Dual-metal-gate-integration complementary metal oxide semiconductor process scheme using Ru positive-channel metal oxide semiconductor and TaC negative-channel metal oxide semiconductor gate electrodes

This article presents the development of a wet removal process on the integration of complementary metal oxide semiconductor (CMOS) dual metals with Ru for positive-channel metal oxide semiconductor and TaC for negative-channel metal oxide semiconductor on high-k HfO2 gate dielectric. The integration scheme focused on the wet etching capability for the first metal and the selectivity control on the high-k dielectrics under the metal gate. Using the developed chemical, ceric ammonium nitrate and nitric acid mixture used for Ru metal removal and HfO2 treated with Ar∕O2 plasma by selective diluted hydrofluoric wet etching, a CMOS dual-metal-gate structure was achieved with satisfactory device fabrication.