Trap Characterization of Microwave GaN HEMTs Based on Frequency Dispersion of the Output-Admittance

Abstract : This paper presents a characterization method of traps, based on the frequency dispersion of the output-admittance characterized by low-frequency S-parameter measurements. As RF performances of GaN HEMTs are strongly degraded by trapping effects, trap characterizations are essential for this power technology. The proposed measurement setup and extraction method allow us to derive the activation energy Ea and the capture cross section σn of the identified traps. A 0.25µm gate length InAlN/GaN HEMT was characterized. A trap was identified with an activation energy of 0.38eV, a capture cross-section of 1.73 10-16cm-2, and a field dependency of the emission rate. These results give an efficient feedback to the technology developments.