EE5342

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EE5342 Semiconductor Device Modeling and
CharacterizationLecture 30 - Spring 2004

• Professor Ronald L. Carter
• ronc_at_uta.edu
• http//www.uta.edu/ronc/

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MOSFET circuitparameters
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Estimating LAMBDA
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SPICE mosfet Model Instance CARM, Ch. 4, p. 290

• L Ch. L. m
• W Ch. W. m
• AD Drain A m2
• AS Source Am2
• NRD, NRS D and
• S diff in squares
• M device multiplier

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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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SPICE ParametersLevel 1 - 3 (Static)
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SPICE ParametersLevel 1 - 3 (Static)

• 0 aluminum gate, 1 silicon gate opposite
  substrate type, 2 silicon gate same as
  substrate.

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SPICE ParametersLevel 1 - 3 (Q N)
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Level 1 Static Const.For Device Equations

• Vfb -TPGEG/2 -Vtln(NSUB/ni) -
  qNSSTOX/eOx
• VTO as given, or
• Vfb PHI GAMMAsqrt(PHI)
• KP as given, or
• UOeOx/TOX
• CAPS are spice pars., technological constants are
  lower case

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Level 1 Static Const.For Device Equations

• b KPW/(L-2LD) 2K, K not spice
• GAMMA as given, or
• TOXsqrt(2eSiqNSUB)/eOx
• 2phiP PHI as given, or
• 2Vtln(NSUB/ni)
• ISD as given, or JSAD
• ISS as given, or JSAS

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Level 1 Static Device Equations

• vgs lt VTH, ids 0
• VTH lt vds VTH lt vgs,
• id KPW/(L-2LD)vgs-VTH-vds/2
• vds(1 LAMBDAvds)
• VTH lt vgs lt vds VTH,
• id KP/2W/(L-2LD)(vgs - VTH)2
• (1 LAMBDAvds)

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n-channel enhancementMOSFET in ohmic region
0lt VTlt VG
e- channel ele implant ion
Channel
VS 0
0lt VDlt VDS,sat
EOx,xgt 0
n
n
e-e- e- e- e-

Depl Reg
p-substrate
Acceptors
VB lt 0
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Subthreshold conduction

• Below O.S.I., when the total band-bending lt
  2fp, the weakly inverted channel conducts by
  diffusion like a BJT.
• Since VGSgtVDS, and below OSI, then NagtnS gtnD, and
  electr diffuse S --gt D

Electron concentration at Source
Concentration gradient driving diffusion
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Subthreshold current data
Figure 10.1
Figure 11.4
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Mobility variationdue to Edepl
Figures 11.7,8,9
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Velocity saturationeffects
Figure 11.10
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SPICE ParametersLevel 2
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SPICE ParametersLevel 2 3
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Level 2 StaticDevice Equations

• Accounts for variation of channel potential for 0
  lt y lt L
• For vds lt vds,sat vgs - Vfb - PHI
• g21-sqrt(12(vgs-Vfb-vbs)/g2
• id,ohmic b/(1-LAMBDAvds)
• vgs - Vfb - PHI - vds/2vds
• -2gvdsPHI-vbs)1.5-(PHI-vbs)1.5/3

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Level 2 StaticDevice Eqs. (cont.)

• For vds gt vds,sat
• id id,sat/(1-LAMBDAvds)
• where id,sat id,ohmic(vds,sat)

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Level 2 StaticDevice Eqs. (cont.)

• Mobility variation
• KP
• KP(esi/eox)UCRITTOX
• /(vgs-VTH-UTRAvds)UEXP
• This replaces KP in all other formulae.

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SPICE ParametersLevel 3
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Project 3

• Project 3 is posted on the web
• See www.uta.edu/ronc/ 5342/projects/5342Proje
  ct3.pdf

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Project 2 Parameter Values Extracted

• RB " 1.233K"
• IRB " 1.000u"
• RBM " 151.8 "
• RE " 2.560 "
• RC " 26.00 "
• CJE " 2.344p"
• VJE " 762.0m"
• MJE " 344.9m"
• CJC " 1.234p"
• VJC " 570.8m"
• MJC " 347.6m"
• CJS " 100.4f"
• VJS " 566.0m"
• MJS " 267.0m"

• IS " 891.8a"
• BF " 113.6 "
• NF " 1.044 "
• VAF " 83.50 "
• IKF " 13.45m"
• ISE " 20.40f"
• NE " 1.772 "
• BR " 2.270 "
• NR " 1.013 "
• VAR " 22.92 "
• IKR " 2.000m"
• ISC " 537.6f"
• NC " 1.675 "

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Project 2 Optimized Parameter Values

• RB " 1.233K"
• IRB " 986.9n"
• RBM " 122.2 "
• RE " 2.831 "
• RC " 11.71 "
• CJE " 2.344p"
• VJE " 762.0m"
• MJE " 344.9m"
• CJC " 1.234p"
• VJC " 570.8m"
• MJC " 347.6m"
• CJS " 100.4f"
• VJS " 566.0m"
• MJS " 267.0m"

• IS " 890.9a"
• BF " 123.7 "
• NF " 1.043 "
• VAF " 86.04 "
• IKF " 14.33m"
• ISE " 28.54f"
• NE " 1.878 "
• BR " 2.657 "
• NR " 1.012 "
• VAR " 21.25 "
• IKR " 6.470m"
• ISC " 537.6f"
• NC " 1.675 "

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Project 2 Parameter Values Used for Data

• RB " 1.234K"
• IRB " 987.0n"
• RBM " 123.0 "
• RE " 2.345 "
• RC " 5.678 "
• CJE " 2.345p"
• VJE " 765.4m"
• MJE " 345.6m"
• CJC " 1.234p"
• VJC " 567.8m"
• MJC " 345.6m"
• CJS " 100.4f"
• VJS " 566.8m"
• MJS " 269.6m"

• IS " 891.0a"
• BF " 123.0 "
• NF " 1.043 "
• VAF " 86.95 "
• IKF " 14.91m"
• ISE " 28.86f"
• NE " 1.876 "
• BR " 2.345 "
• NR " 1.012 "
• VAR " 23.45 "
• IKR " 23.45m"
• ISC " 1.095p"
• NC " 1.875 "

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References

• CARM Circuit Analysis Reference Manual,
  MicroSim Corporation, Irvine, CA, 1995.
• MA Semiconductor Device Modeling with SPICE,
  2nd ed., by Paolo Antognetti and Giuseppe
  Massobrio, McGraw-Hill, New York, 1993.
• MK 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