Properties of Schottky barrier diodes on heteroeptixial α - Ga 2O3 thin films

Abstract

Schottky barrier diodes on α−Ga2O3:Sn heteroepitaxial thin films grown by pulsed laser deposition on m-plane sapphire substrates are reported. Sets of co-planar diodes were fabricated with different metals and different deposition methods. The current rectification and effective Schottky barrier height of oxidized contacts realized by reactive sputtering significantly exceed the values of non-oxidized contacts realized by thermal evaporation or sputtering in an inert argon atmosphere. The best values obtained are rectification of about eight orders of magnitude (±2 V) and 1.3 eV effective barrier height. The current-voltage characteristics of selected non-oxidized and oxidized platinum diodes have been studied as a function of measurement temperature. The temperature dependence of the effective barrier height and the ideality factor of the diodes were fitted taking into account the lateral potential fluctuations of the barrier potential. The determined mean barrier heights and standard deviations are in the range of 1.76–2.53 and 0.2–0.33 eV, respectively, and are classified with respect to the literature and fulfill a well-established empirical correlation (Lajn’s rule) for a variety of Schottky barrier diodes on different semiconducting materials.