Performance assessment of (1 1 0) p-FET high-κ/MG: is it mobility or series resistance limited?

In this article the impact of Si-substrate orientation on mobility performance is studied for p-MOSFET’s with both HfSiON and SiON based dielectrics. Consistent with previous studies, the Ion at fixed Ioff is 100% larger for Si(1 1 0) larger than for standard Si(1 0 0). A thorough analysis of the factors influencing Ion (EOT, mobility and Rseries) for short channel devices (until Lmet = 80 nm) indicates that a 200% increase of the mobility at high Vg is the source of this performance enhancement. The lower Ion increase (only 100%) compared to what is expected from the mobility is only explained by a larger impact of the Rseries (70% of the total resistance) for short channel devices. As a result additional room for Ion improvement can be reached by device and Rseries optimization.