The mechanism of the enhancement in divacancy production by oxgyen during electron irradiation of silicon. I. Experimental

Abstract

Czochralski silicon samples containing different amounts of interstitial oxygen were irradiated with 2-MeV electrons at room temperature to a fixed dose of 1.0×1018 electrons/cm2. Prior to irradiation the interstitial oxygen content of similar specimens had been varied in a controlled way by precipitating different amounts of the dispersed oxygen by suitable heat treatments. The introduced divacancy density correlates linearly to the concentration of the interstitial oxygen. A certain concentration of divacancies is always introduced, independent of the amount of interstitial oxygen present. Our data show that the divacancy concentration correlates much better to the density of introduced vacancy-oxygen complexes than to the initially present dissolved oxygen concentration. Different models for the oxygen enhancement of divacancy production are discussed.