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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。
The effect of annealing to eliminate the thermal donor in Czochralski (CZ) single crystal silicon and the reformation rule of thermal donor in the subsequent thermal process were studied. The experimental results show that annealing at 650 ℃ for 40min can effectively eliminate the thermal donor formed in the lower part of Czochralski silicon ingot and restore the low-life of the Czochralski lead to the actual value. The silicon wafers removed from the thermal donor were cooled at a rate of less than 11 ° C / min after subsequent 900 ° C / 40 min heating, and the thermal donor of the silicon wafers regenerated again. The amount of thermal donor regeneration increased with the cooling rate Decreases, thermal donor re-generation can be avoided when the cooling rate reaches 100 ° C / min. The experimental results also show that the two-step cooling with slow cooling to 550 ° C at a rate of 3 ° C / min and rapid cooling to room temperature at a rate of 100 ° C / min can also avoid the re-formation of thermal donor of the silicon wafer. The experiment also found that the heat-driven silicon under the ingot silicon wafers after heating at 900 ℃ / 40min less life expectancy decreases with the cooling rate decreases; by the above two-step cooling and 3 ℃ / min rate of slow slow one step obtained Life is basically the same.