Oxygen '96

Early Stages of Oxygen Precipitation in Silicon

---

RELATION BETWEEN GROWN-IN DEFECTS AND OXYGEN PRECIPITATES IN CZOCHRALSKI SILICON

K. Sumino

Nippon Steel Corporation, Technical Development Bureau, 20-1 Shintomi, Futtsu, Chiba Prefecture 293, JAPAN

Recently, grown-in defects, called COP (Crystal Originated Particles) or FPD (Flow Pattern Defects), as well as tiny oxide particles built in as-grown Czochralski-grown silicon crystals are calling a great deal of attention in device production technology because these defects seem to be related to the gate oxide integrity. Nobody as yet clarified the entity of such grown-in defects. There is an agreement among many groups on the idea that oxide particles incorporated in the gate oxide film give rise to a low break-down voltage. However, as to the effect of grown-in defects experimental observations as well as their interpretations are quite controversial. There are many arguments insisting that these defects are clusters of frozen-in vacancies formed at high temperatures and act as preferential nucleation sites for oxide precipitates at low temperatures. However, existing data seem to show that the concentration of vacancies at the melting point of silicon is much lower than the concentration of oxygen dissolved in Czochralski-grown silicon and also that the binding of a vacancy and an oxygen atom is stronger than the binding of a vacancy pair. Thus, it is likely that any vacancy-like grown-in defects, if any, in Czochralski-grown silicon are complexes containing oxygen. This paper reports how grown-in defects affect the precipitation behaviour of oxygen at various temperatures and gives an interpretation of the observations on the basis of the above idea.

Last modified: Mon Feb 19 12:11:07 GMT 1996 JG