[Editors] MIT: New material could lead to faster chips

[Elizabeth Thomson]

======================================
MIT: New material could lead to faster chips
--Graphene may solve communications speed limit
======================================

For Immediate Release
MONDAY, MAR. 23, 2009

Contact: Elizabeth A. Thomson, MIT News Office
E: thomson at mit.edu, T: 617-258-5402

Photo Available

CAMBRIDGE, Mass.--New research findings at MIT could lead to  
microchips that operate at much higher speeds than is possible with  
today’s standard silicon chips, leading to cell phones and other  
communications systems that can transmit data much faster.

The key to the superfast chips is the use of a material called  
graphene, a form of pure carbon that was first identified in 2004.  
Researchers at other institutions have already used the one-atom-thick  
layer of carbon atoms to make prototype transistors and other simple  
devices, but the latest MIT results could open up a range of new  
applications.

The MIT researchers built an experimental graphene chip known as a  
frequency multiplier, meaning it is capable of taking an incoming  
electrical signal of a certain frequency — for example, the clock  
speed that determines how fast a computer chip can carry out its  
computations — and producing an output signal that is a multiple of  
that frequency. In this case, the MIT graphene chip can double the  
frequency of an electromagnetic signal.

Frequency multipliers are widely used in radio communications and  
other applications. But existing systems require multiple components,  
produce “noisy” signals that require filtering and consume large  
power, whereas the new graphene system has just a single transistor  
and produces, in a highly efficient manner, a clean output that needs  
no filtering.

The findings are being reported in a paper in the May issue of  
Electron Device Letters and were also reported last week at the  
American Physical Society meeting by Tomás Palacios, assistant  
professor in MIT’s Department of Electrical Engineering and Computer  
Science and a core member of the Microsystems Technology Laboratories.  
The work was done by Palacios along with EECS Assistant Professor Jing  
Kong and two of their students, Han Wang and Daniel Nezich.

“In electronics, we’re always trying to increase the frequency,”  
Palacios says, in order to make “faster and faster computers” and  
cellphones that can send data at higher rates, for example. “It’s very  
difficult to generate high frequencies above 4 or 5 gigahertz,” he  
says, but the new graphene technology could lead to practical systems  
in the 500 to 1,000 gigahertz range.

“Researchers have been trying to find uses for this material since its  
discovery in 2004,” he says. “I believe this application will have  
tremendous implications in high-frequency communications and  
electronics.” By running several of the frequency-doubling chips in  
series, it should be possible to attain frequencies many times higher  
than are now feasible.

While the work is still at the laboratory stage, Palacios says,  
because it is mostly based on relatively standard chip processing  
technology he thinks developing it to a stage that could become a  
commercial product “may take a year of work, maximum two.” This  
project is currently being partially funded by the MIT Institute for  
Soldier Nanotechnology and by the Interconnect Focus Center program,  
and it has already attracted the interest of “many other offices in  
the federal government and major chip-making companies,” according to  
Palacios.

Graphene is related to the better-known buckyballs and carbon  
nanotubes, which also are made of one-atom-thick sheets of carbon. But  
in those materials, the carbon sheets are rolled up in the form of a  
tube or a ball. While physicists had long speculated that flat sheets  
of the material should be theoretically possible, some had doubted  
that it could ever remain stable in the real world.

“In physics today, graphene is, arguably, the most exciting topic,”  
Palacios says. It is the strongest material ever discovered, and also  
has a number of unsurpassed electrical properties, such as “mobility”  
— the ease with which electrons can start moving in the material, key  
to use in electronics — which is 100 times that of silicon, the  
standard material of computer chips.

One key factor in enabling widespread use of graphene will be  
perfecting methods for making the material in sufficient quantity. The  
material was first identified, and most of the early work was based  
on, using “sticky tape technology,” Palacios explains. That involves  
taking a block of graphite, pressing a piece of sticky tape against  
it, peeling it off and then applying the tape to a wafer of silicon or  
other material.

But Kong has been developing a method for growing entire wafers of  
graphene directly, which could make the material practical for  
electronics. Kong and Palacios’ groups are currently working to  
transfer the frequency multipliers to these new graphene wafers.

“Graphene will play a key role in future of electronics,” Palacios  
says. “We just need to identify the right devices to take full  
advantage of its outstanding properties. Frequency multipliers could  
be one of these devices.”

--END--


Written by David Chandler, MIT News Office
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.mit.edu/pipermail/editors/attachments/20090323/bee29cf8/attachment.htm