Performance improvements of solar-grade crystalline silicon by continuously variable temperature phosphorous gettering process using a porous silicon layer

• Published in: Materials science in semiconductor processing 2010-09, Vol.13 (3), p.209-213
• Main Authors: Zhang, Caizhen, Liu, Su, Wang, Yongshun, Chen, Yonggang
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Continuously variable; Continuously Variable Temperature Phosphorous Gettering (CVTPG); Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic transport in multilayers, nanoscale materials and structures; Electronics; Energy; Exact sciences and technology; Gettering; Materials science; Natural energy; Optimization; Optoelectronic devices; Photovoltaic cells; Photovoltaic conversion; Physics; Porous materials; granular materials; Porous silicon; Porous Silicon Layer (PSL); Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Semiconductors; Silicon; Solar cells; Solar cells. Photoelectrochemical cells; Solar energy; Solar-Grade (SOG) silicon; Specific materials
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2010.10.015

The Continuously Variable Temperature Phosphorous Gettering process using a Porous Silicon Layer (PSL-CVTPG) was proposed. PSL-CVTPG process can getter unwanted impurities from Solar-Grade silicon (SOG-Si) wafers and upgrade photovoltaic properties of solar cells more efficiently than conventional Constant Temperature Phosphorus Gettering process using a Porous Silicon Layer (PSL-CTPG). The resistivity, and mobility of majority carriers, and the effective lifetime of minority carriers were evaluated; the results showed that under certain conditions, the gettering effect of the PSL-CVTPG is better than that of the optimum PSL-CTPG. By orthogonal experiments, the optimum PSL-CVTPG conditions were found to be 900 °C/60 min+750 °C/60 min. PSL-CVTPG and CTPG processes under their respective optimum gettering conditions were used in the fabrication of solar cells, and cells based on SOG-Si wafers purified by the PSL-CVTPG process exhibited an amelioration in photovoltaic performances.