Characterization and modeling of traps and RF frequency dispersion in AlGaN/AlN/GaN HEMTs

The performance of GaN transistors is still limited by physical and fabrication problems, mainly related to different kinds of traps. In this work, virgin transistors reveals strong low frequency dispersion both in the transconductance and output conductance, that we attribute to the presence of traps in the GaN channel and the ohmic contacts. These effects have been modeled in the equivalent circuit of the transistors achieving a satisfactory agreement with the measured S-parameters.