Barrier inhomogeneity of schottky diode on nonpolar aln grown by physical vapor transport

Abstract

An aluminum nitride (AlN) Schottky barrier diode (SBD) was fabricated on a nonpolar AlN crystal grown on tungsten substrate by physical vapor transport. The Ni/Au-AlN SBD features a low ideality factor {n} of 3.3 and an effective Schottky barrier height (SBH) of 1.05 eV at room temperature. The ideality factor {n} decreases and the effective SBH increases at high temperatures. The temperature dependences of {n} and SBH were explained using an inhomogeneous model. A mean SBH of 2.105 eV was obtained for the Ni-AlN Schottky junction from the inhomogeneity analysis of the current-voltage characteristics. An equation in which the parameters have explicit physical meanings in thermionic emission theory is proposed to describe the current-voltage characteristics of inhomogeneous SBDs.