Download L25_5342_Sp02

Semiconductor Device
Modeling and Characterization
EE5342, Lecture 25 -Sp 2002
Professor Ronald L. Carter
[email protected]
http://www.uta.edu/ronc/
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MOSFET Device
Structre
Fig. 4-1, M&A*
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n-channel enh.
circuit model
G
RG
S
RB
Cgd
Cgs
RDS
Cbs
Idrain
DSS
RD
DSD
Cbd
D
Cgb
RB
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B
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SPICE mosfet Model
Instance
CARM*, Ch. 4, p. 290
M
MOSFET
General Form
M<nam e> < drain node> <gate node> < source node>
+ <bulk /subs trate node> <model nam e>
+ [L=< value>] [W=< value> ]
L = Ch. L. [m]
+ [AD= <value>] [AS= <value>]
W = Ch. W. [m]
+ [PD= <value>] [PS= <value>]
+ [NRD=< value>] [NRS=<value>] AD = Drain A [m2]
+ [NRG=<v alue>] [NRB= <value>]
AS = Source A[m2]
+ [M= <value>]
Examples
NRD, NRS = D and
S diff in squares
L=25u W=12u
M1 14 2 13 0 PNOM
M13 15 3 0 0 PSTRONG
M16 17 3 0 0 PSTRONG M=2
M = device
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M28 0 2 100 100 NWEAK L=33u W=12u
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, shortchannel model
• Level 4 is the BSIM1 model
• Level 5 is the BSIM2 model, etc.
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SPICE Parameters
Level 1 - 3 (Static)
Param. Parameter Description
Def.
Typ.
Units
1
1
V
VTO
Zero-bias Vthresh
KP
Transconductance
GAMMA
Body-effect par.
0.0
0.35
V^1/2
PHI
Surface inversion pot.
0.6
0.65
V
0.0
0.02
1/V
LAMBDA Channel-length mod.
2.E-05 3.E-05
TOX
Thin oxide thickness
NSUB
Substrate doping
0.0
1.E+15
cm^-3
NSS
Surface state density
0.0
1.E+10
cm^-2
LD
Lateral diffusion
0.0
8.E-05
m
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1.E-07 1.E-07
A/V^2
m
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SPICE Parameters
Level 1 - 3 (Static)
Param. Parameter Description
Def.
Typ.
1
1
600
700
Units
TPG
Type of gate material*
UO
Surface mobility
IS
Bulk jctn. sat. curr.
JS
Bulk jctn. sat. curr. dens.
PB
Bulk junction potential
0.8
0.75
V
RD
Drain ohmic resistance
0
10
Ohms
RS
Source ohmic resistance
0
10
Ohms
RSH
S/D sheet ohmic res.
0
10
Ohms/sq
1.E-14 1.E-15
cm^2/V-s
A
A/m^2
* 0 = aluminum gate, 1 = silicon gate opposite substrate type,
2 = silicon gate same as substrate.
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SPICE Parameters
Level 1 - 3 (Q & N)
Param. Parameter Description
Def.
Typ.
Units
0
1.E-09
Fd/m^2
CJ
Zero-bias bulk cap./A
MJ
Bulk jctn. grading coeff.
0.5
0.5
CJSW
Zero-bias perimeter C/l
0
1.E-09
MJSW
Per. C grading coeff.
0.5
0.5
FC
For.-bias cap. coeff.
0.5
0.5
CGBO
Gate-bulk overlap C/L
0
2.E-10
Fd/m
CGDO
Gate-drain overlap C/L
0
4.E-11
Fd/m
CGSO
G-S overlap C/L
0
4.E-11
Fd/m
AF
Flicker-noise exp.
1
1.2
KF
Flicker-noise coeff.
0.0
1.E-26
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Fd/m
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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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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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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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SPICE Parameters
Level 2
Param. Parameter Description
Def.
Typ.
1
5
NEFF
Total channel chg coeff.
UCRIT
Critical E-field for mob.
UEXP
Expon. coeff. for mob.
0
0.1
UTRA
Transverse field coeff.
0
0.5
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1.E+04 1.E+04
Units
V/cm
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SPICE Parameters
Level 2 & 3
Param. Parameter Description
Def.
Typ.
Units
NFS
Surface-fast state dens.
0.0
1.E+10
cm^-2
XJ
Metallurgical jctn. depth
0.0
1.E-06
m
VMAX
Max. drift v of carr.
0.0
5.E+04
m/s
XQC
Coeff. of ch. Q share
0.0
0.4
DELTA
Width eff. on Vthresh
0.0
1.0
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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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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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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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SPICE Parameters
Level 3
Param. Parameter Description
Def.
Typ.
KAPPA
Saturation field factor
0.2
1.0
ETA
Stat. feedbk on Vthresh
0.0
1.0
THETA
Mobility modulation
0.0
0.05
DELTA
Width eff. on Vthresh
0.0
1.0
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Units
1/V
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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,
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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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4-7a (A&M)
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Figure 4-7b (A&M)
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Figure 4-8a (A&M)
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Figure 4-8b (A&M)
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Project 4
Parts 2, 3, and 4
2. Generate outputs
duplicating Fig 9.9
in M&K*
3. For each simulation, give the complete list of model
parameters used.
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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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Body effect data
Fig 9.9**
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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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