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trollied

Well, this chap managed to make his own chips at home: http://sam.zeloof.xyz/category/semiconductor/

Plus an electron microscope!

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Sam is super impressive, but to be fair he bought premade wafers and bought a used SEM.

Jeri Ellsworth has gone "deeper" into the process and made a few transistors, although at a much larger scale:

https://www.youtube.com/watch?v=w_znRopGtbE

https://www.youtube.com/watch?v=-Qph8BNrnLY

To me this is far more impressive than any of the other stuff posted here. It's actually doing it rather than talking about it or faking the first 99.9% of it.

Did he do his own etching? I'd say buying blank wafers would be a perfectly reasonable place to start, but if you're buying printed wafers, then you might as well buy the whole chip.

Yeah, I don't think people will be pulling pure silicon crystals at home any time soon.

That’s actually quite doable in a garage, assuming you are satisfied with, say, two inch wafers. (Currently, they are approaching 18 inches!)

It’s much easier to produce silicon ingots than to do wafer fab, because of the currently tiny line widths.

But, it would make more sense to simply buy wafers (or epitaxial wafers).

If they do, I imagine they’d leave it at that instead of going on to make a chip.

I believe he bought them with the gates etched & fets doped, and did his own metal. Something like that.

He used wafers with premade structures on it.

No, Sam Zeloof started from blank silicon wafers and did four layers of photolithography to produce PMOS gates. He used boric acid for the boron diffusion. He sputtered an aluminum layer on top for the metal and etched it with phosphoric acid.

http://sam.zeloof.xyz/first-ic/

So he "only" did metal deposition to make the interconnects? I haven't read the story, but I was thinking that there's no way you would handle some of the toxic chemicals used for doping.

They are not really that toxic. You do have to have a chemistry background and use a fume hood and a process sink with acid neutralization capability, like you find in many chem labs.

Good dopant choices would be phosphorus oxychloride and oxidized boron nitride wafers.

As I recollect, he started with silicon wafers with an epitaxy layer. He then did the usual oxidations, diffusions, and metallization, along with all the photolithographic steps. No small feat!

Ok. I was never a process guy, but worked with some back in the day and they told me that one of their phosphorus sources was phosgene gas.

Silane, phosphene, and diborane gases are used to form epitaxial layers on silicon wafers. Those are truly dangerous gases. However, a simple wafer process using the reagents I mentioned can produce very credible ICs, if one buys the epi wafers.

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