Presented at SolarCon China 2012 CPTIC Symposiumseries

1. 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

2. Overview
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3. Background
Polysilicon Processes
• 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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4. Background
Fluidization Fundamentals
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5. Background
Fluidized bed design elements
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6.
Polysilicon Fluidized Bed
Process Evaluation
Advantages Challenges
ª Continuous granular production - Complex flow patterns
=> Reduce operation cost - Gas mix in emulsion
ª Excellent contact high surface volume - Gas bypass in bubbles
- Attrition and Erosion
=> compact process - Quality reduction
ª Low DP for high throughput - Dust generation
=> high capacity - Pipe/Internal deterioration
- Entrainment
ª Excellent heat transfer - Powder inherent, less with TCS
=> low energy consumption - Dust from abrasion/attrition
- Fouling
- Wall
ª Near isothermal conditions and large - Nozzles/distributor
thermal reservoir
- Complex reaction kinetics
- TCS, equilibrium limited
- Silane, competing reactions
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7. Polysilicon Fluidized Bed
Literature
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)
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8. Polysilicon Fluidized Bed
Prior art (old patents)
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9. Polysilicon Fluidized Bed
Protected designs (current patents)
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10. Polysilicon Fluidized Bed
Commercial Processes
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
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11. Polysilicon Fluidized Bed
Commercial design solutions
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12. FBR development
Scope Scale and Objective of stages
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
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13. FBR development
Multi Stage Effort
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14. FBR development
Multi Level Modeling
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15. FBR development
CFD and CPFD for flow and scale up analysis
Reactech
Process
Development
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16. FBR development
Reactor Model for design/analysis/control
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17. FBR development
Experimental
OBJECTIVE
Experimental
methods
to
verify
a
wide
range
of
parameters
that
are
important
in
reactor
model
development
and
for
design
purposes
Characteristics Methods
Particle– External Pressure and Temperature
• Fluidization/Entrainment/Reactivity • Global / Time average => Mb, Hb, Void fraction
• Porosity/Density, Size/Shape, Umf, DPf, Ut • Fluctuations => frequency, regime, forces
• Correlations => size, velocity
Gas • Delta T=> Solids mixing
• Fluidization/Entrainment Intrusive probes
• Density, Viscosity • Capacitance/Fiberoptic/DP
Fluid bed • Local bubble and void properties
• Void, Solid Mixing, Gas dispersion, Mass and Non Intrusive probes
Heat transfer • x-ray, γ-ray, capacitance
Entrainment • High speed samples => local bubble properties
• TDH, Freeboard flow/void, Cyclone feed/ • Multiple samples => Tomography
efficiency, Dipleg operation Tracer studies
• Gas dispersion
• Solids mixing (solid tracer, heat pulse)
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18. Conclusions
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
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