Development of a Ti:W salicide-nitride based multi-layer metallization for VLSI application

A multilayer metallization based upon an alloy of Titanium and Tungsten (30:70 atomic %), has been developed and evaluated. Using AES, XPS and RBS analysis techniques, a process to simultaneously form a refractory oxy-nitride diffusion barrier over a silicide contact has been characterized. By placing 300 Angstrom films\u27 of Ti:W in an 800 mTorr ammonia environment at 800C, it is been demonstrated that silicides and oxy-nitrides of Titanium and Tungsten form in layers, with an overall thickness of 540 Angstroms. A test chip has been designed and fabricated using an nMOS process including the new metallization. Utilizing test structures such as Van Der Pauw resistors, Cross Bridge Kelvin Resistors and Diodes, the effectiveness of the barrier at 500C has been demonstrated and characterized