| 摘要 |
PURPOSE: A nonvolatile memory device for performing 2-bit operation with 2-transistor as a unit cell is provided to improve a trap efficiency of electrons and an integration degree by forming two memory cells between a pair of bit lines and storing 2-bit data. CONSTITUTION: A semiconductor substrate of a first conductive type includes a first and a second channel regions(83,84) adjacent together. A first and a second conductive gates(71,72) are formed on the first and second channel regions(83,84), respectively. A first and a second insulating layers(65,70) are formed between the first and second conductive gates(71,72) and the substrate, respectively. At this time, the first and second insulating layers(65,70) are composed of ONO(Oxide-Nitride-Oxide) structure, wherein the nitride used as an electron trap film. A first and a second junction regions(81,82) of a second conductive type are formed in the substrate and overlapped to the gates(71,72).
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