Ultra-low contact resistance metallization by a silicidation technology employing a silicon capping layer for protection against contamination

An ultra low contact resistance metallization process has been developed by employing Ta silicidation of Si contact surface by ion beam mixing through a tantalum film covered with a Si capping layer. The as-deposited Ta surface is protected in-situ by a very thin Si film in order to prevent the metal surface from being oxidized or contaminated during subsequent processing. As a result, completely native-oxide-free contact metallization has been established. By combining the oxide-free Si/metal-on-Si deposition and ultraclean ion implantation for ion mixing, an ultra low contact resistance of 3.3/spl times/10/sup -9/ (/spl Omega/ cm/sup 2/) has been achieved.<>