Selective area regrowth of n-GaAs with reduced interface carrier depletion using arsenic passivation

Abstract

Selective area molecular beam epitaxy (MBE) of n-GaAs through a Si 3N 4 mask has been explored. An arsenic capping layer was deposited in the MBE growth chamber prior to mask definition, in order to protect the epilayer surface during ex situ processing. After in situ thermal decapping and high-temperature (680°C) regrowth at a low growth rate (0.5 μm/h), the samples were examined with scanning electron and atomic force microscopy. The data unveil selective regrowth with lateral definition on a micrometer length scale and GaAs surfaces with a smooth mirror-like finish. Electrolytic carrier profiling and secondary ion mass spectrometry measurements of the homoepitaxial regrowth interface show a significant reduction of the interface potential barrier, from V bi=0.45 V to V bi=0.07 V, and reduced carbon impurity concentrations, compared to regrowth on non-passivated GaAs epilayers.