On Different Process Schemes for MOSFETs With a Controllable NiSi-Based Metallic Source/Drain

This paper focuses on different silicidation schemes toward a controllable NiSi-based metallic source/drain (MSD) process with restricted lateral encroachment of NiSi. These schemes include thickness control of Ni, Ni-Pt alloying, and two-step annealing. Experimental results show that all the three process schemes can give rise to effective control of lateral encroachment during Ni silicidation. By controlling
t
_Ni
, NiSi-based MSD metal-oxide-semiconductor field-effect transistors (MOSFETs) of gate length
LG
= 55 nm are readily realized on ultrathin-body silicon-on-insulator substrates with 20-nm surface Si thickness. With the aid of dopant segregation (DS) to modifying the Schottky barrier heights of NiSi, both
n
- and
p
-type MSD MOSFETs show significant performance improvement, compared to reference devices without DS.