© 2018 Toshiba Electronic Devices & Storage Corporation
Basic Knowledge of
Discrete Semiconductor Device
September 2018
Toshiba Electronic Devices & Storage Corporation
Chapter I
Basis of Semiconductors
2
© 2018 Toshiba Electronic Devices & Storage Corporation
Gold
Silver
Copper
Iron
Aluminum
etc.
Glass
Rubber
Oil
Plastic
Diamond
etc.
Silicon
Germanium
Selenium
GaAs
etc.
A “semiconductor" is a substance with characteristics intermediate between those of a
"conductor" that conducts electricity like metal and an "insulator" through which
electricity hardly flows. The ease with which electricity flows is related to the magnitude
of the substance’s electrical resistance. If the electrical resistance is high, the current
hardly flows, and if the electrical resistance is low, the electric current flows easily.
When electrical conductivity is expressed by resistivity, semiconductors are distributed in
the range of 10
-4
to 10
8
Ωcm, whereas conductors are 10
-8
to 10
-4
Ωcm and insulators are
10
8
to 10
18
Ωcm.
InsulatorSemiconductor
Conductor
Electrical
Resistance
Low
High
10
18
10
-10
Resistivity: Ωcm
What is a Semiconductor?