FinFET work function metal formation

摘要

An improved method and structure for fabrication of replacement metal gate (RMG) field effect transistors is disclosed. P-type field effect transistor (PFET) gate cavities are protected while N work function metals are deposited in N-type field effect transistor (NFET) gate cavities.

主权项

1. A method of forming a semiconductor structure comprising an N-type field effect transistor (NFET) and a P-type field effect transistor (PFET), comprising:
forming an NFET polysilicon gate; forming a PFET polysilicon gate; forming a mask layer over the PFET polysilicon gate; removing the NFET polysilicon gate to form an NFET gate cavity; depositing an N work function metal on an interior surface of the NFET gate cavity, wherein the mask layer remains over the PFET polysilicon gate during deposition of the N work function metal; recessing the N work function metal; removing the mask layer and PFET polysilicon gate to form a PFET gate cavity; depositing a P work function metal on an interior surface of the PFET gate cavity; and depositing a fill metal in the NFET gate cavity and PFET gate cavity.