用微波光电导衰减仪(μ-PCD)研究了不同温度和时间的恒温和变温磷吸杂处理对铸造多晶硅片电学性能的影响。实验发现:变温吸杂明显优于恒温吸杂,特别是对原生高质量多晶硅;其优化的变温磷吸杂工艺为1000℃/0.5h+700℃/1.5h;而在高温恒温吸杂中,多晶硅少子寿命值反而显著下降。实验现象表明:磷吸杂效果主要是与过渡族金属的溶解、扩散和分凝有关。
The performance changes of cast multicrystalline silicon after isothermal and variable temperature phosphorous gettering treatments with different temperatures and dwell times were studied by Microwave Photo Conductive Decay (μ- PCD). It was found that the efficiency after variable temperature phosphorus gettering was much better than that of isothermal one for cast multicrystalline silicon, especially in the high quality zone of as-grown materials, and the optimal parameter of variable temperature phosphorus gettering was 1000℃/0.5h + 700℃/1.5h. And the minority carrier lifetime decreased noticeably after phosphorus gettering at high temperature. The above results confirm the theory that the efficiency of phosphorous gettering depends strongly on the dislocation, diffusion as well as the segregation of transient metals.