Fujitsu unveils longest-lasting GaN HEMTs
Fujitsu has made GaN HEMTs that will operate for 100 years at 200°C, opening the way for the devices to be used in increasingly demanding applications.
Results presented at the 2007 IEEE MTT-S International Microwave Symposium in Hawaii claim the devices are "the most reliable in the world".
The Japanese IT and communications company is the first to achieve the million-hour record with a 50 V drain voltage by pinch-off testing, the most severe reliability test.
Fujitsu says planned applications for its ultra-reliable HEMTs include satellite communications, cellular base stations and WiMAX, and other wireless technologies.
Delivery of the reliability record hinged upon Fujitsu s investigations of the link between gate leakage current and reliability, and the relationship between the gate leakage current, crystal quality and device structure.
Researchers grew a device with an optimized structure, using Fujitsu s proprietary n-type GaN cap layer, and higher-quality materials.
The HEMT was consequently less affected by the fields from current leakage, and testing it at 300 deg C gave the impressive extrapolated reliability data.
"In order for GaN HEMTs to be used as a high-power, high-voltage endurance devices," explained a Fujitsu spokesman, "they must maintain high reliability "“ a long lifespan "“ as it is anticipated that they must withstand harsh usage conditions, including high temperatures and high drain voltages."
