Highly scalable bulk FinFET Devices with Multi-VT options by conductive metal gate stack tuning for the 10-nm node and beyond

Highly scalable bulk FinFET Devices with Multi-VT options by conductive metal gate stack tuning for the 10-nm node and beyond ■

L. Ragnarsson, S. A. Chew, H. Dekkers, M. Toledano Luque, Bertrand Parvais, A. De Keersgieter, K. Devriendt, A. Van Ammel, T. Schram, N. Yoshida, A. Phatak, K. Han, B. Colombeau, A. Brand, N. Horiguchi, A. V.Y. Thean

Abstract ■

A scalable multi-VT enabled RMG CMOS integration process with highly conformal ALD TiN/TiAl/TiN is described. The multi-VT is implemented by metal gate tuning using two different options. The first relies on bottom-barrier thickness control, the second on implantation of nitrogen into the work function metal. A shift in the effective work function (eWF) of ∼400 mV is realized by adjusting the TiN bottom barrier thickness underneath TiAl, while over 200 mV shifts are achieved by means of implantation of nitrogen into ALD TiN/TiAl/TiN. The gate-stack Tinv, JG, DIT and reliability as well as the device performance are shown to be unaffected by the multi VT process.