It was recalled that the diffusion of neutral H atoms into a semiconductor was accompanied by their binding into molecules. When the thermal dissociation of molecules could be ignored, and for times which were sufficiently long to establish an equilibrium state for the binding of H into complexes with impurity atoms, the formation of molecules was the main process which determined the steady-state profile of atomic H which formed near to the crystal surface. By analyzing secondary ion mass spectrometry data in terms of a model for this process, it was estimated that the diffusivity of H was equal to 1.4 x 10-10 cm2/s at 360C and equal to 5.5 x 10-11cm2/s at 390C. When combined with another result, it was deduced that the overall data (table 18) could be described by:

D (cm2/s) = 0.0385 exp[-1.13(eV)/kT]

N.S.Rytova: Fizika i Tekhnika Poluprovodnikov, 1991, 25[6], 1078-80 (Soviet Physics - Semiconductors, 1991, 25[6], 650-1)

Table 18

Diffusivity of H in GaAs