1. Professor Ronald L. Carter ronc@uta.edu http://www.uta.edu/ronc/
Semiconductor Device Modeling and Characterization – EE5342 Lecture 35 – Spring 2011
Professor Ronald L. Carter

2. Flat-band parameters for p-channel (n-subst)
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3. Fully biased p- channel VT calc
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4. p-channel VT for VC = VB = 0
Fig 10.21*
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5. Ion implantation
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6. “Dotted box” approx
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8. Mobilities
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9. Differential charges for low and high freq
From Fig 10.27*
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10. Ideal low-freq C-V relationship
Fig 10.25*
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11. Comparison of low and high freq C-V
Fig 10.28*
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12. Effect of Q’ss on the C-V relationship
Fig 10.29*
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13. n-channel enhancement MOSFET in ohmic region
0< VT< VG
Channel
VS = 0
0< VD< VDS,sat
EOx,x> 0 n+
e-e- e- e- e- n+
Depl Reg
p-substrate
Acceptors
VB < 0
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14. Conductance of inverted channel
Q’n = - C’Ox(VGC-VT)
n’s = C’Ox(VGC-VT)/q, (# inv elect/cm2)
The conductivity sn = (n’s/t) q mn
G = sn(Wt/L) = n’s q mn (W/L) = 1/R, so
I = V/R = dV/dR, dR = dL/(n’sqmnW)
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15. Basic I-V relation for MOS channel
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16. I-V relation for n-MOS (ohmic reg)ID
non-physical
ID,sat
saturated
VDS,sat
VDS
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17. Universal drain characteristicID
VGS=VT+3V
9ID1
ohmic
saturated, VDS>VGS-VT
VGS=VT+2V
4ID1
VGS=VT+1V
ID1
VDS
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18. Characterizing the n-ch MOSFETVD ID D G S B VT
VGS
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19. Low field ohmic characteristics
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20. MOSFET Device Structre Fig. 4-1, M&A*
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21. 4-7a (A&M)
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22. Figure 4-7b (A&M)
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23. Figure 4-8a (A&M)
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24. Figure 4-8b (A&M)
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25. Body effect data
Fig 9.9**
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26. MOSFET equivalent circuit elements
Fig 10.51*
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27. n-channel enh. circuit modelG RG
Cgd
RDS
Cgs S RD D
Cbd RB
Cbs
Idrain
Cgb
DSS
DSD RB B
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28. MOS small-signal equivalent circuit
Fig 10.52*
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29. MOSFET circuit parameters
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30. MOSFET circuit parameters (cont)
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31. Substrate bias effect on VT (body-effect)
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32. Body effect data
Fig 9.9**
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33. Fully biased n- channel VT calc
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34. Values for fms with silicon gate
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35. Q’d,max and xd,max for biased MOS capacitor
Fig 8.11**
|Q’d,max|/q (cm-2)
xd,max (microns)
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36. I-V relation for n-MOS ohmic ID non-physical ID,sat saturated VDS,sat
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37. MOS channel- length modulation
Fig 11.5*
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38. Analysis of channel length modulation
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39. References
CARM = Circuit Analysis Reference Manual, MicroSim Corporation, Irvine, CA, 1995.
M&A = Semiconductor Device Modeling with SPICE, 2nd ed., by Paolo Antognetti and Giuseppe Massobrio, McGraw-Hill, New York, 1993.
**M&K = Device Electronics for Integrated Circuits, 2nd ed., by Richard S. Muller and Theodore I. Kamins, John Wiley and Sons, New York, 1986.
*Semiconductor Physics and Devices, by Donald A. Neamen, Irwin, Chicago, 1997
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