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