Dependence of grown-in defect behavior on oxygen concentration in Czochralski silicon crystals

The behavior of grown-in voids in the as-grown state and during annealing w as investigated for Czochralski silicon wafers using an atomic force micros cope, Secco etching and an optical precipitate profiler. In previous report s, most grown-in voids have been found to consist of two octahedrons. In th is report, it was shown that the percentage of the voids which consist of o ne octahedron increased as the oxygen concentration decreased. The annealin g behavior of the voids was summarized as follows. In the case of supersatu rated oxygen concentration, growth of the oxide films within the voids occu rred and this reduced their ability to form flow patterns during Secco etch ing. The growth of oxide films within the voids was enhanced by excess inte rstitial silicon atoms injected during annealing in an oxygen ambient. In t he case of undersaturated oxygen concentration, the annihilation of the voi ds was also enhanced due to the injection of interstitial silicon atoms dur ing annealing in an oxygen ambient. Interstitial silicon atoms contributed to both of these phenomena.