At the International Electron Devices Meeting (IEDM) held recently in Washington, DC, Cree, Inc., announced that it has demonstrated record setting radio frequency (RF) continuous wave (CW) power performance from a gallium nitride (GaN) High Electron Mobility Transistor (HEMT). The GaN HEMT device achieved 108 Watts of CW RF output power at 2 GHz. This is 3.7 times higher than has been publicly reported for a single GaN device operating under CW conditions. The peak drain efficiency for this device was 54%.
Cree's GaN HEMT device was grown on a semi-insulating SiC substrate, which has a thermal conductivity about 10 times higher than that of sapphire. This allows the GaN HEMT to more easily dissipate the very high power levels achieved in these devices in CW operation, as evidenced by the 4.5 W/mm obtained on this 24 mm gate width device.
In the same presentation, Cree also reported it has demonstrated a record 12.1 W/mm of pulsed power density in smaller GaN devices measured at 3.5 GHz. The power density for these devices under CW operation was 9.3 W/mm.
John Palmour, Cree's Director of Advanced Devices commented, �We believe these results demonstrate the overwhelming advantage allowed by our GaN on SiC substrate technology. The severe thermal limitations of sapphire substrates make high power CW operation very challenging. The demonstration of power levels over 100 W under CW conditions is a major step forward for this technology. However, more research is required to address the issues of reliability and repeatability for GaN RF devices.�
The work on these GaN discrete devices was funded by Cree and the Air Force Research Laboratories. The GaN devices under development at Cree are being targeted for high frequency (2-35 GHz) commercial broadband communications, as well as military radar and communications applications.
North Carolina-based Cree, Inc. develops and manufactures semiconductor materials and devices based on silicon carbide (SiC), gallium nitride (GaN) and related compounds. The company's products include blue, green and UV LEDs, RF power transistors for use in wireless infrastructure applications, Schottky diodes for power conditioning and switching, SiC crystals used in the production of unique gemstones and SiC wafers sold for use in production and in research and development. Cree has new product initiatives based on its expertise in SiC and GaN-based semiconductors, including blue laser diodes for optical storage applications, high frequency microwave devices for radar and communications systems.
For more information on Cree, visit www.cree.com.