Abstract: A method of manufacturing a nonvolatile semiconductor memory device may include forming a pad oxide layer pattern and a mask pattern on a semiconductor substrate, forming a trench within the semiconductor substrate with the mask pattern functioning as an etching mask, sequentially forming a first device isolation layer and a second device isolation layer that may fill the trench, forming an opening by removing the mask pattern to expose an upper surface of the pad oxide layer pattern and a sidewall of the second device isolation layer, and forming a floating gate forming region having a width wider than the opening by simultaneously removing the pad oxide layer pattern and a sidewall portion of the second device isolation layer exposed by the opening.

Abstract: In a method of manufacturing a semiconductor device such as a SONOS type semiconductor device, a trench is formed on a substrate. An isolation layer protruding from the substrate is formed to fill the trench. After a first layer is formed on the substrate, a preliminary second layer pattern is formed on the first layer. The preliminary second layer pattern has an upper face substantially lower than or substantially equal to an upper face of the isolation layer. A third layer is formed on the preliminary second layer and the isolation layer. A fourth layer is formed on the third layer. The fourth layer, the third layer, the preliminary second layer pattern and the first layer are partially etched to form a gate structure on the substrate. Source/drain regions are formed at portions of the substrate adjacent to the gate structure.

Abstract: A method of manufacturing a nonvolatile semiconductor memory device may include forming a pad oxide layer pattern and a mask pattern on a semiconductor substrate, forming a trench within the semiconductor substrate with the mask pattern functioning as an etching mask, sequentially forming a first device isolation layer and a second device isolation layer that may fill the trench, forming an opening by removing the mask pattern to expose an upper surface of the pad oxide layer pattern and a sidewall of the second device isolation layer, and forming a floating gate forming region having a width wider than the opening by simultaneously removing the pad oxide layer pattern and a sidewall portion of the second device isolation layer exposed by the opening.