The use of spreading resistance and capacitance-voltage methods showed that atomic H passivated shallow acceptors and donors in this material. Deep-level passivation by H also occurred, as revealed by deep-level transient spectroscopic measurements of Schottky diode structures. Effective H diffusion coefficients were deduced for both n+-type and p+-type samples. In the former case, the diffusion was thermally activated and could be described by:

D(cm2/s) = 3.4 x 10-5 exp[-0.55(eV)/kT]

at temperatures of between 100 and 250C. In the latter case, the diffusivity could be described by:

D(cm2/s) = 1.5 x 10-6 exp[-0.45(eV)/kT]

Reactivation of passivated shallow and deep levels occurred at temperatures of between 250 and 300C.

A.Y.Polyakov, S.J.Pearton, R.G.Wilson, P.Rai-Choudhury, R.J.Hillard, X.J.Bao, M.Stam, A.G.Milnes, T.E.Schlesinger, J.Lopata: Applied Physics Letters, 1992, 60[11], 1318-20