Al/n-GaAs Schottky barrier height modified with rare-earth metal interlayer

Schottky barrier heights are measured by current-voltage and capacitance-voltage methods for Al/n-GaAs contacts with a rare-earth metal (Sm, Dy, Yb) interlayer, which forms a stable alloy with Al but does not form an electrically active site in GaAs. The Schottky barrier height for each contact is found to be lowered with diode factor n<1.06, compared to ideal Al/n-GaAs and rare-earth metal/n-GaAs contacts. The mechanisms for the lowering are discussed from standpoints of alloy formation and diffusion across the interface.