Calcium Evaporation from Metallurgical Grade Silicon by an Electron Beam Melting

Semicond. Sci. Technol.

Tan

et al. 2015

Self Cite

An experimental investigation into the removal of aluminum (Al) and calcium (Ca) from molten silicon by using electron beam melting was carried out. Based on the distributions of Al and Ca along the growth direction of the ingot under different solidification conditions, the influence of segregation and evaporation behaviors on the removal of such impurities with both high saturated vapor pressure and low segregation coefficients was investigated. The results showed that the distributions of impurities depend upon the interaction between segregation and evaporation, so that the removal efficiency can be further improved by adjusting the melting parameters. Compared with the traditional electron beam melting process, the energy consumption decreases by 20% during the whole melting and solidification process. It is considered to be a more effective way for the purification of silicon and the reduction of energy consumption by electron beam melting.

Section: Removal Of Impurities By Coupling Of Segregation and Evapora...supporting

confidence: 62%

Segregation and evaporation behaviors of aluminum and calcium in silicon during solidification process induced by electron beam

Jiang

Semicond. Sci. Technol.

Tan

et al. 2015

Self Cite

“…The solubilities of metal impurities in SiO2 films are limited, so a certain thickness is required to remove these impurities. Some melted silicon particles existed in the central part, which illustrates that the temperature of the silicon particles can be increased by EBI [7][8][9]. The microscopic morphologies of the silicon particles were observed using SEM.…”

Section: Resultsmentioning

confidence: 99%

Effect of Electron Beam Injection on the Removal of Metal Impurities in Silicon

Tan

Pang

et al. 2012

AMR

Self Cite

Electron beam injection(EBI) is a process of gathering the electrons in materials using electron beam(EB). The EBI technology is proposed for purification of silicon particles by removing metal impurities through high-temperature oxidation, EBI, and HF acid washing processes. Analysis of silicon particle morphology after high-temperature oxidation using digital camera and after EBI using scanning electron microscope(SEM) were conducted. Then, the composition of silicon particles was analyzed using inductively coupled plasma(ICP). The silicon particle colours turned bright after EBI; therefore, EBI can change the thickness of SiO2 films in addition to increasing the temperature of the silicon particles. The results show that this technology is effective in removing metal impurities in silicon particles.

“…Electron beam melting is an effective method to removal volatile impurities in silicon. Researchers from Dalian University of Technology have done a lot of works on the removal mechanisms of volatile impurities and the influence of beam density on removal efficiency [5][6][7][8] . However, it is still not clear that the influence of electron beam parameters, such as beam density and beam size, on molten pool morphology, so the relationship between beam energy and smelting capacity cannot be estimated accurately.…”

Section: Introductionmentioning

confidence: 99%

Research on the Influence of Electron Beam Parameters on Molten Pool Morphologies during Electron Beam Melting Silicon

et al. 2012

AMR

Electron beam melting is an effective method to remove volatile impurities in silicon, during which impurities such as P, Al and Ca etc. can be removed to less than 0.3×10-4wt.%. However, so far there is few research on the influence of electron beam parameters, such as beam density and beam size, on molten pool morphology, hence electron beam melting process has not been completely understood, which leads to low energy utilization. In this paper, on the basis of beam size calibration, the influence of beam density and beam size on molten pool morphology is investigated and the concept of melting angle is proposed to characterize molten pool morphology. At the same time, the optimal molten pool morphology for impurities removal and the corresponding electron beam parameters are also analyzed.