大注入水平下少子寿命的数值计算与分析

Analysis and Calculation of the Minority Carrier Lifetime at High Injection Levels

实现表面光电压法(SPV)在大注入水平下的少子寿命测量对表面光电压技术的应用和准确测量具有重要意义。本文计算了P型单晶硅片三种复合机制下注入水平与体寿命及表面复合率的关系。结果表明随着注入水平提高,主导复合机制发生改变,且少子寿命并不是一直随注入水平的增加而增加,而与杂质能级位置有关,表面复合率则恰好相反。为验证计算结果,对P型单晶硅片进行了注入水平可调的少子寿命测试。通过样品表面钝化,分离体表寿命,分别得到了注入水平与少子寿命和表面复合率的实验变化关系。理论计算结果与实验数据在测试范围内一致。

The realization of surface photovoltage（SPV） measurement of minority carrier lifetime at high injection levels（light intensity） is of critical importance for its applications and accurate testing.Three recombination mechanisms are introduced to show the relationship among body lifetime,surface recombination velocity and the injection level of p-type silicon.The results illustrate that the mechanism of main recombination changes as the injection level increases.In this case,the lifetime of minority carrier does not simply increase accordingly,but highly influenced by the energy level of impurities,while the surface recombination velocity changes just oppositely against the surface recombination velocity.Measurement of minority carrier lifetime under adjustable injection level has been taken to verify above mentioned results.Surface passivation treatment was applied on the samples to separate the lifetimes of the body and the surface.In this way the corresponding experimental changing of the carrier lifetime and the surface recombination velocity based on different injection levels are clarified respectively.The results of theoretical calculation would meet the experimental data accordingly.