Comparison of the performances of an InAlN/GaN HEMT with a Mo/Au gate or a Ni/Pt/Au gate

• A comparison of InAlN/GaN HEMTs with Mo/Au and Ni/Pt/Au gate contact is described.
• No meaningful variation is noticed during the analysis of DC main characteristics.
• Significant Improvements are reached by Mo/Au devices during trapping analysis.
• Pulsed measurements reveal that traps are probably located under the gate.
• Mo/Au gate stack does not affect significantly device stability in OFF state stress.

In this paper GaN based HEMT structures characterized by a 6.3 nm InAlN barrier layer and a different gate contact (Mo/Au and Ni/Pt/Au) are described. The effects of a different gate contact structure on DC and pulsed main characteristics are discussed. Despite no meaningful variation is noticed during DC analysis, pulsed evaluation demonstrates that the use of a Mo/Au gate contact leads to an improvement of trapping characteristics. Reliability performances of the devices are finally investigated by means of a OFF state three terminals step stress, proving that the use of a Mo/Au stack does not affect significantly the device stability during the stress.