Anomalous tensoelectric effects in gallium arsenide tunnel diodes

Anomalous tensoelectric phenomena induced in a tunnel p-n junction by a concentrated load and by hydrostatic compression were studied. The anomalous tensoelectric effects are caused by the action of concentrators of mechanical stresses in the vicinity of the p-n junction, giving rise to local microplastic strain. Under the conditions of hydrostatic compression prolate inclusions 100–200 å long play the role of concentrators. Analysis of irreversible changes in the current-voltage characteristics of tunnel p-n junctions made it possible to separate the energy levels of the defects produced with plastic strain of gallium arsenide.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 84–88, August, 1987.     

Behavior of excess currents in n-type gallium arsenide tunnel diodes

An investigation was made into the nature of the excess currents in n-type gallium arsenide tunnel diodes and the influence of irradiation with 2.0-MeV electrons on the current-voltage characteristics of the diodes.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 82–86, March, 1981.     

Thermal instability of peak current in tunnel diodes

The effect of temperature change on stability of electrical characteristics of GaAs and GaSb tunnel diodes is studied. It is shown that thermal stresses developed at the boundary between the electrode alloy and the semiconductor lead to deformations (plastic and creep), localized mainly in the electrode layer. These deformations are sensed by the p-n junction which lies close to the phase boundary, which leads to a relaxation of peak current, and its hysteresis-type temperature dependence.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 77–82, December, 1985.We express our gratitude to N. P. Krivorotov for his interest in the study and valuable discussion.     

Effect of intrinsic lattice defects on excess currents of gallium arsenide tunnel diodes

Gallium arsenide tunnel diodes were irradiated with electrons of energy E = 2.0 MeV at room temperature. Secondary hump structures were observed in the region of 0.45 V and 0.65–1.1 V forward bias. The variation in the excess currents of diodes subjected to electronic bombardment is described on the basis of models including three levels; E_B + 0.25 eV, E_B + 0.55 eV, and E_C–0.5 eV. Annealing of radiation-induced defects is shown to take place in two stages at temperatures of 140–180°C and 200–240°C. Switching and memory effects are observed when the current-voltage characteristics (CVC) of tunnel diodes are measured at liquid-nitrogen temperatures in darkness.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 88–92, September, 1976.     

Effect of electron irradiation on the parameters of gallium arsenide pulsed diodes

It is shown that the current-voltage characteristics of diodes produced by various methods vary in approximately the same manner. The behavior of the capacitance C(U) during irradiation can be explained on the basis of the theories developed for planar p-n junctions and Schottky barriers. The recovery time of diodes always increases during irradiation with large doses ( 10¹⁶ electrons/cm²). At smaller doses for diodes of the Schottkybarrier type (weakly formed), _recov always increases with irradiation, perhaps due to a decrease in the concentration n; for strongly formed diodes (having parameters approximating those of diffused diodes), the _recov behavior is governed by the nature of the impurity distribution and by the ratio of the lifetime of the minority carriers to the diode time constant ¯R¯C. With > RC, a decrease in _recov may be observed as a result of a decrease in .Translated from Izvestia VUZ. Fizika, No. 4, pp. 109–113, April, 1970.     

Sources of 1/F noise in gallium arsenide IMPATT diodes

The quasistatic approximation is used to analyze 1/F noise in IMPATT diodes in the static and dynamic (self-oscillating) modes. Sources of 1/F noise are defined in accordance with the fluctuator model: allowance is made for fluctuations of the charge of traps and fluctuations of the electron drift velocity caused by their scattering by traps and metastable neutral centers. It is shown that the fluctuations of the voltage across the diode and the fluctuations of the oscillation frequency are mainly determined by the fluctuations of the trap charge, while the fluctuations of the oscillation amplitude are determined by scattering by neutral centers. A method is developed to determine the intensity of noise sources using the results of measurements of the fluctuations in the static and dynamic modes of IMPATT diodes and a method of checking the model as a whole is checked. Experimental results are presented and these show satisfactory agreement with the calculations. Zh. Tekh. Fiz. 67, 65–70 (August 1997)     

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.     

Thermal oxidation of gallium arsenide

The experimental results of this study of the thermal oxidation of GaAs under atmospheric conditions and in dry oxygen over a temperature range of 400–530C are presented. It is shown that for temperatures in the range of 400–450C the oxide layers are formed according to a parabolic law while for temperatures in the range of 480–530C they are formed according to a linear law. An interesting dependence of the reflectivity of GaAs with an oxide layer on the thickness of this layer during the initial stage of the oxidation process is described, giving evidence of the complex structure of the layer formed.     

Oscillatory photoconductivity of gallium arsenide

The photoconductivity of GaAs in the energy range 1.5 –1.8 eV at 4.2 K exhibits two types of quantum oscillations: Landau oscillations for epitaxial material in high magnetic fields or LO phonon oscillations for high resistivity material. The purity and surface treatment of the samples seem to determine the type of oscillations observed.     

Ion doping of gallium arsenide

Conclusion The survey presented shows that despite the intensive study of the physical problems of ion implantation in GaAs, there is still a number of questions to investigate. Among them are: The role of anomalous diffusion and channeling in the formation of concentration profiles, the anomalous diffusion mechanism, the influence of radiation defects and residual impurities as well as the form of the coating, the interaction between impurities and defects under ion implantation, and the identification of radiation defects, A further study of the above-mentioned questions will permit extension of the application of the ion implantation method to obtain GaAs semiconductor instruments and realization of still unused possibilities of this powerful method of modern semiconductor technology.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 76–90, January, 1980.     

Effect of hydrogen on the photoelectric properties of palladium/anodic oxide/gallium arsenide Schottky diodes

The effect of hydrogen on the photovoltage and I-V characteristics of palladium/anodic oxide/gallium arsenide Schottky diodes is studied. The oxide thickness that is optimal in terms of the hydrogen sensitivity of the diodes and the depth of atomic hydrogen penetration into the oxide are determined. The mechanism behind the hydrogen effect consists in the chemical adsorption of atomic hydrogen on the gallium arsenide surface, which decreases the barrier height and increases the recombination component of the current. It is shown that a thin tunnel-transparent anodic oxide film is nonuniform in thickness and that hydrogen exposure raises the probability of tunneling through the oxide. It is found that the method of hydrogen detection from the photovoltage response offers a higher sensitivity and detectivity but has a lower speed than the reverse current method.     

Two-photon optical-beam-induced current imaging of indium gallium nitride blue light-emitting diodes

Epilayers of packaged indium gallium nitride light-emitting diodes (LED's) are characterized by optical-beam-induced current (OBIC) and photoluminescence laser-scanning microscopy through two-photon excitation. Light scattering and absorption in the packaging material and the p-doped top layer of the LED's are greatly reduced as a result of employing a longer excitation wavelength, with energy that is less than the bandgap of the top p layer. Compared with single-photon OBIC, two-photon OBIC imaging not only exhibits superior image quality but also reveals more clearly the characteristics of the epilayers that are being focused on.