The vacuum tube strikes back: NASA’s 460GHz vacuum tran
Feb 15, 2015 15:11:26 GMT -6
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Post by Johnkenn on Feb 15, 2015 15:11:26 GMT -6
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Way back in the salad days of digital computing (the 1940s and ’50s), computers were made of vacuum tubes — big, hot, clunky devices that, when you got right down to it, were essentially glorified light bulbs. This is why early computers like the ENIAC weighed more than 27 tons and consumed more power than a small town. Later, obviously, vacuum tubes would be replaced by probably the greatest invention of all time — the solid-state transistor — which would allow for the creation of smaller, faster, cheaper, and more reliable computers. Fast forward to 2014, though, and the humble CMOS field-effect transistor (FET) is starting to show its age. We’ve pretty much hit the limit on shrinking silicon transistors any further, and they can’t operate at speeds much faster than a few gigahertz. Which is why NASA’s Ames Research Center is going back to the future with its new vacuum transistor – a nanometer-scale vacuum tube that, in early testing, has reached speeds of up to 460GHz.
The original vacuum tube triode, the main building block of early computers, consists of three separate elements inside a glass bulb. You have a cathode in the middle, which emits electrons; a grid around the cathode; and an anode around the outside. When a voltage is applied to the grid, electrons flow freely across the vacuum from the cathode to the anode. It is functionally identical to how a modern-day solid-state transistor works (a gate that controls the flow of electricity from source to drain). The main problem, though, was that the cathode had to be heated up by a filament so that it would emit electrons — and where there’s heat, there’s a lot of power consumption and a lot wear and tear. As you may know, it wasn’t unusual for old tube-based computers to break down every few hours whenever a tube burnt out.
So, anyway, the high running costs and frustrations of operating a tube-based computer were eventually assuaged by the discovery of processes that allowed for the cheap and plentiful production of integrated circuits with solid-state MOSFETs. And, in the last 40 years or so, we haven’t looked back. Until now.
Moving forward, NASA is faced with the usual stumbling block that all new bleeding-edge technologies face: It’s built a single vacuum-channel transistor in the lab, and now it’s time to try and build large number of them on a single chip. The NASA researchers sound fairly positive about their chances — but really, until they actually get down to it, who knows what issues they might run into? In any case, add vacuum-channel transistors to the rather awesome (and rapidly growing) list of potential methods of pushing past the theoretical limits of silicon.
Way back in the salad days of digital computing (the 1940s and ’50s), computers were made of vacuum tubes — big, hot, clunky devices that, when you got right down to it, were essentially glorified light bulbs. This is why early computers like the ENIAC weighed more than 27 tons and consumed more power than a small town. Later, obviously, vacuum tubes would be replaced by probably the greatest invention of all time — the solid-state transistor — which would allow for the creation of smaller, faster, cheaper, and more reliable computers. Fast forward to 2014, though, and the humble CMOS field-effect transistor (FET) is starting to show its age. We’ve pretty much hit the limit on shrinking silicon transistors any further, and they can’t operate at speeds much faster than a few gigahertz. Which is why NASA’s Ames Research Center is going back to the future with its new vacuum transistor – a nanometer-scale vacuum tube that, in early testing, has reached speeds of up to 460GHz.
The original vacuum tube triode, the main building block of early computers, consists of three separate elements inside a glass bulb. You have a cathode in the middle, which emits electrons; a grid around the cathode; and an anode around the outside. When a voltage is applied to the grid, electrons flow freely across the vacuum from the cathode to the anode. It is functionally identical to how a modern-day solid-state transistor works (a gate that controls the flow of electricity from source to drain). The main problem, though, was that the cathode had to be heated up by a filament so that it would emit electrons — and where there’s heat, there’s a lot of power consumption and a lot wear and tear. As you may know, it wasn’t unusual for old tube-based computers to break down every few hours whenever a tube burnt out.
So, anyway, the high running costs and frustrations of operating a tube-based computer were eventually assuaged by the discovery of processes that allowed for the cheap and plentiful production of integrated circuits with solid-state MOSFETs. And, in the last 40 years or so, we haven’t looked back. Until now.
Moving forward, NASA is faced with the usual stumbling block that all new bleeding-edge technologies face: It’s built a single vacuum-channel transistor in the lab, and now it’s time to try and build large number of them on a single chip. The NASA researchers sound fairly positive about their chances — but really, until they actually get down to it, who knows what issues they might run into? In any case, add vacuum-channel transistors to the rather awesome (and rapidly growing) list of potential methods of pushing past the theoretical limits of silicon.
