STUDY OF PtSi/TiW vs PtSi/Ti-TiN CONTACT STRUCTURES
Miroslav Sumega – Vladimír Áč
The contact structure in integrated circuits (IC) needs to have good ohmic properties with low contact resistance and it needs to be thermodynamically stable to prevent contact degradation. Usually, a structure with a PtSi-TiW-AlCu metallization or a TiSi2- TiN-AlCu metallization in the IC fabrication is used. In this paper, the electrical properties of two contact structures are investigated. On different metallization sandwiches, the function of silicide and barrier layer will be described. The PtSi silicide layer will be used with TiW and Ti-TiN barrier types and the contact properties will be characterized on single contacts and on power MOS transistors. Generally, the TiW barrier process is very dirty because the particles creating. From this point of view, the equipment mean time to cleaning (MTTC) is also derived. Therefore, a TiN barrier implementation will be attractive for manufacturing. The TiN barrier will be tested on a power transistor product which was previously developed with a TiW barrier.
Keywords: PtSi, TiW, TiN, Ti-TiN, silicide, diffusion barrier, Schottky contact, power transistor