Electrical characteristics of amorphous molybdenum-nickel contacts to silicon

Abstract

The electrical characteristics of sputtered, amorphous Mo-Ni contacts have been measured on both p- and n-type Si, as functions of composition (30, 54, and 58 at. % Mo). The contact resistivity on both p+ and n+ Si is in the 10^−6 Ω cm^2 range. The barrier height for as-deposited samples varies between φbp=0.47–0.42 V on p-type Si and between φbn=0.63–0.68 V on n-type Si, as the composition of the amorphous layer goes from Ni-rich to Mo-rich. The sum φbp+φbn always equals 1.12 V, within experimental error. After thermal treatment at 500 °C for 1/2 h, the contact resistivity changes by a factor of two or less, while the barrier height changes by at most ~0.05 V. In light of these results, the amorphous Mo-Ni film makes good ohmic contacts to silicon.