Recycling of SiCl4 in the manufacture of granular polysilicon in a fluidized bed reactor

A process that used chemical vapor deposition (CVD) from the mixture of trichlorosilane (SiHCl3) and silicon tetrachloride (SiCl4) for the production of polysilicon granules in a fluidized bed reactor (FBR) was studied. The effects of the reaction temperature (800–1200 °C), molar ratio of H2 to SiHCl3 and SiCl4, and SiHCl3 fraction in the mixture of SiHCl3 and SiCl4 (0–100%) were studied. The reactant gas was analyzed by a gas chromatography (GC). The surface morphology of the product particles were analyzed by scanning electron microscopy. Well grown product particles were obtained. The reaction temperature and reactant composition significantly affected the Si yield and the amount of produced SiCl4 per kg deposited Si. The results showed that zero net by-production of SiCl4 could be realized by using the mixture of SiHCl3 and SiCl4 as reactant in a FBR while a satisfactory Si yield was remained. A suitable reaction condition for this was 1200 °C and molar ratio H2/SiHCl3/SiCl4 was 16/0.5/0.5. The corresponding one-through SiHCl3 conversion and Si yield were 21.1% and 9.6%, respectively, which were higher than the improved Siemens technology using pure SiHCl3.

[1]  P. Woditsch,et al.  Solar grade silicon feedstock supply for PV industry , 2002 .

[2]  M. G. Norton,et al.  Microstructure and grain growth of polycrystalline silicon grown in fluidized bed reactors , 2009 .

[3]  John Houseman,et al.  Silicon particle growth in a fluidized‐bed reactor , 1987 .

[4]  Tiefeng Wang,et al.  Manufacture of Granular Polysilicon from Trichlorosilane in a Fluidized‐Bed Reactor , 2012 .

[5]  Roland Einhaus,et al.  Silicon feedstock for the multi-crystalline photovoltaic industry , 2002 .

[6]  Erik Stensrud Marstein,et al.  Development of fluidized bed reactors for silicon production , 2010 .

[7]  William Hultz Walker,et al.  Principles of chemical engineering , 1923 .

[8]  K. Okuyama,et al.  Chemical process of silicon epitaxial growth in a SiHCl3-H2 system , 1999 .

[9]  J. Couderc,et al.  Silicon deposition from silane or disilane in a fluidized bed—Part II: Theoretical analysis and modeling , 1995 .

[10]  B. Erik Ydstie,et al.  Size distribution modeling for fluidized bed solar-grade silicon production☆ , 2006 .

[11]  Paulo Roberto Mei,et al.  New processes for the production of solar-grade polycrystalline silicon: A review , 2008 .

[12]  L. Mleczko,et al.  Optimization of Reaction Conditions in a Fluidized‐Bed for Silane Pyrolysis , 2008 .

[13]  S. Pizzini.  Bulk solar grade silicon: how chemistry and physics play to get a benevolent microstructured material , 2009 .

[14]  G. C. Hsu,et al.  Fines in Fluidized Bed Silane Pyrolysis , 1984 .

[15]  J. Couderc,et al.  Silicon deposition from silane or disilane in a fluidized bed—Part I: Experimental study , 1995 .

[16]  V. Titov,et al.  Thermodynamic simulation of silicon deposition from the gas phase of Si-Cl-H system , 2009 .

[17]  Paul E. Ege,et al.  Multi‐scale Modeling and Constrained Sensitivity Analysis of Particulate CVD Systems , 2007 .

[18]  Raymund Sonnenschein,et al.  Silicon for photovoltaic applications , 2006 .

[19]  Madhava Syamlal,et al.  Silicon CVD on powders in fluidized bed: Experimental and multifluid Eulerian modelling study , 2007 .