Increased range of Fermi-level stabilization energy at metal/melt-grown GaAs(100) interfaces

Abstract
We report a room temperature soft x‐ray photoemission spectroscopic study of electronic barrier formation and chemistry at Al, Ag, and Au contacts with horizontal Bridgman‐grown GaAs(100) surfaces, prepared by etching, heat‐cleaning in situ, and As‐capping. As reported previously, we observe a pronounced chemical reaction with formation of dissociated Ga for Al, a minimal interface reaction for Ag, and interdiffusion for Au. However, we find significant differences in the interface electronic barrier heights between the present metal/melt‐grown GaAs(100) contacts and those made on cleaved (110) surfaces as well as on melt‐grown (100) surfaces. We obtain Schottky barrier heights of 0.62, 0.85, and 1.03 eV respectively for Al, Ag, and Au/GaAs interfaces covering a range of 0.41eV—in contrast to the 0.2–0.3 eV range obtained earlier for both cleaved (110) and heat‐cleaned (100) surfaces as well as the 0.7 eV range observed for metal/molecular beam epitaxy GaAs(100) interfaces. This intermediate behavior underscores the dependence of barrier height variation on different growth and interface processing techniques.

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