We carried out a structural-spectroscopic study of AlGaN/GaN epitaxial layers grown by molecular-beam epitaxy with nitrogen plasma activation on a hybrid substrate containing layers of silicon carbide and porous silicon. Using X-ray diffractometry, Raman and photoluminescence spectroscopy, it is shown that thin films formed on a hybrid substrate have minimal residual stresses and intense photoluminescence.

Surface topography, dielectric and pyroelectric properties of semipolar AlN thin films are studied. The growth of AlN was carried out by hydride-chloride vapor phase epitaxy on hybrid SiC layers specially prepared for the growth of semipolar AlN layers. SiC layers were grown on Si substrates of p-type (KDB) with (100)-orientation. The dynamic pyroelectric response of the AlN layer was observed. The pyroelectric current kinetics was analyzed in the frequency range of 10-1000 Hz, and the calculated pyroelectric coefficient was nearly equal to 9 center dot 10(-10) C/(cm(2)K).

The idea of a new method for growing gallium nitride (GaN) epilayers in semi-polar direction by hydride-chloride vapor-phase epitaxy (HVPE) is disclosed. We propose to use Si(210) substrates with the first buffer layer of silicon carbide (3C-SiC) and the second buffer layer of aluminum nitride (AlN). It is experimentally demonstrated for the first time that, under conditions of anisotropic deformation in the GaN/AlN/3C-SiC/Si(210) structure, a GaN epilayer exhibits growth in semi-polar directions.

This paper presents the idea of a new technological method of growing low-defect heterostructures of aluminum and gallium nitrides on a silicon substrate for the UV region. It is experimentally proven for the first time that creating an intermediate silicon carbide nanolayer makes it possible to use vapor-phase epitaxy to obtain high-quality layers of aluminum and gallium nitrides on a silicon substrate with no cracks. The main characteristics of the crystal perfection of these layers - namely, the half-width of the X-ray rocking curves and the half-width of the photoluminescence spectra - taking into account the absence of cracks, significantly excel the values obtained by other authors in this case. It is shown that an exciton band with a maximum emission energy of 3.45 eV and a half-width of 63 meV appears in the photoluminescence spectra of gallium nitride at a temperature of 77 K. (C) 2011 Optical Society of America.

A new approach to the deposition of aluminum nitride (AlN) layers with thicknesses ranging within ∼0.1–10 μm on silicon single crystal substrates by hydride-chloride vapor-phase epitaxy (HVPE) has been developed and implemented, which involves the formation of thin (∼100-nm-thick) intermediate silicon carbide (3C-SiC) interlayers. It is established that wavy convex bands with a height of about 40 nm are present on the surface of as-grown AlN layers, which are situated at the boundaries of blocks in the layer structure. It is suggested that the formation of these wavy structures is related to morphological instability that develops due to accelerated growth of AlN at the block boundaries. Experiments show that, at low deposition rates, AlN layers grow according to a layer (quasi-two-dimensional) mechanism, which allows AlN layers characterized by half-widths (FWHM) of the X-ray rocking curves of (0002) reflections about ωθ = 2100 arc sec to be obtained.

The structure and luminescent properties of gallium nitride (GaN) epilayers grown by hydride-chloride vapor-phase epitaxy (HVPE) in a hydrogen or argon atmosphere on 2-inch Si(111) substrates with AlN buffer layers have been studied. The replacement of hydrogen atmosphere by argon for the HVPE growth of GaN leads to a decrease in the epilayer surface roughness. The ratio of intensities of the donor-acceptor and exciton bands in the luminescence spectrum decreases with decreasing growth temperature. For the best samples of GaN epilayers, the halfwidth (FWHM) of the X-ray rocking curve for the (0002) reflection was 420 sec of arc, and the FWHM of the band of exciton emission at 77 K was 48 meV.

Oriented GaN layers with a thickness of about 10 μm have been grown by hydride-chloride vaporphase epitaxy (HVPE) on Si(111) substrates with AlN buffer layers. The best samples are characterized by a halfwidth (FWHM) of the X-ray rocking curve of ω θ = 3–4 mrad. The level of residual mechanical stresses in AlN buffer layers decreases with increasing temperature of epitaxial growth. The growth at 1080°C is accompanied by virtually complete relaxation of stresses caused by the lattice mismatch between AlN and Si.