Fundamentals of Materials Science and Engineering: An Integrated Approach, 3e

GTBL042-12 GTBL042-Callister-v2 August 13, 2007 18:22

484 • Chapter 12 / Electrical Properties

1020 m−^3 , both carrier mobilities are at their maximum levels and independent of the

doping concentration. In addition, both mobilities decrease with increasing impurity

content. Also worth noting is that the mobility of electrons is always larger than the

mobility of holes.

Influence of Temperature

The temperature dependences of electron and hole mobilities for silicon are pre-

sented in Figures 12.19aand 12.19b, respectively. Curves for several impurity dopant

Electron mobility (m

2 /V-s)

200 300

1025 m–3

1024 m–3

1023 m–3

1022 m–3

<10^20 m–3

400 500 600

0.01

0.1

1

Temperature (K)

(a)

Figure 12.19 Temperature

dependence of (a) electron and (b)

hole mobilities for silicon that has been

doped with various donor and acceptor

concentrations. Both sets of axes are

scaled logarithmically. (From W. W.

G ̈artner, “Temperature Dependence of

Junction Transistor Parameters,”Proc.

of the IRE,45,667, 1957. Copyright

©c1957 IRE now IEEE.)

Temperature (K)

Hole mobility (m

2 / V-s)

200 300

1025 m–3

1024 m–3

1023 m–3

1022 m–3

<10^20 m–3

400 500 600

0.01

0.001

0.1

(b)