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

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.