The basic investigations leading to the fabrication of thick (more than 0.2 mm) monocrystalline layers of GaN on the silicon carbide substrates are performed. GaN layers were grown by sublimation sandwich-method in ammonia atmosphere. GaN polycrystalline powder and metallic Ga were used as a vapor source. The growth was carried out in quartz reactors both horizontal, and vertical types, in furnaces with high-frequency heating. The possibility of growing of thick ...
The characterization of the GaN epilayers from 70 to 250 micrometers thickness grown by SSM on the 6H-SiC substrates was performed. Free carrier concentration in initially undoped GaN samples was found to range between 2 and 6 x 10(exp 17)/cu cm. Rocking curve measurements of the GaN layers grown by SSM reveal the full width of half maximum (FWHM) from 150 to 400 arc.sec. Three- dimensional 15-20 arc.sec. disoriented wirtzite ...
Comparison studies of the crystal quality of SiC substrates grown by Lely method and sublimation sandwich method (SSM) was conducted. SSM-substrates was shown to have considerably promise for high quality GaN epilayers growth. Conditions of the surface treatment of the SiC substrates were optimized for GaN epilayers growth. The best results were reached on very close to (0001) Si- substrate surfaces etched by sublimation technique. Monocrystalline GaN layers was shown ...
We have modified a setup for growing GaN heteroepitaxial layers of large area and obtained 20 such structures on silicon carbide (SiC) and sapphire (Al2O3) substrates of 8 mm2 in size 50-150 micrometers thickness by Sublimation Sandwich Method (SSM). The substrates have been analysed for optimal GaN layer growth conditions, using the available data, and the results indicated that hexagonal SiC (alpha-SiC) is the best material. The substrate/epilayer mismatches may ...
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