The objective of the present work was to prepare 3C-SiC epilayers on base of 6H-SiC substrate and to study epilayer's parameters. Heteroepitaxy was carried out using sublimation epitaxy (SE) in an open system. The presence of 3C-SiC layer in the prepared structures was confirmed by X-ray diffraction. Parameters of Schottky diodes prepared on base of this epilayers were investigated by capacitance-voltage characteristics and DLTS. Also it was investigated influence of proton irradiation and annealing on epilayers Nd-Na value and deep centres concentration.