Defect generation and defect annealing upon gettering in floatzone silicon: an ONP study

(Received 9 November 1989, revised 17 September 1990, accepted 1st February 1991)

Abstract
Generation and annealing of point-like defects induced by the microdefects that appear during gettering processes in dislocation-free single-crystal silicon have been studied by the optical nuclear polarization (ONP) method. From the examination of the nature of microdefects produced in silicon upon ion implantation and subsequent heat treatments, it has been concluded that for reducing concentrations of shallow and deep point-like centers associated. with the microdefects, the rates of ramping down must be decreased radically during the cooling stages of the three-step gettering process used. A model of deep-level point-like centers induced by microdefects is suggested, based on the formation of reconstructed silicon self-interstitials due to the perturbation Of Sp ³ hybridization in the elastic field of a microdefect. It has been shown that only those deep centers take part in processes of superfast recombination of nonequilibrium charge carriers that are located near shallow hydrogen-like centers induced by the deformation potential of microdefects.