Robustness of self-aligned titanium silicide process: Improvement in yield of silicided devices with APM cleaning step

An additional cleaning technique is implemented in the self-aligned silicide (salicide) process. We discover that logic device yield improves significantly with the additional ammonium peroxide mixture cleaning (APM-clean). This significant improvement is believed to be due to the reduction and tighter distribution achieved in both gate to source/drain leakage and junction leakage. In order to incorporate APM-clean in the salicide process, the stability of both C49 and C54 phase TiSi/sub 2/ in APM solution is studied. We found that C54 phase TiSi/sub 2/ shows good stability in APM solution. On the other hand, C49 phase TiSi/sub 2/ exhibits an interesting line-width dependent etch-rate (/spl ges/1.38 /spl Aring//sec), which resulted in higher sheet resistance.