A Millisecond-Anneal-Assisted Selective Fully Silicided (FUSI) Gate Process

We demonstrate, for the first time, an integration-friendly selective PMOSFET fully silicided (FUSI) gate process. In this process, a millisecond-anneal (MSA) technique is utilized for the nickel silicide phase transformation. A highly tensile FUSI gate electrode is created and hence exerts compressive stress in the underlying channel. The highly flexible integration scheme successfully, and exclusively, implements uniform P⁺ FUSI gates for PMOSFETs while preserving a FUSI-free N⁺ poly-Si gate for NMOSFETs with the feature size down to 30 nm. A 20% improvement in FUSI- gated PMOSFET I_on- I_off is measured, which can be attributed to the enhanced hole mobility and the elimination of P⁺ poly-gate depletion.