The diffusion of 2H in p-type 4H–SiC was studied in detail by using secondary ion mass spectrometry. The effective capture radius for the formation of 2H–B complexes at 460C was deduced to be RHB = 2.1nm. This value was in good agreement with that expected for a Coulomb force-assisted trapping mechanism. At higher temperatures, the 2H diffusion obeyed Fick’s law, with a constant effective diffusivity from which the complex dissociation frequency, νHB, was determined. The frequencies exhibited an Arrhenius temperature dependence over 3 orders of magnitude of νHB. The complex dissociation energy was determined to be EdHB = 2.51eV; which was 0.9eV larger than the corresponding value for the 2H–Al complex. This suggested that the atomic configurations for the 2 complexes were significantly different. The extracted dissociation attempt frequency of ν0HB = 1.2 x 1013/s was very close to the characteristic oscillation frequency of the SiC lattice (1.6 x 1013/s). In addition, 2H diffusion in an epitaxial Al multilayer structure demonstrated the influence of internal electric fields on 2H diffusion in p-type SiC.

Hydrogen–Boron Complex Formation and Dissociation in 4H–Silicon Carbide. M.S.Janson, A.Hallén, M.K.Linnarsson, B.G.Svensson: Applied Surface Science, 2001, 184[1-4], 257-62