Minority carrier lifetime evaluation of periphery edge region in high-performance multicrystalline ingot produced by seed-assisted directional solidification

• Published in: Frontiers of physics 2017-10, Vol.12 (5), p.91-97, Article 128103
• Main Authors: Li, Zhong, Li, Jia-Dan, Zhuang, Lin, Hong, Rui-Jiang
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Cosmology; Atomic; Carrier lifetime; Condensed Matter Physics; Crystal defects; defects; Directional solidification; Edge zones; Fourier transforms; Grain boundaries; Grain growth; Grain size; Grain size distribution; Impurities; impurity; Ingots; Lifetime; minority carrier lifetime; Minority carriers; Molecular; Optical and Plasma Physics; Particle and Nuclear Physics; Particle size; periphery edge; Photoluminescence; Physics; Physics and Astronomy; Research Article; seed-assisted directional solidification; Seeds; Service life assessment; Silicon; Silicon wafers; Solidification; Spectrum analysis; 傅立叶变换红外光谱; 多晶硅锭; 定向凝固; 寿命评价; 少数载流子寿命; 性能; 种子; 边缘区域
• ISSN: 2095-0462; 2095-0470
• DOI: 10.1007/s11467-017-0708-4

A high-performance multicrystalline silicon (mc-Si) ingot was produced by seed-assisted directional solidification, and the minority carrier lifetime of the periphery edge region was evaluated. The defects and impurities in the periphery edge region of the silicon wafers were systematically studied with photoluminescence (PL) imaging, minority carrier lifetime mapping, and Fourier transform infrared (FTIR) spectroscopy. Their relationships with the minority carrier lifetime were investigated. The concentration of substitutional carbon, interstitial oxygen, and dislocation clusters is not directly correlated with the low minority carrier lifetime of the edge zone of the mc-Si ingot. Inhomogeneous grain size distribution and contamination with iron impurities were demonstrated to be the main factors affecting the low minority carrier lifetime. By controlling the impurities and improving the grain size distribution, a modified furnace was designed and a higher-quality mc-Si ingot was manufactured.