1

1. ( Si) 2. 3. B

Eg k Boltzmann =8610-6 eV/K

Example 1.1

T=300 K

ni=1.51010 /cm3 51022 cm/3

() 1.

2. donor

P As

() N(negative)

3. aceptor

Al B P(positive)

=== kTE

ipn

g

eBTnnn 22/3

4.

n0 p0

ni Nd n

n0=Nd ( majority ) p0= ni2/ Nd

NA p

p0=NA () n0= ni2/ NA

Example 1.2 T=300 K P Nd=1016cm-3

n0=Nd

(drift)

n 1.

200 inpn =

( )2102 4 316

1.5 102.25 10

10i

od

np cmN

= = =

2. (A/m2)

n =1350 (cm2/V-s) --

p 3.

4. (A/cm2)

p =480 (cm2/V-s) --

n p e=1.6*10-19 C ()

Example 1.3

T=300 K Nd=8*1015cm-3 As n =1350 (cm2/V-s) p =480 (cm2/V-s) E=100 V/cm

EenEenenvJ nndnn +=== )(

EepEepenvJ npdpp +=++=+= )(

1( )n p n pJ en E ep E en ep E E E = + = + = =

ni=1.51010cm-3

J= 170 A/cm2

(diffusion)

Jn

Dn

Jp

Dp

2 10 24 3

15

(1.5 10 ) 2.81 108 10

i

d

np cmN

= = =

PN (Junction) p

n

p n n p

pn

(Vbi)

VT T=300 K 0.026 V

Example 1.5

T=300 K pn

=

= 22 lnln

i

daT

i

dabi n

NNVnNN

ekTV

p Na=1016 cm-3 n Nd=1017 cm-3

()

Cj0 pF PN ()

Example 1-6

T=300 K Na=1016cm-3 Nd=1015cm-3 pn Cjo=0.5PF VR=1V VR=5V

VR=1V VR=5V

PN

( P )

() n p(p n)

IS PN 10-3 10-1 pA ()

1 nA

VT 0.026 V n 1 2

2 1

Example 1.7 T=300 K PN Is=10-14A n=1 vD=+0.70V vD=-0.70V

vD=+0.70V pn iD= 4.93mA vD=-0.70V pn iD= -10-2pA PN - I-V

VT -2 mV/C IS 5 CIS

10 C ( VT )

VB

( PIV )

50-200 V

(Zener) (tunneling) PN 12V

IR 0+ < t < tS ts

tf 10%

DC

1.

IV

2.

IV

3.

1. IV

RV

RVIVRIV DPSDDDPS =+=

Example 1.8

VD ID Is=10-13A

VD=0.619V

2.

Example 1.9

Vr=0.6V rf=10

(1)

( )0.02613 35 (10 )(2 10 ) 1vD

De V = +

(2)OFF

--

AC

=dc + ac

AC

ac vd

VPS=0

Small-signal equivalent circuit

Cd Cj Rd rsN- P-

Schottky barrier diode () n

PN

(0.88)(5) 4.4O DQV I R V= = =

RrviRriRiriv

d

iddddddi +=+=+= )(

0.1sin 19.9sin ( )0.0295 5

id

d

v ti t Ar R

= = + +

0.0995sin ( )o dv i R t V= =

Schottky

PN Schottky Vr

Example 1.12 Pn Schottky IS=10-12A and 10-8A, 1 mA

PN

Schottky

Schottky Is PN

( )3

12

1 100.026 ln 0.53910D

V V

= =

( )3

8

1 100.026 ln 0.29910D

V V

= =

- IC IC

rz VZ IZ

Example 1.13 1.41

Vz=5.6V rz=0` R , I=3mA R

The power dissipated in the Zener diode is

PS ZV VIR

=

(3)(5.6) 16.8Z Z ZP I V mW= = =