Extremely High Peak Current Densities of over 1×106 A/cm2 in InP-Based InGaAs/AlAs Resonant Tunneling Diodes Grown by Metal–Organic Vapor-Phase Epitaxy

Abstract

InP-based InGaAs/AlAs resonant tunneling diodes (RTDs) with extremely high peak current density ( jP) were grown by metal–organic vapor-phase epitaxy. High-temperature growth at 660 °C provides high-quality heterointerfaces and excellent current–voltage (I–V) characteristics. To obtain extremely high jP, the structural parameter dependence of I–V characteristics on barrier and spacer thicknesses and emitter-doping concentration were examined. Clear exponential dependence of jP on barrier thickness was obtained in the barrier-thickness range from 1.2 to 2.8 nm. The reduction of spacer thickness to 2 nm increased jP without deteriorating the peak-to-valley current ratio (PVR). An investigation of Si dopant diffusion into double-barrier regions at the growth temperature supports the validity of reducing spacer thickness. The jP increased as Si doping concentration was increased from 1×1018 to 6×1018 cm-3 in InGaAs emitters. The highest jP reached 1.29×106 A/cm2 with a PVR of 1.5 in a RTD at room temperature with barrier and spacer thicknesses of 1.4 and 2 nm and Si doping concentration in the emitter of 6×1018 cm-3.