Vacancy distribution measurements in CZ Si crystals grown by different pulling rate
Vacancy concentration distribution is estimated by measuring deep levels induced by N2-vacancy complexes in the wafers which are prepared from Si crystals grown by different pulling rate. It is found that the vacancy concentration is very low inside the OSF-ring and a little low in the ring region. Two kinds of the vacancy density profiles are observed in the specimens without the OSF-ring which are prepared from Si crystals grown by fast (1.4 mm/mm) and slow (0.4 mm/mm) pulling rate: one is a gradual and the other is a abrupt zigzag profile. We interpret the gradual profile is caused by macroscopic density change of the octahedral void defects and the abrupt variation is accompanied with the growth striation.
vacancy density profiles estimation of vacancy concentration effect of crystal pulling rate on vacancy density