SEMICONDUCTOR NONVOLATILE MEMORY WHICH HAS IMPROVED TRACKING CHARACTERISTIC

摘要

PROBLEM TO BE SOLVED: To provide a nonvolatile memory obtained by tracking the threshold voltage characteristic of reference-side cell transistors to the characteristic of a core-side cell transistor.

SOLUTION: The nonvolatile memory in which data is stored depending of a difference in threshold voltage has the core-side cell transistor C-MC to which an electric charge is injected depending on stored data and the reference-side cell transistors RA-MC and RB-MC supplying a reference level when reading data from the core-side cell transistor. In the program operation of injecting electric charges depending on the stored data, the core-side cell transistor is impressed with first drain voltage and the reference-side cell transistors are impressed with second a drain voltage lower than the first drain voltage.

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