https://spectrum.ieee.org/semiconductor ... of-nothing
Sounds interesting!
~Phil
Vacuum Transistors!
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pompeiisneaks
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Vacuum Transistors!
tUber Nerd!
Re: Vacuum Transistors!
Interesting development from the field-emission realm. It beats the earlier work on field emission triodes, both in size and complexity.
The field emission triode came out in the early days of silicon micromachining. They used micromaching to make a "forest" of atomically-sharp pointed conductive spikes on a wafer of doped silicon. The points were so sharp that modest voltages could increase the field at the points to the level which would emit electrons just from the field strength, just like the vacuum transistor scheme. Put this forest of emitting spikes in a pit in the silicon surface - which happened incidentally as the easiest way to make the spikes - and two rings of conductors around the pit, and you had a no-fooling triode. In operation, the forest was the field emission cathode, the closest ring of conductor was the grid, and the furthest ring was the plate. A vacuum above the device let you have true triode action, with the electron path be a "fountain" of electrons out of the forest traveling to the plate. The grid could effectively shut this down.
I like the new version. With only two spikes, and a MOS insulated gate, you have the best of both worlds, and a device that scales down to today's tens of nanometer size. Very nice indeed. It may also solve a big issue in CPUs and RAM - quantum leakage. Transistor features on today's silicon logic are so small that quantum tunneling effects make for leakage into the substrate that can't be easily designed out. It's a big problem, and only ad hoc means solve it to any degree. The MOS isolation of the gate in this device offers the possible advantage of a bigger barrier to quantum tunneling leakaage, I would guess.
Neat!
The field emission triode came out in the early days of silicon micromachining. They used micromaching to make a "forest" of atomically-sharp pointed conductive spikes on a wafer of doped silicon. The points were so sharp that modest voltages could increase the field at the points to the level which would emit electrons just from the field strength, just like the vacuum transistor scheme. Put this forest of emitting spikes in a pit in the silicon surface - which happened incidentally as the easiest way to make the spikes - and two rings of conductors around the pit, and you had a no-fooling triode. In operation, the forest was the field emission cathode, the closest ring of conductor was the grid, and the furthest ring was the plate. A vacuum above the device let you have true triode action, with the electron path be a "fountain" of electrons out of the forest traveling to the plate. The grid could effectively shut this down.
I like the new version. With only two spikes, and a MOS insulated gate, you have the best of both worlds, and a device that scales down to today's tens of nanometer size. Very nice indeed. It may also solve a big issue in CPUs and RAM - quantum leakage. Transistor features on today's silicon logic are so small that quantum tunneling effects make for leakage into the substrate that can't be easily designed out. It's a big problem, and only ad hoc means solve it to any degree. The MOS isolation of the gate in this device offers the possible advantage of a bigger barrier to quantum tunneling leakaage, I would guess.
Neat!
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pompeiisneaks
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Re: Vacuum Transistors!
You obviously understand the EE concepts of this a lot more than I do 
But then again I'm a I.T. Guy with some schooling in Civil Engineering, so I'm a bit shifted away from the full understanding of the electronic and physical phenomena and what that all means 
~Phil
But then again I'm a I.T. Guy with some schooling in Civil Engineering, so I'm a bit shifted away from the full understanding of the electronic and physical phenomena and what that all means ~Phil
tUber Nerd!
Re: Vacuum Transistors!
That's actually a reasonable position for you to be in. It's not necessarily an advantage to have wasted a substantial portion of your life pursuing the care and maintenance of electrons. 
It's only an advantage in certain very, very limited, or even downright strange situations.
It's only an advantage in certain very, very limited, or even downright strange situations.
Re: Vacuum Transistors!
Code: Select all
Vacuum-channel transistors could work 10 times as fast as ordinary silicon transistors and may eventually be able to operate at terahertz frequencies, which have long been beyond the reach of any solid-state device. And they are considerably more tolerant of heat and radiation. To understand why, it helps to know a bit about the construction and functioning of good old-fashioned vacuum tubes.They could become another big step forward, after the SSDs.
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SoulFetish
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Re: Vacuum Transistors!
I remember reading about development on these and competing technology like graphene and nanowire transistors.
If you're into some of this, you may be interested in the book "Field Effect Transistors: A Comprehensive Overview" and it isn't just a clever title, it's
fairly comprehensive. .
It's fascinating to read about. It's interesting enough for me to overcome some of the frustration and start teaching myself calculus and Trigonometry, so I can understand the relationships described in the literature.
There's another one called Vacuum "Vacuum Nanoelectronic Devices: Novel Electron Sources and Applications". But, unless you have a good enough knowledge of the mathematical nomenclature and shorthand to understand semiconductor physics (and I do not), it isn't worth reading.
Plus, the future of some of the technologies, such as GaN(Gallium nitride) and SiC(silicon carbide), described in the second book are compete with super-junction power mosfets and IGBTs for the same market, and haven't reached what was projected for them a few years ago.
http://semiengineering.com/what-happene ... n-and-sic/
If you're into some of this, you may be interested in the book "Field Effect Transistors: A Comprehensive Overview" and it isn't just a clever title, it's
fairly comprehensive. .
It's fascinating to read about. It's interesting enough for me to overcome some of the frustration and start teaching myself calculus and Trigonometry, so I can understand the relationships described in the literature.
There's another one called Vacuum "Vacuum Nanoelectronic Devices: Novel Electron Sources and Applications". But, unless you have a good enough knowledge of the mathematical nomenclature and shorthand to understand semiconductor physics (and I do not), it isn't worth reading.
Plus, the future of some of the technologies, such as GaN(Gallium nitride) and SiC(silicon carbide), described in the second book are compete with super-junction power mosfets and IGBTs for the same market, and haven't reached what was projected for them a few years ago.
http://semiengineering.com/what-happene ... n-and-sic/
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pompeiisneaks
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Re: Vacuum Transistors!
Cool thanks! I do have a background in math, did engineering in college, and had to take calculus for three quarters, differential equations, partial differential equations, matrix and vector analysis, and statistics and probability. The only problem is that it's twenty years rusty lol
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tUber Nerd!
Re: Vacuum Transistors!
I second that, excepting my advanced math is 44 years old. Worse yet, I found that with all that fancy math instruction, I only needed anything fancier than Ohm's law a handful of times in actual practice. 
So it's good and rusty.
I am fascinated by SiC devices. I did a lot of power electronics design, and the eternal issue was making the power devices switch fast enough and stay cool enough to not melt down. SiC fixes both of those, certainly the temperature issues.
There was a sliver of info I ran onto a few years ago on hos to make diamond-based semiconductors. Oh, I'd love to work with FETs made from doped diamonds. As I recall, the article said that unfortunately, only God can dope a diamond. Maybe that's been fixed by now.
So it's good and rusty. I am fascinated by SiC devices. I did a lot of power electronics design, and the eternal issue was making the power devices switch fast enough and stay cool enough to not melt down. SiC fixes both of those, certainly the temperature issues.
There was a sliver of info I ran onto a few years ago on hos to make diamond-based semiconductors. Oh, I'd love to work with FETs made from doped diamonds. As I recall, the article said that unfortunately, only God can dope a diamond. Maybe that's been fixed by now.
Re: Vacuum Transistors!
It would have been interesting to add it on my thesis, if I'd only knew it years ago.
My thesis was on industrial applications of cavitation technology (no, it's not only a cause of damages).
One of the applications is the formation of small diamonds from carbon powder.
That one would be another, more advanced application of the same process. Maybe they already do it that way.
You know, you cannot patent the brain.
My last exam of the specialisation in ME has been complements of numerical calculus (partial differential equations and relatives).
One of the matlab codes was the plot of the concentration of a contaminant in a river during time. I set the parameters so that in a 3D plot seemed a wavering handkerchief saying hello to the university
.
My thesis was on industrial applications of cavitation technology (no, it's not only a cause of damages).
One of the applications is the formation of small diamonds from carbon powder.
That one would be another, more advanced application of the same process. Maybe they already do it that way.
You know, you cannot patent the brain.
My last exam of the specialisation in ME has been complements of numerical calculus (partial differential equations and relatives).
One of the matlab codes was the plot of the concentration of a contaminant in a river during time. I set the parameters so that in a 3D plot seemed a wavering handkerchief saying hello to the university
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SoulFetish
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Re: Vacuum Transistors!
Semikron uses sintered IGBT using silver in high power inverters so they can handle the stress of switching without cracking in half from the extreme heat. I believe manufacturers used this technique with SiCs as well.R.G. wrote: ↑Tue Sep 26, 2017 3:15 pm I second that, excepting my advanced math is 44 years old. Worse yet, I found that with all that fancy math instruction, I only needed anything fancier than Ohm's law a handful of times in actual practice.
I am fascinated by SiC devices. I did a lot of power electronics design, and the eternal issue was making the power devices switch fast enough and stay cool enough to not melt down. SiC fixes both of those, certainly the temperature issues.
There was a sliver of info I ran onto a few years ago on hos to make diamond-based semiconductors. Oh, I'd love to work with FETs made from doped diamonds. As I recall, the article said that unfortunately, only God can dope a diamond. Maybe that's been fixed by now.
(I posted a little about this on MEF, so I won't get into it too much).
Before a few weeks ago, I don't think I don't think I had heard much about insulated gate transistor at all. But I acquired what I assumed was some sort of power module years ago along with some other electronics gear for free. I recycled most of it but held onto this (probably to see if I could use some of the parts), and completely forgot about it.
RG, as a power electronics designer, perhaps you'll appreciate this...
I found it while digging around and looking for some other stuff, and turns out, it's a 1200V/600A SKiiP inverter. I wish I knew back when I got it, what I know now. I think it cost around $10k at the time. A buddy of mine told me he thinks the 2000µF/500V MKP capacitors by themselves sold for between $200-$300 a piece. I'm not really even sure what to do with this thing.
I've been doing some research on it a bit and I found this app note from Semikron. It has some great info on switching power semiconductors if you want to check it out -
https://www.semikron.com/dl/service-sup ... h-en-2015/
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Re: Vacuum Transistors!
What to do with it? RAIL GUN!!!
I build and repair tube amps. http://amps.monkeymatic.com
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SoulFetish
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2 others liked this
Re: Vacuum Transistors!
I'll have to add that to the list.
So far, Nickb says turn it into a VFD for an all electric outboard motor, darkfenriz thinks it's a 50kW liquid cooled online bass guitar class D amplifier waiting to happen, and now I've got a potential rail gun...
How do I choose? Hell, I'm moving your rail gun Idea to the top of the list!