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A new approach is proposed to the synthesis of a semipolar GaN on a Si(100) substrate at the surface of which the V-shaped nanostructures with the characteristic size of elements as low as 100 nm are formed. It has been demonstrated that application of buffer layers of 3C-SiC and AlN enables formation of the GaN(10-11) layer characterized by the full width at half maximum value as low as ω θ 45 arcmin for the X-ray diffraction rocking curve. The model based on anisotropic nucleation of AlN on the V-shaped nanostructure is proposed to explain the growth of the GaN layer in a single semipolar direction.

Synthesis of AlN and GaN layers on a Si(100) substrate by chloride vapor-phase epitaxy has been considered. The process includes sulfidizing of the silicon surface, nucleation and growth of an AlN layer, and then formation of a GaN/AlN structure. It has been found that in the case of a (100)Si substrate, GaN nucleates on buffer AlN layers that may have two crystallographic orientations in contrast to a Si(111) substrate, on which a buffer layer may have only one orientation. It has been shown that the treatment of the Si(100) substrate in an aqueous solution of (NH_4)_2S decreases the FWHM of the rocking curve for GaN(0002) by a factor of 1.5.

The results of studies of semipolar GaN(10-12) layers synthesized on a nano-patterned Si(100) substrate are presented. It is shown that in the method metalorganic vapor phase epitaxy, the use of a nanorelief consisting of V-shape groove with inclined faces close to the Si(111) plane can lead to the formation of regions of cubic gallium nitride in the nano-groove. Model of the origin of the cubic phase are based on the formation of AlN nuclei in (0001) and (10-10) nano-groove and the conjugation of the AlN(10-10) and c-GaN planes by the “magic mismatch” mechanism.

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