Boron diffusion from gas phase was implemented for p-type doping of 4H-SiC at 1800 to 2000C. A 2-branch diffusion associated with 2 different diffusion mechanisms was observed. The activation energy Ea and pre-factor D0 were calculated for each diffusion branch, that were Ea=7.258eV/D0=1.931x106cm2/s and Ea=8.742eV/D0=2.126x107cm2/s for fast and slow diffusion, respectively. It was confirmed that the surface layer of diffused B mostly consists of shallow B acceptors, while the tail of diffusion profile had mostly deep level D centers.

Investigation of Two-Branch Boron Diffusion from Vapor Phase in n-Type 4H-SiC. A.V.Bolotnikov, P.G.Muzykov, T.S.Sudarshan: Applied Physics Letters, 2008, 93[5], 052101