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 ( j P ) 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 j P , the structural parameter dependence of I – V characteristics on barrier and spacer thicknesses and emitter-doping concentration were examined. Clear exponential dependence of j P 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 j P 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 j P increased as Si doping concentration was increased from 1×10 18 to 6×10 18 cm -3 in InGaAs emitters. The highest j P reached 1.29×10 6 A/cm 2 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 6×10 18 cm -3 .