Epitaxially grown Si/SiGe interband tunneling diodes with high room-temperature peak-to-valley ratio

Abstract

Room-temperature current–voltage characteristics of Si/Si1−xGex/Si p+-i-n+ interband tunneling diodes are presented. Special attention is paid to the peak current density (PCD) and the peak-to-valley current ratio (PVCR) of the devices. A variation of the SiGe layer width between 4 and 2 nm changes the PCD from 0.4 to 12.6 kA/cm2, at the same time conserving a PVCR of more than 4.1. The optimization of the Ge concentration x in the Si1−xGex layer results in a PVCR of 5.1 for x=48%. Tuning the position of the Si0.52Ge0.48 layer within the intrinsic zone culminates in a structure with a PCD of 8 kA/cm2 and improves the PVCR to the value of 5.45.