Impact of NiSi_2 precipitates electronic structure on the minority carrier lifetime in n- and p- type silicon

摘要

Minority carrier diffusion lengths were measured for the set of n- and p-type silicon samples with NiSi_2 precipitates of different electronic structure. We found that the type of precipitate electronic states in the upper part of band gap had no influence on the recombination activity of NiSi_2 precipitates. Minority carrier diffusion length L was found to be related to the precipitate density N and L ～ 2 × N ~(1/3) for n-type Si samples and L ～ 1 × N~(-1/3) for p-Si samples. Hydrogenation of the p-type Si sample with nanoscale nickel silicide precipitates resulted in an increase of the L value up to a factor of 3, while in n-Si L remained practicaly the same. The only hole emission in the samples of both conductivity types was detected in MCTS measurements and the cross section for the hole capture with the electronic states of the precipitaes was estimated to be as large as 10~(11) cm~(-2).