Lifetime and capture cross-section studies of deep impurities in silicon

Abstract

Many impurities in silicon have multiple energy levels lying deep in the energy gap. Such impurities may determine electron and hole trapping and recombination under non-equilibrium carrier conditions. Models for the deep energy levels and for the capture processes are described. Experimental techniques for the measurement of electron and hole capture cross-sections are compared and their relative merits considered. The present knowledge of capture cross-sections of deep impurities in silicon is essentially confined to gold, indium and zinc. Recent studies of these are reviewed, and compared with cross-sections for (a) shallow impurities in silicon and (b) deep impurities in germanium.