研究了冶金法n型多晶硅片磷吸杂、硼吸杂效果及其机理。研究发现,经1 000℃/4h磷吸杂后,硅片平均少子寿命从1.21μs提高到11.98μs;经950℃/1h硼吸杂后,平均少子寿命从1.52μs提升到10.74μs。两种吸杂处理后,硅片电阻率从0.2Ω.cm提高到0.5Ω.cm。结果表明,两种吸杂工艺使得硅片表面形成的重磷、重硼扩散层对金属杂质有较好的吸杂作用,从而减少载流子的复合中心,改善多晶硅片的性能。
The effect and mechanism of phosphorus/boron gettering of upgraded metallurgical grade(UMG) n-type mc-Si wafers were systematically investigated.The results show that the minority carrier lifetime and resistivity are improved greatly after getterring treatment.The lifetime is increased from 1.21 μs to 11.98 μs and 10.74 μs by phosphorus gettering and boron gettering at 1 000 ℃ for 4 hours and 950 ℃ for 1 hour thermal treatment,respectively.It is concluded that the improvements are mainly due to the heavy phosphorous and boron diffusion layer formed on the surface,which can absorb the heavy metal impurities and decrease recombination centers.