walter fry wrote:
At last something I can understand,,In the late 1960's I heard a comment
that the next great breakthrough would be three dimensional chip
architecture, at that time it was thought that heat dissipation would
become the biggest hurdle
Heat dissipation is a huge issue still.
What causes most of the slowdown in going from CPU to main memory is
the pads and PC board. On chip signals have orders of magnitude less
capacitance and so can go at least an order of magnitude faster.
One technology that is being considered is optical interconnect. That
would provide a tremendous speedup to this pathway. The technology
isn't ready yet. I don't know how long it will take to appear.
But once you have optical interconnect, it can be used on chip as
well as off chip. Recall that Herb indicated the speed limit of
current processors is basically caused by interconnect. Optical
interconnect changes that and greatly reduces the speed cost of long
distance signaling
Perhaps vertical integration is waiting for optical interconnects, which
would probably be GaAs due to higher speed than Si as well as higher
efficiencies
WF
Silicon has improved to the point where GaAs's speed advantage is
not so high.
I think vertical integration is constrained by power. The
exception is RAM, which potentially doesn't need as much.
A way to eliminate the power problem would be to switch to
a carbon substrate. Diamond is an excellent thermal conductor.
And the resulting transistors can run at much higher temperatures
without melting.
--
Allen Brown
work: Agilent Technologies non-work: http://www.peak.org/~abrown/
[EMAIL PROTECTED] [EMAIL PROTECTED]
I think I think; therefore, I think I am. ---Ambrose Bierce
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