metal - snvhome.netsnvhome.net/ee-braude/malam/lectures/Lecture_10_spring_2014.pdf · after hu/Chenming-Hu_ch5.pdf 3 םירבחמ )Schottky עגמ( מ"למל תכתמ ןיב רישי

MOS metal oxide semiconductor. MOS (MOS (MOS Cap

(MOSFET). , .

MOS

Courtesy to http://www.eecs.berkeley.edu/~hu/Chenming-Hu_ch5.pdf

2

"

nMOSFET

"

MOSFET MOS +2 pn

http://www.clker.com/clipart-13197.htmlhttp://www.eecs.berkeley.edu/~hu/Chenming-Hu_ch5.pdfhttp://www.eecs.berkeley.edu/~hu/Chenming-Hu_ch5.pdfhttp://www.eecs.berkeley.edu/~hu/Chenming-Hu_ch5.pdfhttp://www.eecs.berkeley.edu/~hu/Chenming-Hu_ch5.pdfhttp://www.eecs.berkeley.edu/~hu/Chenming-Hu_ch5.pdf

: MOS "

, . .MOS

MOSFET . MOS Cap

1 - 2

10 20 ( , .(

3

nMOSFET

"

,70 - - gate " Al. 70 - , (polysilicone (poly-Si

- .

" MOS .2 () 2008 .

.2 gate -

4

MOS

equipotential AC - DC.

0 , () .

" (uniformly doped) () - interface

.2 -

, " - bulk , ,)

.( punch-through . MOS 1) - D) ,- x

.

MOS

5

. 1

.

)

skin) (

layer) 1 - ( .(

(10223 -)

.

t

Gate

()

x

x

()

x

()

MOS

6

. 1

t

Gate

()

x

x

()

x

()

'1

0

QxEair

'

''

0 C

Qt

QV

air

g

:

o 2

o ( - gate(

o = 1

o 0 = 8.85 1014

o

tC air 0'

) ) :

, 2

:

MOS

7

MOS . 2 "

1016) 10173).

, -

skin layer , MOS ."

- -

200 300 . " .

"

,

Gate

()

x

x

()

x

()

"

MOS

8

MOS . 2

'1

0

QxEOX

'

''

0 C

Qt

QV OX

OX

g

:

o 2

o ( - gate(

o = 3.9

o 0 = 8.85 1014

o ( (

OX

OX

tC 0'

) ) :

, MOS 2

:

Gate

()

x

x

()

x

()

"

9

MOS

, = 0 .

. -

-

.(work function , ) ,Mg : 3.66 )

4.1 Al, 5.15 Ni .(

. 1

0

0 )vacuum level( .

.

10

MOS

. .

:

2 = 8 . .

. 2

2 - electron affinity of 2

. vacuum level( 0( 2 - = 1 .

0 2

2

11

MOS

:

= 1.1 .

. p " . 3

electron affinity of = 0

)vacuum level( "0

4 :" ( . " ). GaAs Si, 4.07 Ge, 4.03

" . "

0

" = 0 = + . . -

12

( - ") Schottky

MS) 0) "

"

- "

"-

0

"

0 :

.

13

( - ") Schottky

.' " " :

"

SMMS

" , ,0 .

.( ) "

2 , , ) " < ) "

.

14

MOS

after http://www.eecs.berkeley.edu/~hu/Chenming-Hu_ch5.pdf

) " Schottky) 3 ." , , :

(zero bias) .pn Schottky ,

zero bias - MOS

+

"


15

MOS

Flat band - . "- Flat band ,

:

Flat band voltage ( )

+

"

qqV MSSMFB

o " o

:

eVSiM 05.4

V

q

EEV FCMMFB 7.0

after http://www.eecs.berkeley.edu/~hu/Chenming-Hu_ch5.pdf


16

MOS

afte

r http

://ww

w.e

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erk

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du

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u/C

he

nm

ing

-Hu

_ch

5.p

df

gate -

.gate -

)

pn .(

+

Accumulation < ()

+

"

o - gate

o

2 - . 2 .

o 2 - bulk.


17

MOS

2 , ,

.

Accumulation < ()

+

"

- ~100 200

2 ,

.(bulk -)

:( ) bulk -

kT

q

Asurface

surface

eNp

o 2 - bulk.

afte

r http

://ww

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ecs.b

erk

ele

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du

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u/C

he

nm

ing

-Hu

_ch

5.p

df


18

MOS

:

Accumulation < ()

o o 3.9~ "( (

o

2

OXsurfaceFBg VVV

.

FBgOX VVV

, Gauss :

o

o

2 (

)

OX

OXOX

OX

accOXOXOX

OX

accOX

tC

C

QtEV

QE 0

0

''

''

+

"

+

"

afte

r http

://ww

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ecs.b

erk

ele

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du

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u/C

he

nm

ing

-Hu

_ch

5.p

df


19

MOS Depletion > > ()

) gate - ( -

-

gate.

) pn .(

2 - . 2 .

.W

+

"

o - ) (

afte

r http

://ww

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du

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u/C

he

nm

ing

-Hu

_ch

5.p

df


20


2 , ,

.

+

"

.

.

afte

r http

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du

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he

nm

ing

-Hu

_ch

5.p

df


21


+

"

:

0

2

2

Si

Asurface

WqN

o

2

o

2

o

OX

surfaceASi

OX

A

OX

dep

OX

C

qN

C

WqN

C

QV

'

2

''

'

0

,pn ,

A

surfaceSi

qNW

02

afte

r http

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he

nm

ing

-Hu

_ch

5.p

df


22


+

"

o

2

o o

OX

SiO

OXt

C02'

, - .

:

OX

A

Si

AFB

OXsurfaceFBg

C

WqNWqNV

VVV

'2 0

2

afte

r http

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du

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u/C

he

nm

ing

-Hu

_ch

5.p

df


23


+

"

" ) . MOS 2 ,

, = () )

: bulksurface

o ) ( - bulk

, - bulk -

i

AFbulkSiibulk

n

NkTEEq ln

afte

r http

://ww

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erk

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du

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he

nm

ing

-Hu

_ch

5.p

df


24

MOS Threshold of inversion = ( )

+

"

."

2 - , - bulk Si . , , " (n - p - )

afte

r http

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du

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he

nm

ing

-Hu

_ch

5.p

df


25


+

"

o - "

-

.

FbulkSiiSiOSisurfaceiF EEEE 2

Asurface Nn

afte

r http

://ww

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erk

ele

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du

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he

nm

ing

-Hu

_ch

5.p

df


26


+

"

, " 2:

i

Abulksurface

n

N

q

kTln22

:

OX

bulkASi

bulkFB

OXsurfaceFBT

C

qNV

VVV

'

222 0

afte

r http

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du

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he

nm

ing

-Hu

_ch

5.p

df


27


+

"

, :

A

bulkSi

qNW

22 0max

afte

r http

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du

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he

nm

ing

-Hu

_ch

5.p

df


28

MOS Strong inversion < ( )

, 2 :gate -

+

"

< , "

2 inversion) layer), "

n ) (

)

2)

)

2 )

afte

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nm

ing

-Hu

_ch

5.p

df


29


+

"

o

2

o

2

o

2

:

OX

invdep

bulkFB

OXsurfaceFBg

C

QQV

VVV

'

''2

OX

invT

OX

inv

OX

bulkASi

bulkFBC

QV

C

Q

C

qNV

'

'

'

'

'

222 0

TgOXinv VVCQ ''

afte

r http

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du

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he

nm

ing

-Hu

_ch

5.p

df


30

MOS

. : ) ,

. .(

+

"

:

2 )

,

,( .

MOS

.( )

afte

r http

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nm

ing

-Hu

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5.p

df

Strong inversion < ( )


31

MOS

" :

WOXt

AAD qNNNnpqx Wx 0

Poisson:

00

Si

A

Si

qNx

x

xE

Wx 0

Poisson:

xWqN

xESi

A

0

Wx 0

. 1 "

32

MOS

() :

WOXt

0x 0 xtOX

Poisson:

constxE

x

x

xE

Si

00

. 2

0 xtOX

33

MOS

WOXt

-dielectric displacement

2:

OX

A

xOX

Si

xtSi

A

x

WqNxExEW

qNxE

OX

00000

. 2

0

00

0

x

Six

OX xExE

" - = 0

00

xx

xDxD

34

MOS

WOXt

)

(1 -

. 3

0 OXtx

xE

35

MOS -1' MOS = 0.1

( = 10153) ( = 300).

Si = , 11.8 = 1.5 10

103.

:

=

2 ( = (0 =

:

Vn

N

q

kT

i

Abulk 298.0

105.1

10ln026.0ln

10

15

36

MOS -1'

=

2 ( = (0 =

()

mcmC

VcmF

qNW

bulksurfaceA

surfaceSi

624.010106.1

298.01085.88.112

2

31519

14

0

cm

V

cmF

cmcmC

WqN

xESi

A

x

3

14

531519

00

1056.91085.88.11

1024.610106.1

37

MOS -2'

:

MOS ,p = 10

163 . Si = , 11.8 = 1.5 10

103.

mcmC

VcmF

qNW

A

bulkSi

3.010106.1

347.01085.88.112

22

31619

14

0max

Vn

N

q

kT

i

Abulk 347.0

105.1

10ln026.0ln

10

16

= 2

38

MOS Accumulation < ()

p-type Si

OXt

OXC'

39

MOS Accumulation < ()

p-type Si

:

2

0''cm

F

tCC

OX

OXOXtot

o MOS

2

o

2

o = 3.9

o 0 = 8.85 1014

o ( (

OXC '

40


p-type Si

WOXt

OXC' WC '

200

111

'

1

'

1

'

1

cmF

Wt

CCC Si

OX

OXWOXtot

41


p-type Si

:"

o MOS

2

o

2

o

2

OXC' WC '

o o o = 3.9o = 11.8

o 0 = 8.85 1014

42


p-type Si

maxW

maxWOXt

OXC' max'WC

43


:" ()

2

max

00

111

'

1

'

1

'

1

max cmF

Wt

CCCSi

OX

OXWOXtot

o MOS

2

o

2

o

2

OXC ' max'WC

o o o = 3.9o = 11.8

o 0 = 8.85 1014

, ( )

p-type Si

maxW

35

45

55

65

75

-4 -2 0 2 4

f = 1MHz

f = 150 Hz

44

MOS C

apaci

tan

ce [

pF

]

nMOS ) .( -

Gate voltage (DC) Vg [V]

Capacitance of nMOS vs applied gate voltage Vg at the

low (f = 150 Hz) and high (f =1MHz) frequencies

high frequency

low frequency

45

MOS ?

MOS " " DC - gate , AC ) AC .

300 400 Hz) 1~) MHz).

, . 2 - , gate. MOS

:

2

0max ''

cm

F

tCC

OX

OXOX

nMOS

after R. Pierret. Semiconductor device fundamentals

high frequency

low frequency

Vg [V]

46

MOS ?

,

, 2.

:

2

max

00

max

00

min

max

max

''

'''

cm

F

Wt

Wt

CC

CCC

Si

OX

OX

Si

OX

OX

WOX

WOX

nMOS


high frequency

low frequency

Vg [V]

47

MOS R

elati

ve c

ap

aci

tan

ce

[dim

ensi

on

less

]

depletion

accumulation inversion

OXtot CC '' OXtot CC ''

max

max

''

'''

WOX

WOX

totCC

CCC

high frequency

low frequency



afte

r R

. Pie

rret

. Sem

icon

duc

tor

dev

ice

fun

dam

enta

ls

Voltage Vg [V]

48

MOS R

elati

ve c

ap

aci

tan

ce

[dim

ensi

on

less

]



afte

r R

. Pie

rret

. Sem

icon

duc

tor

dev

ice

fun

dam

enta

ls

high frequency

low frequency


49

MOS R

elati

ve c

ap

aci

tan

ce

[dim

ensi

on

less

]



depletion

strong accu-

mulation

strong

inversion

Voltage Vg [V]

wea

k a

ccu

mu

lati

on

wea

k i

nve

rsio

n

afte

r R

. Pie

rret

. Sem

icon

duc

tor

dev

ice

fun

dam

enta

ls

50

MOS

) - nMOS )

.

.

2

max

00

max

00

min

max

max

''

'''

cm

F

Wt

Wt

CC

CCC

Si

OX

OX

Si

OX

OX

WOX

WOX

nMOS



51

MOS

.

2

max

00

max

00

min

max

max

''

'''

cm

F

Wt

Wt

CC

CCC

Si

OX

OX

Si

OX

OX

WOX

WOX

nMOS



Documents

metal - snvhome.netsnvhome.net/ee-braude/malam/lectures/Lecture_10_spring_2014.pdf · after hu/Chenming-Hu_ch5.pdf 3 םירבחמ )Schottky עגמ( מ"למל תכתמ ןיב רישי