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Giancarlo Champin
Martha Townsend
WRIT 340
26 February 2013
How Transistors Have Changed the World
Introduction
Since the validation and acceptance of the famous Maxwell equations, which described
the space-time characteristics of electromagnetic waves, scientists and engineers have been
trying to use them to create electronics. While there have been many notable technologies
created from these powerful equations, the most important one is the transistor. To illustrate just
how amazing this piece of technology is, consider this: without the discovery of the transistor,
LCD televisions, computers, IPods and any other electronic device with a microchip would not
be possible. To fully appreciate how important transistors are, let’s take a look at how they work
and then move on to a brief history of how they were developed. Next, we’ll examine how
transistors are omnipresent in our lives today and then examine what future holds for transistors
and how these changes will make technology an even bigger part of our lives.
What is a Transistor and What Does it Do?
Before we can talk about all the new technology that transistors have helped bring along,
it is important to understand the basics of transistor function. A transistor’s main function is to
control the flow of electricity. This simple, yet powerful idea is how engineers make it possible
to construct amazing electronics like cell phones and computers. A modern day transistor, like
the one shown in Figure 1, has five main components: the gate, the oxide, the substrate, the
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source and the drain. By applying a voltage on the gate, a current of electrons is generated that
moves between the substrate, specifically from the source to the drain. The oxide provides a
needed layer of insulation between the metal and the semiconductor substrate. A semiconductor
is just a special type of element that allow electron flow after performing special procedures on
them. So a basic example of how a transistor works would be a power button on a smart phone.
By pressing down on the power button we apply a voltage to the transistor controlling power,
thereby turning on the phone since it allows electricity to flow – hence, ‘switched’ on!
Figure 1: Basic Model of a Transistor http://www.doitpoms.ac.uk/tlplib/semiconductors/images/mosfet.jpg
A Brief History of the Development of Transistors
It took a little over a hundred years of research before we finally developed the modern
day transistor. In fact, the famous chemist/physicist J.J. Thomson (Figure 2) performed
experiments on large, glass vacuum tubes called ‘cathode’ tubes in the late 1800’s. What he
found – and eventually won a Nobel Prize for – is that by varying the electricity going through
one leg of the tube, one could control the flow of electricity through the rest of the device
(Haviland). As you may have noticed, this is the exact same thing that a transistor does. This was
a huge breakthrough at the time and many technologies flourished because of it – for example in
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radio technology, because AM signals need to be amplified or attenuated by the receiver so that
the listener can hear the tuned station.
Figure 2: J.J. Thomson in his lab http://www.manep.ch/img/photo/challenges/nanotubes/thompson.jpg
Eventually by the 1930’s, the cathode tubes were too inefficient for the applications
needed at that time; for example, these tubes could not be turned on for long amounts of time
because of over-heating. Also, the tubes were too big for some of the technology being
envisioned – for example, a huge glass tube could never be used for a cell phone or computer. So
scientists began doing more research into devices that could control the flow of electricity. Early
researchers knew that semiconductor materials had special electrical properties but did not know
if there was a way to control current in a semiconductor like in a cathode tube. In 1947, John
Bardeen and Walter Brattain, two engineers working for Bell Laboratories, discovered such a
way. What they did was stick two metal contacts near each other in the semiconductor, and by
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varying the amount of electricity they applied to the metal, they found they could control the
flow of electricity inside the semiconductor itself (Haviland). And thus the first transistor was
made on a semiconductor.
Figure 3: Clean Room at Intel Factory http://api.ning.com/files/PHOUgYb622b5266LVFbpJnckib7uyCTdGrbsTEiK0zghrut1IrEWhMycWmtsP8hWmv8fhYBBW7agFevQ66d0w__/SemiconductorCleanRoom.jpg
Many of the problems of the cathode tube technology, such as over-heating, brittleness,
and size, were solved. Nowadays, the processes for manufacturing transistors on semiconductors,
such as Silicon, have become so advanced that companies invest billions of dollars into the
facilities that make them. For example, Intel recently received support from President Obama for
the construction of a new fabrication lab in Arizona that has a price tag of $5 billion (Swartz)!
These labs contain some of the world’s most advanced technology and even have clean rooms
(Figure 3) to be extra careful that contamination from the outside world doesn’t ruin the chips.
These new facilities are capable of producing millions of transistors on small pieces of
semiconductor (Swartz). In fact, the new plant that Intel is building will be able to fit 10 million
transistors on an area the size of a period at the end of a sentence (Swartz).
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Where Are Transistors Being Used Today
It was Intel co-founder Gordon E. Moore in 1965 who first noted in one of his papers that
the number of transistors that was possible to fit in a single silicon wafer was approximately
doubling every two years (Strickland). This conjecture has been remarkably accurate even up
until today. Since we have been able to make our devices smaller, we also decrease the distance
electrons have to travel and therefore make transistors faster, and more efficient. These advances
in transistor science has resulted in a substantial increase in the role that these tiny little
components play in our everyday lives.
For example, before transistors were made small enough where we could fit millions onto
one little chip, televisions were being built using the aforementioned vacuum tubes. These TVs
were delicate, consumed a lot of power and needed to be warmed up. However, once they were
developed, the new transistors quickly made that technology obsolete, and by the late 1960’s
Japan’s Sony Corporation was manufacturing televisions solely out of transistors (“Sony…”).
This dramatically reduced the size of the television, and while TV screens today can still be
enormous, they are also super thin and relatively lightweight. In addition to that, we can now
have products like smart TVs which can connect to the internet and download movies or games
at the click of a button. All of this has contributed to a more enjoyable and convenient viewing
experience for viewers.
Similarly, with the advancement in solid state physics – which is just jargon for the
science of making transistors on semiconductors – the cell phone became possible. The first cell
phones to come out, however, were large, bulky and too expensive to be available for the masses.
The technology, however, kept improving and nowadays, almost anyone in the United States can
own a cell phone. The top-of-the-line touch phones, like the Samsung Galaxy and the Apple
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IPhone, can contain billions of transistors in the components that make up their hard-drive,
memory, and touch screen, not to mention those required for its basic antenna functions.
The End of Moore’s Law and the Future of Transistors
Although we have enjoyed the benefits of Moore’s Law for the last forty years, it is not
guaranteed to be true for eternity. Many of the transistors that are manufactured today have
shrunken down to the nanometer scale. The problem is that since these devices are so small, it is
difficult to really understand and control what is happening at the quantum level, even for the
most brilliant scientists in the world. To give you an idea of how small we’re talking about, the
diameter of hair is about 100 micrometers, these devices are 1000 times smaller than that. As a
result, it is becoming clear that soon, in the next five to ten years, the current methods for making
transistors smaller will not be as effective or efficient. In the coming decades there will be a need
to develop new methods for decreasing the size of transistors or making them more efficient.
Figure 4: Image of 3D Transistor http://i.i.com.com/cnwk.1d/i/tim/2011/05/04/Intel-22nm_Transistor_610x527_270x233.jpg
One such innovation that took place recently is Intel’s 3-D transistor (Figure 4). The MIT
Technology Review annually lists its top ten technological advances. Intel was honored with this
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distinction by creating a transistor that instead of using the typical design, as shown in Figure 1,
now uses a design that is upright and perpendicular to the plane of the metal. In addition to
reducing the space required for transistors, this 3-D transistor also reduces the amount of leakage
current – which is wasted current -, speeds up the transistors by 37% and consumes as little as
half of the power that a normal transistor uses(Freedman). These improvements would make
drastic progress in the cell phone industry by increasing the speed of phones and the time in
between charges. In fact, Intel hopes to use these transistors in handheld mobile devices in the
coming years (Freedman). Figure 5 shows the differences between a traditional 2-D transistor
and the new 3-D transistor.
Figure 5: 2-D vs. 3-D Transistor http://arabisays.blogspot.com/2011/05/transistor-era-moves-to-3d.html
Going beyond the immediate future, the quantum transistor is the next innovation far off
in the horizon. In experiments by Thomas Schimmel at the Karlsruhe Institute of Technology, it
was proved that a transistor could be created by repositioning a single atom (“Single-Atom
Transistor”). Although this advanced design is nowhere near being ready for mass production,
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Schimmel and his team showed that it could be done. In theory, this would mean that devices
such as computers would be much smaller than they are now and would consume much less
power. Also, computers would also be able to perform more than one function at once – to
illustrate just how amazing that would be, the only thing on the planet that can perform more
than task at once is the human brain. This shows the immense potential for continued growth in
this highly important industry.
Conclusion
Transistors have come a long way since solid state physics was first investigated. From
the initial research on vacuum tube triodes and cathode waves, scientists and engineers are now
working with circuits that can contain billions of transistors on a single chip. The significance of
their contribution cannot be overstated. Due to these advancements, technology has become
more widely available for mass consumption. Entire industries, from microchip manufacturing,
to software companies, and even social media companies – any company that has a computer
really – rely on transistors to for their businesses. Think about it, without transistors how would
you be able to check your email on your phone before heading off to work or how would you run
that computer application for the project you were working on. Without transistors, we would
still be reaching out to grandma with written letters instead of simply Skyping her. Transistors
have made a tremendous, positive impact on our world today and will continue shaping our
world as we move on into the future.
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Works Cited
Freedman, David H. "3-D Transistors." MIT Technology Review. MIT, May 2012. Web. 16 Apr.
2013. <http://www2.technologyreview.com/article/427674/3-d-transistors/>.
Haviland, David B. " The Transistor in a Century of Electronics." NobelPrize.org. N.p., 19 Dec.
2002. Web. 16 Apr. 2013.
<http://www.nobelprize.org/educational/physics/transistor/history/>.
"Single-Atom Transistor." Institut Für Angewandte Physik (AG Schimmel). Karlsruhe Institute of
Technology, 2010. Web. 16 Apr. 2013. <https://www.aph.unikarlsruhe.de/schimmel/singleatomtransistor.html>.
"Sony Founder Masaru Ibuka's New Year's Dream Comes True." Sony. Sony Corporation, 17
Nov. 2009. Web. 16 Apr. 2013.
<http://www.sony.net/SonyInfo/CorporateInfo/History/capsule/21/index.html>.
Strickland, Jonathan. "How Moore's Law Works." HowStuffWorks. N.p., 29 Feb. 2009. Web. 16
Apr. 2013. <http://www.howstuffworks.com/moores-law.htm>.
Swartz, Jon. "Intel's New $5 Billion Plant in Arizona Has Obama's Blessing."
USATODAY.COM. N.p., 29 Mar. 2011. Web. 16 Apr. 2013.
<http://usatoday30.usatoday.com/tech/news/2011-03-28-intel-manufacturing.htm>.