| 摘要 |
High integration and making a non-volatile semiconductor memory efficient have been promoted. The memory cell consists of a floating gate, a control gate constituting a word line WL and a MOS transistor having an assist gate. The thickness of the gate oxide film of the assist gate is thinner than the thickness of the gate oxide layer of the floating gate, and the dimensions of the assist gate (gate width) in the direction lying along the word line WL is smaller than the gate length of the floating gate in the direction lying along the word line WL. Moreover, the channel dopant concentration underneath the assist gate is lower than the channel dopant concentration underneath the floating gate.
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