Two major concerns for silicidation of ultra-shallow junctions, namely the silicon-consumption- induced junction leakage and the series resistance increase, were compared among conventional post-junction-silicide (PJS) contact, silicide-as-a-diffusion-source (SADS) contact, Silicon-On-Insulator (SOI) contact, and elevated-source-drain (ESD) contact. Even though we found that ESD contacts would be the ultimate solution for both problems, SOI and SADS contacts provide better resistance to silicon-consumption-induced series resistance increase over conventional PJS contact because both are able to maintain a high dopant concentration at the silicide/silicon interface and thus a low specific contact resistivity. While there is no junction leakage concern for SOI contact, the SADS junction is also distinguished by low leakage owing to its lack of implant damage in the silicon substrate and uniformly doped junction along the silicide/silicon interface contour. MOSFET devices with SADS source/drain were demonstrated with quarter-μm technology. Epitaxial cobalt disilicide (CoSi2) was formed using the Ti/Co bilayer technique as a diffusion source. While both ESD and SOI processes still suffer from process complexity, integration and materials issues, we conclude that SADS contacting is a promising alternative for deep submicron devices.