Schottky-barrier modificationof low-energy Ar-ion bombarded GaAs and Si

摘要

Epitaxially grown GaAs (p- and n-type) and n-Si were bombarded with low energy Ar-ions. Current voltage measurements on Schottky barrier diodes fabricated on the sputtered p-GaAs (Sc) and n-Si (Pd) showed that the series resistance and ideality factor were increased as the Ar-ion dose was increased. The respective increase and decrease in barrier heights of Sc/p-GaAs and Pd-Si diodes were attributed to the presence of donor-type surface states in the bombarded material. The barrier heights of Au Schottky diodes made on n-GaAs changed nonmonotonically with Ar-ion sputter voltage. Variations of barrier height in the 0-1 kV range were explained by the introduction of donor-type defects. We demonstrated that the introduction of high concentrations of continuous level defects above 1 kV resulted in Fermi level pinning to become the dominant mechanism for controlling the effective barrier of current transport. Our results have shown that Schottky barrier properties could be changed by controlled amounts by varying the bombarding ion dose or sputter voltage.