The problems of obtaining of insulating propel-ties in the bulk single-crystal silicon carbide by vanadium and aluminium doping under the LETI method growth process are considered. It was defined that the solubility limit of vanadium in SiC makes 10(19) cm(-3). The resistivity of obtained SiC:V,Al material exceeds 10(7) Ohm.cm at 20 degreesC. It can be applied as a semi-insulating substrate material for extreme electronics based on silicon carbide or nitrides. The grown crystals exhibit visual spectrum photoconductivity with long-time relaxation.