Silicides for 22nm and Beyond

Abstract

Silicide engineering for high-performance CMOS logic devices is challenged by aggressive scaling of critical dimensions, new high-performance elements, and requirements of morphological stability. While NiSi can satisfy many of the integration challenges, incorporating Pt forms a more robust [NixPt(1-x)]Si and improves morphological stability. In light of the challenges created by performance enablers, we review our latest results indicating whether a replacement for NiPt(1-x)Si is needed and highlight our investigations into alternative silicide materials such as Er, Yb, and Ir. We also discuss the architecture and performance needs beyond 32nm technology.

Silicide Formation Process of Er Films with Ta and TaN Capping Layers

“…As a silicide-forming rare earth (RE) metal, Er has attracted a great deal of interest because its silicide phase (ErSi 2– x ) has an extremely low Schottky barrier height (<0.3 eV) with respect to n-type Si . Its unique material characteristics are particularly attractive for source/drain contact applications in both conventional metal-oxide-semiconductor field-effect transistors (MOSFETs) and Schottky barrier MOSFFETs. , However, the most difficult challenge from a process point of view is that it is extremely vulnerable to oxidation during the silicide-forming annealing process in an inert gas atmosphere, in which a small amount of residual oxygen still exists.…”

Effects of the Mo composition of Mo-alloyed Yb/Si contacts on the microstructures and electrical properties

“…As the scale-down of metal-oxide-semiconductor field-effect transistors (MOSFETs) continues, the resistance rising from the contact between metal and silicon among the source= drain (S=D) series resistances becomes dominant due to the decrease in contact area. [1][2][3][4][5][6] To reduce the contact resistance, attention has been focused on the development of new contact materials with a low Schottky barrier height (SBH) such as rare-earth (RE) metal silicides (Er, Yb) for n-type Si and Pt, and Ir silicide for p-type Si. Among the RE silicides, ytterbium silicide is a promising contact material, because it has a very low SBH on n-type silicon (0.2-0.4 eV) and is reported to have an epitaxial relation with Si(001) and (111).…”