A method of manufacturing a non-volatile memory device including a tunnel oxide layer, a preliminary charge storing layer and a dielectric layer on a semiconductor layer is disclosed. A first polysilicon layer is formed on the dielectric layer. A barrier layer and a second polysilicon layer are formed on the first polysilicon layer. The second polysilicon layer, the barrier layer, the first polysilicon layer, the dielectric layer, the preliminary charge storing layer and the tunnel oxide layer are patterned to form a tunnel layer pattern, a charge storing layer pattern, a dielectric layer pattern, a first control gate pattern, a barrier layer pattern and a second polysilicon pattern. A nickel layer is formed on the second polysilicon layer. Heat treatment is performed with respect to the second polysilicon pattern and the nickel layer to form a second control gate pattern including NiSi on the barrier layer pattern.