltage characteristics can be used to determine the dependence of the surface potential at the dielectric-semiconductor interface on the voltage and the distribution of the surface state density over energy in the forbidden band. The results of studies of these dependences for diodes prepared by thermal annealing at various temperatures are given. The possible causes of changes in the forward and reverse current, and the dependence of the surface potential on the voltage and distribution of surface state density in energy under the action on the diodes of a gaseous mixture containing hydrogen are analyzed. V. D. Kuznetsov Siberian Physicotechnical Institute at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 69–83, January, 1998.     

Linear parameters of helical instability in thick silicon wafers at 300 K

An analysis is performed on the dependence of the threshold electric field intensity (E_t) of helical instability of a semiconductor plasma on the magnetic induction and threshold frequency on E_t at a temperature of 300 K allowing for the form of the volt-ampere characteristic curve of the specimen. It is shown that when the field dependence of the charge carrier concentration in the specimen is taken into account, the variation in the rate of surface recombination and volume lifetime in the process of preparing the specimen, the variation in the path of the threshold curve, and the variation in the field dependence of the threshold frequency are satisfactorily described by helical instability theory for the case of a homogeneous plasma for n p and _{n p}. The basic cause of incomplete matching of the experimental and theoretical curves is apparently due to not fulfilling the condition on homogeneity of the plasma and the electric field in the presence of the injection of charge carriers from the contacts.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 49–53, August, 1991.The author is grateful to Yu. V. Medvedev for performing the measurements of the parameters by microwave techniques and to O. N. Merkulova for her assistance in writing the computer program.     

Current transfer mechanism in metal-dielectric-metal systems based on vanadium-phosphorus glasses

Based on an analysis of the volt-ampere characteristics and temperature dependence of conductivity, the mechanism of current transfer is discussed in thin-film systems of metal/vanadium -phosphorus glass/metal. The conclusion is drawn that the magnitude of the current in samples obtained by sputtering of the glass on a hot backing (T_b = 200°C) is determined by the resistance of the volume of the glass film, but for samples sputtered on a cold backing (T_b = 30–90°C), by the resistance of the potential barriers at the metalglass interface. It is supposed that current transfer in a film of glass is accomplished by polarons of small radius.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No.2, pp. 107–115, February, 1976.     

Influence of oxygen adsorption on the surface potential of a metal oxide semiconductor

Analytical expressions describing dependences of the surface density of adsorbed oxygen ions and energy band bending in the subsurface region of a metal oxide semiconductor on the oxygen concentration that consider not only the process of neutral gas particle adsorption, but also their charge transfer at the expense of electron capture from the conduction band are presented. It is demonstrated that the heat of oxygen ion absorption is equal to the sum of the heat of neutral particle adsorption and the energy gap between the Fermi level and the level of the oxygen ion on the semiconductor surface. When the adsorption equilibrium is established, an analytical expression describing the time dependence of the energy band bending can be obtained only for small change of the oxygen concentration in the gas mixture.     

Basic physics of semiconductor hydrogen sensors

The most probable physical models of hydrogen sensors based on thin stannic oxide films, MOS-structures, and tunnel MOS-diodes are discussed. The emphasis is on the mechanisms of formation of sensor response to hydrogen. The analytical equations describing the dependence of the response on the hydrogen concentration nH₂ are derived for all types of sensors. The relations describing the dependences of the SnO ₂-sensor conductivity and response on the absolute humidity of a gas mixture are given. It is shown that the relaxation time τ_rel of the response of SnO ₂-and MOS-structure sensors is determined by the relaxation time τ_a of hydrogen atom adsorption on the SnO ₂ and SiO ₂ surfaces, respectively. For the MOS-diodes, τ_rel = τ_a at nH₂ and τ_rel = τ_d at nH₂≥7.5·10³, where τ_d is the relaxation time of hydrogen atom diffusion through an SiO ₂ layer. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 84–98, April, 2008.     

The effect of an anisotropic pressure on the reverse currents and the lifetime of minority carriers in germanium diodes

The effect of pressure on the reverse currents, the lifetime of minority carriers and the charging capacitance of fused germanium diodes is considered. The p-n junctions are arranged in the (111) crystallographic plane. It is established that the reverse current increases rapidly with increased pressure. The lifetime of minority carriers falls by a factor of 1.5 to 2 up to a pressure of 3 · 10⁹ dyne/cm² and the charging capacitance increases. Starting from a pressure of 3 · · 10⁹ dyne/cm² the lifetime of minority carriers increases and the charging capacitance is reduced to a particular constant value. A qualitative explanation of the dependence of _e, Cj and I_rev is given.     

Charge transport mechanism in metal-Tb2GeS5-Ge structure

Structures of the metal-amorphous film of an insulator (or semiconductor)-semiconductor type are being used more and more widely in electronics. Interest therefore attaches to an investigation into the characteristics of such structures based on new insulating and semiconducting materials. In the present paper, the charge transport mechanism in aluminum-amorphous film of Tb₂GeS₅-germanium structures, which can generate an alternating current in the rf range, is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 3–7, January, 1981.     

Time Dependence of the Capacitance of a MOS Silicon Tunnel Diode under the Influence of Hydrogen

The results of theoretical and experimental investigations into the time dependence of the capacitance of MOS silicon diodes with a thin tunnel dielectric and a palladium field electrode under the influence of a gas hydrogen-containing mixture are presented. Analytical expressions are derived that describe the time dependence of the capacitance of the space charge region (SCR) of the MOS tunnel diode operating in depletion and enrichment regimes. It is demonstrated that the time dependence of the SCR capacitance of the MOS diode placed in the gas mixture is caused by diffusion of hydrogen atoms from the field electrode to the SiO _x –n-Si interface. The relaxation time of hydrogen atom accumulation at the interface is 47 s for the diode with a SiO _x layer thickness of 3.7 nm placed in the gas mixture with 0.3 vol.% of H₂. It has been established that the flat band voltage and the SCR capacitance of the MOS diode change under the influence of the gas mixture due to the decreased density of surface acceptor states at the SiO _x –n-Si interface, the increased positive charge density in the dielectric, and the decreased contact potential difference.     

Silicon oscillistor as a thermometer with frequency output

We present experimental results for a silicon thermometer (p⁺-p-n⁺ device placed between the poles of a permanent magnet) with a frequency output. Measurements were made for temperatures in the range 77–335 K. When the temperature increases from 77 K to 335 K the device sensitivity decreases from 40 kHz/K to 3.1 kHz/K for a pulsed operating voltage of 65 V. The device sensitivity can be controlled through the operating voltage. We analyze the basic properties of thermometer element using the theory of the bulk helical instability of the semiconductor plasma. We compare its performance parameters with those of previously known devices with frequency outputs.V. D. Kuznetsov Siberian Physico-technical Institute at Tomsk University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 48–53, February, 1995.     

Determining effective lifetime of minority carriers from growth curve of voltage across A p-n junction

Experimental data from determinations of the effective lifetime of the minority carriers, their rate of surface recombination, and their rate of recombination at a non-rectifying contact is reported for germanium alloy diodes. The method of determining these quantities is based on a transition process of switching the diode from the neutral to the conducting state using a current pulse cycle.