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The morphology, chemical composition, and electronic properties of Al2O3/InGaAs interfaces with and without anodic oxide layers, formed in DC plasma (O2, Ar) with different contents of the fluorinating component (CF4), were studied. It is shown that thin fluorinated anodic oxide layers, in combination with annealing at 300 °C, reduce the density of interface states by a factor of 3–4 over the entire bandgap. The minimum state density values near the midgap determined by the Terman method are about 2 × 1012 eV−1 cm−2. However, it is demonstrated that, in contrast to the Al2O3/InGaAs interface, the interface with a fluorinated oxide is not stable and degrades when heated above 300 °C. [ABSTRACT FROM AUTHOR]

The accumulation capacitance oscillations behavior in the n-InAs metal-oxide-semiconductor structures with different densities of the built-in charge (Dbc) and the interface traps (Dit) at temperature 4.2 K in the magnetic field (B) 2–10 T, directed perpendicular to the semiconductor-dielectric interface, is studied. A decrease in the oscillation frequency and an increase in the capacitance oscillation amplitude are observed with the increase in B. At the same time, for a certain surface accumulation band bending, the influence of the Rashba effect, which is expressed in the oscillations decay and breakdown, is traced. The experimental capacitance-voltage curves are in a good agreement with the numeric simulation results of the self-consistent solution of Schrödinger and Poisson equations in the magnetic field, taking into account the quantization, nonparabolicity of dispersion law, and Fermi-Dirac electron statistics, with the allowance for the Rashba effect. The Landau quantum level broadening in a two-dimensional electron gas (Lorentzian-shaped density of states), due to the electron scattering mechanism, linearly depends on the magnetic field. The correlation between the interface electronic properties and the characteristic scattering times was established. [ABSTRACT FROM AUTHOR]

The influence of electron energy quantization in a space-charge region on the accumulation capacitance of the InAs-based metal-oxide-semiconductor capacitors (MOSCAPs) has been investigated by modeling and comparison with the experimental data from Au/anodic layer(4-20 nm)/n-InAs(111)A MOSCAPs. The accumulation capacitance for MOSCAPs has been calculated by the solution of Poisson equation with different assumptions and the self-consistent solution of Schrödinger and Poisson equations with quantization taken into account. It was shown that the quantization during the MOSCAPs accumulation capacitance calculations should be taken into consideration for the correct interface states density determination by Terman method and the evaluation of gate dielectric thickness from capacitance-voltage measurements. [ABSTRACT FROM AUTHOR]

It is shown that the fluorine-containing anodic layers at the n-In0.53Ga0.47As surface, in contrast to the fluorine-free anodic layers, form a SiO2/InGaAs interface with the unpinned Fermi level, where the density of states decreases upon annealing at a temperature of 300°C to (2–4) × 1011 and (4–5) × 1012 eV–1 cm–2 near the bottom of the conduction band and the center of the band gap, respectively. An increase in the annealing temperature leads to a reverse increase in the density of states (350°C) and pinning of the Fermi level (400°C). [ABSTRACT FROM AUTHOR]

Current-voltage ( I- V) characteristics of Au/Ti/ n-InAlAs/InP Shottky barriers have been studied in a temperature range of 100-380 K. It is established that, as the temperature increases from 100 to 200 K, the ideality factor drops from 1.58 to 1.1, while the barrier height grows from 0.55 to 0.69 eV. With a subsequent temperature increase from 200 to 380 K, both the ideality factor and barrier height vary, but only weakly. This behavior agrees well with the model of lateral inhomogeneity of the barrier height (Tung model), which is confirmed by the linear dependence of the barrier height on the ideality factor at temperatures within 100-200 K. Calculations according to this model yielded the value of 0.88 eV for the homogeneous-junction barrier height, 10 cm V for the mean-square deviation of the Gaussian distribution of barrier heights, 3.7 × 10 cm for the effective area of regions with reduced barrier heights, and 10.7 A cm K for the Richardson constant. [ABSTRACT FROM AUTHOR]

The influence of the mask material used for formation of GaN mesa-structures using plasma-chemical etching in a BCl : Ar : N atmosphere is studied. It is shown that a bilayer SiO/Cr mask in which the thickness of the chromium layer is six to seven times smaller than a desired etch depth provides effective protection of the surface and allows the formation of structures with a flat surface for an etch depth of up to 2.5 μm. When the mask is produced by conventional lithography, the slope of the side walls is no more than 10° and decreases when liftoff lithography is applied. [ABSTRACT FROM AUTHOR]