V. F. Kostryukov

Vaporization and thermodynamic properties of the PbO-V2O5 system

The vaporization of individual lead and vanadium oxides and a wide range of compositions of PbO-V2O5 melts has been studied. The thermodynamic characteristics of the PbO-V2O5 system have been determined, PbO-V2O5 melts show negative deviations from the ideal behavior because of the formation of thermally stable compounds in their condensed phase. For gaseous lead vanadate PbV2O6, the thermodynamic functions have been calculated and the standard enthalpies of formation and atomization have been determined.

Effect of inert components (Y2O3, Al2O3, and Ga2O3) on the chemistimulating effect of the Sb2O3 activator of GaAs thermal oxidation

Chemistimilated thermal oxidation of gallium arsenide was studied using Sb2O3 activator oxide in compositions with Ga2O3, Al2O3, and Y2O3 inert components. For Sb2O3-Y2O3 compositions, the thickness of the resulting oxide layer on GaAs was found to be a linear function of composition over the enter range of the compositions. For antimony oxide compositions with Ga2O3 and Al2O3 inert components, nonadditivities were observed near the component ordinates. For the Sb2O3-Ga2O3 system, the chemistimulating efficiency noticeably weakened at low concentrations of the inert component. The linear trend observed for this system within 0–60 mol % Sb2O3 is additively determined by the oxide layer thickness on GaAs in the presence of Sb2O3 and in the absence of activator. In the presence of inert Al2O3, the chemistimulating effect was enhanced near the Al2O3 ordinate and the resulting function was nonadditive with respect to the thicknesses reached in the presence of the individual components.

Role of solid- and gas-phase interactions in the coaction of the oxides in MnO2 + PbO and MnO2 + V2O5 compositions activating the thermal oxidation of GaAs

Spatial separation of the oxides in MnO2 + PbO and MnO2 + V2O5 binary compositions activating the thermal oxidation of GaAs has made it possible to locate the interactions between these oxides that are responsible for the nonlinear effects observed in their coaction. The solid-phase interactions enhance the chemostimulating activities of both oxides (a positive nonlinear effect takes place). The gas-phase interactions cause a marked negative deviation from the additive chemical stimulation effect.

Role of an inert component in compositions with manganese(II) and manganese(IV) oxides in studying nonlinear effects in GaAs thermal oxidation

GaAs thermal oxidation by mixtures containing manganese(II) and manganese(IV) oxides and gallium arsenide-inert components was studied.

Thermal oxidation of GaAs under action of V2O5–MnO2 oxide chemostimulating formulations with particles size of 50–150 μm

Thermal oxidation of GaAs under action of V2O5–MnO2 formulations of the different composition with particles size of 50–150 μm has been studied. The revealed nonlinear effect of the combined action of the chemostimulators results from their interference accelerating their transformations, changing their evaporation, and affecting their incorporation into the oxide film growing at the GaAs surface.

Combined influence of chemostimulator oxides V2O5 and MnO2 introduced via the gas phase on InP thermal oxidation

The effect of combined gas-phase introduction of vanadium(V) and manganese(IV) oxides on thermal oxidation of InP consists in acceleration of the oxide film formation on the InP samples regardless of the chemostimulators mixture composition. The nonlinear oxide film thickness at the InP surface as a function of the chemostimulators mixture composition has been rationalized as a result of mutual influence of V2O5 and MnO2 changing their heat-induced reactivity and evaporation behavior.

Ammonia response of thin films grown on GaAs using PbO + Bi2O3 mixtures

Thin oxide films exhibiting gas-sensing properties in an ammonia atmosphere have been grown on GaAs surfaces by chemically stimulated thermal oxidation. As shown by electrical measurements, the synthesized materials are n-type. We have studied the effect of thermal processes on the gas-sensing performance of the thin films grown on GaAs using PbO + Bi2O3 mixtures and obtained the temperature dependences of the carrier concentration and mobility in the films.

Spectral ellipsometry study of thin films grown on GaAs by chemically stimulated thermal oxidation

We demonstrate that spectral ellipsometry can be used to characterize thin films grown on GaAs by chemically stimulated thermal oxidation and to determine their thickness in the nanometer range. Our results show that, in the long-wavelength region, spectra of the films studied are well described by the Cauchy model. A two-layer model is used to interpret the spectrum of a heavily doped sample.

Chemically stimulated synthesis of gas-sensing films on the surface of GaAs

Thin nanofilms have been grown on the surface of GaAs via chemically stimulated thermal oxidation. The thickness of the oxide films on the surface of GaAs has been shown to be a nonlinear function of the composition of the mixture of the chemical oxide stimulators. The oxide films obtained, consisting predominantly of Ga2O3, contain small amounts (≤3 at %) of Sb2O3 and V2O5 and exhibit gas-sensing properties in ammonia and carbon monoxide atmospheres, with the highest NH3 sensitivity of 1.29 in the temperature range 200–240°C and the highest CO sensitivity of 1.26 in the range 180–220°C.

Contribution from the solid-phase interactions of activating oxides to their nonlinear joint effect on the thermal oxidation of GaAs

The contribution from the solid-phase interactions in the PbO + Sb2O3 and PbO + Bi2O3 activating compositions to the multichannel process of GaAs thermal oxidation has been determined by spatial separation of the oxides. The solid-phase interactions make a positive contribution to the overall negative nonlinear effect in the dependence of the oxide film thickness on the GaAs surface on the activator batch composition. The contributions from the oxide interactions on the semiconductor surface and in the gas phase have been evaluated for the PbO + Sb2O3 composition.