Heterogeneous integration of InAs/GaSb tunnel diode structure on silicon using 200 nm GaAsSb dislocation filtering buffer
An InAs/GaSb tunnel diode structure was heterogeneously integrated on silicon by solid source molecular beam epitaxy using a 200 nm strained GaAs1-ySby dislocation filtering buffer. X-ray analysis demonstrated near complete strain relaxation of the metamorphic buffer and a quasi-lattice-matched InAs/GaSb heterostructure, while high-resolution transmission electron microscopy revealed sharp, atomically abrupt heterointerfaces between the GaSb and InAs epilayers. In-plane magnetotransport analysis revealed Shubnikov-de Haas oscillations, indicating the presence of a dominant high mobility carrier, thereby testifying to the quality of the heterostructure and interfaces. Temperature-dependent current-voltage characteristics of fabricated InAs/GaSb tunnel diodes demonstrated Shockley-Read-Hall generation-recombination at low bias and band-to-band tunneling transport at high bias. The extracted conductance slope from the fabricated tunnel diodes increased with increasing temperature due to thermal emission (Ea ~ 0.48 eV) and trap-assisted tunneling. Thus, this work illustrates the significance of defect control in the heterointegration of metamorphic InAs/GaSb tunnel diode heterostructures on silicon when using GaAs1-ySby dislocation filtering buffers.