In the nitrogen-doped and fast-pulled crystals, the nitrogen plays a role to disturb the growth of vacancy clusters by reducing the vacancy-rich region and the vacancy concentration. Thus, the oxidation-induced stacking fault ring (OSF-ring) is formed near the edge region and its width depends on the nitrogen-doping concentration. The vacancy clustering is severely suppressed and the increased residual vacancy causes the anomalous oxygen precipitation. A conceptual model based on the reduction of point defect concentration could explain the nitrogen-doping effects.