7.6 LEARNING OBJECTIVES 379
fact that typical semiconductors do not exhibit the magnetic properties needed to realize practical
inductance values.
ICs are made bymicrofabricationtechnologies. The low cost of IC production is a result of
planar processingin which fabrication begins with a very flat disc of silicon wafer, 5 to 10 cm in
diameter and only 0.5 mm thick. The small electronic structures to be built on it are then produced
photographically. The technique is known asphotolithography, in which a photosensitive lacquer
(known asphotoresist), which has the property of hardening when struck by light, is used. The
fabrication method requires a series of masks, photoetching, and diffusions.
MOSFET chips generally utilize either ap-channel or ann-channel device; hence, these
chips are known as PMOS and NMOS, respectively. Alternatively, bothp-channel andn-channel
devices are used to form compound devices, in which case they are known as complementary
MOS (CMOS). Whereas the CMOS has the advantage of low power consumption, only a smaller
number of devices can be placed on the chip. MOS technologies are popularly used in computer
circuits due to their higher packing densities. Bipolar technologies, however, are used in high-
speed applications because they respond more quickly. The device fabrication methods are too
involved to be presented in this introductory text.
Small-scale integration(SSI) is used typically for a 20-component op amp, whereaslarge-
scale integration(LSI) puts an entire microprocessor, typically with 10,000 components, on a
single chip. The chief benefits from integrating many components on an IC are low cost, small
size, high reliability, and matched characteristics. Of the many IC packaging technologies, the
most popular is thedual-in-line package(DIP), which consists of a rectangular plastic or ceramic
case enclosing the IC, with protruding pin terminals. While an op amp is commonly supplied in
an 8-pin DIP for insertion into some larger circuit, a microprocessor may have a 40- to 64-pin
DIP to accommodate the many external connections needed for an LSI chip.
7.6 Learning Objectives
Thelearning objectivesof this chapter are summarized here so that the student can check whether
he or she has accomplished each of the following.
- Understanding of electrical conduction in semiconductor materials.
- i–vcharacteristics of a semiconductor diode (or of apn-junction).
- Diode modeling and analysis of elementary diode circuits.
- Zener diode, its circuit model, and simple applications.
- Breakpoint analysis of a circuit containing two or more ideal diodes.
- Half-wave and full-wave rectifier circuits.
- Basic operation of bipolar junction transistors, along with their input and output character-
istics.
- Small-signal equivalent circuits and large-signal models of BJT.
- Recognizing the more common BJT configurations, and determining the voltage and current
gains.
- Basic operation of JFETs and their characteristics.
- JFET small-signal equivalent circuit (for low frequencies) and its applications for simple
circuit configurations.
- Basic operation of MOSFETs (enhancement and depletion types) and their characteristics.
