Nonvolatile semiconductor memory device and method of manufacturing the same

摘要

A semiconductor memory device includes a semiconductor substrate. Two diffusion layers are separately arranged along a first direction on the surface of the semiconductor substrate and include impurities. Two element separation layers are separately arranged along a second direction in a surface of the semiconductor substrate and define an element region. A first insulating layer is disposed on the substrate. A first conductive layer is disposed on the first insulating layer between the two diffusion layers and between the two element separation layers. A second conductive layer is disposed on the first conductive layer and is smaller than the first conductive layer in the first direction and the second direction. A second insulating layer is disposed on the second conductive layer. A third conductive layer is disposed on the second insulating layer.