The Essential Guide to Semiconductors – Running Start

In this chapter…

About This Book

Some Words to Know

Few things have altered modern life as much as the discovery of semiconductors, and certainly none in living memory. Modern electronics have completely changed the way we talk with each other and who we talk with. It has changed medical research, entertainment, record keeping, travel, and exploration. There’s almost no business, profession, or industry that hasn’t changed since the introduction of solid-state electronics in the last 50 years.

Computers are only the beginning of it. PCs and other types of computers are often made the figurehead for the entire electronics industry, but less than half of the world’s electronics are used in computers of any kind. Most of them go into more mundane, but probably more useful products like thermostats, automobile antilock brake systems, air conditioning, televisions, x-ray scanners, radios, and cellular telephones. It’s the everyday, little-seen effects of modern electronics that make it so ubiquitous and so much a part of our lives.

One of the basic building blocks of modern electronics is the transistor, a device that became a household word in the 1960s with the introduction of transistor radios. In 2001, the semiconductor industry manufactured about 60 million transistors for every man, woman, and child on Earth. By 2010, this number is expected to be about 1 billion transistors per capita. Once scientific marvels, these tiny flakes of silicon have now become more plentiful than rice.

About This Book
It’s normal to be curious about something that so fundamentally separates our daily lives from those of our grandparents. However, the nature of electronics, semiconductors, and chip making is inherently technical and, to be honest, pretty dull to the nonengineer. How can we keep up with this fast-moving business without becoming a nerd?

Plenty of people fly in airplanes without being pilots. Lots of people sail on ships or ride ferries without nautical experience. You can drive a car without being a mechanic. By the same token, plenty of people work in the massive electronics and semiconductor industries without first earning engineering degrees. This book is intended for them: the curious, intelligent adults who want a primer on the terms, words, and concepts behind this endlessly fascinating business, science, and technology.

Although this book is organized logically into a progression of chapters, it’s not necessary to read them in order, or even to read them all. Some chapters are paired and might be best read together, such as Chapters 3 and 4, which deal with how silicon chips are designed and built. In general, feel free to browse and let your curiosity take you where it may.

I have made a deliberate attempt to avoid jargon, buzzwords, and acronyms through this book. In the back you’ll find a glossary that defines many of the three-letter acronyms (TLAs) common to this business, even if those terms are never used in this book. If nothing else, keep a bookmark in the glossary so you can turn to it quickly in time of need.

Some Words To Know
Most businesses have their own specialized vocabulary that’s impenetrable to outsiders. Plumbers, doctors, miners, and pilots all use words and phrases that the rest of us don’t understand. It’s the same with chip makers and designers. Most of their professional lingo isn’t of interest to us here, but some of these words have leaked into general usage. I’ll define others throughout this book as we need them.

What’s a Chip?
The most common word you’ve undoubtedly already heard related to semiconductors is chip, as in silicon chip, memory chip, or computer chip. Chips are little flakes of silicon that have been carefully worked on in such a way that they do amazing things. There are millions of different kinds of chips made for cell phones, antilock brake systems, televisions, radios, and innumerable other devices. Memory chips and microprocessors are both examples of chips. Big or small, all chips are made in more or less the same way, from the same basic materials, namely silicon and aluminum.

What’s Silicon?
Silicon is a perfectly normal substance: It’s sand. Believe it or not, all the world’s advanced silicon chips are basically made out of sand. Whether the chips are used in computers, satellites, cell phones, video games, or household thermostats, they all have the same humble beginnings on a beach somewhere. (Technically, industrial-grade silicon is specially manufactured, not scooped off the beach with a pail, but it’s the same stuff either way.)

Here is one important point to remember: silicon is not the same as silicone. Silicon rhymes with “drawn” and is the sandy stuff chips are made of. Silicone rhymes with “throne” and is the stuff that cosmetic surgeons use. You can also find silicone grease at the hardware store; it makes good weatherproofing and stops squeaky hinges. It’s an unfortunate trick of the English language that these two words are so close together. They really have nothing in common and are not related at all. You’re sure to mark yourself as an amateur if you accidentally mention “silicone chips.”

Silicon Valley, of course, is the nickname for the Santa Clara Valley of California. It’s a roughly 50-mile stretch between San Francisco (at the north end) and San Jose (at the south end). There’s no natural silicon there, although judging from some of the inhabitants, there is a fair amount of silicone.

What’s a Semiconductor?
Semiconductor is a word that only chemists should really be using. It means a chemical or a substance that conducts electricity, but not very well. Some materials, like copper, conduct electricity quite well. That’s why houses are built with copper wires. Other materials, like rubber and plastic, don’t conduct electricity at all. That’s why power cords are plastic on the outside: to protect us from the electricity inside. Finally, there’s a third class of materials, the semiconductors, that conduct electricity better than plastic but not as well as copper. For reasons it’s not important to explain, this makes semiconductors great materials for building chips, and silicon is one of the best semiconductors available.

We also use the word semiconductor to refer to things made from silicon (see Figure 1.1). For example, in this book you’ll read about computer chips “and other semiconductors.” That doesn’t mean materials other than silicon. It means manufactured items that are made from silicon. In that sense, semiconductor is basically the same as chip or component.


Not all semiconductors are chips; casino operators might say not all chips are semiconductors, either. The only other good joke in this category involves a railroad conductor who had his hours cut back: He became a semiconductor.

Figure 1.1. Practically all electronic devices are made from purified silicon sand. The silicon is processed into a number of different sh
What’s a Transistor?
Everybody has heard of a transistor radio (at least, everyone of a certain age), but how many know what a transistor really is? Is it a big thing or a little thing? Good or bad? The answers to these questions are little and good.

Transistors are the smallest, most basic building blocks in most electronics. They are the bricks from which the soaring towers are made. Transistors can be combined to make nearly anything an electrical engineer can imagine. An electrical engineer might describe a day’s work as a 5,000-transistor circuit the way a cook might enthuse over a three-egg omelet.

Transistors can be made as big or as small as you like, but the overwhelming trend is to make them smaller. The first transistors, created in the 1950s, were as big as your thumb. Modern transistors are—hold your breath—about one-millionth of an inch across. You could easily inhale a thousand transistors and not know it. You can also fit more than 10 million transistors on your fingernail, and in Chapter 4 we’ll see exactly how these modern miracles are put together.

What’s an IC?
IC (integrated circuit) is just another term for a chip. You can use the terms IC and chip interchangeably.

What’s a Component?
A component is similar to a chip, but the term is a little broader. All chips are components, but not all components are chips. Pretty much any electrical type of device you might make from silicon is a component. Chips are the most common type of component, but there are other types of electrical components, too, like resistors and capacitors.

What’s a Circuit?
Circuit is a medium-strength technical word to describe an electronic design. Architects create blueprints; electrical engineers create circuits. To these people, electricity always travels in a circle, like horses around a track. Therefore, any electronic design is called a circuit. Whether it’s a big design (like an entire television) or a small design (like a single chip), it’s still called a circuit. In this book, you’ll see circuit used as a catch-all term for many different kinds of electrical designs.

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