Aluminum doping of SiC single crystals with powder source results in a exponential axial decrease in charge carrier concentration caused by aluminum source depletion and defect generation through high initial aluminum concentrations. Therefore we applied an additional gas flow to the PVT-Growth-Setup leading direct into the growth cell. Thus a continuous supply of aluminum atoms out of an external reservoir was possible. With the Modified-PVT-Method high quality crystals with improved axial (4H: 2-10 16cm-3<p<4·1016cm-3; 6H: 8·1016cm-3<p<1,2·10 17cm-3) and lateral (4H: Δp/p<10%; 6H: Δp/p<25%) charge carrier homogeneity were grown. Additionally the Dependence of the remaining doping variations on compensation with residual nitrogen and growth mechanisms together with measures for further improvement will be discussed. © 2002 Trans Tech Publications.