Investigating Minority Carrier Trapping In N-Type Cz Silicon By Transient Photoconductance Measurements

Minority carrier trapping was investigated in n-type Cz silicon by means of transient-photoconductance (PCD). A simplified Hornbeck and Haynes model was developed for fitting results from transient-PCD to calculate trap density, and it was found to be identical to the model developed for quasi-steady-state photoconductance technique. This indicates that the model can be applied to all photoconductance techniques for lifetime measurement. The results revealed that the trap density is dependent on the concentration of interstitial oxygen and thermal donors, indicating a good agreement with reported results and the results from annealing experiments in this work. Meanwhile, a deep trap energy level was revealed, probably implying that traps also act as recombination centers in n-type silicon. By studying detrapping processes, the concentration of the trapped holes was found to decrease exponentially with time, resulting in a detrapping constant of 167 s. (C) 2012 American Institute of Physics.[http://dx.doi.org/10.1063/1.3689786]