Nonvolatile semiconductor memory device

摘要

A nonvolatile memory element is formed by layering a lower electrode, a variable resistor and an upper electrode in sequence. The variable resistor is formed in which crystallinity and amorphism are mixed. Thus, the nonvolatile memory element is formed. More preferably, the variable resistor is a praseodymium-calcium-manganese oxide represented by a general formula, Pr_1-xCa_xMnO₃, that has been formed at a film forming temperature from 350° C. to 500° C. Alternatively, the variable resistor is formed as a film at a film forming temperature that allows the variable resistor to become of an amorphous state or a state where crystallinity and amorphism are mixed and, then, is subjected to an annealing process at a temperature higher than the film forming temperature, in a temperature range where the variable resistor can maintain the state where crystallinity and amorphism are mixed.