Fujitsu shows off a new high electron-mobility transistor (HEMT) which uses gallium nitride (GaN). The company says this transistor can work in extreme conditions, it can operate even at a temperature of 200°C for more than one million hours, which is equivalent to over 100 years.
As wireless communication data-rates continue to become increasingly faster, power consumption in base stations - such as those for mobile phones – is also increasing. GaN HEMTs are promising as devices to realize lower power consumption for high power amplifiers in next-generation high-speed wireless communication systems. However, in order for GaN HEMTs to be used as high power, high voltage-endurance devices, they must maintain high reliability - a long lifespan – as it anticipated that they must withstand harsh usage conditions, including high temperatures and high drain voltages.
In long-term reliability testing, Fujitsu analyzed and discovered that in GaN HEMTs a correlation exists between gate leakage current and reliability (Figure 1). 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)