OXYGEN PARTITIONING ANALYSIS DURING CZOCHRALSKI SILICON CRYSTAL-GROWTH VIA A DOPANT MARKER AND A SIMPLE TRANSFER-FUNCTION MODELING TECHNIQUE .1. ROTATION RATE TRANSIENTS

Intermediate transient oxygen redistribution during commercial size scale Czochralski silicon crystal growth caused by a step change in crystal rotation rate has been examined. Since a regular solute like phosphorus or boron is conservative and well-behaved during Czochralski growth of silicon, the melt was intentionally doped so that the dopant could act as a marker and its redistribution analyzed first. From this result, the time-varying degree of melt convection that influences the observed oxygen redistribution profile can be quantitatively determined provided that oxygen and the marker solute are incorporated by the same type of mechanism at the crystal interface. It is found that the traditional solute segregation equation in conjunction with a transfer function modeling technique, where only a single oxygen species present in the melt, is insufficient to account for all the transient oxygen profiles in the silicon crystals. The possibility of having two simultaneously incorporated and inter-reacting oxygen species during Czochralski silicon crystal growth is then examined and found to provide the needed degree of freedom to explain these results.