Semiconductor materials have been studied in laboratories
as early as 1830. The first materials studied were elements
and compounds, which are poor conductors if heated. However,
when light is shine on them, it would generate an electrical
current that could pass through them in one direction only.
This means we can control the direction of flow of electricity.
Another example, radio receivers required a device called
a rectifier to detect signals. Ferdinand Braun used the rectifying
properties of the galena crystal, a semiconductor material
composed of lead sulfide, to create the cat's whisker diode.
The rectifying properties create a voltage potential between
the metal contact and the semiconductor such that electrons
would ‘slide’ down the potential when going in
one direction, but need to ‘climb’ up the potential
in the opposite direction. Thus the first semiconductor device
was produced.
(Transistor)
By 1874, electricity was being used not only to carry power,
but also to carry information. The telegraph, telephone, and
later the radio were the earliest devices in the industry
that would eventually be called electronics.
(Rectifier) |
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(Capacitor) |
In the first half of the 20th century, The electronics industry
was dominated by vacuum tube technology, but they were fragile,
bulky, unreliable, power hungry, and produced considerable
heat. Vacuum tube is in fact a glass tube which has its air
inside evacuated, and it has positive, negative electrodes
so that electrons move from the cathode to the anode. To encourage
the electrons to do that, the cathode is heated to high temperature
(at least a few hundred degree Celsius) so that electrons
got so hot that they ‘jump’ out of the cathode.
A way to control the flow of electron is using a third electrode,
called grid. This is slightly more negative than the cathode
so it can retard the electrons by varying its potential. It
was not until 1947, with the invention of transistor by Bell
Telephone Laboratories, that the vacuum tube trouble was solved.
Transistor is like solid state equivalent of vacuum tube,
with no vacuum and glass tube; electrons move from cathode
to anode (they are called source and drain now) and the electron
flow is controlled by a gate which acts similar to the grid
in vacuum tube. In Compared to vacuum tube, transistors were
smaller, more durable, reliable, consume less power and produce
less heat. Transistor allows engineers to design more complex
IC circuits and equipment comprising hundreds or thousands
of discrete components such as diodes, capacitors, rectifiers
and transistors. This creates another problem; these components
still have to be interconnected to constitute electronic circuits,
and to hand-solder thousands of components to thousands of
bits of wire is costly and time-consuming. It is unreliable
too; soldered joint can fail and therefore every joint can
be a potential source of problem. The challenge is to search
for cost-effective and reliable ways of producing and interconnecting
these components.
(common diode nowadays) |
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(common LED nowadays) |
Packaging each component (transistors, resistors, and capacitors)
and hand wiring the components into circuits were extremely
inefficient. The USA military began to look for more efficient
way to make electronic circuits. One of the solutions was
the Micro-Module program sponsored by the U.S. Army Signal
Corps. The concept was to make all the components in uniform
size and shape, with the wiring construct into the components.
Then, the modules could be snapped together to form circuits,
eliminating the demand for wiring the connections. It means
that resistors, capacitors, transistors all have the same
size, just like Lego and you snap them together to form a
circuit of your design.
(Jack Kibly's IC - picture is provided
by Texas Instruments Semiconductor Asia)
Texas Instrument was working on the Micro-Module program
when Jack Kilby joined the company in 1958. Because of his
work with Centralab in Milwaukee, Kilby was familiar with
the problem faced by the industry. However, he did not think
the Micro-Module can solve the basic problem of large quantities
of components in complex circuits (imagine what happens if
you are designing a large and complex circuit like a computer
processor!). Therefore Kilby commenced searching for another
options and in the process decided the only object a semiconductor
house could make cost effectively was a semiconductor. Moreover,
he commenced to write down and sketch out his idea in July
of 1958, when everyone else had left for the annual two-week
vacation. It was in a deserted laboratory at Texas Instrument's
brand new Semiconductor Building where Jack Kilby first hit
on the idea of the integrated circuit. By September, he has
a working integrated circuit built on a piece of semiconductor
material. On September 12, 1958, several executives of Texas
Instrument, including the former Chairman Mark Shepherd, gathered
for the demonstration given by Kilby. They saw a sliver germanium,
with protruding wires, glued to a glass slide. It was a rough
device, but when Kilby pressed the switch, a sine curve appeared
across the oscilloscope screen, it was a simple oscillator
circuit. His invention operated successfully. That means he
had solved the problem. In the year 2000, Jack Kilby, the
inventor of integrated circuit, became one of the recipients
of the Nobel prize in Physics.
- Click the above link to view the video on web
In 1959, Jean Hoerni and Robert Noyce, who later founded
Intel, developed a new process called planar technology at
Fairchild Semiconductor which enabled them to diffuse various
layers onto the surface of a silicon wafer to make a transistor,
leaving a layer of protective oxide on the junctions. This
process allowed metal interconnections to be evaporated onto
the flat transistor surface and replaced the hand wiring.
The new process used silicon instead of germanium, and made
commercial production of ICs possible. The initial resistance
to the new IC technology gave way to enormous popularity.
By the end of the 1960s, nearly 90% of all the electronic
appliances were products of integrated circuits. Now we have
more than one million transistors on a single computer chip!
The impact of Kilby’s tiny chip go beyond anyone’s
imagination at that time. Nowadays, many of the electronics
products could not have been developed without it. From the
small chip that Kilby built, modern computer industry raised.
Those room-size machines built in 1940s and 1950s are transformed
into today’s array of mainframes, minicomputers, personal
computers and personal digital assistant. The chip restructured
communications, created a plethora of new ways for instant
exchanges of information between people, businesses and nations.
In fact, human beings could not explore space or land on the
moon without the chip. The applications of the chip have reached
into education, transportation, manufacturing and entertainment.
The worldwide electronics market has grown from $29 billion
to nearly $957 billion since 1961. Projections point out that
in the 21st century it will become the world’s single
largest industry. This expansion will rely on the continued
development of newer and better technologies — like
those being developed around the world, e.g. wireless communication/internet
connection, and DNA decoding.
(Sound Chip - IC)
In the future, there will be more new amazing encounter with
electronic equipment with continuing advances in semiconductors.
Perhaps in the next few years, you can call your overseas
friend and seeing his/her smiling face in the screen on your
cell phone. Your mother can turn on the oven from her car
phone as she leaves her office at the end of the day. When
you get home, dinner will be nearly done. Even better, it
may be able to set your car on autopilot, then, you are free
to look over notes for your next day’s meeting on your
commute home. In USA, plans are being made for you to order
a movie from the web, and within a matter of seconds, it is
ready to view on your television at home. It sounds like science
fiction, but new breakthroughs are only a short stride away,
or already ready to be implemented.
However, there are several problems that can hinder the steady
progress of IC; one of them is the speed of electrons that
will ultimately set the limit on how fast information can
travel. The power consumption, which leads to heat generation,
is another. If you have too many transistors pack into a tiny
area, and you can remove the heat generated by them. They
would soon fail because of overheating (it means you can no
longer control the electrons). Another problem to consider
is that presently we base our physics in the classical regime
but as the size of the IC gets smaller, then, it would come
a time when quantum mechanics which governs the property of
physical world in small dimension, will become important.
This would mean a complete re-estimate of the IC is needed.
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