The p-type doping of 6H-SiC was achieved via the diffusion of B at above 1900C. The doping profiles were clearly divided into steep (zone-I) and long-tail (zone-II) regions. The B diffusion in both regions could be well fitted using erfc functions but using differing diffusion coefficients, giving:

D (cm2/s) = 3.2 x 100 exp[-6.1(eV)/kT]

for zone I and

D (cm2/s) = 1.0 x 10-1 exp[-4.6(eV)/kT]

for zone II.

Investigation of Boron Diffusion in 6H-SiC. Y.Gao, S.I.Soloviev, T.S.Sudarshan: Applied Physics Letters, 2003, 83[5], 905-7