Effects of titanium sputtering schemes and preamorphization on the junction characteristics of Ti salicide

Abstract

We studied the effects of Ge preamorphization (PAM) and Ti deposition method on 0.25 μm Ti-salicide junctions in comparison with As PAM. For each PAM scheme, ion implantations are performed at 2E14 ion/cm2 dose and 20 keV energy using As75 and GeF4 ion sources. Ionized physical vapor deposition and collimated type dc-magnetron sputtering are used for depositing ∼300 Å Ti for this study. Ge PAM showed lower sheet resistance (∼48 Ω /sq.) and better within-wafer uniformity than As PAM at 0.25 μm line width of n+/p-well junctions. This is attributed to enhanced C54-silicidation at n+ junction. At p+ junctions, comparable performance in sheet-resistance reduction at fines lines for both As and Ge PAM schemes. Junction leakage current (JLC) levels are below ∼1E14 A/μm2 at area patterns for all process conditions, whereas no degradation in JLC are shown under Ge PAM condition even at edge-intensive patterns. Junction breakdown voltage and contact resistances are satisfactory at all process conditions.