A novel in situ plasma treatment for damage-free metal/high-k gate stack RIE process

A dry etch process for metal/high-k stacks has been developed to solve the integration problems associated with wet etch removal of high-k dielectric from the source and drain (S/D) areas. An in-situ plasma (O₂) treatment has been introduced for the first time to cure the damage induced by the high-k dry etch process. Excellent electrical performances, such as dramatically improved leakage current, superior I_on/I_off performance, and suppressed short channel effects (gate induced drain leakage, drain-induced barrier lowering, V_t distribution) are achieved. With this novel process, metal/high-k gate stack dry etch process for very short channel devices becomes more manufacturing worthy, which has been one of the critical integration challenges in realizing gate first CMOSFETs with metal/high-k