A non-volatile semiconductor device includes a memory cell in a first area of a substrate, a low voltage transistor in a second area of the substrate, and a high voltage transistor in a third area of the substrate. The memory cell includes a tunnel insulation layer formed on the substrate, a charge trapping layer pattern formed on the tunnel insulation layer in the first area of the substrate, a blocking layer pattern formed on the charge trapping layer pattern and a control gate formed on the blocking layer pattern. The control gate has a width substantially smaller than a width of the blocking layer pattern and the width of the control gate is substantially smaller than a width of the charge trapping layer pattern. In addition, an offset is formed between the control gate and the blocking layer pattern such that a spacer is not formed on a sidewall of the control gate.