6 ms·
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
by jpmattia 12y ago
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.))
- dang 12y agoOk, we'll at least take it out of the title here.
- deleted 12y ago[deleted]
- deleted 12y ago[deleted]
- pbhjpbhj 12y agoI don't understand - why not "introducing" - it seemed to be an introductory level article on the topic of "vacuum transistors"?
- jpmattia 12y agoI guess that was the correct interpretation and why the IEEE editors allowed it. They did mention that they did not introduce the architecture (which is what it sounded like originally) about midway through the article.
- valarauca1 12y agoThe 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 tunneling, carbon would have a 0.2%. The problem is that same switch would take 5x as much power to switch. Which means a modern 220w cpu would now need 1100watts of power :x
- jpmattia 12y ago> 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. I should have said electron affinity rather than electronegativity: You're not trying to get electrons from the valence band into the vacuum, just from the conduction band to the vacuum. Diamond actually has a negative electron affinity, which is why the vacuum electronic folks were excited about it.
- ars 12y agoYou 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.
- marcosdumay 12y agoYou can have 5x the voltage without changing the power consumption if you reduce the capacitance. If you keep the transistors at the same size, a computer working with 5x mode voltage will use 5x more power if operating at the same frequency. (But you can probably make it run faster...) That said, except for very few embedded applications, computers today operate on a voltage that's much bigger than the silicon band gap. I'm not convinced it'd be a problem.
- cfallin 12y agoActually, all else being constant, 5x voltage yields 25x power: P = CV^2 * f (multiply by activity factor if pedantic; assuming all transistors toggle every cycle here.)
- marcosdumay 12y agoAnd, of course, you are right.
- tesseract 12y agoThe silicon band gap is ~1.1V at room temperature. Mainstream modern processor core voltages are around 1.2V (maybe less for the very latest parts) and "ultra low voltage" processors operate as low as 0.7V.
- andrewflnr 12y agoEven if the technology is old, the article itself is very much an introductory one. That may be what they meant.