MARK LUNDSTROM: Hello.
I'm Mark Lundstrom, and I'd like to say a few words about this course
that I'll be teaching.
This is a course on transistors, specifically on the MOSFET,
the most important type of transistor.
Now in looking at this image of the first transistor, that
was demonstrated 70 years ago, it will be
hard to predict that this would become such an important technology.
But one can make the case that the transistor was actually
the most important invention of the 20th century.
There's a fascinating story behind the invention
of the transistor and its development.
And you can find a really interesting series online to learn more about that.
Today, the smartphones that we all carry around
contain billions and billions of these devices.
So if we're looking at a cross section of a MOSFET here,
this is one that is a few years old, but it clearly shows the main points.
There's a region that is a source of electrons.
Electrons flow across the transistor, out the drain,
under the control of a third electrode we call
the gate, which controls their flow.
The first objective of this course is to understand
the physical operation of this device.
How does current flow in response to the voltages we apply to the terminals?
Now, the second objective is to relate those current voltage characteristics
to understand the transistor characteristics
and understand how they impact real circuits, digital and analog circuits.
The special part of this course really concerns the treatment
of very small transistors, modern day transistors,
making use of an understanding that developed beginning 20 years ago, when
we started doing experiments on small molecules
and understanding their current voltage characteristics.
Today, the evolution of transistor technology
has carried their dimensions to the nanoscale.
The heart of the transistor is the channel, the gap between the source
and the drain.
Today, it's about 20 nanometers long.
That's only 100 atoms or so.
The thin insulator that separates the channel from the gate electrode
is only four or five atoms thick.
So these are very small, very interesting devices.
And we'll talk about how we can understand simply
but soundly the physics of current flow in these small devices.
The course has five units.
The first is just a description of the transistor as a black box,
if we apply voltages to the terminals what currents flow
and then how those characteristics impact digital and analog circuits.
The second part of the course is a completely non-mathematical description
of the physics.
So there's a very simple way that we can understand how these devices operate
with little or no mathematics.
The third part of the course has to do with MOS electrostatics.
This is a traditional part of MOS device courses.
It first became important and began developed in the '60s,
but it continues to be important today.
The fourth unit of the course is really what's special about this course.
Here we'll use an understanding of current flow
at the nanoscale that has been developed over the past 10 or 20 years.
And we'll apply this to MOSFETS and learn
how current flows from long channel length of a micrometer down
to short channel lengths of 20 or so nanometers.
And in the fifth unit, we'll talk about a few other topics,
the limits of transistors, and some other types of transistors.
So if you take this course, you'll gain a very clear
sound physical understanding of how MOSFETS work.
If you're primarily interested in making use of transistors,
this may be all that you need.
If you're going to be developing and advancing transistor technology,
you'll want to dive deeper.
And this course provides you with a good starting point to do so.
I'll assume that you have a basic understanding
of semiconductor physics, concepts like bandgaps, affected masses, doping.
If you'd like a refresher, you can have a look at my edX
course, the primer on semi-conductors.
And finally, I'd just like to mention that this course is
one of a series of courses that we're producing at Purdue.
These are short, but not shallow courses that
are intended to provide people with the breadth
that they need to work in today's multi-disciplinary environment.
So if you're interested in learning more about transistors,
I'd invite you to join the course, and I look forward to seeing you soon.