1. Professor Ronald L. Carter ronc@uta.edu http://www.uta.edu/ronc/
Semiconductor Device Modeling and Characterization EE5342, Lecture 25 -Sp 2002
Professor Ronald L. Carter
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2. MOSFET Device Structre Fig. 4-1, M&A*
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3. n-channel enh. circuit modelG RG
Cgd
RDS
Cgs S RD D RB
Cbs
Cbd
Idrain
Cgb
DSS
DSD RB B
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4. SPICE mosfet Model Instance CARM*, Ch. 4, p. 290
L = Ch. L. [m]
W = Ch. W. [m]
AD = Drain A [m2]
AS = Source A[m2]
NRD, NRS = D and
S diff in squares
M = device multiplier
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5. SPICE mosfet model levels
Level 1 is the Schichman-Hodges model
Level 2 is a geometry-based, analytical model
Level 3 is a semi-empirical, short-channel model
Level 4 is the BSIM1 model
Level 5 is the BSIM2 model, etc.
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6. SPICE Parameters Level 1 - 3 (Static)
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7. SPICE Parameters Level 1 - 3 (Static)
* 0 = aluminum gate, 1 = silicon gate opposite substrate type, 2 = silicon gate same as substrate.
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8. SPICE Parameters Level 1 - 3 (Q & N)
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9. Level 1 Static Const. For Device Equations
Vfb = -TPG*EG/2 -Vt*ln(NSUB/ni) q*NSS*TOX/eOx
VTO = as given, or
= Vfb + PHI + GAMMA*sqrt(PHI)
KP = as given, or
= UO*eOx/TOX
CAPS are spice pars., technological constants are lower case
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10. Level 1 Static Const. For Device Equations
b = KP*[W/(L-2*LD)] = 2*K, K not spice
GAMMA = as given, or
= TOX*sqrt(2*eSi*q*NSUB)/eOx
2*phiP = PHI = as given, or
= 2*Vt*ln(NSUB/ni)
ISD = as given, or = JS*AD
ISS = as given, or = JS*AS
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11. Level 1 Static Device Equations
vgs < VTH, ids = 0
VTH < vds + VTH < vgs,
id = KP*[W/(L-2*LD)]*[vgs-VTH-vds/2]
*vds*(1 + LAMBDA*vds)
VTH < vgs < vds + VTH,
id = KP*[W/(L-2*LD)]*(vgs - VTH)^2
*(1 + LAMBDA*vds)
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12. SPICE Parameters Level 2
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13. SPICE Parameters Level 2 & 3
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14. Level 2 Static Device Equations
Accounts for variation of channel potential for 0 < y < L
For vds < vds,sat = vgs - Vfb - PHI
+ g2*[1-sqrt(1+2(vgs-Vfb-vbs)/g2]
id,ohmic = [b/(1-LAMBDA*vds)]
*[vgs - Vfb - PHI - vds/2]*vds
-2g[vds+PHI-vbs)1.5-(PHI-vbs)1.5]/3
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15. Level 2 Static Device Eqs. (cont.)
For vds > vds,sat
id = id,sat/(1-LAMBDA*vds)
where id,sat = id,ohmic(vds,sat)
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16. Level 2 Static Device Eqs. (cont.)
Mobility variation
KP’ =
KP*[(esi/eox)*UCRIT*TOX
/(vgs-VTH-UTRA*vds)]UEXP
This replaces KP in all other formulae.
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17. SPICE Parameters Level 3
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18. Project 4 Part 1
Generate outputs duplicating any 8 of the following 14 figures in A&M*
Figure 4-7a and b,
Figure 4-8a and b,
Figure 4-9a and b,
Figure 4-10,
Figure 4-11a only,
Figure 4-12a only,
Figure 4-13,
Figure 4-15,
Figure 4-19,
Figure 4-20,
Figure 4-23
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19. 4-7a (A&M)
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20. Figure 4-7b (A&M)
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21. Figure 4-8a (A&M)
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22. Figure 4-8b (A&M)
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23. Project 4 Parts 2, 3, and 4
2. Generate outputs duplicating Fig 9.9 in M&K*
3. For each simula-tion, give the com-plete list of model parameters used.
4. Give a brief discussion of how Level 1, 2, and 3 are selected by Pspice depending on the parameter set used.
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24. Body effect data
Fig 9.9**
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25. 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.
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