Suppression of Leakage Current of CdF2/CaF2 Resonant Tunneling Diode Structures Grown on Si(100) Substrates by Nanoarea Local Epitaxy

Abstract

CdF2/CaF2 resonant tunneling diode (RTD) structures of 100 nm diameter were fabricated in SiO2 hole arrays formed on Si(100) substrates. RTD structures were grown by molecular beam epitaxy (MBE) in SiO2 hole arrays. After the growth of the initial CaF2 layer at a substrate temperature of 120 °C, in situ annealing at 500 °C was carried out to reduce the density of defects or pinholes in the barrier layer. In the measurement of current–voltage (I–V) characteristics, negative differential resistance (NDR) was clearly demonstrated at room temperature. The peak-to-valley current ratio (PVCR) was 106. The valley current was significantly suppressed. Results obtained here strongly indicates that the RTD structures proposed in this study are promising for high-quality NDR elements compatible with Si LSI technology based on Si(100) substrates.