VARIABLE RESISTIVE ELEMENT, AND NONVOLATILE SEMICONDUCTOR STORAGE DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a variable resistive element capable of performing forming at a low current and a stable switching operation at a low voltage and a low current, and provide a nonvolatile semiconductor storage device with low power consumption and a large capacity by including the variable resistive element.SOLUTION: A variable resistive element 1 holds a variable resistor 13 between a first electrode 14 and a second electrode 12. The variable resistor 13 includes at least two layers of metal oxide or metal oxynitride, a resistance change layer 15 and a high oxygen layer 16. The high oxygen layer 16 is inserted between the first electrode 14 having a work function smaller than that of the second electrode and the resistance change layer 15. An oxygen concentration of the metal oxide is adjusted so that a ratio to a stoichiometric composition of an oxygen composition ratio to a metal element is larger than a ratio to a stoichiometric composition of the oxygen composition ratio to a metal element of the metal oxide constituting the resistance change layer 15.