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Purified Silicon Makes Bigger, Faster Quantum Computers
- analog31 2y agoI remember learning that germanium can be highly purified, so I looked up its itsotopes. What a mess, 5 isotopes with three prominent ones. https://en.wikipedia.org/wiki/Isotopes_of_germanium https://en.wikipedia.org/wiki/Isotopes_of_germanium
- andrewflnr 2y agoHow do they get this beam of pure Si-28 though? Do they just end up having to centrifuge a smaller amount, or can they do some sort of mass spectrometry trick?
- generuso 2y agoThe article refers to a prior work where an ion implanter used mass-spectrometry to prepare an isotopically pure beam. I think it is common for ion implanters to have a mass filter to keep various impurities out. The mentioned in the article silicon-based kilogram standard used centrifuge-enriched material. I think it was bought from some boutique isotope separation company.
- fuzzfactor 2y agoThis reminds me about one time when I was buying surplus equipment there was an ion milling machine in mint condition and it went for $100 to the only scientist who had a lab to put it in and wanted to move the very heavy base unit.
- hinkley 2y agoI could have sworn I read that Intel was already using depleted silicon more than a decade ago and they made it sound like it was a standard for high frequency chips. Is that wrong? I’m getting a sense the article is playing fast and loose with the state of the state/art to aggrandize their accomplishments. I distrust the author.
- wtallis 2y agoDepletion in the context of semiconductors isn't referring to isotopes (in the manner of depleted uranium) but rather to charge carrier depletion in a region of silicon. Technologies like Fully-Depleted Silicon on Insulator (FD-SOI) are mainstream for some kinds of chips (eg. radios).
- hinkley 2y agoNo, I’m talking about isotope removal, but I can’t find anything now because all results point to the above article or similar ones. If memory serves it had something to do with the isotopes changing the stresses in the crystal lattice and affecting the behavior.
- raziel2701 2y agoThis is not scalable at all. It's too fragile, the area purified is tiny and rough. A classic academic solution that can only happen in the lab.
- ooterness 2y agoHow much overlap is there between isotope separation technology? The article mentions using centrifuges to separate silicon-28 from -29. Could the same equipment be used to separate uranium-235 from -238? Is this a question of difficulty? Of scale? Or does Intel become a nuclear proliferation risk?
- justinclift 2y agoThe researchers managed to produce samples with fewer than 3 parts per million of ^29Si—some 1/10,000 less ^29Si impurities than what exists in natural silicon. Is 1/10000th less correct? That doesn't sound like a worthwhile figure?
- wtallis 2y agoThe article is definitely describing the change in a confusing way, but it mentions earlier that the starting point of naturally-occurring silicon is 4.5% Si-29, so getting that down to 3ppm is a reduction by a factor of 15,000.
- justinclift 2y agoThanks, reducing it by a factor of 15k sounds worthwhile. :)