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.     

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.     

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.     

Plasma reflection in gallium arsenide

Procedures recently proposed for determining electrophysical parameters of highly doped semiconductors from the IR reflection spectra are analyzed. The case of n-type GaAs is discussed. Optical and Hall measurements have been carried out for a few samples, and it has been found that the electron density determined from the optical measurements is in good agreement with the Hall values, while the mobilities may differ significantly. It is concluded that mechanical polishing causes problems.Translated from Izvestiya VUZ. Fizika, No. 10, pp. 65–69, October, 1969.     

Porous gallium arsenide with arsenic clusters

It is for the first time that the possibility is demonstrated of preparing gallium arsenide with arsenic clusters under conditions of annealing of its porous layers obtained by electrochemical etching. It is found that the clusters are concentrated in porous layer barriers, their size ranges from 1 to 10 nm, and the density reaches 4×10¹⁸ cm⁻³. Under conditions of annealing in the temperature range from 400 to 600°C, an improvement in the structure quality of the porous layer is observed, and the lattice parameter (reduced for this layer) increases to approach a value characteristic of a single crystal. When highly alloyed substrates of the n-type are used, the inversion of the type of conductivity is observed in the surface part of the porous layer, which is due to the emergence of deep-lying acceptor centers. Thermal annealing leads to a narrowing of the inversion layer and to a more uniform distribution of electrically active centers over the porous layer thickness.     

Electrophysical properties of heat-treated gallium arsenide

The electrical conductivity, Hall effect, ionization energy, and defect concentration of GaAs samples subjected to various forms of heat treatment were studied. The original material comprised single crystals grown by the Bridgman and Czochralski methods with electron concentrations of 2·10¹⁵–7·10¹⁷ cm^–3. The ionization energy and defect concentration were calculated with an electronic computer. The thermal conversion of GaAs was attributed to traces of copper, lattice defects, and residual impurities. The mobility varied in a complicated manner with the temperature of heat treatment in GaAs samples retaining their original n-type conductivity.Translated from Izvestiya VU Z, Fizika, No. 3, pp. 69–76, March, 1973.     

Optical properties of laser-type gallium arsenide

Measurements of the optical properties of laser-type Ga As indicate a peak in the refractive index at the absorption edge frequency. The magnitude of the peak decreases as the doping levels are increased and the slope of the absorption edge decreases.     

Phonon heat transport in gallium arsenide

The lifetimes of quantum excitations are directly related to the electron and phonon energy linewidths of a particular scattering event. Using the versatile double time thermodynamic Green’s function approach based on many-body theory, an ab-initio formulation of relaxation times of various contributing processes has been investigated with newer understanding in terms of the linewidths of electrons and phonons. The energy linewidth is found to be an extremely sensitive quantity in the transport phenomena of crystalline solids as a collection of large number of scattering processes, namely, boundary scattering, impurity scattering, multiphonon scattering, interference scattering, electron–phonon processes and resonance scattering. The lattice thermal conductivities of three samples of GaAs have been analysed on the basis of modified Callaway model and a fairly good agreement between theory and experimental observations has been reported.     

Heat-stimulated currents in semi-insulating gallium arsenide

The energy spectrum of charge carrier traps of semi-insulating n-type gallium arsenide has been investigated by the method of heat-stimulated currents and the parameters characterizing these traps have been estimated. Trap acceptor levels with energies 0.37, 0.41 and 0.17, 0.28, 0.32, 0.34, 0.38, 0.40 eV have been found for samples with the specific resistivity 2.7 · 10⁷ and 1.6 · 10⁸ · cm, respectively. The results obtained are well explained within the framework of the theory of a compensated semiconductor.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 11, pp. 22–26, November, 1971.The authors are grateful to A. P. Vyatkin, V. G. Voevodin, and E. V. Kozeev for kindly providing the gallium arsenide crystals and stimulating the research.     

Residual lattice absorption in gallium arsenide

The residual lattice absorption of GaAs in the three and four phonon regime is measured over a range of temperatures. The spectra reveal persistent structural features which are interpreted theoretically in terms of phonon density of states effects.