Methods of forming recessed gate electrodes having covered layer interfaces

摘要

Methods of forming a gate electrode can be provided by forming a trench in a substrate, conformally forming a polysilicon layer to provide a polysilicon conformal layer in the trench defining a recess surrounded by the polysilicon conformal layer, wherein the polysilicon conformal layer is formed to extend upwardly from a surface of the substrate to have a protrusion and the protrusion has a vertical outer sidewall adjacent the surface of the substrate, forming a tungsten layer in the recess to form an upper surface that includes an interface between the polysilicon conformal layer and the tungsten layer, and forming a capping layer being in direct contact with top surfaces of the polysilicon conformal layer and the tungsten layer without any intervening layers.