Cobalt silicide layers on Si. II. Schottky barrier height and contact resistivity

TLDR: In this paper, the barrier height and contact resistivity of CoSi-Si contacts were determined from current-voltage characteristics, using a transmission-line model and found to be comparable to those for Al−Si contacts.

Abstract: Cobalt silicide layers have been grown by electron‐beam vacuum deposition of Co onto Si wafers and subsequent thermal treatment. The barrier height φB and contact resistivity ρc of the Co‐Si contacts were determined from current‐voltage characteristics. The barrier height for Co on P‐type Si decreases on annealing and reaches a value of 0.38 eV after annealing at 450 °C. The barrier height on N‐type Si is then 0.68 eV. Presumably these are the values for a CoSi‐Si contact. Annealing at higher temperatures results in a higher barrier (0.40 eV) on P‐type Si and a lower barrier on N‐type Si, probably by the formation of CoSi2. The values for the contact resistivity on P‐type Si were determined using a transmission‐line model and found to be comparable to those for Al‐Si contacts. Annealing above 400 °C results in a decrease of the contact resistivity, mainly due to an increase in the boron concentration. By annealing above 500 °C the contact resistivity increases again, in agreement with the increased barrie...