Methods to form multi threshold-voltage dual channel without channel doping

摘要

Methods to form multi V_t channels, including a single type of WF material, utilizing lower annealing temperatures and the resulting devices are disclosed. Embodiments include providing an interfacial-layer on a semiconductor substrate; forming a first high-k dielectric-layer on the interfacial-layer; forming a second high-k dielectric-layer and a first cap-layer, respectively, on the first high-k dielectric-layer; removing the second high-k dielectric and first cap layers in first and second regions; forming a second cap-layer on the first high-k dielectric-layer in the first and second regions and on the first cap-layer in a third region; performing an annealing process; removing the second cap-layer from all regions and the first cap-layer from the third region; forming a third high-k dielectric-layer over all regions; forming a work-function composition-layer and a barrier-layer on the third high-k dielectric-layer in all regions; removing the barrier-layer from the first region; and forming a gate electrode over all regions.