Effect of electron energy on defect introduction in silicon

Abstract

Using Hall effects measurements, the electron energy dependence of the defect introduction rates of the E c −0·17 eV, E c −0·4 eV, and E v + 0·3 eV levels has been determined. The introduction rates of the two levels at E c −0·17 eV and E c −0·4 eV were found to be relatively insensitive to incident electron energy as predicted by simple displacement theory. The defect introduction rate for the E v + 0·3 eV level is found to increase rapidly with increasing electron energy. It is also observed that the energy dependence of the E v + 0·3 eV level appears to be a function of material resistivity in that the dependence becomes steeper at lower resistivities. At resistivities of the order of 15 Ω−cm the energy dependence of the defect introduction rate of the E v + 0·3 eV level is identical to the observed energy dependence of the degradation of minority carrier lifetime in 10 Ω−cm n on p silicon solar cells. Empirically it is observed that this energy dependence appears to be proportional to the second power of the simple displacement theory, suggesting that formation of these defects may be controlled by second order kinetics.