7 Semiconductor Devices
7.1 Semiconductors
7.2 Diodes
7.3 Bipolar Junction Transistors
7.4 Field-Effect Transistors CONTENTS ix
7.5 Integrated Circuits
7.6 Learning Objectives
7.7 Practical Application: A Case Study—Electronic Photo Flash
Problems
Turning our attention to the internal structure of integrated-circuit (IC) building blocks, we
encounter a new family of circuit elements known assemiconductor devices, which include diodes
and transistors of various kinds. These circuit elements are nonlinear in theiri–vcharacteristics.
Nonlinearity complicates circuit analysis and calls for new methods of attack. However, the
semiconductor devices are extremely important for theelectronic circuits.
Active circuitscontain not only passive circuit elements (such as resistors, capacitors, or
inductors) but also active elements such as transistors. All of the analog and digital blocks
discussed in Chapters 5 and 6 are active circuits, and transistors are essential for their internal
construction.
We shall present in this chapter the most important semiconductor devices, such as diodes,
bipolar junction transistors, and field-effect transistors. Chapters 8 and 9 will deal with their
applications in analog and digital circuits.
7.1 SEMICONDUCTORS
Semiconductors are crystalline solid materials whose resistivities have values between those of
conductors and insulators. Conductivity ranges from about 10−^6 to about 10^5 S/m. Silicon is by far
the most important semiconductor material used today. The conductivity of pure silicon is about
339
