The Mechanism of Growth of GaN Films by the HVPE Method on SiC Synthesized by the Substitution of Atoms on Porous Si Substrates
The mechanisms of nucleation and growth of GaN films on porous silicon substrates with a buffer layer of silicon carbide grown by new method of substitution of atoms directly in the subsurface layer of the Si substrate were studied. P-type Si(111) plates with a deposited system of periodic mesopores of a diameter of 17 nm and a depth of 1.5 μm were used as the substrates for growth of SiC buffer layer. The buffer AlN layers of a thickness of the order of 500 nm followed by GaN layers of a thickness of the order of 5 μm were deposited by the HVPE method on SiC/Si substrates prepared in different ways. SEM micrographs, Raman and photoluminescence spectra of these samples are given. The influence of the Si substrate preparation method and the conditions of the SiC layer synthesis on the growth mechanisms of both AlN and GaN films has been experimentally revealed. The formation of two types of V-defects during the growth of GaN was observed. A theoretical model for the formation of defects of the first and second types is developed.
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