高温退火对铸造多晶硅片中位错密度的影响

对铸造多晶硅片进行了1 000~1 400℃的高温退火和不同方式冷却实验,用显微观察法对退火硅片及其相邻姊妹片位错密度进行了测量统计。研究了退火温度和冷却方式对铸造多晶硅片中位错密度的影响。结果证实:当退火温度在1 100℃及以下时,硅片的位错密度并没有降低反而增加了;当退火温度在1 320℃及以上时,硅片的位错密度明显降低,其幅度随温度提高增大;但退火后如断电随炉冷却而不控制冷却速率,位错密度又会提高。

Effect on High Temperature Annealing on Dislocation Density of Multicrystalline Silicon Wafers

High temperature annealing at 1 000-1 400 ℃ and various subsequent cooling experiments for multicrystalline silicon wafers were carried out.Dislocation density of the sample wafers was analyzed with dislocation microscopic observation method.The effects of the annealing temperature and the cooling methods on the dislocation density of multicrystalline silion were studied.The results confirm the abnormal phenomenon that the dislocation density of the silicon wafer increases after annealing at 1 100 ℃ or below.After annealing at 1 320 ℃ or higher,the dislocation density in the wafers decreases remarkably,increases when the subsequent cooling isn’t controlled and the wafer was left to cool down naturally in the off-power furnace.