SEMICONDUCTOR DEVICE PHYSICS AND DESIGN

2.7. MOBILE CARRIERS 59

1017

1016

1015

1014

1013

1012

1011

1010

109

108

107

106

1000 500 200 100 27 0 –20

T ( ̊C)

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

1000/T (K–1)

Ge

Si

GaAs

INTR INSIC

CARRIER

DENSITY

ni

(cm

–3

)

GaN

105

104

Lowest measured unintentional carrier

concentration in GaN.

Figure 2.18: Intrinsic carrier densities of Ge, Si, GaAs, and GaN as a function of reciprocal
temperature. Currently, the lowest measured unintentional background density in GaN at room
temperature is around 1 × 1015 cm−^3 , indicating that the electronic properties are dominated by
defects (either extrinsic or intrinsic point defects).