Improved electrical parameters of vacuum annealed Ni/4H-SiC (0 0 0 1) Schottky barrier diode

Abstract

The reported work has been focused on the improvement of electrical parameters of Schottky diode using vacuum annealing at mild temperature in Ar gas ambient. Nickel Schottky barrier diodes were fabricated on 50 μm epitaxial layer of n-type 4H-SiC (0 0 0 1) substrate. The values of leakage current, Schottky barrier height ( ϕ B ), ideality factor ( η) and density of interface states ( N SS ) were obtained from experimentally measured current–voltage ( I– V) and capacitance–voltage ( C– V) characteristics before and after vacuum annealing treatment. The data revealed that ϕ B , η and reverse leakage current for the as-processed diodes are 1.25 eV, 1.6 and 1.2 nA (at −100 V), respectively, while for vacuum annealed diodes these parameters are 1.36 eV, 1.3 and 900 pA (at same reverse voltage). Improved characteristics have been resulted under the influence of vacuum annealing because of lesser number of minority carrier generation due to incessant reduction of number of available discrete energy levels in the bandgap of 4H-SiC substrate and lesser number of interface states density at Ni/4H-SiC (0 0 0 1) interface.