Tubes In Chips ?

"The main advantage new nanoscale vacuum tubes have over semiconductor-based transistors is that they carry currents through air"

okay.

I have a horrible memory for time, but I can distinctly remember sitting in the lounge at the library at Worcester Polytechnic Institute reading an article with more or less that headline.

The place puts the time in the late 1980's -- I was there from 1986 to

1990.

At that time they were trying to make cold-cathode triodes by machining Really Pointy cathodes out of silicon. I'm not sure how these people hope to get their high electric field, or how they propose to keep the occasional silicon atom from getting ripped off of the cathode along with the electrons.

Vacuum tubes on silicon are, I think, yet another one of those always- pending major advances.

--

Tim Wescott 
Wescott Design Services 
http://www.wescottdesign.com 

I'm looking for work -- see my website!

Did you also read about ovonics ? They tried to make transistors out of it but for some reason they weren't good enough to compete with the bipolars. I read about it in the 1980s.

Back then they said it had the potential for applications like solar cells. There is a wiki on it that gave me a bit more, they started on it in the 1

960s. And part of the technology is used in solar cells. It is also used in some rechargeable batteries, enough so that GM found it useful to but the company that held the patents.

It doesn't surprise me you read about these tubes a long time ago. Though t he article didn't dwell on it, it appears this is just another building on past work.

I have been saying for a long time that nothing has been invented for a ver y long time. It is all just refinement. And not too long ago Ir ead that wh en Bell Labs invented the transistor they were trying to make an FET but th at didn't work out. Later, FETs became viable in the market to the point wh ere they are actually preferred for many applications. And all the differen t types, just how different are they ? What is an IGBT ? Two devices in one package as far as I can see. About the simplest IC around.

It has been surprising really. Electric cars in the early 1900s, I mean lik e 1901. Automatic transmissions with lockup torque converters. Disc brakes was either Tucker or Cord I think.

I'll have to get some scans of the really old books I have and Dropbox them up. Might be interesting.

FYI, AFAIK all basic devices are patterned, most quite intricately so. So, in that sense, pretty much everything with silicon inside, is an "IC"!

Even something seemingly basic, like the schottky diode. SiC schottky diodes would've never been realized, if they were limited to the fundamentals -- a schottky (rectifying metal-semi) junction and nothing else. The breakdown voltage of such a structure, in SiC, I think is something like 200V -- a rather useless achievement for using a whole freaking other material. Si PN diodes are quite reasonable at that rating, and Si "schottky" are available up to 300V now. (Quotes, because they're a whole lot more than just the schottky junction, to achieve that kind of breakdown rating!)

To achieve the 1200V+ ratings they get out of SiC schottky, they do all the same tricks, but optimized for a higher voltage material.

So even something as seemingly basic as a diode, utilizes intricate patterning, vertical trench cutting, diffusion, epitaxy, etc...

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: http://seventransistorlabs.com

They might have it under control this time, because the resonant structures are lumpy shaped, and metallic. Who knows?

The requirement of radiation (not necessarily visible light, but at least IR I guess) is peculiar, and probably wouldn't be all that helpful. (What's the quantum yield on that?) I suppose you could fabricate the thing with a facing IR LED. And, hey, if you watch it with an IR-sensitive camera, it would look like a heater, wouldn't it? ;-)

Looking forward to any evaluations of longevity...

Hm, correlation detectors would surely be the first to apply this. You can gate the optical input with the grid voltage, then bounce the freed electrons into a secondary emission cascade or something.

Tim

--
Seven Transistor Labs, LLC 
Electrical Engineering Consultation and Contract Design 
Website: http://seventransistorlabs.com

I'm not sure; that laser is labeled (in the illustration) UV. So, it has the potential of really evolving charge from a cathode, without heating, and without fragile pointy structures.

The whole point of nano-scale field emission structures is that they can be small and pointy without being fragile.

It's been a promising idea for a few decades now. Maybe somebody has finally got it right. I'm not holding my breath.

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Bill Sloman, Sydney

** What about the FETS that were patented and improved (series of patents) by Julius Edgar Lilienfeld. US Pat 1,745,175 Jan 1930, US Pat 1,877,140 Sep 1932 and US Pat 1,900,018 Mar 1933. It had been alleged at one time that Bell / Shockley stole the technology.