IBM Develops Transistor Capable of 210GHz

Homer Simpson writes: "IBM will announce on Monday that it has developed the world's fastest silicon transistor. They claim to have refined their silicon-germanium chip-manufacturing technology to produce transistors that are far thinner than existing ones. This will allow information to travel faster while using a lot less power. The new transistor can operate at 210Ghz (yikes!) using a measly milliamp of electrical current (80% faster than todays technology while using half the power)." Reader Geheimnis points out an announcement on IBM's site about this as well.

Comments

That's bandwidth, not clock speed

[overshoot]

At the speeds these little sweeties work, there is no such thing as digital. (Actually, there's no such thing as digital, period, but at low speeds you can squint and pretend.) The 210 GHz number is what's called the Ft (that's f-sub-tau) or unity-gain crossover frequency. At 210, the device takes as much power in as out, so an amplifier chain loses everything above that.

In practice, you need quite a bit more than unity gain. So you operate the thing down in the 50 GHz region as a front-end amplifier and demultiplexer for OC-768 fiber interfaces, which are currently ruled by indium-phosphide devices. IBM is the only outfit with a SiGe process that plays in this game. The advantage isn't in running the whole bag at outrageous frequencies, it's in running the front-end and back-end at the high rate and being able to put low-power, low-speed CMOS (low-speed=3.125 GHz or so) on the same chip.

HTH.

Engineer-to-English translation

[frankie]

Caveat Lector: I am not a chip designer; this is probably wrong. But if overshoot won't explain himself, someone else ought to try.

At the speeds these little sweeties work, there is no such thing as digital.

Transistors don't really send 1s and 0s, they allow current to pass through (or not). As you flip them on and off more quickly, things that used to look like square waves (digital) begin to show their sine wave (analog) roots.

unity-gain crossover frequency. At 210, the device takes as much power in as out

If I'm reading this correctly, F_tau seems to indicate how fast you can "overclock" an individual transistor and still get a usable signal out of it.

In practice, you need quite a bit more than unity gain. So you operate the thing down in the 50 GHz region

Since real-world chips contain lots of transistors in a row, you need to slow it down enough that you can get a usable signal all the way from one end to the other.

front-end amplifier and demultiplexer for OC-768 fiber interfaces, which are currently ruled by indium-phosphide devices.

OC-768 is a honking large optical backbone. It runs a whole lot of frequencies all at once (multiplex). In order to convert it back to something like plain-old-ethernet, you need to split the signal up again.

Indium-Phosphide is just a different compound to make chips from, like Silicon-Germanium, or Gallium-Arsenide. Apparently InP is the current industry standard for demulitplexers.

IBM is the only outfit with a SiGe process that plays in this game.

By now the rest should make more sense. Assuming I didn't totally screw up. Overshoot?

Where is it all going today?

[ackthpt]

Faster transistors, denser chips, lower power, more logic, but to do what? Run WinXP? It would be remarkable to see a headline more like this:

Microsoft Announces Tighter, Faster Code For New OS Product
We've removed 50,000,000 lines of unnecessary code, says Gates, boots up much faster, uses less memory and far more stable, thanks to only focusing on needed code. Converting portions of Office from PL/1 and Cobol also noted as helpful...

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