Diffusion Rate of Li in Si at Low Temperatures

The method of ion drift in the electric field of an n-p junction has been used to measure the diffusion constant of Li in Si between 25^ and 125^, taking particular care to avoid chemical and electrical interactions which might affect the results. When these data are combined with previous high-temperature data, there is obtained D= (2. 50. 2) 10^-3exp- (0. 6550. 01) ekT cm^2/sec, the data extending over eight decades in D. The results are compared with those from ion-pair relaxation experiments, and it is shown that the latter are consistant with the ion-drift results.