Comparative Scalability of PVD and CVD TiN on HfO2 as a Metal Gate Stack for FDSOI cMOSFETs down to 25nm Gate Length and Width

This paper compares, for the first time, the scalability of physical- and chemical-vapor-deposited (PVD and CVD) TiN on HfO₂ as a gate stack for FDSOI cMOSFETs down to 25nm gate length and width. It is shown that not only the intrinsic material properties but also the device architecture strongly influences the final gate stack properties. Reliability issues, stress and gate control in the sub-35nm scale are reported and explained, thanks to material, electric data and mechanical simulations. In spite of its lower performance on large device dimensions, PVD-TiN demonstrates a better overall trade-off, leading to a 17% ion improvement on 25nm short and narrow devices