CVD-grown amorphous SiC_xO_y-Si heterojunction: A unique Schottky diode

Silicon oxycarbide (SiC_xO_y), commonly used as low-κ inter layer dielectric in technological

applications, is limited in performance due to dielectric breakdown in the presence of defect

states. In this work, chemical vapour deposition technique has been used to fabricate carbon

rich  SiC_xO_y-n-silicon heterojunction using liquid polycarbosilane as precursor. The resulting

devices showed Schottky diode like behaviour with current rectification value as high as 28k

at ±5V. Localised defect states originating from free residual carbon in the deposited films,

arising between valance band maxima and Fermi level of the oxycarbide, were found to be

responsible for the Schottky diode nature of the fabricated devices. A comprehensive band

diagram of the heterojunction, alongside an insight of carrier transport process, is presented

based on valance band edge spectroscopy. The devices showed excellent performance

stability and robustness against hard breakdown even at 200V of applied reverse bias for long

time. Stability and performance reproducibility of the heterojunctions were remarkably

maintained even after hundreds of rapid and successive voltage sweeps in ambient condition

that has long term implication in power electronics.