This paper reports the results of degradation tests performed at Vgs = -5V and increasing Vds levels on GaN HEMTs with different gate materials: Ni/Au/Ni, ITO and Ni/ITO. At each step we measured the electrical and optical characteristics of the transistors to analyze the degradation process. We found that (i) stress induces a permanent degradation of the gate diode, consisting in an increase in the leakage current; (ii) this change is due to the generation of parasitic conductive paths, as the electroluminescence maps suggest; (iii) devices based on Indium Tin Oxide showed higher reliability. These data strongly support the hypothesis that the robustness is influenced by processing parameters, since all analyzed devices come from the same epitaxial wafer.
Gate material - dependent degradation of reverse biased GaN HEMTs
DE SANTI, CARLO;MENEGHINI, MATTEO;MENEGHESSO, GAUDENZIO;ZANONI, ENRICO
2011
Abstract
This paper reports the results of degradation tests performed at Vgs = -5V and increasing Vds levels on GaN HEMTs with different gate materials: Ni/Au/Ni, ITO and Ni/ITO. At each step we measured the electrical and optical characteristics of the transistors to analyze the degradation process. We found that (i) stress induces a permanent degradation of the gate diode, consisting in an increase in the leakage current; (ii) this change is due to the generation of parasitic conductive paths, as the electroluminescence maps suggest; (iii) devices based on Indium Tin Oxide showed higher reliability. These data strongly support the hypothesis that the robustness is influenced by processing parameters, since all analyzed devices come from the same epitaxial wafer.Pubblicazioni consigliate
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