1. Henok Abebe Collaborators
MOSIS
Compact Modeling for Symmetric and Asymmetric Double Gate MOSFETs
Henok Abebe
The MOSIS Service
USC Viterbi School of Engineering
Information Sciences Institute
Collaborators
Ellis Cumberbatch and Hedley Morris:
CGU School of Mathematical Sciences, USA
Vance Tyree:
USC/ISI MOSIS, USA
Shigeyasu Uno:
Nagoya University, Department of Electrical and Computer Engineering, Japan
1st International MOS-AK Meeting, co-located with CMC Meeting and IEDM Conference, Dec , San Francisco, CA

2. Outline 1-D symmetric undoped DG MOSFET modeling.
MOSIS
Outline
1-D symmetric undoped DG MOSFET modeling.
2-D asymmetric and lightly doped DG MOSFET modeling.
Mid-section electrostatic potential approximation.
Long channel mobile charge and current models for asymmetric DG MOSFET.
Preliminary simulation results and comparison with numerical 2-D data.

3. 1-D symmetric undoped DG MOSFET modeling
MOSIS
1-D symmetric undoped DG MOSFET modeling
Undoped and symmetric.
Relatively small silicon thickness (eg. tsi=5nm).
Two gate voltages are taken to be the same.
Thin gate oxide (eg. tox=1.5nm).

4. 1-D symmetric DG (continued)
MOSIS
1-D symmetric DG (continued)
Boundary conditions
Poisson equation

5. 1-D symmetric DG (continued)
MOSIS
1-D symmetric DG (continued)
Exact solution using the first two boundary conditions:
Surface potential:

6. 1-D symmetric DG (continued)
MOSIS
1-D symmetric DG (continued)
Interface boundary condition equation for β:

7. 1-D symmetric DG (continued)
MOSIS
1-D symmetric DG (continued)
Total mobile charge per unit gate area:
Channel current:

8. Summary of the 1-D symmetric DG MOSFET
MOSIS
Summary of the 1-D symmetric DG MOSFET
For charge and current calculations, equation needs solving at source and drain only.
Have efficient iteration algorithm to solve for
Results are very accurate (see WCM proceedings Vol. 3, pp. 849,  June 1-5, (2008), Boston)

9. 2-D asymmetric and doped DG MOSFET modeling
MOSIS
2-D asymmetric and doped DG MOSFET modeling
Scaling

10. 2-D asymmetric (continued)
MOSIS
2-D asymmetric (continued)
Parabolic potential approximation:

11. 2-D asymmetric (continued)
MOSIS
2-D asymmetric (continued)
Boundary conditions:

12. 2-D asymmetric (continued)
MOSIS
2-D asymmetric (continued)
Surface potentials:
Explicit solutions can be calculated for wsf and wsb.

13. Mid-section electrostatic potential approximation
MOSIS
Mid-section electrostatic potential approximation
Long channel approximation:

14. Mid-section (continued)
MOSIS
Mid-section (continued)

15. Long channel mobile charge and current models for asymmetric DG MOSFET
MOSIS
Long channel mobile charge and current models for asymmetric DG MOSFET
Total mobile charge per unit gate area:
Channel current:

16. Preliminary simulation results and comparison with numerical 2-D data
MOSIS
Preliminary simulation results and comparison with numerical 2-D data
Mid-section potential versus relative gate voltage and relative surface potential with 5nm silicon thickness (lightly doped asymmetric DG MOSFET)

17. Preliminary simulation (continued)
MOSIS
Preliminary simulation (continued)
Mid-section potential versus relative gate voltage and silicon thickness with 1.5nm oxide thickness (lightly doped symmetric DG MOSFET)

18. Preliminary simulation (continued)
MOSIS
Preliminary simulation (continued)
Channel current and output conductance versus source-drain voltage with 5nm silicon and 1.5nm oxide thicknesses (lightly doped symmetric DG MOSFET)

19. Preliminary simulation (continued)
MOSIS
Preliminary simulation (continued)
Channel current and tansconductance versus gate voltage with 5nm silicon and 1.5nm oxide thicknesses (lightly doped symmetric DG MOSFET)

20. Preliminary simulation (continued)
MOSIS
Preliminary simulation (continued)
Channel current and output conductance versus source-drain voltage with 5nm silicon and 1.5nm oxide thicknesses (lightly doped symmetric DG MOSFET)

21. Preliminary simulation (continued)
MOSIS
Preliminary simulation (continued)
Channel current and tansconductance versus gate voltage with 5nm silicon and 1.5nm oxide thicknesses (lightly doped symmetric DG MOSFET)

22. Preliminary simulation (continued)
MOSIS
Preliminary simulation (continued)
Channel current and output conductance versus source-drain voltage with 5nm silicon and 1.5nm oxide thicknesses (lightly doped symmetric DG MOSFET)

23. Preliminary simulation (continued)
MOSIS
Preliminary simulation (continued)
Channel current and tansconductance versus gate voltage with 5nm silicon and 1.5nm oxide thicknesses (lightly doped symmetric DG MOSFET)

24. University of Southern California (USC) Viterbi School of Engineering
Information Sciences Institute (ISI)
The MOSIS Service
Marina del Rey, California
MOSIS