Chapter 1: Semiconductor Diodes
 

Chapter 1: Semiconductor Diodes
Introduction

One of the noteworthy things about this field, as in many other areas of technology, is how little the fundamental principles change over time. Systems are incredibly smaller, current speeds of operation are truly remarkable, and new gadgets surface every day, leaving us to wonder where technology is taking us. However, if we take a moment to consider that the majority of all the devices in use were invented decades ago and that design techniques appearing in texts as far back as the 1930s are still in use, we realize that most of what we see is primarily a steady improvement in construction techniques and application of those devices rather than the development of new elements and fundamentally new designs. The result is that most of the devices discussed in this text have been around for some time, and that texts on the subject written a decade ago are still good references with content that has not changed very much. The major changes have been in the understanding of how these devices work and their full range of capabilities, and in improved methods of teaching the fundamentals associated with them. The benefit of all this to the new student of the subject is that the material in this text will, we hope, have reached a level where it is relatively easy to grasp and the information will have application for years to come.
The miniaturization that has occurred in recent years leaves us to wonder about its limits. Complete systems now appear on wafers thousands of times smaller than the single element of earlier networks. The first integrated circuit (IC) was developed by Jack Kilby while working at Texas Instruments in 1958. Today, the Intel® Pentium® 4 processor has more than 42 million transistors and a host of other components. Recent advances suggest that 1 billion transistors will soon be placed on a sliver of silicon smaller than a fingernail. We have obviously reached a point where the primary purpose of the container is simply to provide some means for handling the device or system and to provide a mechanism for attachment to the remainder of the network. Further miniaturization appears to be limited by three factors: the quality of the semiconductor material, the network design technique, and the limits of the manufacturing and processing equipment.



The first device to be introduced here is the simplest of all electronic devices, yet has a range of applications that seems endless. We devote two chapters to the device to introduce the materials commonly used in solid-state devices and review some fundamental laws of electric circuits.