METHOD AND STRUCTURE FOR FORMATION OF REPLACEMENT METAL GATE FIELD EFFECT TRANSISTORS

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Embodiments of the present invention provide a process that maintains a “keep cap” metal nitride layer on PFET devices within a CMOS structure. The keep cap metal nitride layer is in place while an N-type work function metal is formed on the NFET devices within the CMOS structure. A sacrificial rare earth oxide layer, such as a lanthanum oxide layer is used to facilitate removal of the n-type work function metal selective to the keep cap metal nitride layer.