A semiconductor integrated circuit device is provided. The semiconductor integrated circuit device includes a plurality of isolation regions which are formed within a semiconductor substrate and define active regions. A tunnel layer and a trap seed layer are formed in each of the active regions and are sequentially stacked between the isolation regions. A trap layer is formed on the trap seed layer and protrudes further than a top surface of each of the isolation regions. A blocking layer is formed on the trap layer. A gate electrode is formed on the blocking layer.