Patent ID: 8669615
Filing Date: 2014-03-11
Classification: H01L

Abstract:
1. A FIN field effect transistor (FET) device, comprising: a semiconductor-on-insulator (SOI) wafer comprising an oxide layer and a SOI layer over a buried oxide (BOX), and a plurality of fins patterned in the oxide layer and the SOI layer such that at least one first group of the fins which corresponds to at least one first FIN FET device has at least one first pitch, and at least one second group of the fins which corresponds to at least one second FIN FET device has at least one second pitch; an interfacial oxide on the fins; and gate stacks on the interfacial oxide, each of the gate stacks having (i) a conformal gate dielectric layer present on the interfacial oxide, (ii) a conformal gate metal layer on the conformal gate dielectric layer, and (iii) a conformal work function setting material layer on the conformal gate metal layer, wherein the conformal work function setting material layer is configured to act as a doping source to alter a work function of the gate stacks, and wherein an amount of the conformal gate metal layer and an amount of the conformal work function setting material layer present in the gate stacks varies proportionally to a pitch of the fins since there are different size gaps to fill between the fins based on the pitch of the fins, and wherein variations in the amount of the conformal work function setting material layer on the fins alters a threshold voltage of the FIN FET devices, and thus by having the fins patterned so as to have the at least one first pitch and the at least one second pitch the amount of the conformal work function setting material layer is varied by having the different size gaps for the work function material to fill in as a function of the pitch of the fins so as to configure the at least one first FIN FET device to have a threshold voltage that is different from a threshold voltage of the at least one second FIN FET device.