Suppression of nonideal leakage current in a-InGaZnO Schottky diode with edge termination structures

The nonideal reverse leakage current of amorphous indium-gallium-zinc-oxide (a-IGZO) Schottky barrier diode was comparatively investigated with and without the passivation layer. Based on experimental and simulation results, the underlying mechanism was revealed as the trap-assisted tunneling along the defective a-IGZO sidewall. The edge termination structures, dubbed “sidewall covering,” and “edge capping” were specifically proposed to mitigate the edge electric field and, thus, suppress the nonideal leakage current. This enables the simultaneously improved ideality factor ( n) and Schottky barrier height ( ΦB), respectively, of 1.16 and 1.13 eV, together with the noticeably enhanced breakdown voltage.