Fluidized Deposition Reactor for Silicon Production

Paul Ege1, Alireza Abbasi1, Jin-Seok Seo2, Jun-Suk Lee2, Jung-Hyun Lee2 1- Reactech Process Development Inc, Canada 2- KCC Corporation, Republic of Korea

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Overview

•  Siemens Rod Deposition •  High Energy / High Quality •  SiHCl3(g) +H2 = HCl(g) + Si(s) •  SiH4 = Si(g)+Si(s)+ H2

•  Metallurgical Routes •  Low Energy / Low Quality

•  Fluid Bed deposition •  Low Energy / Medium-High Quality •  SiH4 = Si(g)+Si(s)+ H2 •  SiHCl3(g) +H2 = HCl(g) + Si(s) •  4 SiHCl3= 2 H2+ 3 SiCl4+ Si(s)

•  Silane Freespace •  Low Energy / Medium quality

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Background Polysilicon Processes

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Background Fluidization Fundamentals

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Background Fluidized bed design elements

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Polysilicon Fluidized Bed Process Evaluation

ª  Continuous granular production => Reduce operation cost

ª  Excellent contact high surface volume => compact process

ª  Low DP for high throughput => high capacity

ª  Excellent heat transfer => low energy consumption

ª  Near isothermal conditions and large

thermal reservoir

   

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-  Complex flow patterns -  Gas mix in emulsion -  Gas bypass in bubbles

-  Attrition and Erosion -  Quality reduction -  Dust generation -  Pipe/Internal deterioration

-  Entrainment -  Powder inherent, less with TCS -  Dust from abrasion/attrition

-  Fouling -  Wall -  Nozzles/distributor

-  Complex reaction kinetics -  TCS, equilibrium limited -  Silane, competing reactions

Advantages Challenges

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Ø  JPL work in 1980ʼ’s many references Ø  Furusawa Hom/Het kinetics (1988) Ø  Lai & Dudukovics (MEMC) 1986

•  Describes a multi step mechanism

Ø  Caussat et. Al. study on FBR (1995-98) •  Bubbling reactor model and exp data

Ø  Mlezcko et. Al. Solarworld (2004) Ø  Pina et.al REC process (2006)

•  PF/CSTR approach

Ø  Ydstie-Balaji independent(2009)

Ø  Parker Barracuda (2010)

Polysilicon Fluidized Bed Literature

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Polysilicon Fluidized Bed Prior art (old patents)

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Polysilicon Fluidized Bed Protected designs (current patents)

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MEMC – SiH4 FBR •  Two stage process; high production with dust, low

production to adsorb dust and anneal •  Seed, quench, el.mag. heat, coating and valves •  Recent – multiple beds for growth, and special distributor •  Appears to be traditional bubbling fluid bed behavior •  Dimensions and capacities not revealed

REC – SiH4 FBR •  Submerged Spouted bed one or more spouts •  Nozzle design with secondary orifice, internal grinding,

annular withdrawal, halogen injection, tapered bed •  Recent radiant heated bed with internal liner and cooling

below injector

Others in development •  Wacker, KRICT, AEP, SILIKEN – TCS based •  Samsung-MEMC, KCC – Silane based •  Independent developers

Polysilicon Fluidized Bed Commercial Processes

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Polysilicon Fluidized Bed Commercial design solutions

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①  Review stage ü  Review literature/patents for IP/Cost/Risk feasibility analysis

②  Lab/Bench Scale (inches diameter) ü  Establish reaction kinetics and flow for basic reactor models ü  Validate process conditions and scale up strategy for pilot/commercial

③  Pilot/Demo Scale (feet diameter) ü  Validate commercial challenges in long term continuous operation ü  Verify scale up predictions and design for commercial ü  Well instrumented small commercial unit with many interruptions ü  Risk in scale best taken here!

④  Commercial Scale (meters diameter) ü  Target uninterrupted production with minimum disturbance ü  Start-up and stabilize, then optimize Yield/Capacity/Quality/Economics

FBR development Scope Scale and Objective of stages

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FBR development Multi Stage Effort

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FBR development Multi Level Modeling

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Reactech  Process  Development    

FBR development CFD and CPFD for flow and scale up analysis

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FBR development Reactor Model for design/analysis/control

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Characteristics

OBJECTIVE  Experimental  methods  to  verify  a  wide  range  of  parameters  that  are  important    

in  reactor  model  development  and  for  design  purposes  

Particle– External •  Fluidization/Entrainment/Reactivity •  Porosity/Density, Size/Shape, Umf, DPf, Ut Gas •  Fluidization/Entrainment •  Density, Viscosity Fluid bed •  Void, Solid Mixing, Gas dispersion, Mass and

Heat transfer Entrainment •  TDH, Freeboard flow/void, Cyclone feed/

efficiency, Dipleg operation

Pressure and Temperature •  Global / Time average => Mb, Hb, Void fraction •  Fluctuations => frequency, regime, forces •  Correlations => size, velocity •  Delta T=> Solids mixing Intrusive probes •  Capacitance/Fiberoptic/DP •  Local bubble and void properties Non Intrusive probes •  x-ray, γ-ray, capacitance •  High speed samples => local bubble properties •  Multiple samples => Tomography Tracer studies •  Gas dispersion •  Solids mixing (solid tracer, heat pulse)

FBR development Experimental

Methods

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Ø  Polysilicon FBR is promising technology for low cost high quality production

Ø  Prior art allows development of Polysilicon FBR. Challenge will be to avoid design details already patented

Ø  Significant development challenges require serious long-term effort from lab through pilot to commercial scale.

Ø  REC successfully commercialized new technology

Ø  Several new projects at different development stages

Ø  KCC progressing well with solid foundation from Bench scale efforts fast approaching demonstration scale pilot production

Conclusions

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