Semi-insulating 6H SiC substrates, 2", 3" and 100mm in diameter, and n(+) 4H SiC substrates, 2" and 3" in diameter, are grown at H-VI using the Advanced Physical Vapor Transport (APVT) technique [1]. The process utilizes high-purity SiC source and employs special measures aimed at the reduction of background contamination. Semi-insulating properties are achieved by precise vanadium compensation, which yields substrates with stable and uniform electrical resistivity reaching ∼ 10(11) &UOmega;-cm and higher. Conductive n+ 4H SiC crystals with the spatially uniform resistivity of 0.02 &UOmega;-cm are grown using nitrogen doping. Crystal quality of the substrates, their electrical properties and low temperature photoluminescence are discussed.