Applied Physics Letters · 2006 · 44 citations · 10 references
Natural SciencesMaterials EngineeringMaterials ScienceElectronic MaterialsSemiconductor DevicesThin FilmsAtomic Layer DepositionChemical Vapor DepositionSemiconductor Device MaterialsSemiconductor InterfacesThin Film Electrical PropertiesThin-film MaterialsInterdiffusionInterdiffusion At InterfacesMetal GatesSilicon-on-insulator TechnologyThin-film Interface EngineeringWork FunctionWork Function EngineeringWork Function Tuning
We demonstrate that the metallic capping layer has a strong impact on the effective work function (EWF) of the metal gate. Specifically, the EWF of atomic-layer-deposited (ALD)-TaN could be increased from 4.5to4.8eV with chemical-vapor-deposited-TiN capping, which is sufficient amount of work function modification for silicon on insulator based devices. A strong interdiffusion of Ti atoms into the ALD-TaN film is observed and correlated well with the changes in the EWF change. Ti capping experiments confirm that the Ti interdiffusion can actually modify the EWF of Ti/ALD-TaN stack.
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