ACTFEL Device Modeling via SPICE

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ACTFEL Device Modeling via SPICE

• J. P. Bender and J. F. Wager
• Department of Electrical and Computer Engineering
• Center for Advanced Materials Research
• Oregon State University
• Corvallis, Oregon 97731-3211
• http//www.ece.orst.edu/jfw

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Organization

• Fowler-Nordheim Diode Model
• Double-sheet Charge Model

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Fowler-Nordheim Diode Model
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Fowler-Nordheim Diode model Q-V
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Fowler-Nordheim Diode model C-V
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Fowler-Nordheim model Transient response
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Fowler-Nordheim model Transferred Charge Curve
Fowler-Nordheim Model
Experimental Data
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FN Model Scaling with Varying Vmax
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Modified Fowler-Nordheim Diode Model
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Double-sheet Charge Model
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Two-sheet Charge Model Band Diagram
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Two-sheet Charge Model Equivalent Circuit
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Two-sheet Charge Model

• 1. Emission Mechanisms
• Field emission (pure tunneling)
• Thermal emission
• Trap-to-band impact ionization
• 2. Charge Capture
• The probability that an electron crossing a
  sheet of charge is captured depends on
• Electric field at the sheet
• Occupancy of the sheet

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Two-sheet Charge Model
Space Charge Creation via Field Emission
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Two-sheet Charge Model
Space Charge Creation via Trap-band Impact
Ionization
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Two-sheet Charge Model Static Space Charge

• Ionized traps are not allowed to refill
• FB 1.5 V (experimental value)
• Bulk trap depth 1.38 V

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Transferred Charge Capacitance Overshoot
(Two-sheet charge model)
Experimental Data
Fowler-Nordheim Diode model
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Conclusions

• Fowler-Norheim Diode
• Simple yet accurate SPICE model for devices
  without space charge
• Two-sheet Charge Model
• Demonstrates mapping of device physics to SPICE
• Large amounts of C-V overshoot in SPICE