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"Electronic Materials"

© H. Föll


Hyperscripts of AMAT:
General Information



What are Electronic Materials? And why should you know something about them. Lets look at these two questions in turn.
What are Electronic Materials?
Once upon a time, electronic materials where associated with things like Cu alloys for wires, Mica for high quality insulation, transformer oil, maybe glass for bulbs, and possible some tungsten for filaments. Very exciting - if you like Mica and the like.
Well, those times are long since gone (even so some text books did not seem to notice until the nineties). If you want to get an idea of what constitutes electronic materials now, think first about some typical electronic products, and then on what you will find inside. Take a screw driver (or, if necessary, a chisel, a crowbar, a bit of dynamite) and take your notebook apart.
List what you find inside in terms of electronic materials; i.e. materials that are absolutely essential for its function and that cannot be easily replaced by some other material without loss of functionality. Think about this for a minute, then activate the link to compare lists.
What you will find are a lot of very special materials with very special properties that were "invented" and developed for electronic products. This is quite different from the old days of electronic engineering, when out forbearers essentially just took what they found to produce wires, motors, generators, light bulbs, and the like.
Hey, you might say, that's not true. We all know that Edison tested thousands of materials for his light bulb; he did not just take what he could find.
OK - you are right. Up top a point. Edison (and others) certainly searched for optimum materials for whatever applications they had in mind, but this search was almost purely empirical. Product development was based on Maxwells equations (which do not contain anything profound about materials except some galactic properties like conductivity, dielectric constant or magnetic permeability), and solid common sense. Edison knew that hot objects glow - the hotter the brighter - and that you could heat a material if you pass current through it. He did not have to invent the laws of radiation first; he didn't even have to know them. This also goes for all the other great old inventors - Siemens, Tesla, Bell, Reis, .... .
But the combined genius of all these guys would not have been sufficient to come up with a transistor, a liquid crystal display, or a GaAlAs Laser. No way.
While they did come up with the vacuum tube and even some weird early semiconductor devices (the first radios were "crystal detectors", completely mysterious and not working too well), modern electronic products are mostly the result of quantum theory applied to solids, especially crystals.
Only after solid state physics was born, Bardeen, Shockley, and Brattain in 1947 could invent the transistor - on paper. Only after "the theory" was done, the first transistor shown below was made. Similar for Jack Kilby and his first integrated circuit in 1958 - although he could already be more empirical, drawing on solid semiconductor knowledge accumulated by then.
First transistor
First transistor (a metal - Ge - metal affair).
First IC
First IC (rivaled by the technologically more advanced (planar technology)
of Noyce and Moore 1958).

While the paragons of a new age shown above do not look all that convincing, they were not just some soldered-together tinker toys with the aim of "let's see what this does". They were painstakingly made to specifications based on involved solid state theory.
Since then, a veritable technical revolution took place - and it is still going on. And this revolution was based exclusively on some special electronic materials, identified and developed to breathtaking perfection not so much by trial and error, but by involved theory based on an emerging understanding of the properties of materials that we simply did not have before 1930 or so.
The foremost material in this context is Silicon, but many other semiconductors, magnetic and dielectric materials, polymers, liquid crystals, special metals, and so on, are now dedicated to electronic products.
The long and short of it: While metals and steel are still of prime importance to humankind (you would most certainly, if banned to an uninhabited island, pick a steel object as the only thing to take with you), electronic materials - and nothing else - shaped the second half of the 20th century.
Yes! Electronic materials - and not software, cars, airplanes and so on. Software comes after Si, and cars would not be so much different from what they were in the sixties if it weren't for Si. Programmers in the sixties, in principle, could easily have written windows 2000, too - it just would have made no sense whatsoever without computers to run it.
And the game is not yet over. Ask yourself why we did not make all the products you can buy now a few years ago. There was a time - not that long ago, when cellular phones, PC's, and the like did not even exist, not to mention that they were ridiculously expensive, slow and generally simple just a few years ago.
It's not that we couldn't think of it. We could not make it - for lack of suitable materials and technologies. Progress in electronic materials and the technologies to render them usable still drives the electronic revolution - and nobody knows how much longer this will go on and where it's headed to.
Why me?
By now, I have also answered the second question.
If you are studying Materials Science and Engineering - electronic materials is where the action is. No more needs to be said.
If you are an electrical engineer, you may not care about materials - maybe you care about coding and decoding signals instead. That is fine, but no electrical engineer can really claim that title without at least a faint notion of what really processes the signals. Note that the limit of what your signal processors can do is pretty much given by the limits of the materials and technologies employed in making signal processors.
Even if you are a hard-core computer scientist, who only wants to study computer science to be better able to write programs, you must know a few basics about the materials that make your professional existence possible - if you make even the faintest claim to be an educated person. And if you do not make that claim - tough luck. You are studying at an university, and rest assured that we - the university teachers - will make sure that even you will be educated.


Contrary to its title, this Hyperscript does not cover everything usually subsumed under "Electronic Materials"
There is no basic crystallography, thermodynamics, solid state theory ("free electron gas"), semiconductor physics and so on, because these topics were covered in the required lecture courses for the diploma students before they can subscribe to this course.
Here we look at what has not been covered in the preceding lectures - mainly dielectrics, magnetics, and Si technology - without repeating the basics.
If you are vaguely familiar with the topics mentioned above, you should have no problem with the contents of this Hyperscript.

Hyperscript instead of Paper.

I chose to write a Hyperscript, instead a conventional paper script, because it is more fun for me. I do not know if it is also more fun for you - but I sure hope so.
Some of my philosophy around Hyperscripts can be found in the link.
You may or may not agree, but if you want to use the Hyperscript, here are a few useful informations:
The Hyperscript consists of 5 major parallel "strings" which are:
Here you will find some basic background knowledge about subjects that should be known, but can bear to be repeated.
Backbone 1
This is the main part - it would be the "book" in a conventional format.
Backbone 2
Additional "chapters of the book" that are not in the top priority of the course, but may be used on occasions.
All those pictures, graphs, movies and other materials that would drive your book editor up the wall if you would try to include it in a conventional book.
Typical exercise questions together with typical solutions
Everything you do not have to know, but may take an interest in. This may include hard-core science or interesting recent developments in the field, but also anecdotes or historical notes.
A complete overview of what is contained in the Hyperscript can be found in the "Matrix of Modules". If you want to browse, that's where you start.
I sincerely believe that Hyperscripts will replace classical text books in years to come. But I also believe that nobody (including myself) knows at present how to produce the perfect, defect-free Hyperscript. Only time will tell. Being willing to learn, I do invite comments and suggestion for improvements. Please get in touch via e-mail:

e-mail an H. Föll