Fujitsu Laboratories announced the development of a new technology for high power gallium nitride (GaN) high electron-mobility transistors (HEMT), paving the way for commercialization of high power GaN HEMTs.

Gallium nitride (GaN) features strong resistance to voltage breakdown, compared to conventional semiconductor materials such as silicon (Si) or gallium arsenide (GaAs).

The new technology enables the transistors to operate even at the high temperature of 200 degrees Celsius for more than one million hours, equivalent to over 100 years, under pinch-off condition with a drain voltage of 50 volts (50V), thereby enabling the world’s longest lifecycle for GaN HEMTs. Fujitsu will strive toward applying GaN HEMTs using this new technology for the high-speed wireless communications market, such as for satellite communication (VSATs), cellular base stations, WiMAX base stations, and other high-speed wireless communications infrastructure. GaN HEMTs are promising as devices to realize lower power consumption for high power amplifiers in next-generation high-speed wireless communication systems.

Details of the new technology were presented at the 2007 IEEE MTT-S International Microwave Symposium (IMS).

In long-term reliability testing, Fujitsu analyzed and discovered that in GaN HEMTs a correlation exists between gate leakage current and reliability. Furthermore, Fujitsu observed that the increase in gate leakage current depends on the quality of crystal and the structure of GaN HEMTs. Fujitsu improved crystal quality and optimized the layer structure to mitigate the electric field in a gallium-nitride HEMT structure with few surface traps by using its proprietary n-type GaN cap layer (surface layer).