s you read this, two of our most advanced
fabs here at Intel are gearing up for the
commercial production of the latest
Core 2 microprocessors, code-named
Penryn, due to start rolling off the lines
before the year is up. The chips, based on
our latest 45-nanometer CMOS process technol-
ogy will have more transistors and run faster and
cooler than microprocessors fabricated with the
previous, 65-nm process generation. For compute-
intensive music, video, and gaming applications,
users will see a hefty performance increase over
the best chips they are now using.
A welcome development but hardly big news, right? After
all, the density of transistors on chips has been periodically
doubling, as predicted by Moore’s Law, for more than 40 years.
The initial Penryn chips will be either dual-core processors with
more than 400 million transistors or quad-core processors with
more than 800 million transistors. You might think these chips
don’t represent anything other than yet another checkpoint in
the inexorable march of Moore’s Law.
But you’d be wrong. The chips would not have been possible
without a major breakthrough in the way we construct a key
component of the infinitesimal transistors on those chips, called
the gate stack. The basic problem we had to overcome was that
a few years ago we ran out of atoms. Literally.
To keep on the Moore’s Law curve, we need to halve the size
of our transistors every 24 months or so. The physics dictates
that the smallest parts of those transistors have to be dimin-
ished by a factor of 0.7. But there’s one critical part of the tran-
sistor that we found we couldn’t shrink anymore. It’s the thin
layer of silicon dioxide (SiO
insulation that electrically isolates
the transistor’s gate from the channel through which current
flows when the transistor is on. That insulating layer has been
slimmed and shrunk with each new generation, about tenfold
since the mid-1990s alone. Two generations before Penryn, that
insulation had become a scant five atoms thick.
We couldn’t shave off even one more tenth of a nanometer—
a single silicon atom is 0.26 nm in diameter. More important, at
a thickness of five atoms, the insulation was already a problem,
wasting power by letting electrons rain through it. Without
a significant innovation, the semiconductor industry was in
danger of encountering the dreaded “showstopper,” the long-
awaited insurmountable problem that ends the Moore’s Law
era of periodic exponential performance gains in memories,
microprocessors, and other chips—and the very good times
that have gone with it.
The solution to this latest crisis involved thickening the