Hole trap, leakage current and barrier inhomogeneity in (Pt/Au)-Al0.2Ga0.8N/GaN heterostructures

International audience; In this work, we report on the electrical characteristics of Pt/Au Schottky contacts to Al0.2Ga0.8N/GaN heterostructures. Indeed, we have realized gate current-voltage I(V) and deep level transient spectroscopy (DLTS) measurements. The behavior study of series resistance RS, ideality factor n, the effective barrier height Φb and leakage current with the temperature have emphasize barrier height inhomogeneity and extended defect in the (Pt/Au)Al0.2Ga0.8N/GaN system. The abnormal behavior of all these parameters can be attributed to the presence of traps thermally activated. Using the DLTS technique, we have detected one hole trap having an activation energy of 0.28eV and a capture cross-section of 1.9 × 10-19cm2. This trap should be a threading dislocation extending from the GaN layer to the surface.