多晶硅真空定向凝固过程杂质富集和电阻率的模拟与实验研究  

Simulation and Experimental Study on Impurity Enrichment and Resistivity of Polycrystalline Silicon During Vacuum Directional Solidification

作　　者：张家豪 马文会[1] 吕国强[1] ZHANG Jiahao;MA Wenhui;LV Guoqiang(Faculty of Metallurgical and Energy Engineering,Kunming University of Science and Technology,Kunming 650093,China)

机构地区：[1]昆明理工大学冶金与能源学院,云南昆明650093

出　　处：《昆明理工大学学报（自然科学版）》2023年第3期25-31,共7页Journal of Kunming University of Science and Technology(Natural Science)

基　　金：国家自然科学基金项目(51864031)。

摘　　要：采用全局瞬态多晶硅真空定向凝固多物理场模型,模拟分析了硅料在Marangoni效应下不同凝固阶段时,温度场、应力场对杂质富集及电阻率的影响,并通过实验研究了硅锭中Fe杂质的分凝、富集形态以及硅锭的电阻率的变化规律.研究结果表明:硅锭中的最大热应力随着凝固时间的增加从13.2 MPa逐渐增大至40.2 MPa,在坩埚内壁和坩埚底部存在较大应力.通过对下拉速率为10μm/s的样品进行成分分析和电学性能检测,得出Fe杂质在硅锭顶部富集且最高为2.619×10^(-3),电阻率为0.154Ω·cm,富集状态从最初的大三角块状转变成不规则条状大量存在,发现硅锭从4/6高度处电阻率急剧下降,电阻率骤降是由于此时杂质富集过高导致,Fe杂质为2.171×10^(-3),电阻率为0.216 2Ω·cm.This study used a global transient multi-physical field model to simulate and analyze the effects of temperature and stress fields on impurity enrichment and resistivity of silicon under the Marangoni effect at different solidification stages during vacuum directional solidification of polycrystalline silicon.Experimental studies were conducted to investigate the segregation and enrichment of Fe impurities in silicon ingots,as well as the variation of resistivity.Results show that the maximum thermal stress in the silicon ingot increases from 13.2 MPa to 40.2 MPa with increasing solidification time,and there is a large stress on the inner wall and bottom of the crucible.Composition analysis and electrical performance tests were conducted on a sample with a pull-down rate of 10μm/s,and it was found that Fe impurities were enriched at the top of the silicon ingot with a maximum of 2.619×10^(-3),and the resistivity was 0.154Ω·cm.The enrichment state changed from the initial large triangular block to irregular strips.The resistivity of the silicon ingot sharply decreased from 4/6 height due to excessive impurity enrichment,where the Fe impurity concentration was 2.171×10^(-3) and the resistivity was 0.2162Ω·cm.

关 键 词：多晶硅 定向凝固 热应力 杂质富集 电阻率 

分 类 号：TQ127.2[化学工程—无机化工] TM914.4[电气工程—电力电子与电力传动]