| 摘要 |
<P>PROBLEM TO BE SOLVED: To effectively prevent a deterioration in a variable resistive element of an RRAM by suppressing variations of resistive states. <P>SOLUTION: A memory cell array 10 provided with a plurality of memory cells M provided with a variable resistive element R whose electric resistance changes to two or more different resistive states, a determination circuit for partitioning the range of resistance values, which the variable resistive element R can take, into a plurality of target ranges and a plurality of middle ranges and determining whether the resistance value of the memory cell M is within any range among the plurality of target ranges and the plurality of middle ranges, and a write circuit 13 for applying a voltage pulse to the variable resistive element R so as to make a resistance value be within one range among the target ranges and writing information in the memory cells M are provided. Two or more middle ranges exist between two adjacent target ranges. In the determination circuit, a voltage pulse is applied to a memory cell M in which the resistance value of the memory cell M is not determined to be within a predetermined target range on a first application condition set differently at least in each middle range. <P>COPYRIGHT: (C)2012,JPO&INPIT |
