As discussed in Chapter 1, the evolution of solid-state materials and the subsequent development of the technology for integrated circuit fabrication have revolutionized electronics and made possible the modern information and technological revolution. Using silicon as well as other crystalline semiconductor materials, we can now fabricate integrated circuits (ICs) that have more than a billion electronic components on a single 2 cm×2 cm die. Most of us have some familiarity with the very high-speed microprocessor and memory components that form the building blocks for personal computers and workstations. As this edition is being written, technology for the 1-gigabit (Gb) memory chip is being transferred to manufacturing in a number of companies around the world. The memory array alone on this chip will contain more than 10⁹ transistors and 10⁹ capacitors -- more than 2 billion electronic components on a single die!

Our ability to build such phenomenal electronic system components is based on a detailed understanding of solid-state physics as well as on development of fabrication processes necessary to turn the theory into a manufacturable reality. Integrated circuit manufacturing is an excellent example of a process requiring a broad understanding of many disciplines. IC fabrication requires knowledge of physics, chemistry, electrical engineering, mechanical engineering, materials engineering, and metallurgy, to mention just a few disciplines. The breadth of understanding required is a challenge, but it makes the field of solid-state electronics an extremely exciting and vibrant area of specialization.

It is possible to explore the behavior of electronic circuits from a "black box" perspective, simply trusting a set of equations that model the terminal voltage and current characteristics of each of the electronic devices. However, understanding the underlying behavior of the devices leads a designer to develop an intuition that extends beyond the simplified models of a black box approach. Building our models from fundamental characteristics enables us to understand the limitations and appropriate uses of particular models. This is especially true when we experimentally observe deviations from our model predictions. One goal of this chapter is to develop a basic understanding of the underlying operational principles of semiconductor devices that enables us to place our simplified models in the appropriate context.

The material in this chapter provides the background necessary for understanding the behavior of the solid-state devices presented in subsequent chapters. We begin our study of solid-state electronics by exploring the characteristics of crystalline materials, with an emphasis on silicon, the most commercially important semiconductor. We look at electrical conductivity and resistivity and discuss the mechanisms of electronic conduction. The technique of impurity doping is discussed, along with its use in controlling conductivity and resistivity type.