GTBL042-12 GTBL042-Callister-v2 August 13, 2007 18:22
Chapter 12 Electrical Properties
It was noted in Section 5.12 that an
image is generated on a scanning
electron micrograph as a beam of
electrons scans the surface of the
specimen being examined. The
electrons in this beam cause some of
the specimen surface atoms to emit
x-rays; the energy of an x-ray photon
depends on the particular atom from
which it radiates. It is possible to
selectively filter out all but the x-rays
emitted from one kind of atom. When
projected on a cathode ray tube, small
white dots are produced that indicate
the locations of the particular atom
type; thus, a “dot map” of the image is
generated.
Top: Scanning electron
micrograph of an integrated circuit.
Center: A silicon dot map for the
integrated circuit above, showing
regions where silicon atoms are
concentrated. Doped silicon is the
semiconducting material from which
integrated circuit elements are made.
Bottom: An aluminum dot map.
Metallic aluminum is an electrical
conductor and, as such, wires the
circuit elements together.
Approximately 200×.WHY STUDYthe Electrical Properties of Materials?
Consideration of the electrical properties of materials is
often important when materials selection and processing
decisions are being made during the design of a
component or structure. For example, we discuss in
Web Module E materials that are used in the several
components of one type of integrated circuit package.The electrical behaviors of the various materials are
diverse. Some need to be highly electrically conductive
(e.g., connecting wires), whereas electrical insulativity is
required of others (e.g., the protective package
encapsulation).