Low-leakage-current metal–insulator–semiconductor–insulator–metal photodetector on silicon with a SiO2 barrier-enhancement layer

Abstract

We show that the leakage current through a metal–semiconductor–metal photodetector can be reduced by placing a thin interfacial silicon dioxide layer between the Schottky metal and the silicon substrate. We measure a factor 5.2 reduction in leakage-current density to 18 μA/cm2 at 5 V, a weaker increase in dark current with bias, and a factor 3.5 improvement in photoresponsivity to 0.39 A/W. We do not observe any noticeable reduction in device speed using this interfacial oxide.