New Ti-SALICIDE process using Sb and Ge preamorphization for sub-0.2 μm CMOS technology

A new process for thin titanium self-aligned silicide (Ti-SALICIDE) on narrow n⁺ poly-Si lines and n⁺ diffusion layers using preamorphization implantation (PAI) with heavy ions of antimony (Sb) and germanium (Ge) has been demonstrated for application to 0.2-μm CMOS devices and beyond. Preamorphization enhances the phase transformation from C₄₉Ti_xSi _x to C₅₄TiSi₂ and lowers the transformation temperature by 80°C so that it occurs before conglomeration in narrow lines. Preamorphization by Sb and Ge implantation yields better results than that by As. The sheet resistance of TiSi₂ on heavily As doped poly-Si lines are 3.7 Ω/□ and 3.8 Ω/□ for the samples preamorphized by Ge and Sb implantations even with line width down to 0.2 μm. There is less leakage in the Ti-SALICIDE diode with preamorphization than without it. The probable reasons and mechanisms are discussed