How Microchips Work(exclusivearchitecture.com) |
How Microchips Work(exclusivearchitecture.com) |
Silicon Oxide is almost perfectly lattice matched to silicon, but completely insulating. Which means it's incredibly easy to grow features onto polished silicon wafers because the oxidation product of the material is exactly what you need in order to build up insulating features - i.e. MOSFET junctions, capacitors and conductive paths.
But you are complety right, the oxidation properties of Si are really fortunate and ICs would have taken decades longer if it were not for that. SiO2 is really the unsung hero of the silicon age.
- SiO2 has a high bandgap and a very good insulator.
- It is quite inert to many chemical and gasses. (e.g. germanium oxide is soluble in water, which is a headache)
- It can easily be grown on stoiciometric form by oxidizing silicon and will form an abrupt interface to Si.
- The formation proceeds by diffusion of oxygen to the Si interface. This is in contrast to other metal oxides, where the metal will diffuse to the surface and create a nonstoiciometric mixture.
There is no other semiconductor that forms as good an oxide. Very few metals form insulating oxides on their surface, one notable exception is Aluminum.
Edit: The famous paper that describes the SiO2 formation kinetics was actually co-authored by Andy Grove, from intel CEO fame.
I’ve always found of fascinating that silicon was right there at the beginning of material science, and has stuck around since. Same for copper.
I don’t actually think the universe has intentions, but copper, silicon, and dogs do sometimes make me question that belief, it is just a little suspicious that our species would have such loyal friends.
> Electronic grade silicon (EG-Si): 99.9999999 pure ('nine nines pure') Thats one impurity atom in every 10.000.000 silicon atoms.
I believe that should be 1.000.000.000 (10^9 atoms) to correspond to nine nines pure. Just as one impurity atom in every 100 (10^2) atoms would be 99% (two nines) pure.
Thanks everyone for all the positive feedback - so rewarding to see! I have already made some corrections to a detail where I gave an incorrect number with the "nine-nines-purity" and it should be 1 impurity in 1.000.000.000 silicon atoms. Thanks gshubert17 for pointing that out.
I have noticed that my website is currently down with a timeout - sorry for that. I hope this is going to be resolved asap.
Cheers! MK
> Microchips – also referred to as integrated circuits – are considered to be among the greatest technological achievements of the last century. Their invention has paved the way for a digital revolution that keeps changing the world to the present day.
...
> The ENIAC computer from 1946 had over 17.000 vacuum tubes and suffered a tube failure on average every two days, which was time-consuming to troubleshoot and repair. With the invention of the transistor in 1947 by Bell Labs, the components became significantly smaller, but the transistors were still wired together individually. This reduced power consumption of those computers and their overall size, but not their wiring complexity. It was not before the invention of integrated circuits before computers became way more efficient and easier to operate and maintain.
I find it on some level hilarious that one of the fundamental breakthroughs that allowed the technological revolution pick up speed and perception-wise cross the barrier from "sophisticated machinery" to "magic" was, in some sense, proper cable management.
In larger electronic and electromechanical systems, cables and connectors ("harnessing", collectively) are still major weak points.
[1] - https://store.steampowered.com/app/1444480/Turing_Complete/
Then I realized that if the products for building roads weren't around, then we wouldn't have had those roads in the first place, and I wouldn't have been reflecting on how lucky we were to have all this stuff.
Not even mentioned yet:
- Excellent mechanical properties of the single crystal (think MEMS, or wafers that don't break all the time)
- Piezoresistive properties can be used to measure strain (also quite unique due to silicon band structure)
- Optical properties perfectly suited to detect visible light (think detectors, image sensors). Good combination of band gap and carrier lifetime to build solar cells.
Gallium Arsenide works fine. So does Indium Phosphide. etc.
Silicon was much simpler to start and then path dependence kicked in. So, we poured R&D money at silicon because it was "better" than everything else. Then, because we poured R&D money at silicon, it was "better" than everything else. Lather, rinse, repeat.
Point being, you can't delete an element from the universe and expect everything else to be the same. Silicon exists because of the physics in this universe. So do silicon based computers.