定向凝固提纯对工业硅杂质及电阻率的影响

摘要

以1101工业硅为原料,采用真空感应熔炼加定向凝固提纯方法制备了多晶硅铸锭,通过电感耦合等离子体发射光谱仪、扫描电镜、四探针电阻率仪、导电类型测试仪等对其化学成分、组织、电阻率及导电类型等进行了分析.结果表明:多晶硅锭中约50%的区域纯度达到99.99%,其中铁、铜、镍等金属杂质去除率均在90%以上;分凝效应使得杂质元素重新分布,导致粗大柱状晶在铸锭54%高度处停止生长,此时其成分及电阻率发生突变,导电类型也由P型转变为N型.%Multicrystal silicon (mc-Si) ingot was prepared using 1101 commercial silicon as raw material by vacuum induction melting and unidirectional solidification purification.The chemical composition, microstructure,resistivity and conductive type of the ingot were analyzed by inductive coupled plasma-optical emission spectrometer,scanning electron microscopy, four points resistivity test machine and conductive type tester.The results show that nearly half of the mc-Si ingot was purified to 99.99％, and over 90％ of the metal impurities including Fe, Cu and Ni had been removed.The impurities had been redistributed by the segregation effect, which led to the break-up of large columnar crystals growth at 54％ height.While the impurity composition and resistivity changed greatly, and the conductive type changed from P type to N type.