Study on effect of impurity concentration and thermal stress on vacancy-oxygen complexes in n-type G12 single crystal silicon by Czochralski method

Abstract

During the growth process of Czochralski single crystal silicon, supersaturated interstitial oxygen atoms aggregate and precipitate to form intrinsic oxygen precipitates. These oxygen precipitates have a significant impact on the electrical properties and yield of silicon wafers. The purpose of the current work is to investigate the heterogeneous nucleation process of oxygen precipitates through VO_x (x = 1,2) complexes during the crystal growth. In the current work, a combined approach of numerical simulation and experimentation was adopted for in-depth exploration of the effects of stress, phosphorus-doped concentration, and interstitial oxygen concentration on VO_x (x = 1, 2) complexes. Moreover, the temperature characteristics and distribution patterns of VO_x complexes during the growth process of single crystal silicon were also thoroughly analyzed. The result indicates that the concentration of VO_x complexes is higher at the center and lower part of the edge in the radial direction. Stress can significantly increase the concentration of VO_x complexes. When the phosphorus-doped concentration and interstitial oxygen concentration were both gradually elevated from 10¹⁶ cm⁻³ to 10¹⁹ cm⁻³, the concentration of VO_x complexes tended to increase accordingly, and the upward trend was particularly notable when the concentration reaches 10¹⁹ cm⁻³. Except for the doping concentration of 10¹⁹ cm⁻³, the doping concentration of phosphorus has a greater effect on the VO_x complexes than that of oxygen. These research findings hold significant guiding significance for understanding and precisely controlling the internal gettering ability of oxygen precipitates, laying foundation for the growth of high-quality single crystal silicon.