Possible Candidates for Impurities in mc‐Si Wafers Responsible for Light‐Induced Lifetime Degradation and Regeneration
Possible Candidates for Impurities in mc‐Si Wafers Responsible for Light‐Induced Lifetime Degradation and Regeneration
复制标题
DOI：
10.1002/solr.201700159
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Dennis Bredemeier;D. Walter;Jan Schmidt
中科院分区：
文献类型：
--
作者：
Dennis Bredemeier;D. Walter;Jan Schmidt
我们研究了不同厚度的多晶硅（mc-Si）晶片在高温下的光致载流子寿命退化和再生。实验结果表明，晶片越薄，退化越不明显，再生发生得越快。我们在最近提出的缺陷模型的框架中解释了这一结果，其中寿命再生归因于复合活性杂质扩散到晶片表面，在那里它被永久捕获。对测得的厚度相关寿命演化进行建模，使我们能够确定在75 °C温度下杂质的扩散系数在（5 ± 2）× 10− 11 cm 2s − 1范围内。将从我们的测量中提取的扩散系数与文献中公布的数据进行比较，可以排除大多数杂质。尽管文献中报道的扩散系数数据存在很大的不确定性，但仅对镍、钴和氢获得了合理的一致性。我们的研究的一个重要的实际意义是，薄于120 μm的mc-Si晶片不会遭受明显的光致寿命退化。
We examine the light‐induced carrier lifetime degradation and regeneration at elevated temperature in multicrystalline silicon (mc‐Si) wafers of different thicknesses. The experimental results show that the thinner the wafer the less pronounced the degradation is and the faster the regeneration takes place. We interpret this result in the framework of a recently proposed defect model, where the lifetime regeneration is attributed to the diffusion of the recombination‐active impurity to the wafer surfaces, where it is permanently trapped. Modeling the measured thickness‐dependent lifetime evolutions enables us to determine the diffusion coefficient of the impurity to be in the range (5 ± 2) × 10−11cm2s−1at a temperature of 75 °C. Comparing the diffusion coefficient extracted from our measurements with data published in the literature allows us to exclude most impurities. Despite the large uncertainties in the diffusion coefficient data reported in the literature, reasonable agreement is only obtained for nickel, cobalt, and hydrogen. One important practical implication of our study is that mc‐Si wafers thinner than 120 μm do not suffer from pronounced light‐induced lifetime degradation.