Effects of B or Al Interface Layers on Thermal Stability of Ni Silicide on Si

Abstract

A new method is proposed to address the degradation of thermal stability in Ni silicide on heavily doped N-type Si substrates. Layered deposition of Al or B at the Ni/Si interface prior to silicidation was found to improve the thermal stability of Ni silicide, as evaluated by the sheet resistance vs. silicidation temperature properties. The improvement is attributed to suppression of the agglomeration of silicide layers. An Al layer was effective only when it was located at the Ni/Si interface prior to the silicidation process. The use of a B layer was preferable to that of Al when considering lower junction leakage.