| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a non-volatile semiconductor storage device which can reduce write-in time, and the data write-in method for the device. SOLUTION: The device is provided with a latch circuit Q22, Q21 and with the write control circuit 12 which writes by charging the corresponding bit line to the ground voltage, if latch data is the data '00' that makes the threshold voltage of a storage cell a value most separated from the threshold voltage in the initial erase state, and by charging to a voltage VB higher than the ground voltage, if the latch data is the data that makes other threshold voltage. Concretely, in the case of quarternary value, the device is so constituted that the write-in of the data '10', '01' and that of the data '00' are carried out parallelly, and that the electric field is raised relating to the tunnel oxide film of the cell in which the data '00' is written.</p> |
