L23 08April03 1

Semiconductor Device Modeling and CharacterizationEE5342, Lecture 23Spring 2003

Professor Ronald L. Carterronc@uta.edu

http://www.uta.edu/ronc/

L23 08April03 2

Discussion of IC-CAP Parameter Extraction Lang.• Download and bring a copy of:

– http://www.uta.edu/ronc/neff.txt– http://www.uta.edu/ronc/iseff.txt– copy as *.xfm to your gamma acct– import *.xfm to appropriate setup

• A brief PEL overview in 4/8 lecture.• IC-CAP user guide at:http://eesof.tm.agilent.com/docs/iccap/ic_ug/icug_2001.pdf

L23 08April03 3

Importing an .xfm file into a DUT

• open DUT• select Extract / Optimize• /File/Open - select .xfm - select

"browse" to select neff.xfm• Be sure variables selected are in DUT• Can plot in DUT/Plots as neff, neff.m

and neff.s• Likewise for iseff

L23 08April03 4

neff.xfmLINK XFORM ”neff"{data{HYPTABLE "Link Transform"{element "Function" "Program"}BLKEDIT "Program Body"{ k = 1.38066e-23 q = 1.60218e-19 T = 273.16 + TNOM Vt = k*T//q

L23 08April03 5

neff.xfm (cont.) vbe = vb - ve ! neff = dv/d(ln(i))/(Vt) lnic = log(ic.b) y = derivative(lnic,vbe,1) !dy/dx = derivative(x,y,1) return y//Vt}dataset{datasize BOTH 51 1 1. . . meas and simu data ...}}}

L23 08April03 6

iseff.xfmLINK XFORM "iseff"{data{HYPTABLE "Link Transform"{element "Function" "Program"}BLKEDIT "Program Body"{ k = 1.38066e-23 q = 1.60218e-19 T = 273.16 + TNOM Vt = k*T//q

L23 08April03 7

iseff.xfm (cont.) vbe = vb - ve ! neff = dv/d(ln(i))/(Vt) lnic = log(ic.b) y = derivative(lnic,vbe,1) !dy/dx = derivative(x,y,1) ne = y//Vt return exp(log(ic)-vbe/(ne*Vt))}dataset{datasize BOTH 51 1 1. . . meas and simu data ...}}}

L23 08April03 8

Values for gate workfunction, m

V 17.5q/E :Si-poly p

V 05.4 :Si-poly n

V 55.4 :W ,Tungsten

V 65.5 :Pt ,Platinum

V 6.4 :Mo ,Molybdenum

V 1.5 :Au ,Gold

V 28.4 :Al ,umminAlu

gSim

Sim

m

m

m

m

m

L23 08April03 9

Values for ms

with metal gate

02586.0V ,12.1E ,19E8.2N

10E45.1n ,05.4 ,28.4

NN

lnV :Si-n to Al

nN

lnVq2

E

n

NNlnV :Note

n

NNlnV :Si-p to Al

tgC

iSiAlm,

d

CtSiAlm,ms

i

at

g2i

aCt

2i

aCtSiAlm,ms

L23 08April03 10

Values for ms

with silicon gate

i

dt

g

d

Ct

d

CtSi

gSims

i

at

g2i

aCt

2i

aCtSiSims

nN

lnVq2

E

NN

lnV :Note

NN

lnVq

E :Si-n to poly p

nN

lnVq2

E

n

NNlnV :Note

n

NNlnV :Si-p to poly n

L23 08April03 11

Experimental valuesfor msFig 10.15*

L23 08April03 12

Calculation of thethreshold cond, VT

Ox the across Q induce to added

voltage the isV where V,VV

sub)-p sub,-(n xNqQ is

charge extra the and x of value

the reached has region depletion

The inverted. is surface the when

reached is condition threshold The

d,max

FBT

d,maxBd,max

d,max

L23 08April03 13

Equations forVT calculation

substr-n for 0 substr,- p for 0V

qN

22x ,xNqQ

,0nN

lnV ,0Nn

lnV

C

Q2VV :substrn,p

d,a

n,pd,maxd,maxa,dd,max

i

dtn

a

itp

Ox

',maxd

n,pFBT

L23 08April03 14

Fully biased n-MOScapacitor

0y

L

VG

Vsub=VB

EOx,x> 0

Acceptors

Depl Reg

e- e- e- e- e- e- n+

n+

VS VD

p-substrate

Channel if VG > VT

L23 08April03 15

Effect of contacts,VS and VD

material type-n induced allyelectronic

the contacts V and type-p the

contacts V since ,VV2VV

bend-band total let size, D.R. compute To

... ,VV21

V where ,VVyV

so ,V at not are regions contact The

C

BCBpabi

DSavgC,CGOx

B

L23 08April03 16

Computing theD.R. width at O.S.I.

Ex

Emax

x

aSi

x Nq

dxdE

a

CBpSi,maxd qN

VV22x

CBp VV2area

,maxda,maxd xqNQ

L23 08April03 17

Computing thethreshold voltage

DR the charge

and channel the invert to

required is where ,

'

'2 ,max

VVV

C

QVVV

FB

Ox

dSpFBT

L23 08April03 18

)VV(2/1V or VVV

VV,V

DsGsGox

BDs

)VV(2 Bending Band Total

VVVVV

)n/Nln(V2

NnN,NN 2V

from goes BB Total

sBp

sBnsidepsidea

iat

asdaapbi

L23 08April03 19

aqN

))sVBV(p2(E2

max,dX

O.S.I. At

xE

maxE

max,dXX

max,damax.d XqNQ

)VV(2area sBp E

aqNdxdE

L23 08April03 20

oxmax,dFB...ThGBBT

BsGT

oxmax,dsPFBT

C/)Q(BB.TVVVV

chosen values V&V for VV

C/)Q(V2VV

L23 08April03 21

Fully biased MOScapacitor in inversion

0y

L

VG>VT

Vsub=VB

EOx,x> 0

Acceptors

Depl Reg

e- e- e- e- e- e- n+

n+

VS=VC VD=VC

p-substrate

Channel

L23 08April03 22

Flat band with oxidecharge (approx. scale)

Ev

Al SiO2p-Si

EF

m

Ec,Ox

Eg,ox

~8eV EFp

Ec

Ev

EFi

'Ox

'ss

msOxmsFB

Ox

Oxc

Ox

'ss

x

ssm

ss

C

QVV

xV

dxdE

q1Q

E

surface gate the on

is Q'Q' charge

a cond FB at then

bound, Ox/Si the at

is Q' charge a If

q(fp-ox)

q(Vox

)q(m-

ox)

q(VFB

) VFB= VG-VB, when Si bands

are flat

Ex

+<--Vox-->-

L23 08April03 23

Flat-band parametersfor n-channel (p-subst)

0nN

lnVq2

E

n

NNlnV

gate, Si-poly n a For

den chg Ox/Si the is 'Q ,x

'C

'C'Q

V :substratep

i

at

g2i

actms

sms

ssOx

OxOx

Ox

ssmsFB

L23 08April03 24

MOS energy bands atSi surface for n-channel

Fig 8.10**

L23 08April03 25

Fully biased n-channel VT calc

0V ,

qN

VV22x

,xNqQ' ,0Nn

lnV

VV'C

'Q2VVV

VV :substratep

a

CBpd,max

d,maxad,maxa

itp

FBOx

,maxdpFBCT

Tthreshold at ,G

L23 08April03 26

References

* Semiconductor Physics & Devices, by Donald A. Neamen, Irwin, Chicago, 1997.

**Device Electronics for Integrated Circuits, 2nd ed., by Richard S. Muller and Theodore I. Kamins, John Wiley and Sons, New York, 1986