Process for fabricating a semiconductor device including a nonvolatile memory cell

A nonvolatile memory device includes a floating-gate electrode (14) overlying a surface (24) of a substrate (10). A diffusion barrier layer (34) extends from the substrate surface (24) along a wall surface (30) of the floating-gate electrode (14) to an upper surface (32) of the floating-gate electrode (14) and overlies the upper surface (32). The diffusion barrier layer (34) blocks the silicidation of the floating-gate electrode (14) and prevents ionic contaminants from diffusing to the floating-gate electrode (14). A charge control region (42) of the floating-gate electrode (14) is capacitively coupled to a well region (40) within the substrate (10). The well region (40) functions as a diffused control-gate electrode and regulates the voltage of the floating-gate electrode (14).