SEMICONDUCTOR MEMORY DEVICE WITH ISLAND-TYPE SEMICONDUCTOR LAYER AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A semiconductor memory device and a manufacturing method thereof are provided to reduce the influence of back-bias effect on the device and to increase remarkably the capacitance ratio of a floating gate and a control gate by using an island-type semiconductor layer. CONSTITUTION: A semiconductor memory device includes the first conductive type semiconductor substrate(100) and a memory cell. The memory cell is composed of at least one island-type semiconductor layer(110), a charge storage layer formed at both sidewalls of the semiconductor layer, and a control gate(520). The memory cell is arranged in series. The semiconductor layer has different cross-sectional areas from bottom to top. The semiconductor layer has an insulating layer for passing electric charges.