| 摘要 |
The semiconductor memory device which can easily control threshold voltage comprises: (a) a first conductive type substrate; (b) a first conductive type first epitaxial layer formed on (a), and being higher in impurity concentration than (a), and defining a channel region; (c) at least two first conductive type second epitaxial layers; (d) a second conductive type second region formed on one of layers (c) to serve as a bit line; (e) a second conductive type third region formed on the other one of layers (c) to serve as a charge storage region; (f) a first gate electrode formed on the portion of the first layer (b) defining the channel region to serve as a word line.
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