1

5-1

1.

2. MOSFET(

3. MOSFET

4.

5. MOSFET

6. MOSFET2nd order effect

7. JFET

5-2

(transistor)(valve)

(a) (b)

2

5-3

bipolar junction transistor, BJTfield effect transistor, FET

BJT pn

p+ nE

B

Cp

VEB VBC

E B C

E B C

5-4

FET (channel)

S

D

G

S

D

G

pFET nFET

3

5-5

FET(Junction Field Effect Transistor, JFET)(Metal-Oxide-Semiconductor FET, MOSFET)

(Source)

(Drain)

(Gate)1

np+

(Gate)2

p+

tL p n+

(S)

(G)

n+

(Metal)

(Oxide)

(Semiconductor)(Body)

(D)

JFET\pn

MOSFETMOS

5-6

BJTpoint contact transistorBell Laboratory(John Bardeen, 1908-1991)Walter Brattain, 1902-1987William Shockley, 1910-19891947pn1956

FETBJTFETFET

1985K. von KlitzingMOSFET(Integer Quantum Hall Effect, IQHE)

1998(HEMT, high mobility transistor)Fractional Quantum Hall Effect)

, "", , , 2000.

2000(Zhores I. Alferov)(Herbert Kroemer)(Jack St. Clair Kilby)

HONOR LIST

4

5-7

1964 for fundamental work in the field of quantum electronics, which has led to the construction of oscillators and amplifiers based on the maser-laser principle Charles Hard Townes, Nicolay Gennadiyevich Basov, Aleksandr Mikhailovich Prokhorov

1973L. Esaki (tunneling effect)

5-8

MOSFET

p n+

(S)

(G)

n+

(Metal)

(Oxide)

(Semiconductor)(Body)

(D)

(S)

(D)

(G)

(S)

(D)

(G)

(body)

nMOSFET(NMOS)

MOSFETMOSFET

5

5-9

pn+

(S)

(G)

n+

(Oxide)

(Body)

(D)

C

n+

p

C

pnNMOS(cut off)

S D

GID

VGS

VDS>0

IG=0

VGS=0

5-10

pNMOS

pn+

(S)

(G)

n+

(D)

n+

0

6

5-11

pn+

(S)

(G)

n+

(D)

VGS=Vt

Vt (threshold voltage)()

pn+

(S)

(G)

n+

(D)

VGS>VtVGS-Vt

n+

VGSVt

5-12

n+

n+

(1)(2)

(3)(4)

n+

(1)(2)

(3)(4)

CC

pn+

(S)

(G)

n+

(D)

VGSVt

7

5-13

1.00.80.60.40.20

ID(mA)

0.40.20VDS (V)

VGS=4V

3.5V

3.0V

2.5V VGS2.0V= Vt

VDSMOSFETVGSVtVGS>VtDS

VDS DSI-V

MOSFET

5-14

n+

n+

C

VG

VS VDVGS VGD

n+

n+

C

VG

VSVD

VGSVGD

Vt

VDS

Vt

L

ID

VDS

ID

VDS

(a) (b)

8

5-15

n+

n+

C

VG

VSVDVGS

VGD

VDS

Vt

n+

n+

C

VG

VS

VDVGS

VGD

VDS

Vt

L

X

ID

VDS

ID

VDS

VDSS

triode

saturation

(c) (d)

5-16

VGD= Vt(pinch off)VDSVGDVtDLL

9

5-17

ID(mA)

VDS (V)

VDSS (=VGS-Vt)

VGS=4V

VGS=3.5V

VGS=3.0VVGS=2.5V

VGS2.0V

1086420

3210 4

(a)

(b)(c)

(d)

VGSMOSFET

(Analog Switch)

(VCCS)

)( GSD Vi

)( GSDS VR

5-18

MOSFET

MOSCoxMOStoxox

MOSL()W()MOS

(threshold voltage)VtMOSFET

(bias voltages)VGS, VDS, VS ,VB(body)

ID

10

5-19

MOSFET

DSDS

DS

p n+

(S)

(G)

n+

(Metal)

(Oxide)

(Semiconductor)(Body)

(D)

L

W

(D)(S)

E(x)

Q(x)J(x)

ox

oxoxtGSox t

CVCQxQ === )()(

Q [C/m2]: Cox [F/m2]:

GS>Vt

5-20

LE DS=

[A/m]=[C/sm]L

VCEQQvJ DStGSoxnndn )( ===

iD DStGSnDStGSoxnnD VLWkV

LWCWJi )()( ===

=

=

)(

)(1

tGSnDS

DSDDS

tGSnD

DSDS

VL

Wkig

VL

Wki

r

(DS)

Process transconductance parameter: oxnn Ck = [A/V2]

DS

Aspect ratio: W/Llayout()LW

11

5-21

DS

)21( DStGSox VC

iD

DS

n+

n+

C

G

SD

GSGD

DS

Vt

)( tGSox VC )( tGDox VC

DSDStGSnDSDStGSoxnD VLWkV

LWCi )

21()

21( ==

iD

iDDS(parabola)

Triode rigionGDVtDS GS-Vt

or

5-22

n+

n+

C

G

SGS

GD

DSVt

iD

DS

DSsat

GD=VtDSsat=GS-Vt

oriD

22 )(21)(

21

tGSntGSoxnD VLWkV

LWCi == Saturation region

GD VtDS GS-Vt

orDSDSsat iDDS(GS-Vt)

12

5-23

iD (mA)

DS (V)

DSsat (=GS-Vt)GS=4V

GS=3.5V

GS=3.0VGS=2.5V

GS2.0V

1086420

3210 4

triode

saturation

cutoff

iDsat(mA)

GS (V)

1086420

0 321

Vt

4

OFF (S)

ON (S)

cutoff

saturation

triode

(S)

(D)

(G)

(S)

(D)

(G)

2

21

DSnD LWki =

2)(21

tGSnD VLWki =

5-24

n-channel MOSFET

iD (mA)

DS (V)

DSsat (=GS-Vt)GS=4V

GS=3.5V

GS=3.0VGS=2.5V

GS2.0V

1086420

3210 4

triode

saturation

cutoff

(S)

(D)(G)

iD

GSDS

iG=0

Open circuit

G

D

S

VCCS

Nonlinear resistance

GS2)(

21

tGSn VLWk

G D

S

GS

G D

S

rDS

)21(1 DStGSn

DSDS VL

Wkr

g ==

13

5-25

IC

n+

p

C

n+

pn+

(S)

(G)

n+

(D)

VGS=Vt

Vt

CX

5-26

n+

C

X

pFlat-band condition

qs: Bending of surface potential

VGS =0

VGS=Vt

qVbi, B

qs

VGS

Q

Vt

14

5-27

s

pn(built-in potential)

i

D

i

A

i

DAbi n

NkTnNkT

nNNkTqV lnlnln 2 +==

p n

(depletion region)(space charge region)

EC

EV

qVbi

Eg

xd

qp qnqnqp

+=

DA

bid NNq

Vx 112 Si

5-28

MOSFET

MetalOxide p-Si

Flat-band condition

EC

EV

MetalOxide p-Si

Threshold condition

EC

EV

qpqs

s =2 p

xd

qox

qVt

oxpoxstV +=+= 2

15

5-29

Metal

Oxidep-Si

EC

EV

qpqs

xd

qox

E=0E=0 ESiEox

sox

tox

Vt

oxoxox tE=i

Aps n

NqkT ln22 ==

0

A

psd qN

x)2(2

=ESiSi

Sisoxox EE =Eox

ox

psA

A

ps

ox

A

ox

dAox

oxoxdASis

qN

qNqN

xqNE

ExqNE

)2(2

)2(2

=

=

=

==

ox

psAp

oxox

psAp

oxpt

CqN

tqN

V

)2(22

)2(22

2

+=

+=

+=

body(S)

5-30

ox

psApFB

oxox

psApFBt

CqN

V

tqN

VV

)2(22

)2(22

++=

++=

Vt

1. flat-band conditionVGS=0VFB VFB

2. Vt

3. Vt-2 mV/C

4. VGS=0MOSFET

16

5-31

n+

C

X

pqs: Bending of surface potential

VGS=Vt qVbi,B

qVSB

5. (B)(S)VSBbody effect

qs +qVSB

[ ]ox

sApSBpt

ox

SBpsApFBt

CqN

VV

CVqN

VV

222

)2(22

0 ++=

+++=

Body-effect parameter

VSB

5-32

MOSFETMOSFETNMOS(n-channel MOSFET)PMOS (p-channel MOSFET)VGS=0(depletion type)(enhancement type)

iD

GS (V)

0

n-channelenhancement

n-channeldepletion

p-channelenhancement

p-channeldepletion

n-channelp-channeliD

17

5-33

p-channel MOSFET

n p+

(S)

(G)

p+

(Metal)

(Oxide)

(Semiconductor)(Body)

(D)

(S)

(D)

(G)

(S)

(D)

(G)

(body)

iD

5-34

PMOS

iD (mA)

SD (V)

SDsat (=Vt-GS)GS=-4V

GS=-3.5V

GS=-3.0VGS=-2.5V

GS-2.0V

1086420

3210 4

triode

saturation

cutoff

(S)

(D)(G)

iD

GSSD

iG=0ox

oxoxtGSox t

CVCQxQ === )()(S

GSVt

DSDStGSp

SDSDGStoxpD

VL

Wk

VL

WCi

)21(

)21(

=

=

2

2

)(21

)(21

tGSp

GStoxpD

VL

Wk

VL

WCi

=

=

GDVt

GDVt

GS Vt

18

5-35

n-channelenhancement

n-channeldepletion

p-channelenhancement

p-channeldepletion

S

Digital Circuit

5-36

Depletion-type MOSFETiD

GS (V)

0

n-channeldepletion

p-channeldepletion

IDSS

GS =0MOSFETMOSFET

MOSFETSi

19

5-37

5-38

MOSFET2nd order effect

MOSFET

20

5-39

Channel length modulation effect

n+

n+

C

VG

VS

VDVGS

VGD

VDS

Vt

L

X

VDSsat

L

DSSX(VDSsat)BJTEarly Effect

lambda AV=

1

5-40

GS

2)(21

tGSn VLWk

GD

S

ro

ro

DDA

o IIVr 1=

)1()(21 2

DStGSnD VLWki +=

2

1

2

1

LL

VV

A

A

21

5-41

(BS)

n+

C X

pFlat-band condition

qs: Bending of surface potential

VGS =0

VGS=Vt0 qVbi, B

n+

BS=0

n+

C X

pFlat-band condition VGS =0

qVbi, B

BS

22

5-43

Vtk

1. Vt-2 mV/C

ox

bsBbFBt C

qNVV

)2(22

++=

i

Bb n

Nq

kT ln=

*

5.1

)()(me

TTTT

Ck

RR

ox

=

=

=

kT

2.

5-44

iDsat

GS (V)

iD

DS

T>T

23

5-45

MOSFET

1. (NMOS)pn(avalanche breakdown)50100V

2. (NMOS)punch-through

3. 50V)

pn+

(S)

(G)

n+

(D)

CMOS(PMOS+NMOS)

npnpnp BJTlatch-up

5-46

MOSFET

MOSFET

pn+

(S)

(G)

n+

(D)

pn+

(S)

(G)

n+

(D)

(gate capacitive effect)

1. MOSFETtriodeWLCox CgsCgd

2. GS

oxgdgs WLCCC 21

==

032

=

=

gd

oxgs

C

WLCC

24

5-47

3. 0== gdgs CC

(body)

oxgb WLCC =

4. Overlap capacitance:Lov0.1~0.2m13CgsCgdCov

oxovov CWLC =

p

n+n+

Lov

5-48

(Junction Capacitances)

(B)pn

0

0

0

0

1

1

VV

CC

VV

CC

DB

dbdb

SB

sbsb

+=

+=

NMOStox=20nm, L=2.4m, W=10m, Lov=0.15m, Csb0=Cdb0=40fF, |VSB|=|VDB|=2V

21.4 fF21.4 fF2.6 fF30.6 fF2.6 fF1.75 fF/m2

CdbCsbCgdCgsCovCox

25

5-49

(Junction Field Effect Transistor, JFET)

(Source)

(Drain)

(Gate)1

n

p+

(Gate)2

p+

t

W

L

(S)

(D)

(G)

JFET input

(preamp)

5-50

S D

GID

VGS0

IG=0

1.00.80.60.40.20

ID(mA)

0.40.20VDS (V)

VGS=0V

-0.5V

-1.0V

-1.5V VGS-2.0V

Triode region:

pnnp+ntRDS

n(pinch off)(pinch-off voltage) Vp

26

5-51

S D

G

n

p+

p+

L ID

VDS

S D

G

n

p+

ID

VDS

p+

VGSVDSIDVDS

5-52

S D

G

n

p+

ID

VDS

D

G

n

p+

p+

L

p+

S

ID

VGD=Vp

VGD

27

5-53

XS D

qVDSS

L

n

VDSLLVDSXVpVDSVXS(=VDSS)VDSL

VDSVGS-Vp(=VDSS)VDSIDVDSIDVDS(constant-current)(saturation)

qVDS

5-54

iD(mA)

DS (V)

VDSS (=VGS-Vp)

VGS=0V

VGS=-0.5V

VGS=-1.0VVGS=-1.5V

VGS-2.0V

1086420

3210 4GS (V)

iD (mA)

1086420

-2 10-1

Vp

IDSS

)1(12

DSp

GSDSSD V

Ii +

=

Triode

=

2

12p

GS

p

GS

p

GSDSSD VVV

Ii

NJFETNMOS PJFETPMOS