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Comment: Re:Why are we saving a law? (Score 1) 183

by MattskEE (#47307147) Attached to: How Vacuum Tubes, New Technology Might Save Moore's Law

Moore's Law has never been a law and nobody treats it as one.

It started off as an observation which happened to basically be correct. Then it became more of a roadmap, with industry using it to set technology targets and allocating R&D resources so that they can continue following Moore's "Law".

Comment: Re:That would be handy for radio astronomy too (Score 1) 183

by MattskEE (#47307057) Attached to: How Vacuum Tubes, New Technology Might Save Moore's Law

Yeah the graphene comparison is spurious, except that it's a wider audience article and graphene has been getting inexplicably large amounts of press recently.
A fair point, but I still don't excuse them for being part of the graphene press problem instead of the solution.

As for the other comparisons: what's the maximum speed of a MOSFET? You can get silicon BJTs into the hundreds of GHz, but I'm not sure about MOSFETS
Maximum published speed I've seen for a Si N-MOSFET is around 450GHz at 32nm, not sure of the best reference but here is a non-peer-reviewed one I quickly dug up: http://www.intel.co.kr/content... obviously as this is silicon the voltages are extremely low so it can't do much in the way of power but people have made circuits in the 100GHz range

And as for advantages over Group III-V transistors: it works with silicon which is less faffy to work with than GaAs for example.
GaAs is still in play because it's the most mature III-V technology and is capable but application space is being taken over by Si, GaN, and InP so it's not IMHO a great point of comparison. The nice thing about vacuum electronics is that it doesn't require a III-V material which may make for easier integration with CMOS, though there are groups working on III-V CMOS integration. And I don't think there's that much advantage to it being on Silicon, most wafer fab tools can handle a variety of wafer types, the processes are not so different, plus GaN-on-silicon is being produced though it still isn't quite as good as GaN-on-SiC for example.

The full article doesn't actually make a bunch of wild-ass claims and is pretty good. They're not making lots of OMG YOAR NEXT COMPUTAR SI TEH VALVES!!11 claims.
The description of the technology is well-written. But I can make any technology look good by simply not comparing it against the best of its competitors, and outright mis-reporting the capabilities of the technologies I do compare it to. Just because they're not as bad as,many "2D" device papers out there doesn't mean they should get a pass for being deliberately misleading.

Comment: Re:That would be handy for radio astronomy too (Score 1) 183

by MattskEE (#47306795) Attached to: How Vacuum Tubes, New Technology Might Save Moore's Law

1 atmosphere of helium needs to be sealed from air, but mechanically is simpler because of the lower pressure difference.

That's not how partial pressures work at all. It only matters about the relative pressure of each individual gas if you don't want it leaking in. If you want to keep out nitrogen and oxygen it makes no difference if the package has 1atm of helium only or a vacuum.

Comment: Re:That would be handy for radio astronomy too (Score 4, Interesting) 183

by MattskEE (#47304395) Attached to: How Vacuum Tubes, New Technology Might Save Moore's Law

I just noticed another disingenuous aspect to their claim - they say that because this operates at "atmospheric" pressure it will be more reliable than vacuum tubes of yore.

But these vacuum FETs are filled with 1 atmosphere of helium, so the partial pressure difference with the outside world for all other gases will still be the same as though it was operating with a full vacuum, and this device would require the same long-term hermetic packaging as a vacuum tube. It relies on helium to extend the mean free path of the electrons, though to be fair as dimensions are scaled down further from the current 100nm to say 20nm perhaps neither helium nor vacuum would be required. Still it seems to be a very misleading claim.

Comment: Re:That would be handy for radio astronomy too (Score 1) 183

by MattskEE (#47304369) Attached to: How Vacuum Tubes, New Technology Might Save Moore's Law

Vacuum micro/nano-electronics are interesting for RF/mm-wave applications as the transport can be ballistic which could theoretically enable ultra-high-frequencies with scaling of the size.

I haven't yet found a paper for the 460GHz claim in the IEEE Spectrum article so I'm not sure exactly which figure of merit they have picked for that claim, but rest assured that their comparisons to other transistor technologies are highly flawed.

InP devices for example already operate up to 1THz power gain cutoff frequencies and have for some years. Simple circuits including amplifiers have been demonstrated in the 600GHz range with both InP HBTs and HEMTs. Even silicon certainly operates in the multi-hundred-GHz range, not the 40GHz which is for some reason cited in the article. Using graphene as a point of comparison is somewhat laughable as graphene has yet to demonstrate any truly practical advantage over group-IV or III-V transistor technologies, and has never been close to beating other leading device technologies on clock speed despite heavy press coverage.

Comment: Re:The world... (Score 1) 236

by MattskEE (#47233409) Attached to: Are the Glory Days of Analog Engineering Over?

Even though shot noise comes about due to the quantized nature of electrons flowing over a barrier it is not treated at the circuit level as a quantized phenomenon, just as a white noise source like thermal noise.

This is unlike "telegraph" or "popcorn" noise which appears at the circuit level as a definitively quantized noise source.

Comment: Re:Lead is mentioned some 16 times (Score 2) 93

by MattskEE (#47133287) Attached to: How LEDs Are Made

The lead frames are not typically made with any lead, it is just a case of easily confused homonyms.

In "lead frames", "lead" refers to the metal pins coming out of the packages, which are connected to the LED die. It not typically made with any lead content (Pb, element 82) due to RoHS restrictions. It could be made of tin-plated copper, or various alloys of tin, copper, and silver. Older ones would likely have been Pb-plated copper.

Comment: Re:Good. (Score 1) 157

by MattskEE (#46849821) Attached to: Lucasfilm Announces Break With <em>Star Wars</em> Expanded Universe

Yup, I stopped reading the expanded universe during the New Jedi Order series. It's been many years since I read a NJO series book but it seemed like they were all filled with war and unhappiness. Bad stuff happened in other books too but it didn't seem hopeless and the other books/trilogies/series generally had a happy ending of some sort.

Comment: Re:And so this is Costco's fault? (Score 2) 440

by MattskEE (#46618149) Attached to: Million Jars of Peanut Butter Dumped In New Mexico Landfill

A bit of salt makes most foods taste better (in the opinion of most people) and adding salt is in no way a scam.

I personally have a strong taste preference for the natural style peanut butters which have just peanuts and salt, but I have been disappointed whenever I have tried an unsalted nut butter.

Comment: Re:RFID? (Score 1) 130

by MattskEE (#46401919) Attached to: Ask Slashdot: Automatically Logging Non-Computerized Equipment Use?

At my uni some labs rely on a RFID badge system for charging for the access, others rely on a logsheet. Access is basically always restricted to authorized users by RFID badge.

The logsheet works well if a lab has proper oversight, most labs I've seen that run like this have a fully booked reservation calendar anyway so they know pretty well who is using it at any time. People who don't show up for reserved time or don't log time properly get in trouble and may have access restricted or revoked if the problem continues.

No matter the system you basically need to have "boots on the ground", i.e. somebody in charge of the equipment who is in the lab pretty regularly and makes sure that people show up for their reservations, makes sure they stay logged in with their swipe card or fill out the logbook properly, and makes sure they use the equipment properly and safely.

This is mainly a people problem, not a technical problem.

Comment: Re:Penny wise and pound foolish? (Score 1) 130

by MattskEE (#46401729) Attached to: Ask Slashdot: Automatically Logging Non-Computerized Equipment Use?

I don't think you fully understand how this type of setup works in a University - this type of billing setup is common in the labs and departmental machine shops at my uni. It's important to keep in mind that even within a department there are a number of fairly independent faculty members and their research groups who win grants to do their work and buy equipment with this grant money for their labs, and then there may be multiple departments within a single building. Overhead charged to research grants helps pay for the building maintenance and department staff but usually doesn't generally pay for any upkeep of equipment, supplies, or staffing of any of the research labs.

If a professor lets other people use his equipment without paying for it then lots of people will want to use it (because it's free) and it can become a money sink where the professor who owns the equipment is paying for all supplies and upkeep but he can't enforce oversight of the equipment because there's no cost recovery to pay for a tech or grad student to maintain the tool, train new users, and watch over usage. Since there's no oversight parts will get misplaced, people will mistreat it and damage the tool. I've seen it happen. So they need to charge other users something, to fairly allocate cost it might as well be hourly.

If there is a group of professors who all benefit from each others' labs then they can share access equally, and each professor is responsible for the cost of maintaining and staffing their lab, much like a network peering arrangement. But if it's a very one-sided sharing then charging for access makes a lot of sense, otherwise one professor ends up subsidizing the others.

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