Characterization of Schottky contacts on n-GaN at high temperature

The operation of Schottky contacts on n-GaN with Ni/Au, Ni/Pt/Au, Pt/Ni/Au and Pt/Ti/Au multilayers working up to 400/spl deg/C has been investigated. Electrical measurements were performed as the temperature was either increasing or decreasing. Schottky contact parameters have been extracted using the standard, Norde and Lien methods. Moreover, a non linear fitting has been developed, which together with the Lien method provides the most reliable values. All diodes worsen in their leakage currents and barrier heights as they are heated, but they recovered during the cooling. After the thermal treatment, the characteristics of Ni-based diodes improve while Pt-based diodes degrade. This behaviour is likely related to the metal-semiconductor interfaces.