New silicidation technology by SITOX (silicidation through oxide) and its impact on sub-half micron MOS devices

A novel method for Ti salicide (self-aligned silicide) that uses silicidation through oxide (SITOX) has been developed. In the SITOX process, a thin (5 nm) thermal oxide layer is grown before Ti deposition and the silicidation reaction occurs through the thin oxide layer. SITOX-TiSi/sub 2/ is nearly single-crystalline and has a diameter from 25 to 225 mu m/sup 2/. One of the advantages of SITOX TiSi/sub 2/ over conventional TiSi/sub 2/ is its thermal stability. SITOX TiSi/sub 2/ does not agglomerate, even during high-temperature anneal at 1100 degrees C. This excellent thermal stability allows the use of the TiSi/sub 2/ layer as a solid diffusion source for the formation of the source/drain regions. This method eliminates Si damage that is caused by ion implantation. The junction leakage current is an order of magnitude less with a TiSi/sub 2/ diffused source/drain than that with a conventional implanted source/drain. Furthermore, the SITOX TiSi/sub 2/ device has superior electrical properties, such as low contact resistance and barrier effect against Al penetration.<
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