This paper presents an original characterization method of trapping phenomena in gallium nitride high electron mobility transistors (GaN HEMTs). This method is based on the frequency dispersion of the output-admittance that is characterized by low-frequency S-parameter measurements. As microwave performances of GaN HEMTs are significantly affected by trapping effects, trap characterization is essential for this power technology. The proposed measurement setup and the trap characterization method allow us to determine the activation energy Ea and the capture cross-section σnof the identified traps. Three original characterizations are presented here to investigate the particular effects of bias, ageing, and light, respectively. These measurements are illustrated through different technologies such as AlGaN/GaN and InAlN/GaN HEMTs with non-intentionally doped or carbon doped GaN buffer layers. The extracted trap signatures are intended to provide an efficient feedback to the technology developments

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This paper presents a characterization method of traps in GaN HEMTs, based on the frequency dispersion of the output-admittance characterized by low-frequency S-parameter measurements. As RF performances of GaN HEMTs are significantly affected by trapping effects, trap characterization is essential for this power technology. The proposed measurement setup and extraction method allow us to derive the activation energy E a and the capture cross section σ n 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 1.73x10 -16 cm 2 , and a field dependency of the emission rate. These results are used to give an efficient feedback to the technology developments.

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