Increasing the power-added efficiency of GaN-based HEMTs

The team’s AlGaN/GaN HEMTs produce a power-added efficiency of just over 85 percent at 2.45 GHz, beating the previous record, also held by Fujitsu, of 82.8 percent.

According to the team, the increase in efficiency results from improved crystal quality of the GaN channel and mitigation of effects of residual silicon at the interface between the substrate and the epitaxial layers.

For both generations of record-breaking HEMTs, Fujitsu’s engineers have grown epilayers on native substrates – and for the latest devices, this has involved a 4-inch foundation.