Chapter 12

Metal–Oxide–SemiconductorField-Effect Transistor:

Additional Concepts

.

12.1.1 Nonideal Effects…..subthreshold

kT

eV

kT

eVsubI DSGS

D exp1exp

12.1.2 Nonideal Effects…..channel length modulation

DI

DD ILL

LI

'

'DI

Where is the actual drain current and is the ideal drain current. Since is a function of , is now also a function of even though the transistor is biased in the saturation region.

DD ILL

LI

'

L

'DI

DSVDSV

12.1.3 Nonideal Effects…..mobility variation

3/1

00

E

Eeffeff

0Where and are constants determined from experimental results.

0E

12.1.4 Nonideal Effects…..velocity saturation

2/12

1

sat

eff

eff

v

E

12.2 MOSFET Scaling

See Table 12.1