Area-selective regrowth followed by AsH3 surface treatment and its application for ultra-shallow GaAs sidewall tunnel junctions

Low-temperature (290 °C) area-selective regrowth (ASR) by the intermittent injection of triethylgallium (TEGa) and arsine (AsH3) in an ultra-high vacuum (UHV) was applied for the fabrication of ultra-shallow sidewall GaAs tunnel junctions with the junction area in the order of 10−8 cm2. Fabricated tunnel junctions have shown the record peak current density up to 35,000 A/cm2 at 100 μm long strip structure. It is shown that the tunnel junction characteristics are seriously dependent on the sidewall orientation and the regrown interface quality, which was determined by the surface treatment conditions under AsH3 just prior to regrowth. The junction characteristics and AsH3 surface treatment effects are discussed in view of the orientation dependence of Be doping and control of surface stoichiometry.