【摘要】 研究退火消除直拉单晶硅中热施主的效果以及在后续热过程中热施主的再形成规律。实验结果显示,采用650℃保温40min的退火可有效消除直拉单晶硅锭肩下部形成的热施主,并使其少子寿命恢复到实际值。消除了热施主的硅锭肩下部硅片在后续的900℃/40min加热后以小于11℃/min的速率冷却,硅片的热施主会再次生成,热施主的再生成量随冷却速率增加而减少,当冷却速率达100℃/min时可避免热施主的再次生成。实验结果还显示,采用3℃/min速率慢冷至550℃再以100℃/min的速率快冷至室温的两步冷却也可避免该硅片热施主的再次生成。实验还发现,消除了热施主的硅锭肩下部硅片经900℃/40min加热后的少子寿命随冷却速率的增加而降低;经上述两步冷却与3℃/min速率一步慢冷得到的少子寿命基本相等。更多还原

【Abstract】 The effect on eliminating thermal donors(TDs)by annealing and re-formation behavior of TDs during subsequence thermal processes in Czochralski silicon(Cz-Si) was investigated.The experimental results show that the TDs below shoulder of Cz-Si ingot can be effectively eliminated by annealing at 650℃ for 40 minutes,and the minority carrier lifetime of the wafers should be recovered to actual value.TDs should be re-formed when the Cz-Si wafer eliminated TDs heated with 900℃/40min and with cooling rate less than 11℃/min,With increase of the cooling rate,the amounts of re-formed TDs decrease,when the cooling rate increase to 100℃/min,the TDs were almost not re-formed.The experimental results also indicated that two step cooling that cool with 3℃/min rate to 550℃ then with 100℃/min rate to room temperature can also avoid TDs re-forming.It was also found that minority carrier lifetime in the Cz-Si showed a tendency of decrease with increase of the cooling rate.The minority carrier lifetime of Cz-Si wafers after the two step cooling was almost the same as that after cooling with 3℃/min rate to room temperature.更多还原