The latest news from academia, regulators
research labs and other things of interest
Posted: December 5, 2008
HRL Laboratories Demonstrates World's First Graphene RF Field-Effect Transistors Under DARPA's CERA Program
(Nanowerk News) HRL Laboratories, LLC, announced today it has demonstrated the world's first graphene RF field effect transistors (FETs) as part of the Carbon Electronics for RF Applications, or CERA program. The milestone is the first in the proposed 51-month, three-phase program to develop a new generation of carbon-based radio-frequency (RF) integrated circuits for ultra-high-speed, ultra-low-power applications.
The goal of the effort, sponsored by the Defense Advanced Research Projects Agency (DARPA) and under the management of the Space and Naval Warfare Systems Center (SPAWAR), is to exploit the unique qualities of graphene carbon to create components that will enable unprecedented capabilities in high-bandwidth communications, imaging, and radar systems. HRL is collaborating with a group of universities, commercial companies and the Naval Research Laboratory (NRL) on the program.
The FETs are made from epitaxially grown graphene materials with state-of-the-art, on-state current of 1180 µA/µm at a drain bias of 1 V. The transistor’s RF performance was characterized using an HP8510, yielding an extrinsic current gain cut-off frequency (ft) of 4 GHz with 2 µm gate length. A record maximum oscillation frequency (fmax) of 14 GHz is achieved at Vds = 5 V. The RF speed performance is expected to be improved as the graphene FETs are scaled to below 100 nm gate length with reduced parasitic capacitance and resistance.
While graphene FETs have been demonstrated before, most used exfoliated graphene films. "HRL, working with the NRL, demonstrated graphene FETs using epitaxial film operating in the RF frequency range,” said Jeong-sun Moon, Senior Research Scientist with the Microelectronics Laboratory at HRL. “This is a key step toward wafer-scale high-speed graphene RF FETs that operate in the RF domain."
The military’s ability to develop sophisticated imaging and communications systems is hindered by RF component cost, limited resolution, and high power dissipation. A graphene-on-Silicon platform could revolutionize a number of military applications because of its high performance, scalability, integration and low cost.
Graphene is a single layer of carbon atoms densely packed in a honeycomb crystalline lattice configuration—like chicken wire on an atomic scale. The advantages of this configuration are its high current-carrying capacity, excellent thermal conductivity and low-voltage operational potential.
Moon said the current results are very promising. "The next step will be to continue to optimize material synthesis and device processing to see if we can harness the unique properties of graphene to make a new generation, state-of-the-art technology for future high-speed, low-cost military RF systems-on-chips," he said.
In upcoming phases of the project, the HRL team will fabricate FETS on 100-mm wafers and then scale up the process to 200-mm wafers to create a demonstration prototype of the new generation of carbon-based RF integrated circuits.
About HRL Laboratories
HRL Laboratories, LLC, Malibu, California (www.hrl.com) is a corporate research-and-development laboratory owned by The Boeing Company and General Motors specializing in research into sensors and materials, information and systems sciences, applied electromagnetics, and microelectronics. HRL provides custom research and development and performs additional R&D contract services for its LLC member companies, the U.S. government, and other commercial companies.