STRUCTURE AND METHOD FOR MANUFACTURING SEMICONDUCTOR MEMORY DEVICE

摘要

A method of manufacturing a semiconductor memory device, and a structure thereof are provided to relieve concentration effect of electric field by forming an edge of an active region as a gentle curve, and to expand the width of a channel extraordinarily without increasing the design rule by realizing the active region of 3D embossing shape. A pad insulating layer is formed on a semiconductor substrate(100). The pad insulating layer is etched selectively to expose the semiconductor substrate. An LOCOS oxide layer is formed on the substrate by performing an oxidation process to the substrate. A trench is formed by etching the semiconductor substrate under the LOCOS oxide layer and the LOCOS oxide layer by performing an anisotropic etching process. An insulating layer(112) is deposited on the entire surface of the semiconductor substrate on which the insulating layer is deposited. The substrate is flattened to expose the pad insulating layer. The exposed pad insulating layer is removed. A trench device isolation layer and an active region of the domed shape are formed by leaving the insulating layer of a specified thickness within the trench by etching bird's beak of the LOCOS oxide layer and the insulating layer deposited in the trench. A tunnel oxide layer(114) and a poly-silicon layer(116) are deposited sequentially on the resultant structure. And a gate electrode is formed by removing the tunnel oxide layer and the polysilicon layer.