Improvement in Platinum Silicidation for 0.8 m BICMOS Process

Abstract

AbstractPlatinum Silicidation involves interdiffusion of Pt and Si which finally results in the formation of PtSi. The quality of Platinum Silicide strongly influences the electrical properties such as schottky barrier height and its contact resistance. We demonstrate a two step process using rapid thermal processing (RTP) with 400 °C 30 sec silicidation in N2 atmosphere, followed by 500 °C 30 sec oxidation in O2/N2 mix. The two temperature step process gave better electrical and material characteristics compared to a single step silicidation at 400°C with N2/O2 mix. The two step silicidation recipe also had lower sheet resistance, no unreacted platinum (based on X-ray diffraction analysis) and uniform SiO2 layer (based on Auger Electron Specrtroscopy) on top of silicide, to protect it from aqua regia.