BJTs & FETsA.

311311::

20020055--20062006

22::

BJTs & FETsA.

EmitterBase

Collector

Intrinsic BJT

BJTs & FETsA.

intrinsic transistor pn ,

o (minority charge)

(. Punchthrough p-n n-p)

BJTs & FETsA.

npn

EB C

BJTs & FETsA.

. , .

. . C

BJTs & FETsA.

(, ) (Vbe=0, Vbc=0)

BJTs & FETsA.

(, ) (Vbe>0, Vbc

BJTs & FETsA.

: x=0 x=WB :

( )

=kTqVnn BEpBpB exp0 0

( ) 0=BpB Wn :

( ) ( )

=

BpBpB W

xnxn 10

:

( ) ( )B

pBn

pBnnB W

nqD

dxxdn

qDJ0==

BJTs & FETsA.

:

:

( )

===kTqVn

WDqAA

Wn

qDAJI BEpBB

nEE

B

pBnEnBC exp

00

=kTqVISI BEC exp

0pBB

nE nWDqAIS =

. IS (collector saturation current) .

BJTs & FETsA.

: x=-WE-xBE x=-xBE :

( )

=kTqVpxp BEnEBEnE exp0

( ) 0nEBEEnE pxWp = :

( ) ( )[ ] 00 1 nEE

BEnEBEnEnE pW

Xxpxpxp +

++=

:( ) ( )

E

nEBEnEp

nEppE W

pxpqDdxxdpqDJ 0==

BJTs & FETsA.

:

. :

:

== 1exp0 kTqVp

WD

qAAJI BEnEE

pEEpEB

= 1expkTqVISI BE

FB

BpaB

EndE

E

pnE

B

npB

F WDNWDN

WD

p

WDn

==0

0

. F (forward current gain) .

BJTs & FETsA.

K :

F C IBBpaB

EndEF WDN

WDN=

To F

NdE>>NaB WE>>WB To npn Dn>Dp

- : F C IB E-B (. surface recombination, depletion region recombination .), (Kirk Effect base push-out), high current injection .

BJTs & FETsA.

. . .

-. . .

. , . . .

BJTs & FETsA.

:

:

=kTqVISI BEC exp

= 1expkTqVISI BE

FB

F: 50-300

= 1expexpkTqVIS

kTqVISI BE

F

BEE

BJTs & FETsA.

:

:

=kTqVISI BCE exp

= 1expkTqVISI BC

RB

R: 0.1-5

= 1expexpkTqVIS

kTqVISI BC

R

BCC

BJTs & FETsA.

:

:

RF

BC

R

BE

FB

ISISkTqVIS

kTqVISI

+

=

1exp

1exp

.

:

BJTs & FETsA.

:

:

. . .

BJTs & FETsA.

+

= 1exp1expkTqVIS

kTqVISI BC

R

BE

FB

= 1expexpexpkTqVIS

kTqV

kTqVISI BC

R

BCBEC

=kTqV

kTqVIS

kTqVISI BCBEBE

FE expexp1exp

: Hybrid-

(Ebers-Moll)

BJTs & FETsA.

Mo : (VBE>0, VBC

BJTs & FETsA.

Mo : (VBE0)

() VBC,on0.5V

To

BJTs & FETsA.

Mo : (VBE>0, VBC>0)

() VC,satVBE,on-VBC,on=0.2V

BJTs & FETsA.

Mo : A (VBE

BJTs & FETsA.

) : Hybrid-

) : -Model

ECC

CCBCE

iii

iiiii

=

+=

+=+=1

/

1+= a

BJTs & FETsA.

() )

)

r0 ( )

(CBO)

n. uCB

BJTs & FETsA.

n+ Sub-Collector

p Base +

Collector Contact

EMITTER BASE

COLLECTOR

S.I. GaAs Substrate

n- Collector AlGaAs Emitter

Isolation Implant

BASE

EmitterBaseBaseCollector

HBT Epitaxial LayersS.I. GaAs Substrate

BJT

T (GaAs)

T (SiGe)

BJTs & FETsA.

PNP

pnp npn

BJTs & FETsA.

npn pnp

npn ( )

pnp ( )

BJTs & FETsA.

iC uBE uBE = 0,5V . , uBE 0,6V 0,8V

uBE C

mVo2

: Vbe (turn-on) . Si: Vbe,on0.7V GaAs: Vbe,on1.4V

BJTs & FETsA.

iC uCB VC VB ( )

( )

BJTs & FETsA.

iC uC uCE, ,

, . uCE VA . VA 50 100V Early

BJTs & FETsA.

iC uC () uBE uCE

iC uCE IS

.

+=

A

CEVu

SC VueIi T

BE

1

+A

CEV

u1

1

=

=

BEuCEC

O uir

C

AO IVr

BJTs & FETsA.

iC

BJTs & FETsA.

(, *1)

(, *2)

dc

-

CCCCCEC RIVVV ==

BC VV >

beBEBE uVu +=T

beV

u

SC eIi =Tbe Vu

BJTs & FETsA.

- ()

beT

CCC uV

IIi +=

dc ac

bembeT

Cc uguVIi ==

T

Cm V

Ig = (. ac ), , IC *2

BJTs & FETsA.

- () . ube dc VBE. , dc IC

iC uBE

BEBECC VuIi == ,

CC IiBE

Cm u

ig=

=

. ac dc ( ) ac *1

BJTs & FETsA.

be

T

CCCB uV

IIii 1+==

bBB iIi +=

dc ac bembeT

Cb u

guVIi ==

1

B

T

b

be

IV

iur ==

,

mgr =

BJTs & FETsA.

cCC

EiIii +==

eEE iIi +=

dc ac beT

Ebe

T

Cce uV

IuVIii ===

E

T

e

bee I

Viur ==

,

mme gg

ar 1=

( ) err 1+=

BJTs & FETsA.

cCC uVu +=

ac be

c

uu

( ) CcCCCCCCC RiIVRiV +== ( ) CcCCCC RiRIV =CcC RiV =

( ) cbeCmCbem uuRgRug ==

Cmbe

c Rguu =

*2

BJTs & FETsA.

(, )

, ,

ac dc, ac

1CC 2CC

EC

dc ac

BJTs & FETsA.

() ( )

rRR Bi //=rRB >>

rRi

oCo rRR //=oC rR

BJTs & FETsA.

()

( )

( )s

oLCu Rr

rRRA += ////

. RS . RS

BJTs & FETsA.

RE

BJTs & FETsA.

() ( )

ibBi

ii RRiuR //==

b

bib i

uR =

1+ei

ee

b

ee

ie Rr

uRrui +=+=

iu ( )( )ee Rr ++1

, , ( )1+

BJTs & FETsA.

() ()

( )( )eeBi RrRR ++= 1//

Cout RR

i

o

sig

i

sig

ou u

uuu

uuA ==

sigi

i

RRR+

( )LCe RRi //

( )eee Rri +( )( )ee

CL

sigi

i

RrRR

RRR

++//

1+r

( )( )ee

CL

RrRR

+//

BJTs & FETsA.

, ,

BJTs & FETsA.

() ( )

ei rR

Co RR = usig, . . RC

0=eieai

BJTs & FETsA.

()

Rsig RC

, ,

i

o

sig

i

sig

ou u

uuu

uuA ==

sige

e

Rrr+

( )LCc RRi //

mcee giri 1=

( ) ( )sige

LCLCm

sige

e

RrRRRRg

Rrr

++=////

BJTs & FETsA.

, ,

BJTs & FETsA.

()

ibBi RRR //=( ) ( )[ ]Loe Rrr //1 ++

++= 1//

// Bsig

eoo

RRrrR

BJTs & FETsA.

()

( )

i

o

sig

i

sig

ou u

uuu

uuA ==

sigi

i

RRR+

( )Loe Rri //

( )[ ]oLee rRri //+( ) 1////

BJTs & FETsA.

AA

iR

0=

LRi

om v

iG

( )( )

L

LoC

LoCmL

B

RRrR

RrRgRrR

////

//////

oR

s

ov v

vA

i

oi iiA

rrRB //

CoC RrR //

mg

( ) ( )( )

s

LoC

LoCmsB

B

RrRrR

RrRgRrR

rR

+

+

////////

////

( )( )( )emB

eeB

RgrRRrR

+++

1//1//

( ) ( ) CBs emoC RrRR

RgrR

++

//11//

em

m

Rgg

+ 1

( )( )[ ]

( )( )

( )( )

ee

LC

sem

LC

em

LCm

semB

emB

RrRR

RRgrRR

RgRRg

RRgrRRgrR

+++

++++

//1

//1

//1//1//

( ) ( )( )

L

LC

LCem

m

L

emB

RRR

RRRg

gR

RgrR

//

//1

1//

++

er

CR

mg

se

LC

RrRR

+//

L

LC

RRR //

( ) ( )[ ]LoeeB RrRrR ////1// ++

++ 1////

BseE

RRrR

( )( )( )

( ) sLL

eLoE

LoE

si

i

RrRR

rRrRRrR

RRR

++++

++

1

1////////

( )L

L

L

i

RRR

RR //1 +

Common Collector (Emitter Follower)

Common Base

Common Emitter with a Resistance Re

Common Emitter

: . ? .