RMG nMOS 1st process enabling 10x lower gate resistivity in N7 bulk FinFETs

A novel RMG process in which the n-type work function metal (nWFM) is deposited first and then selectively removed from the pMOS devices is presented for the first time. The key benefit of this nMOS 1st process lies in increased gate-fill space which results in about 10× improvement in the pMOS effective gate resistivity at gate lengths (LG) around 22 nm, an improvement which is predicted by modeling to extend down to LG<;14 nm. The complete removal of the nWFM in the pMOS devices is evidenced by restored p-type effective work function (eWF) values in large area capacitors and matched pMOS threshold voltage (VT) values in bulk FinFET devices with LG down to 22 nm. Furthermore, selective removal of the nWFM is confirmed physically down to LG~16 nm providing further evidence that the process is scalable towards N7 dimensions.