Defect reorganization induced by pulsed magnetic field in porous InP

We present results of investigations of the effect caused by weak magnetic field (B = 60 mT) in porous InP crystals of impurity-defect composition. This effect was found when studying the spectra of radiative recombination within the range 0.6 to 2.0 µm at 77 K. It was obtained that field influence initiates long-term changes in the intensity of radiative recombination inherent to centers of different nature. A possible mechanism of observed transformation is discussed

Effect of pulsing magnetic field on radiative recombination spectra of GaP and InP single crystals

We present the results of investigations concerning the effect caused by weak magnetic field (B = 15 mT and 60 mT) treatment on GaP and InP single crystals of impurity-defect composition. This effect was found when studying the radiative recombination (luminescence) spectra within the range 0.6 to 2.5 µm at 77 K. It was obtained that a short-term influence of field initiates long-term changes in the intensity of radiative recombination inherent to centers of different nature. General regularities in behavior of the luminescence intensity have been found. This intensity changes with the concentration of recombination centers. A possible mechanism of observed transformations has been discussed

Optimization of technological parameters of ohmic contact junctions for GaAs-AlGaAs-based transistor structures

The work deals with study and optimization of the technological parameters of ohmic contacts for HEMTs. It is shown that the depth of fusion front penetration into semiconductor is the main factor that determines ohmic properties of contact junctions

Effect of weak magnetic fields treatment on photoluminescence of III-V single crystals

The long-term transformations of photoluminescence of GaP, GaAs and InP single crystals treated with pulsed weak magnetic fields are obtained. The treatments were performed in two regimes, namely, single-pulse (τ = 30 ms) and multi-pulse (τ = 1.2 ms) ones, at varying magnitudes of magnetic induction. The defect structure transformations were inferred from the radiative recombination spectra in the 0.6-2.5 μm at 77 K. A possible mechanism of observed modifications related to the electron spin transformation is discussed

Influence of pulse magnetic fields treatment on optical properties of GaAs based films

Long-term transformations of the optical reflectance of GaAs epitaxial structure under weak magnetic field treatment (B = 60 mT, f = 10 Hz, τ = 1.2 ms, t = 5 min) have been obtained. Optical measurements were performed within the wavelength range 800…1100 nm at 300 K. Non-monotonous changes of reflectance were observed. Experimental results have been interpreted in terms of diffusion of point defects, resulting from destruction of metastable complexes (probably [VAs+impurity]), from the internal boundaries to the surfaces of the investigated structures. The method for detection of non-equilibrium complexes in multilayer objects has been proposed

A silicon carbide thermistor

We consider a silicon carbide thermistor with multilayer Au–TiBx–Ni2Si ohmic contacts intended for operation in the 77 to 450 K temperature range

Properties of SiO₂-GaAs and Au-Ti-SiO₂-GaAs structures used in production of transmission lines

We investigated electrophysical properties of the SiO₂-GaAs and Au-Ti-SiO₂-GaAs structures that are used in technological process when manufacturing transmission lines for microwave integrated circuits. The SiO₂-GaAs structures were formed using different techniques, namely, (i) monosilane oxidation in oxygen, (ii) high-temperature tetraethoxysilane decomposition, (iii) high-frequency cathode sputtering of quartz in argon plasma, and (iv) electron-beam evaporation of quartz in a vacuum. The SiO₂ films obtained using monosilane oxidation or electron-beam evaporation of quartz demonstrated better properties. For the Au-Ti-SiO₂-GaAs structures a layer structure transformation was shown to occur, with formation of TiOx-SiO₂ junction and gold atoms penetration over the whole adhesion layer thickness. The microwave oscillator modules made using the Au-Ti-SiO₂-GaAs (Si) structures demonstrated output power of 10-60 mW in the 8 mm wavelength range

Formation of ohmic contacts to n(p)-gan and measurement of their contact resistivity

We propose multilayer ohmic contacts to n- and p-GaN layers, with titanium boride as diffusion barrier. It is shown that the optimal method of contact resistivity measurement is the transmission line method (TLM) with circular contact geometry. The Ti−Al−TiBx−Au contact metallization to n-GaN retains its layer structure after thermal annealing at temperatures up to 900 °C. The contact resistivity ρс is (6.69±1.67)×10⁻⁵ Ω⋅cm². For the Au−TiBx−Ni−p-GaN contact structure, the contact resistivity is (1±0.15)×10⁻³ Ω⋅cm²

Heat tolerance of titanium boride and titanium nitride contacts to gallium arsenide

For contacts prepared from titanium borides by and nitrides ion-plasma sputtering onto gallium arsenide both formation mechanisms and thermal stability were investigated. We used a combination of structural, secondary-emission, optical and electrophysical methods, such as electronography, X-ray diffraction, atomic force microscopy, Auger electron spectroscopy, secondary-ion mass spectrometry, taking photoluminescence spectra and I - V curves. A physical model for contact formation was proposed. According to it, BxGa₁₋xAs (GaNxAs₁₋x) solid solutions are formed at the phase interfaces when titanium borides (nitrides) are deposited. The defects are produced in the semiconductor near-surface regions during heterostructure formation and further heat treatment. The correlation between the physico-chemical interactions at contact interfaces and the contact electrophysical parameters occurs through these defects. The objects of our investigation demonstrated high thermal stability. This was due to their two-layer structure formed by components having well-pronounced antidiffusion properties. As a result, the interdiffusion processes at the phase interfaces are drastically weakened

Ohmic contacts to Hall sensors based on n-InSb-GaAs(i) heterostructures

We consider ohmic contacts to the n-InSb epitaxial layers grown on a semi-insulating GaAs substrate. The ohmic contacts are formed through titanium metallization with subsequent gilding. Using the structural (AFM and XRD) and analytical (AES) techniques, we showed that thermal annealings at Т = 300 °С (for 60 s) and 360 °С (for 30 s) do not change the phase composition of the metallization. This ensures thermal stability of the contacts and Hall sensors made on the basis of Au–Ti–n-InSb–GaAs(i) structures