A nonvolatile memory device and method of making the same are provided. Memory cells may be provided in a cell area wherein each memory cell has an insulative structure including a tunnel insulating layer, a floating trap layer and a blocking layer, and a conductive structure including an energy barrier layer, a barrier metal layer and a low resistance gate electrode. A material having a lower resistivity may be used as the gate electrode so as to avoid problems associated with increased resistance and to allow the gate electrode to be made relatively thin. The memory device may further include transistors in the peripheral area, which may have a gate dielectric layer, a lower gate electrode of poly-silicon and an upper gate electrode made of metal silicide, allowing an improved interface with the lower gate electrode without diffusion or reaction while providing a lower resistance.