Nonvolatile semiconductor storage device

A nonvolatile semiconductor storage device comprising:

• a word line made of a conductive material extending in a first direction;
• a first electrode provided on the word line and electrically connected to the word line;
• a high resistance ion diffusion layer provided on the first electrode on opposite side from the word line and electrically connected to the first electrode, the ion diffusion layer including a high oxygen concentration region and a low oxygen concentration region, the high oxygen concentration region being in contact with the first electrode, the low oxygen concentration region being provided on the high oxygen concentration region, the low oxygen concentration region being in contact with the high oxygen concentration region, the high oxygen concentration region having a higher oxygen concentration than the low oxygen concentration region;
• a second electrode provided on the ion diffusion layer on opposite side from the word line, the second electrode being in contact with the low oxygen concentration region, the second electrode being configured to supply a metal into the low oxygen concentration region upon application of a positive voltage relative to the first electrode;
• and
• a bit line provided on the second electrode on opposite side from the word line, electrically connected to the second electrode, and made of a conductive material extending in a second direction orthogonal to the first direction,
• the second electrode including the metal supplied into the low oxygen concentration region.