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Книги2 / 1988 Kit Man Cham, Soo-Young Oh, John L. Moll, Keunmyung Lee, Paul Vande Voorde, Daeje Chin (auth.) Computer-Aided Design and VLSI Device Development 1988

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362

Table of Symbols

Cp

peripheral capacitance coefficient

Cp

coefficient of auger recombination

Cp

peak concentration

CT

total impurity concentration

Cv

normalized vacancy density

ct

electrically active impurity concentration

equilibrium oxidant concentration in the oxide

c

speed of light in vacuum

D

diffusivity

Dc

counter-doping dose

Deff

effective diffusion coefficient

D j+

diffusivity due to positive vacancies

Di

diffusivity due to negative vacancies

Dr

diffusivity due to doubly negative vacancies

Df

diffusivity due to neutral vacancies

dk

mask thickness at kth segment

Dn

n- pocket dose

DN

diffusivity under non-oxidizing condition

D<lK

diffusivity due to oxidizing ambient

E

electric field strength

Ee

electron energy of conduction band edge

Efp

quasi-Fermi level for holes

Ej

electron energy at the intrinsic Fermi level

Em

maximum electric field

En

electric field normal to current flow

Ep

electric field parallel to current flow

ESAT

critical field for velocity saturation

E ~

activation energy of oxide viscosity

F, fF, pF

Farad unit, lE-lS F, lE-l2F

F,F1, F 2, F 3

oxidants fluxes

Table of Symbols

363

 

empirical parameter in mobility model

 

channel conductance

 

transconductance

 

oxide growth rate in the z-direction

h

transport coefficient

I

current

I (x,y)

Implant profile

IDD

maximum available current from power supply

IDs

drain to source current

IDSAT

drain to source current at saturation

IH

latchup holding current

h

transistor subthreshold leakage current

Imax

maximum concentration

IPT

punchthrough current

ISUB

substrate current

IT

latchup triggering current

ITH

transistor threshold current

 

impurity flux

 

electron current density

 

hole current density

 

coefficient of current density

K

scaling factor

k

Boltzmann constant

k

surface reaction coefficient

L

inductance

L

channel length

L

decay length in thin oxide regime

LD

length of uniform drain region

Leff

effective channel length

364

Table of Symbols

 

minimum channel length

 

polysilicon gate length

 

length of uniform source region

 

diffusion length of vacancies

 

effective length of potential barrier

m

segregation coefficient

N

NA-ND

N

number of nodes

N+

doping concentration in n+ polysilicon

NA

acceptor concentration

N;"

ionized acceptor concentration

NB

substrate doping

Nc

correction concentration for oxidation

ND

donorconcenuation

Nt,

ionized donor concentration

N;

inuinsic carrier density

N;

dopant concentration, inert ambient

Nix

concentration in x-direction, inert ambient

Niy

concentration in y-direction, inert ambient

No

coefficient of band gap narrowing

No

dopant concentration, oxidizing ambient

Nox

concentration in x-direction, oxidizing ambient

Nqy

concentration in y-direction, oxidizing ambient

Np,N;

implantation dose

Ns

subsuate surface impurity concentration

Nw

N-well doping concentration

 

surface electron concentration

n

unit vector normal to the surface

nelectron density intrinsic carrier density

n;,e

effective intrinsic carrier density

run

nanometer unit (lE-9 m)

Table of Symbols

365

p

Gaussian probability distribution

p

pressure

p

hole density

Q

minority carrier concentration in GEMINI

QB

integrated carrier in GEMINI punchthrough simulation

QL

integrated carrier in GEMINI channel-length simulation

QNA

channel implant dose

QND

depletion implant dose

Qn

electron density per unit area in the channel

Qss

interface fixed charge density

Qw

integrated carrier in GEMINI channel-width simulation

qelectron charge

resistance recombination

drain series resistance pocket peak depth

range of Gaussian implant distribution source series resistance

subthreshold slope

empirical parameter in mobility model poly gate side-wall spacer thickness

T

absolute temperature

Tax;

oxide thickness

t

time

U

active impurity concentration

U(n,p)

electron and hole recombination rate

366

v

V=

V+

VB

VBS

Vc

VD

VDD

VDS

VDSAT

Vjb

VG

VGS

V;

V;

Vin

Vout

VPT

Vp

Vs

Va

VSB

VSS

VT

VTO

VT(LOW)

VT(HI)

VTLC

VTN

VTP

W

WD

oxide growth velocity negative vacancies doubly negative vacancies positive vacancies substrate bias voltage

substrate to source bias voltage empirical parameter in mobility model drain bias voltage

circuit bias voltage

drain to source bias voltage saturation drain voltage flat-band voltage

gate bias voltage

gate to source bias voltage

itb device parameter in sensitivity matrix nominal value of V;

inverter input voltage inverter output voltage punchthrough voltage barrier potential source bias voltage saturation velocity

source bias with respect to the substrate circuit ground voltage

transistor threshold voltage

threshold voltage at zero substrate bias low drain bias threshold voltage

high drain bias threshold voltage long channel threshold voltage n-channel threshold voltage p-channel threshold voltage

transistor channel width drawn channel width

Table of Symbols

Table of Symbols

367

Weff

effective channel width

 

x

x-coordinate

 

X

process feature

 

X

average value of process feature

 

Xd

depletion depth

 

Xi

initial oxide thickness

 

Xj

diffusion junction depth

 

X 0

oxide thickness

 

1'j

counter-doping junction depth

 

y

y-coordinate

 

Zc

characteristic impedance

 

Z •

effective width of potential barrier

 

t:.L

channel length variation

 

Mp

standard deviation in y-direction

 

6.W

channel width loss per side

 

n

material boundaries

 

e

vector stream function

 

V

gradient operator

 

Q

empirical parameter in mobility model

 

o¢n

increment of electron quasi-Fermi potential

 

o<fJp

increment of hole quasi-Fermi potential

 

edielectric constant JJ. mobility

JJ.oxide viscosity

J.I.i

ith moment of an implant distribution

J.'n

electron mobility

JJ.o

zero-field mobility

I1p

hole mobility

<fJ

electric potential

368

0'

Tp

()

1-D

2-D

Table of Symbols

hole quasi-Fermi potential electron quasi-Fermi potential internal potential

difference between intrinsic and hole Fermi level oxide density

resistivity standard deviation

standard deviation of Gaussian implant distribution electron life time

hole life time

z-component of stream function one-dimensional two-dimensional

Subject Index

Avalanche breakdown, 171,212,295

grid,92-93

 

input file, 98

BIRD,14

input format, 97-100

Bird's beak, 235, 259

input structure, 88-89

Body effect, 188-190

mobility model, 93-97

Boron encroachment

numerical technique, 92

LOCOS, 252, 258

output, 101

modified LOCOS, 259-261

CMOS, 271-273

SWAMI, 265-267

cross-section, 25

Boundary-value method, 61

n-well, 235, 277

Breakdown, source-drain, 171, 212,

p-well, 246, 248

295

submicron, 271-273

Buried channel, 328

trench isolated, 233

 

Capacitance

CAD, 8

depletion layer, 170

CADDET

gate oxide, 170

basic equation, 90-92

Channel implant

device simulations, 97-101,

deep, 187

211-230,315-333

depletion, 328-333

flow chart, 92-94

n-channel, 186-188

370

shallow, 187

Channel length, effective, 183, 317 Channel profile

n-channel, 179, 182 p-channel, 279, 290

Channel width drawn, 252

effective, 167, 183,252,257 extraction of effective, 255-257 loss, 255-257, 268

Channeling, 279 Characteristic impedance, 133 Counter-doping, 144, 277-280

dose, 144,278 energy, 144 junction, 279-280

Critical electric field, 212 Current continuity equation stream function form, 91 time dependent form, 103

Current transport equation, 104

Degradation

hot electron, 212-213, 295 linear transconductance, 217

saturation transconductance, 217 Depletion layer capacitance, 170 Depletion mode MOSFET, 326-333 Device optimization, 174

Device simulation, history, 13-14 DIBL (see Drain-induced barrier lowering)

Diffusion

across interfaces, 38-39

Subject Index

concentration enhanced, 163 continuity equation, 35 field-driven, 35-36 gradient-driven, 35

high concentration, 36-38, 51-53, 163

low concentration, 37, 48-49 moving boundary, 49-51 oxygen enhanced, 38,157-162 vacancy assisted, 36-37

Diffusivity arsenic, 37 boron,37,157 effective, 59 intrinsic,36-37

phosphorus, 37-38 Direct matrix solution, 106

Double diffused drain, 213, 295 Drain electric field, 221-229 Drain-induced barrier lowering,

197-207, 280-289 Duality, 135

Einstein's relation, 90 Electric field

channel, 212

critical, velocity saturation, 212 drain,212,221-229

maximum, drain, 212, 225-226 normal,94

parallel, 94 Electromigration, 4

FCAP2,13O

Subject Index

371

FCAP3,136 FIELDAID, 14

Factorial experiments, 144 Fermi-Dirac integral, 75 Fermi-Dirac statistics, 90 Finite-difference method, 79 Flat-band voltage, 326 Fringing component, 338

GEMINI

basic equation, 75-77

device simulations, 177, 181-184 capability, 72-73

channel length simulation, 80-83 channel width simulation, 83-85 five-point finite-difference approximation, 79

grid,77

input file, 80-86 numerical technique, 79

punchthrough current calculation, 76-77

SWAMI simulations, 265-268 trench simulations, 238-245

Gate oxide capacitance, 180

effect on subthreshold slope,

284-285

Gaussian implant profile, 27 Glass-transition temperature, 59 Graphical post-processing, 16 Green's function, 14-15,61 Gummel's iteration, 92,105 Gummel-Scharfetter formula, 105

Hot electron degradation, 174,212, 295

ICCG, 105, 130 Impact ionization, 212

Implantation energy, 324 Impurity profile

n - pocket, 303 n-channel, 45,179,182 p-channel, 158,279,290 sourcejdrain,45,68,179 SWAMI,266

trench structure, 239 Inductance, 133

Interconnect capacitance, 335-345, 348-355

Interconnect resistance, 346-347 Interface damage, 212

Inverter circuit, 181, 320 Ion implantation

boron, 153-154

distribution moments, 29-30 gaussian profile, 27

Pearson IV profile, 30,153-154 projected range, 29

standard deviation, 29 Isolation, 251-269

Jacobian matrix, 106

LDD (see lightly-doped drain) LOCOS, 252-258

modified,259-261 Latchup, 233-234