OXYGEN-TRANSPORT MECHANISM IN CZOCHRALSKI SILICON MELT .2. VICINITY OF GROWTH INTERFACE

The mechanism governing oxygen transport in the vicinity of the growth interface with varying rates of crystal rotation was investigated bot h experimentally and computationally. Rotation induces a sweeping flow out of-high oxygen content melt contributing to uniform radial oxygen concentration. At low rates of rotation, low oxygen content melt flow s into the growth interface region, rarefying the oxygen concentration at the boule periphery and affecting the longitudinal micro-oxygen di stribution. Calculation verified the correlation between radial veloci ty and oxygen fluctuation, that fluctuation within the crystal is attr ibutable to the now of low oxygen content melt from the free surface. At higher rotational speeds, radial outflow obstructs flow from free s urface, resulting in a relatively uniform longitudinal micro-oxygen di stribution within the boule.