Capacitance--voltage characteristics of metal dielectric semiconductor structures with atomic layer deposition Al2O3 on n- and p-Cd0.22Hg0.78Te (with and without a surface graded-gap layer) preliminary oxidized in oxygen glow discharge plasma (with the resulting oxide thickness of 2 nm) have been studied. The obtained structures reveal the positive fixed charge with a density of ~(1-6)·1011 cm-2. The ratio between a slow surface states density and a surface band gap width is almost independent on graded-gap layer presence, with the value of ~(4-8)·1011 cm-2·eV-1. The proposed passivation approach provides near-ideal low-frequency capacitance-voltages characterized by weak influence of fast surface states. Films of CdHgTe grown without the graded-gap surface layer are proved to be much more sensitive to the process of oxidation in glow discharge plasma. Keywords: mercury cadmium telluride, film, surface states, plasma.

Capacitance−voltage characteristics of metal dielectric semiconductor structures with atomic layer deposition Al2O3 on n- and p-Cd0.22Hg0.78Te (with and without a surface graded-gap layer) preliminary oxidized in oxygen glow discharge plasma (with the resulting oxide thickness of 2 nm) have been studied. The obtained structures reveal the positive fixed charge with a density of ∼ (1−6) · 10^11 cm^(−2). The ratio between a slow surface states density and a surface band gap width is almost independent on graded-gap layer presence, with the value of ∼ (4−8) · 10^11 cm^(−2) · eV^(−1). The proposed passivation approach provides near-ideal low-frequency capacitance-voltages characterized by weak influence of fast surface states. Films of CdHgTe grown without the graded-gap surface layer are proved to be much more sensitive to the process of oxidation in glow discharge plasma.

This paper describes a technique that makes it possible, by analyzing the capacitance-voltage characteristics of metal-insulator-semiconductor or metal-semiconductor structures, to determine the concentration of the background donor impurity in undoped i-In0.53Ga0.47As layers with a thickness less than the width of the space charge region in the near-surface region of the semiconductor in strong inversion mode.

This paper describes a technique that makes it possible, by analyzing the capacitance-voltage characteristics of metal-insulator-semiconductor or metal-semiconductor structures, to determine the concentration of the background donor impurity in undoped i-In0.53Ga0.47As layers with a thickness less than the width of the space charge region in the near-surface region of the semiconductor in strong inversion mode. Keywords: InGaAs, MIS structure, capacitance-voltage characteristic, dopant, space charge region.

It is shown that the fluorine-containing anodic layers on the n-In0.53Ga0.47As surface, in contrast to the anodic layers without fluorine, form a SiO2/InGaAs interface with an unpinned Fermi level, the state density on which decreases during annealing at a temperature of 300 °C to values (2-4) 1011 and (4-5) 1012 eV-1cm-2 near conduction band bottom and the band gap middle, respectively. An increase in the annealing temperature leads to a reverse increase in the state density (350 ºС) and pinning of the Fermi level (400 ºС).

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).

The C – V characteristics of Au/Al 2 O 3 /In 0.52 Al 0.48 As and Au/SiO 2 /In 0.52 Al 0.48 As metal–insulator–semiconductor structures have been studied. It has been established that the fragmentary measurement of the C – V characteristics of InAlAs-based metal–insulator–semiconductor structures, in contrast standard registration method to at a constant voltage sweep rate, significantly weakens the effect of the hysteresis phenomena and allows one to record stationary curves. It is shown that the density of fast interface states calculated by the Terman method from such C – V characteristics slightly changes over the InAlAs band gap and amounts to (3–6) × 10 11 and (1–3) × 10 11 eV –1 cm –2 for MIS structures with Al 2 O 3 and SiO 2 , respectively.

Matrix photosensitive elements based on a HgCdTe semiconductor solid solution on silicon substrates with 640 × 512 elements at a pitch of 25 μm with a long-wavelength sensitivity of 5 μm at half maximum are designed and produced. The scheme and topology are developed according to which matrix multiplexers with 640 × 512 elements at a pitch of 25 μm, which ensure operating modes at a clock frequency up to 10 MHz, are manufactured. Using a hybrid assembly method on indium bumps, a matrix photodetector with 640 × 512 elements at a pitch of 25 μm is produced. The best photodetector specimens are characterized by the following parameters: average NETD value <13 mK and the number of workable elements > 99.5%.

Photoelectrical characteristics of scanning IR detectors with implemented time delay and integration mode are analyzed. A new "shifted cellular" layout of photosensitive elements in the FPA structure is proposed. Advantages of the new FPA configuration in terms of threshold sensitivity for small-size/point objects are demonstrated. The analysis is based on the Monte Carlo simulation of the diffusion process of photogenerated minority charge carriers in the photosensitive layer photodiode arrays. The analysis is performed taking into account the main photoelectric parameters of FPA elements: photosensitive layer thickness, diffusion length of charge carriers, optical absorption length, their design parameters: geometric sizes of FPA elements, diameters of p-n junctions, and design parameters of the optical system: optical-spot diameter.

The C–V characteristics of Au/Al2O3/In0.52Al0.48As and Au/SiO2/In0.52Al0.48As metal–insulator–semiconductor structures have been studied. It has been established that the fragmentary measurement of the C–V characteristics of InAlAs-based metal–insulator–semiconductor structures, in contrast standard registration method to at a constant voltage sweep rate, significantly weakens the effect of the hysteresis phenomena and allows one to record stationary curves. It is shown that the density of fast interface states calculated by the Terman method from such C–V characteristics slightly changes over the InAlAs band gap and amounts to (3–6) × 1011 and (1–3) × 1011 eV–1 cm–2 for MIS structures with Al2O3 and SiO2, respectively.

The capacitance-voltage (С-V) characteristics of Au/Al2O3/In0.52Al0.48As and Au/SiO2/In0.52Al0.48As metal-insulator-semiconductor (MIS) structures were studied. It was found that the measurement of the C-V characteristics of MIS structures based on InAlAs by the fragment method, in contrast to the standard technique at a constant bias voltage scan rate, significantly reduces the hysteresis effect and allows to obtain stationary curves. It was shown that the fast interface states density calculated by the Terman method from such C-V characteristics varies slightly along the InAlAs band gap and amounts to (3-6) 1011 eV-1cm-2 and (1-3)·1011 eV-1cm-2 for MIS structures with Al2O3 and SiO2, respectively.

Abstract—The characteristics of MWIRs focal plane aeeays made in the form of a hybrid chip based on a planar n+–p-HgCdTe focal matrix with 2048 × 2048 elements and a silicon multiplexer are considered. The temperature dependence of the reverse current of elements in the 125–300 K range had a characteristic Arrhenius dependence with an activation energy close to the band gap of the semiconductor and was limited by the diffusion component of the current. At a lower temperature, the current was limited by the generation of carriers with the participation of a deep level near the middle of the forbidden band. The histogram of the detectability of the elements of the matrix had the form of a symmetric curve with a maximum and an average value ≈ 1.3 × 1012 cm Hz1/2/W.

Modern designs of time delay and integration (TDI) IR linear scanning focal plane arrays (IR FPAs) are analyzed. Advanced designs of linear IR FPAs with increased sensitivity and spatial resolution are proposed. The analysis is based on Monte-Carlo simulation of the diffusion of photogenerated charge carriers in photodiode arrays based on mercury–cadmium–telluride epitaxial layers taking into account the main photoelectric and design parameters of the detectors and optical system.

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.

The InAlAs surface morphology (AFM), chemical composition (XPS) and the Ti/InAlAs interface structure (HREM), during the Au/Ti/n-In0.52Al0.48As/InP(001) mesa-structure Schottky barrier formation, were studied. The current-voltage (I-V) dependences analysis of the formed Schottky barrier in the temperature range of 100–380K was carried out. It was shown that the I-V dependences are well described by the thermionic emission theory at temperatures above 200K with the ideality factor and the barrier height close to 1.09 and 0.7eV, respectively. At temperatures below 200K, the I-V behavior is attributed to the Schottky barrier anomalies, which are explained by the existence of nanometer-sized patches with a low barrier height having a Gaussian distribution (Tung model). According to this model, the temperature dependences of the barrier height and ideality factor were described with the following parameters: the homogeneous barrier height of 0.88eV and standard deviation of 10−4cm2/3V1/3. In the analysis of the modified Richardson plot, the Richardson constant (10.7Acm−2K−2) and the area fraction (24%), occupied by the patches with a low barrier height and diameter ~80nm, were calculated. The patches appearance is explained by the presence of the spikes detected on the InAlAs surface by the AFM method.

We analyzed the C-V curves of CdхHg1-хTe-based (x ∼ 0.22) MIS structures with Al2O3 as an insulator. Alumina films were deposited on p and n type CdхHg1-хTe by atomic layer deposition. C-V curve specific features at high and low frequencies were found to be a result of the semiconductor-dielectric interface surface state influence. The surface state density was derived from the fitting experimental C-V curves at high and low frequencies with the theoretical model. The calculated curves were obtained by solving Poisson and continuity equations within the drift-diffusion model. The charge exchange between the surface states and permitted bands was supposed to be conducted using the Shockley-Read-Hall mechanism.

The MBE method has been applied to grow InSb layers on InSb substrates. These layers have served as a basis for fabricating mid-wave IR photodetector arrays. The characteristics of photodetector arrays on epitaxial InSb layers have been compared with those of series-produced single-crystal InSb arrays.

The characteristics of SWIR (1.6-3 mu m) 320 x 256 and 1024 x 1024 focal plane arrays (FPA's) based on n-type In-doped HgCdTe heteroepitaxial layers are reported. The HgCdTe layers were grown by molecular beam epitaxy on silicon substrates with ZnTe and CdTe buffer layers. p-n junctions were formed by arsenic ion implantation into HgCdTe film. Reverse current in the temperature range from 210 to 330 K was found to be limited by the diffusion mechanism. At the same time in the temperature range from 140 to 210 K the reverse current was dominated by the thermal generation of charge carriers through deep traps located in the middle of the band gap. At 170 K NETD was less than 40 mK (C) 2016 Elsevier B.V. All rights reserved.