The transient ion drift in the depletion region of a Schottky barrier was used to determine ion diffusivities at moderate temperatures. The pulsed reverse bias led to temperature-dependent capacitance transients which were similar to deep-level carrier emission transients. A simple theoretical model, together with classical transient signal analysis, permitted the ion diffusion constant to be deduced. When the method was applied to the diffusion of Cu, data were obtained for the previously uninvestigated temperature range of 280 to 400K (table 37). These results agreed well with both low-temperature and high-temperature diffusion data and they could all be described by the expression:

D(cm2/s) = 4.5 x 10-3exp[-0.39(eV)/kT]

T.Heiser, A.Mesli: Applied Physics A, 1993, 57[4], 325-8

Table 37

Diffusivity of Cu in Si