Innovative Dephosphorization from Silicon by Flux Purification Method under a Gradient of Oxygen Potential

2016 Fiscal Year Final Research Report

• Project/Area Number: 26420753
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Metal making/Resorce production engineering
• Research Institution: The University of Tokyo
• Principal Investigator: Yanaba Yutaka 東京大学, 生産技術研究所, 技術専門職員 (90723247)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 太陽電池 / シリコン / 脱リン / マルチフラックス / 酸素ポテンシャル

Outline of Final Research Achievements

In this research, "Dephosphorization from Silicon by Multiplex Flux Under a Gradient of Oxygen Potential" was proposed as a highly efficient method for removing impurities from silicon raw materials for solar cells. A multi-flux, which is simultaneously contain CaO-SiO2(-Al2O3) based glass as a liquid phase and 2CaO・SiO2 as a solid phase having solid solution effect with phosphorus, was prepared by heating, melting and rapidly cooling in an Ar atmosphere in an electric furnace without an air exposure.
The obtained flux was heated in a deoxidized Ar gas flow to equilibrate with a low oxygen partial pressure, and then was conducted by blowing with a short time and quenching in an Ar-O2 flow with higher oxygen partial pressure.
Raman spectroscopy was carried out to analyze the peaks attributable to silicon-oxygen bonds, and the proportion of non cross-linked oxygen in silicon was investigated.

Free Research Field

高温物理化学