Formation of CoSi 2 by ion beam mixing and rapid thermal annealing

Abstract

A low-temperature method of fabricating low-resistivity CoSi 2/p + and CoSi 2/n + contacts is described. Single-crystal Si〈100〉 was implanted with group III or V ions through a 28.4 nm thick evaporated Co film for ion beam mixing and junction doping. Appropriate implantation parameters were chosen which caused a maximum of ion-induced damage at the Co/Si interface and a dopant maximum within the silicide formed later on. By subsequent rapid thermal annealing (RTA), a shallow junction and a 100 nm thick CoSi 2 layer with a resistivity of 17 μΩ cm were formed simultaneously. The CoSi 2 films were characterized by TEM, XRD and sheet resistance measurements. SIMS and carrier concentration measurements were used to determine dopant distribution and junction depth. Specific contact resistances of CoSi 2/n + and CoSi 2/p + junctions are presented.