Quantum transistors move closer

From: Brian Atkins (brian@posthuman.com)
Date: Mon Dec 08 1997 - 11:19:23 MST


Looks like they have found a way to mass produce them. Sorry for
the formatting.

Transistor Technology Takes a
                     Quantum Leap
                     by Ilan Greenberg

                     4:58am 8.Dec.97.PST
                     Isaac Newton wouldn't approve of what Sandia
                     National Laboratories is doing to the tried-and-true
                     transistor.

                     Conventional transistors are based on classical
                     physics principles, but basic science researchers
                     at Sandia Labs in Albuquerque, New Mexico,
                     recently demonstrated a new transistor that
                     makes use of quantum theory - specifically, it
                     uses a technique called quantum mechanical
                     tunneling of electrons.

                     "It's pretty hard to make high-frequency
                     transistors. This is true even after the federal
                     government has pumped millions into funding
                     university research. So considering that context,
                     we're pretty happy with our results," says Jerry
                     Simmons, head of the nanoelectronics group at
                     Sandia.

                     Called the Double Electron Layer Tunneling
                     Transistor, or DELTT, the three-terminal quantum
                     transistor is considered a breakthrough in
                     transistor design because quantum tunneling
                     leapfrogs current transistor technology in terms of
                     its extremely high speed. The transistor will be
                     capable of blistering speeds by relying on a single
                     quantum transition between two electron states,
                     something traditional transistors are unable to do.

                     Quantum tunneling can also allow the same
                     integrated circuit functions to be achieved with far
                     fewer transistors. And because the transistor only
                     needs existing nanotechnology to build its
                     atomically precise two-dimensional layers of
                     electrons - a new level of miniaturization for
                     transistors - the DELTT is expected one day to be
                     reliably manufactured in large numbers using
                     existing semiconductor production facilities, a
                     challenge long thought to be a limitation with
                     quantum transistor design. Manufacturing the
                     quantum transistor is years in the future, however.

                     "Right now it's a research device. We've only
                     demonstrated it in the past year," says Simmons.
                     "I don't want to get in there worrying about
                     production yield - it's my function to demonstrate
                     that it's worthwhile to move it into the next stage."

                     Simmons expects the device to work at room
                     temperature by the end of next year, but even then
                     it may be several more years before the
                     technology is ready for production. "A real chip
                     needs a million working transistors, and thus
                     extremely high yields. We're on our way, but there
                     still are obstacles to commercialization, and I
                     can't say when it will actually be manufactured,"
                     he says.

                     Regardless of its manufacturing timeline,
                     transistor researchers who have examined the
                     fundamental research behind the chip say Sandia
                     has produced a major advance in electronic
                     design.

                     "This is a premier piece of research," says Paul
                     Berger, associate professor of electrical and
                     computer engineering at the University of
                     Delaware. "I've seen some of these things before,
                     but nothing with this kind of complexity and
                     sophistication. We're going to have to look for
                     alternative ways of computation, and this quantum
                     transistor is certainly noteworthy and needs to be
                     addressed."

                     Future applications for the quantum transistor
                     include cellular phones and eventually desktop
                     CPUs, Simmons says. Ultimately, Simmons
                     hopes the transistor will find itself in three broad
                     categories of devices: ultra-low-power static
                     memory elements, which will require exceptionally
                     low currents; ultra-high-speed logical processing
                     elements, which will require very small feature
                     sizes and somewhat higher currents; and
                     far-infrared detectors.

                     Sandia's interest in transistor design is one part of
                     the government laboratory's larger charter, which
                     is to assure the safety, security, and reliability of
                     nuclear weapons. As part of this mission, the
                     7,500-person lab also conducts research into
                     basic science. While at some point the quantum
                     transistor is likely to find itself attached to a
                     nuclear warhead, the national defense laboratories
                     are also increasingly participating in technology
                     transfer programs with civilian industries.

                     The Sandia team will present their research
                     advance at the International Electronic Devices
                     Meeting in Washington, DC, on Monday, and will
                     publish various aspects of their research in the
                     upcoming issue of the journal Applied Physics
                     Letters.

-- 
The future has arrived; it's just not evenly distributed.
                                                       -William Gibson
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