Neutron-Bombardment Damage in Silicon

Abstract

Neutron-bombardment damage in silicon is compared to electron-bombardment effects which have been previously analyzed. A discrete energy level 0.27 ev above the valence band previously ascribed to the acceptor member of a defect pair having a separation greater than 50 A, is found to be produced by both neutrons and electrons. A spectrum of energy levels running from 0.16 ev below the conduction band toward the middle of the gap is ascribed to a defect pair with variable spacing, and related to the discrete level 0.16 ev below the conduction band which was found previously in electron-bombardment of silicon, and there ascribed to a close-spaced pair of defects. Lifetime effects are found to be dominated by levels near the middle of the energy gap, which may be related to the above spectrum. A very rapid decrease in mobility at low temperature is ascribed to bombardment-induced inhomogeneities.