Molecular beam epitaxy regrowth using a thin In layer for surface passivation

Abstract

We report a molecular beam epitaxy regrowth technique using a thin In layer for surface passivation. X-ray photoemission spectroscopy measurements show that an In layer as thin as a few tenths of an angstrom is adequate for the effective protection of the underlying III-V epilayers from carbon and oxygen contamination, while still providing exposure to the atmosphere. C–V depth profilings of the regrown pseudomorphic high electron mobility transistors (PHEMTs) reveal no significant residual charge carriers near the regrowth interface. The regrown PHEMTs with 1 μm gate length have a transconductance as high as 330 mS/mm and ft over 23 GHz.