SEMICONDUCTOR MEMORY, MANUFACTURING METHOD OF SEMICONDUCTOR MEMORY, AND INFORMATION REWRITING METHOD OF SEMICONDUCTOR MEMORY

摘要

A semiconductor memory device is provided to extend a difference between output current when a first multiple layer is recorded and output current when the first multiple layer is not recorded by increasing the output current when the first multiple layer is not recorded and by decreasing the output current when the first multiple layer is recorded. A first diffusion region is formed in a semiconductor substrate. A gate insulation layer(32) is formed on the semiconductor substrate in a position separated from the first diffusion region. A gate electrode(31) is formed on the gate insulation layer. A first multiple layer(141) is formed on the semiconductor substrate between the first diffusion region(11) and the gate insulation layer. A third diffusion region(113) is formed near the first multiple layer in the semiconductor substrate, having a lower impurity density than the first diffusion region. After a first charge is accumulated as a main body in the first multiple layer, a second charge having an opposite polarity to that of the first charge is accumulated as a main body. The first multiple layer includes a charge accumulation layer(143) for accumulating the first charge and an insulation layer for insulating the semiconductor substrate from the charge accumulation layer.