Decreasing Defect‐State Density of Al2O3/GaxIn1−xAs Device Interfaces with InOx Structures

Control of defect densities at insulator/GaxIn1−xAs interfaces is essential for optimal operation of various devices like transistors and infrared detectors to suppress, for example, nonradiative recombination, Fermi‐level pinning, and leakage currents. It is reported that a thin InOx interface layer is useful to limit the formation of these defects by showing effect of InOx on quantum efficiency of Ga0.45In0.55As detector and on photoluminescence of GaAs. A study of the Al2O3/GaAs interface via hard X‐ray synchrotron photoelectron spectroscopy reveals chemical structure changes at the interface induced by this beneficial InOx incorporation: the InOx sheet acts as an O diffusion barrier that prevents oxidation of GaAs and concomitant As bond rupture. Novel crystalline oxide structure between GaAs(100) and atomic layer deposition grown Al2O3 is shown to result in improvement of practical IR detectors. Hard X‐ray photoelectron spectroscopy analysis shows that different InOx structures can give rise to different charge carrier recombination mechanisms, but they are straightforwardly suppressed with an optimal amount of In in the interfacial layer.