1. 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

2. Organization:
Fowler-Nordheim Diode Model
Double-sheet Charge Model

3. Fowler-Nordheim Diode Model

4. Fowler-Nordheim Diode model: Q-V

5. Fowler-Nordheim Diode model: C-V

6. Fowler-Nordheim model: Transient response

7. Fowler-Nordheim model: Transferred Charge Curve
Experimental Data

8. FN Model Scaling with Varying Vmax

9. Modified Fowler-Nordheim Diode Model

10. Double-sheet Charge Model
Space charge formation is allowed at two discrete locations within the phosphor layer
Each sheet can emit and capture electrons

11. Two-sheet Charge Model Band Diagram

12. Two-sheet Charge Model Equivalent Circuit

13. 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

14. Two-sheet Charge Model
Space Charge Creation via Field Emission

15. Two-sheet Charge Model
Space Charge Creation via Trap-band Impact Ionization

16. 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

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

18. Conclusions Fowler-Norheim Diode Two-sheet Charge Model
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