A technique to obtain deep penetrating ohmic contacts for electrical measurements on ion implanted silicon

Abstract

Deep penetrating ohmic contacts have been made on silicon samples by implanting, through metal masks, quasi-channelled 150-250 keV phosphorus ions at doses of 10¹⁵ at cm^-2 and forming a surface eutectic layer Au-Si by short annealing of the Au film which had been vacuum evaporated on the implanted areas. Such contacts have proved to be satisfactorily ohmic and to give reproducible resistivity and Hall effect measurements within 3*10^-3; they are therefore suitable in the stripping technique determination of ion implanted concentration profiles.