The electrical characteristics of Schottky diodes fabricated on silicon surfaces subject to low‐energy (10 keV) argon ion implantation have been studied as a function of Ar+ion dose. Significant changes in electrical characteristics are seen for ion doses as low as 5×1011cm−2, well below the amorphization threshold dose for Si. In conjunction with the ion energy threshold established earlier for Si surface damage effects (∼25 eV), these results outline fundamental limits on the effect of ion‐assisted dry etching processes on Si surface barriers.