【摘要】 研究了不同条件下退火对冶金法太阳能级多晶硅锭不同部位的位错、晶界及择优生长取向的影响。利用金相显微镜,电子背散射衍射和X射线衍射仪分别对退火前后多晶硅锭的位错、晶界和择优生长取向的变化规律进行表征,结果表明:退火前后多晶硅中的位错密度大小始终是中部<底部<顶部。1100℃下随着保温时间的延长,多晶硅中的位错密度逐渐减小,到5.0h后达到回复的极限程度;小角度晶界比例不断减小,直至消失;大角度晶界中R型晶界比例先增加后减小,CSL晶界比例缓慢增加,孪晶晶界Σ3比例呈稳定地增加,到退火5.0h后,其比例约占30%;主峰〈111〉织构峰强一直增加,〈311〉织构峰强则是逐渐减小至零,而〈511〉、〈531〉、〈620〉织构强度则是先减小、后增大、最后再减小,退火保温5.0h后择优生长取向达到高度一致。另外,还得到了不同温度下的极限回复程度。更多还原

【Abstract】 Impact of thermal annealing on the solar grade polysilicon produced by metallurgical method was investigated under different experiment condition.The dislocation,grain boundaries and preferred growth orientation were characterized by optical microscopy,EBSD and XRD.The results show that the number of dislocation in the polysilicon ingot before or after annealing is always middle <bottom <top.Under 1100℃condition,the dislocation density is decreased by prolonging the annealing time.It goes to the limit level of returning after 5.0h.The amount of angle grain boundaries is decreasing steadily,until disappearing;the proportion of R grain boundaries is increasing firstly and then declining;but the proportion of CSL and Σ3 grain boundary increasing steadily,the Σ3 is about 30% after 5.0h annealing.The peak intensity of 〈111〉always increases,but the 〈311〉 reduces gradually to zero.In addition,for〈511〉,〈531〉,〈620〉,firstly,the peak intensities decline,then increase,finally,they decline again.All the crystal grains of different position achieve a high consistent preferred growth orientation after 5h thermal annealing.Moreover,the limit returning level of different temperature conditions is obtained.更多还原