High rectifying behavior in Al/Si nanocrystal-embedded SiO_xN_y/p-Si heterojunctions

Abstract

We examine the electrical properties of MIS devices made of Al/Si nanocrystal-SiO x N y /p-Si. The J-V characteristics of the devices present a high rectifying behavior. Temperature measurements show that the forward current is thermally activated following the thermal diffusion model of carriers. At low reverse bias, the current is governed by thermal emission amplified by the Poole-Frenkel effect of carriers from defects located at the silicon nanocrystals/SiO x N y interfaces, whereas tunnel conduction in silicon oxynitride matrix dominates at high reverse bias. The devices exhibit a rectification ratio >10 4 for the current measured at V = ± 1 V. Study reveals that thermal annealing in forming gas (H 2 /N 2 ) improves the electrical properties of the devices due to the passivation of defects.