How the integrated circuit works

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How the Integrated Circuit Works: Everything You
Need to Know
It’s that little mastermind behind all of our electronics, plotting its
way to take over the world. No, we’re not talking about Pinky and the
Brain here, but the integrated circuit, or IC! These little black chips
are filled with much mystery, but what kind of powers do they
hold? That’s what we will find out on our blog today.
The main ingredient of today’s electronics rests on the hidden
power of the integrated circuit, and you’ll likely be using them in
your own projects. So here’s everything you need to know, on how
an IC works!
Integrated Circuit!
So, what exactly is an integrated circuit? In its most basic form, an
IC is simply a collection of teeny tiny electronic components
organized on a piece of silicon. Compared to their larger brothers
and sisters, the components found on an IC can be nearly
microscopic in size, and each IC contains a unique collection of
diodes, transistors, microprocessors, capacitors, etc… all found on
something smaller than a dime!

All of your standard, common components have been miniaturized
to fit inside this integrated circuit.
What’s the benefit of putting all of these components together into
one integrated circuit? There are many! Here’s just a few:
 Space Savers. Instead of requiring an entire printed circuit
board filled with a ton of transistors, diodes, and other parts,
you can get all of that advanced functionality in a fraction of
the size.
 Greater Complexity. The level of complexity found in such a
small package has allowed us to build some pretty amazing
things. Like self-landing rockets, and satellites with built-in
navigation. Imagine trying to make those things with billions
of through-hole components!
 Common Goals. By creating a tiny integrated circuit with an
exact purpose, you can put a bunch of these together to all
achieve a common goal. Need a tracking device for your car?

One IC can provide GPS, another can send messages, and a
final microcontroller IC can control all the data going back and
forth.
And of course, you also have the benefit of taking all of those
separate yet connected parts found on a conventional circuit and
putting them all together in one place! That gives you all of that
advanced functionality you need in a pre-made circuit without
having to build it yourself!
The integrated circuit truly is the brains behind all of today’s
electronic devices, and you’ll be hard pressed to not find them
everywhere, like in radars, televisions, video processing, missiles,
and yes, even juice makers! The list is endless. Just take a quick
scan of all the electronic devices in your home, and you’re bound to
find an IC inside of nearly all of them. But from where did they
come?
The Beginnings of the Integrated Circuit
Before the integrated circuit rolled around, vacuum tubes were the
kings of the day, being used to amplify electrical signals and power
computers the size of an entire room! But these monolithic vacuum
tubes broke down regularly and pumped out a ton of heat in the
process.
So in 1947, three American physicists one-upped the vacuum tube by
making the first transistor. These things were a fraction of the size of
a vacuum tube, used way less power, and didn’t break nearly as

much. And if you combine a bunch of these transistors together?
You get an integrated circuit!
The first transistor, invented in 1947 by three American physicists
to replace the cumbersome vacuum tube.
The first integrated circuit was developed by two gentlemen – Jack
Kilby and Robert Noyce. Kilby was working at Texas Instruments at the
time, where he had an idea to construct all of the parts of an
electronic circuit on a single chip. He soon put his idea into reality,
and built the world’s first integrated circuit on September 12, 1958, on a
slab of germanium.

The first integrated circuit using germanium, created by Jack Kilby
in 1958.
Over at Fairchild Semiconductor, Robert Noyce was also working
away. Using a new chemical technique known as the planar process,
Noyce went on to create another variation of the integration in
1959; this time put to work on silicon, which is still used today!

Robert Noyce (left) and Jack Kilby (right), both created their own
versions of the first integrated circuit, around the same time
Of course, both companies rushed to secure a patent on their
inventions, and on April 25, 1961, the patent office awarded the first
integrated circuit patent to Robert Noyce! Today, both Kilby and Noyce
are credited with inventing the integrated circuit, and Kilby later
went on to receive the Nobel Prize in Physics in 2000 for his
contribution to the future of electronics. The world would soon
move past the simple one-transistor integrated circuit from Noyce
and Kilby, and an entire manufacturing process would soon be born
to pump out these little black chips to the world.
Doping It Up – How an IC Is Made
At the heart of an integrated circuit are layers of silicon wafers
(semiconductors) and copper that comes together to create the
electronic components that we use today in our breadboards –

transistors, resistors, diodes, etc. in a miniaturized form. When you
organize all of these parts together in an integrated circuit, then
you have created a die. But how exactly is this die made? That’s
where doping comes in
Semiconductors & Doping
Semiconductors are not just conductors or insulators; they’re both!
While many people thought that conductors and insulators were
evenly split categories, this truth gets a little fuzzy the farther you
journey into the periodic table. There are several materials,
including silicon and germanium, that can act as both insulators
and conductors depending on what kind of impurities are added to
them. This process of adding impurities is called doping, and here’s
how it works in a nutshell:
 N-Type Doping. Let’s say you have a piece of silicon, and you
add the chemical element antimony to it. This is going to give
silicon more electrons than it normally has, while also
allowing it to conduct electricity. This doped silicon is
called N-type silicon.
 P-Type Doping. If you take the same silicon and add the
chemical element boron to it, then you’ll remove some of the
silicon’s electrons, leaving behind gaps that act as negative
electrons that can carry electric current in the opposite
direction of n-type silicon, and so you’ve created p-type
silicon.
 Putting It Together. By placing both n-type and p-type silicon
together, you can create pathways for electrons to flow. And

this exchange of electrons being exchanged is the basis behind
the on and off, or 1 and 0 binary function of today’s
transistors, integrated circuits, and digital electronics!
Here you can see the difference between n-type (left) and p-type
(right) doping and its effects on silicon’s electrons.
There are several methods to make the doping process happen. One
of them is called sputtering, which is basically where doping
material is fired at a silicon wafer in machine-gun like fashion.
There’s also another method called vapor deposition, which uses
gas to transmit the impurities as a film onto the surface of a silicon
wafer. Here’s the entire process that a piece of silicon will go
through to become an integrated circuit:
 Wafers. Scientists first grow silicon crystals in the shape of
long cylinders like a tube of cookie dough. These then get
sliced super thin, creating what are called wafers.

 Masking. Next, heat and ultraviolet light are applied to each
wafer, leaving behind a coating of silicon dioxide and a
protective layer called photoresist.
 Etching. It’s now time for a chemical bath where these
masked wafers will have some of their photoresist removed,
leaving a pattern for where n-type and p-type areas will be
placed.
 Doping. The etched wafers are heated yet again with gasses
that contain our doping impurities to create our n-type and p-
type silicon.
 Testing. The now completed wafers are now run through a
testing machine to verify proper connections. Any wafer that
doesn’t pass gets tossed.
 Packaging. All of the wafers that pass the testing phase are
then packaged into the black boxes that we’re used to seeing
on a circuit board!

The six-step process for making an integrated circuit, starting with
wafer creation to the final packaging we’re used to seeing on a
circuit board.
Common Types of ICs
Integrated circuits come in all shapes and sizes, and can all be
wrapped up into three general categories:
 Digital Integrated Circuits. These ICs work on the binary
system that powers all of the digital electronics of today,
using a system of 1s and 0s to make some amazing things
happen. In digital integrated circuits, you’ll find logic gates,
transistors, etc. all bundled into a single chip to power things .

 Analog Integrated Circuits. Unlike its digital cousin, the
analog IC works by tackling those always-changing analog
signals and can perform some heavy tasks including filtering,
amplification, and modulation.
 Mixed-Signal Integrated Circuits. When you combine both
digital and analog functionality on a single chip, then you’ve
created a Mixed-Signal IC. You’ll find these guys being used
for things like clocking/timing regulation and digital-to-analog
or analog-to-digital conversion.
Within the realm of digital integrated circuits, you’ll find a ton of
variety, including logic gates, timers, microcontrollers,
microprocessors, FPGAs, and sensors. These ICs all pack in millions,
and even billions of transistors on a single circuit. But how do you
tell the difference between each? This is where package types can
help.
Making Sense of Package Types
The brain of an integrated circuit is skillfully hidden beneath a
protective package that you’re used to seeing on a circuit board.
Package types are all standardized, making it easy to solder to
circuit boards or connect to breadboards for prototyping. On each
package, there’s a set of silver pins, and these allow the IC to
connect to other parts of your circuit. While there are may different
package types, we’ll cover the most common that you’re bound to
encounter in your projects:
Dual-Inline Packages (DIP)

This package type is part of the through-hole family, and you can
easily recognize these chips by looking for their long, rectangular
shapes with parallel rows of pins. This package type is ideal for use
on breadboards and can include anywhere from 4 to 64 pins.
Your typical Dual-Inline Package type with two rows of pins and a
long, rectangular shape.
Small Outline Packages (SOP)
SOP ICs are closely related to DIPs, except they’re applied as
surface-mount components instead of through-hole. These chips
won’t be used in your breadboarding experiments and will require
some advanced machinery to apply precisely. SOP ICs come in

several varieties, including Thin Small-Outline Packages (TSOP) and
Thin-Shrink Small-Outline Packages (TSSOP).
Similar to the DIP with the double row of pins, however, these
devices are surface mounted.

Quad Flat Packages (QFP)
This package type is easily identified by pins jutting out from all
four directions of the IC. These useful chips can have anywhere
from 8 to 70 pins on each side, which can give them a whopping
300 pins to work with during a PCB layout process! You’ll find a ton
of microprocessors using the QFP package type, including the
popular ATmega328.
A Quad Flat Package, used in the popular ATmega328.
Ball Grid Arrays (BGA)
The last package type, and also the most advanced is the Ball Grid
Array. These complex package types include small balls of solder on
the bottom arranged in a pattern or grid. Routing all of the pins on
a BGA can be quite difficult, often taking hours to route the nets out
of the tight spacing (called fanout routing). You’ll find the BGA

package type used for only the most advanced microprocessors, like
those on the Raspberry Pi.
Today’s modern Ball Grid Arrays have hundreds of pins that can
take hours to route by a designer.
Moore’s Law and the Future of Integrated
Circuits
Since integrated circuits came into existence in the 1960s,
engineers began putting dozens of components on a single chip in
what was called small-scale integration, or SSI. Shortly after,
hundreds of components were being placed in the same footprint,
then thousands, and millions! Noticing a trend here?
Gordon Moore, co-founder of Intel, sure did. Moore made the
observation, and also the prediction that the number of components
being placed on a chip was doubling roughly every one to two
years, and would continue to do so. This is the famous Moore’s
Law.
The steady and gradual climb of transistors being packed into an IC
year after year, known as Moore’s Law.
Today, Moore’s Law is running into some trouble. By 2006, we
were squeezing in over 300 million transistors on a single chip. But
today’s ICs are “only” packing in about 1 billion transistors. This is

way off of Moore’s prediction, which says we should be using 4-5
billion. So what’s the problem? Several things:
 The problem with space. The more components that we pack
into the same space, the more problems we find. Like possibly
having one rogue atom go astray that can ruin an entire chip
and provide some questionable reliability.
 It keeps getting hotter. Having millions and billions of
transistors packed into such a small space creates a huge
problem with heat, how are you going to handle that increase
in temperature in the already shrinking size of our devices?
 Strange behavior. When you start packing in transistors
together, then quantum mechanics come about, and electrons
start jumping around for no reason. This becomes a problem
in your computer, where stray electrons can mean the
difference between clean and corrupted data.
So what’s the solution? Some propose that it’s time to end our use of
silicon and move on to other conductive materials like graphene. But we
still haven’t figured out a way to reliably manufacture this new
material. There’s also the option to replace electrons with
something faster, like photons! Whether either of these alternatives
will power the future of our computers is yet to be seen. Here’s a
great video that sums up the challenges we’re facing with Moore’s
Law, and where we might be headed in the future (laser computers,
anyone?)
Today, Electronics. Tomorrow, the World!

So that’s it for the wild and crazy world of integrated circuits. Can
we guess what the future will hold as we advance into packing
more and more transistors into a smaller space? It’s anybody’s
guess. But if there’s one thing for certain, it’s that integrated
circuits will continue to serve as the little masterminds behind all
of our electronic devices.

How the integrated circuit works

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