Titanium barrier for nickel silicidation of a gate electrode

摘要

Nickel silicidation of a gate electrode is controlled using a titanium barrier layer. Embodiments include forming a gate electrode structure comprising a lower polycrystalline silicon layer, a layer of titanium thereon and an upper polycrystalline silicon layer on the titanium layer, depositing a layer of nickel and silicidizing, whereby the upper polycrystalline silicon layer is converted to nickel silicide and a titanium silicide barrier layer is formed preventing nickel from reacting with the lower polycrystalline silicon layer.