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The Vacuum Transistor: A Device Made of Nothing

spectrum.ieee.org

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Re: The Vacuum Transistor: A Device Made of Nothing

#21

Post by jerf »

Kapura wrote: post #17

I'm no scientographer, but it seems to me that a dependence on helium may be a stumbling point for getting cheap vacuum transistors to the market. The ongoing helium shortage[1] is driving the price of helium up which could make helium-based vacuum transistors expensive, limiting widespread adoption. It could be that high-speed helium vacuum transistors become a speciality product for those projects that feel the nee…

Well, let's see, a modern chips die size is on the order of 300mm^2. Let's be generous (I think) and call it 5mm thick. A single helium canister can contain around 300 cubic feet of helium [1]. Those are nasty units to work with by hand, but https://www.google.com/search?q=%28300+cubic+feet%29+%2F+%28... suggests one such cylinder would be enough for 5.5 million new chips, assuming the entire chip was just helium. You can probably safely add at least two more entire factors of magnitude for the fact the chip will still mostly be silicon (or something), my gut suggests 3 or 4 is probably even closer.

Oh, sure, there will be losses and such, but this is still a trivial expense next to the billions of dollars of fab work that will be required. In these quantities we literally use gold without hardly a second thought for price.

[1]: http://www.praxairdirect.com/Product2_10152_10051_14626_-1_1...

Re: The Vacuum Transistor: A Device Made of Nothing

#22

Post by flogic »

Kapura wrote: post #17

I'm no scientographer, but it seems to me that a dependence on helium may be a stumbling point for getting cheap vacuum transistors to the market. The ongoing helium shortage[1] is driving the price of helium up which could make helium-based vacuum transistors expensive, limiting widespread adoption. It could be that high-speed helium vacuum transistors become a speciality product for those projects that feel the nee…

According to the article, if the device is small enough it doesn't require helium or a vacuum.

Re: The Vacuum Transistor: A Device Made of Nothing

#23

Post by reitzensteinm »

Kapura wrote: post #17

I'm no scientographer, but it seems to me that a dependence on helium may be a stumbling point for getting cheap vacuum transistors to the market. The ongoing helium shortage[1] is driving the price of helium up which could make helium-based vacuum transistors expensive, limiting widespread adoption. It could be that high-speed helium vacuum transistors become a speciality product for those projects that feel the nee…

Intuitively, this makes sense at human scales.

But microprocessors are tiny. The i7 4770, which is in my machine right now, has a die size of 177mm^2. The die has a thickness of 775um, for a volume of ~137mm^3.

Even if you made the whole processor out of helium, you could make 100,000 of them out of a single 14 liter party balloon.

The Zeppelin NT, which holds 8225m^3 of helium, contains enough for 60 billion high end processors.

Re: The Vacuum Transistor: A Device Made of Nothing

#24

Post by jpeg_hero »

Kapura wrote: post #17

I'm no scientographer, but it seems to me that a dependence on helium may be a stumbling point for getting cheap vacuum transistors to the market. The ongoing helium shortage[1] is driving the price of helium up which could make helium-based vacuum transistors expensive, limiting widespread adoption. It could be that high-speed helium vacuum transistors become a speciality product for those projects that feel the nee…

> That is, you don’t, in fact, need to maintain any sort of vacuum at all for what is nominally a miniaturized piece of “vacuum” electronics!

Re: The Vacuum Transistor: A Device Made of Nothing

#25

Post by ars »

valarauca1 wrote: post #9
jpmattia wrote: post #2

I'm surprised the IEEE editors allowed the word "Introducing" in the title. Vacuum FETs are often a target of the diamond thin-film community. (Diamond has a very interesting electronegativity: Very little energy is required to get an electron out of diamond and into the "vacuum" (usually air.))

The problem is with carbon in general is it has a band gap 5x larger then Silicon. Which overall (but not entirely) means if you want to build a transistor with Diamond (or graphene) you need to put 5x as much voltage into it. The reason graphene is great for transistors is with its higher band energy its 5x harder for it to soft set itself. So if we pretend todays 11nm transistors have a 1% chance of electron tunnel…

You started by saying 5x voltage, switched to 5x power, and ended with 5x energy.

Those are not the same thing. You can have 5x voltage without changing the power or the energy.

Re: The Vacuum Transistor: A Device Made of Nothing

#26

Post by Retric »

jerf wrote: post #21
Kapura wrote: post #17

I'm no scientographer, but it seems to me that a dependence on helium may be a stumbling point for getting cheap vacuum transistors to the market. The ongoing helium shortage[1] is driving the price of helium up which could make helium-based vacuum transistors expensive, limiting widespread adoption. It could be that high-speed helium vacuum transistors become a speciality product for those projects that feel the nee…

Well, let's see, a modern chips die size is on the order of 300mm^2. Let's be generous (I think) and call it 5mm thick. A single helium canister can contain around 300 cubic feet of helium [1]. Those are nasty units to work with by hand, but https://www.google.com/search?q=%28300+cubic+feet%29+%2F+%28... suggests one such cylinder would be enough for 5.5 million new chips, assuming the entire chip was just helium. Yo…

300mm^2 * 5mm = 1.5 milliliters

24k Gold is 42$/gram, 1 gram is 0.052 milliliters.

So, 42 / .052 * 1.5 = 1,211$.

Note: The important parts are not 5mm thick etc, but gold is rather expensive by volume.

Re: The Vacuum Transistor: A Device Made of Nothing

#27

Post by bradyd »

flogic wrote: post #22
Kapura wrote: post #17

I'm no scientographer, but it seems to me that a dependence on helium may be a stumbling point for getting cheap vacuum transistors to the market. The ongoing helium shortage[1] is driving the price of helium up which could make helium-based vacuum transistors expensive, limiting widespread adoption. It could be that high-speed helium vacuum transistors become a speciality product for those projects that feel the nee…

According to the article, if the device is small enough it doesn't require helium or a vacuum.

"And we’ll have to devise proper packaging methods for these 1-atmosphere, helium-filled devices."

Actually it does require helium, but no vacuum.

Re: The Vacuum Transistor: A Device Made of Nothing

#28

Post by jpmattia »

zwieback wrote: post #11

Would a guitar amp built with these sound like a tube amp?

> Would a guitar amp built with these sound like a tube amp?

It would be nice, right? Most folks worry about getting vacuum electronics to simply work, so I couldn't dig up anything on the nonlinearities of a vacuum transistor amplifier. (For those who don't follow such things: The nonlinearities of guitar amps are intimately related to how it sounds. Many musicians still use tube amps because the world has become accustomed to that sound. It is the gold standard of distorted amplifiers to some of us.)

That said I'm not optimistic. A quick check of a Fender Twin Reverb schematic (http://support.fender.com/schematics/guitar_amplifiers/65_Tw...) shows that that the final amp has pentodes, different than the triode that the OP's article is talking about, and those pentodes have separated heaters for the cathode. So the temperature of the electrons coming off the cathode are going to be much hotter. (Another name for the monolithic vacuum devices used to be "cold cathode", because it acted like a thermionic emitter but without a heater.)

There's a lot that's different. Of course, the only way to know for sure is to plug it in and crank it up to 11.

Re: The Vacuum Transistor: A Device Made of Nothing

#30

Post by Terr_ »

daveslash wrote: post #19
pimlottc wrote: post #12

Regarding the opening anecdote - some have suggested the Soviets used vacuum tubes so that their planes would survive the electromagnetic pulse from a nuclear explosion.

DISCLAIMER: This is what I remember once hearing in an ECE class. I was hesitant to post this comment given that it might be garbage, but perhaps someone can help confirm or disprove this. I once heard that one of the reasons the Soviets continued to use analog systems was that they were "faster, more compact, and more power efficient" [than a digital computer]. This came at the cost of flexibility. For example, an o…

I think the #1 reason was military-logistical: Easy to manufacture lots of them from domestic factories, stockpile at airfields, and replace by hand. Some sources suggest resistance to temperature-fluctuations and EMP were also factors.
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