Ion-beam induced CoSi 2 layers: formation and contact properties

Abstract

In this study, the influence of Ge and As ion energy, respectively, on the mixing behavior and the contact properties of the CoSi system was investigated by Monte Carlo simulations, SIMS, RBS, TEM, and electrical measurements. To achieve silicided n + p junctions, 30 nm Co on Si was mixed with (1–5)×10 15 cm −2 Ge or As ions in the energy range from 50 to 200 keV. Silicidation was performed in a RTA system at 700 and 1000°C. In the case of Ge mixing, the n + p junction was formed by As implantation either before or after silicidation. It could be shown that ion-beam mixing with Ge and As ions followed by rapid thermal annealing lead to homogeneous silicidation for all mixing energies and ion species used. SIMS analysis of doping profiles as well as measurement of leakage currents revealed, however, that only Ge ion-beam mixing is an appropriate method for formation of low-resistivity, homogeneous silicide contacts either on previously or subsequently formed shallow n + p junctions.