Variable resistive element, manufacturing method for same, and non-volatile semiconductor memory device

A variable resistive element comprising:

• a metal oxide layer between a first electrode and a second electrode where an electrical resistance between the first and second electrodes reversibly changes in accordance with application of an electrical stress across the first and second electrodes, wherein
• the metal oxide layer has a filament which is a current path where a density of a current flowing between the first and second electrodes is locally high,
• a portion including at least a vicinity of an interface between a certain electrode, which is one or both of the first and second electrodes, and, the filament, on an interface between, the certain electrode and the metal oxide layer is provided with an interface oxide which is an oxide of a certain element and different from an oxide of the metal oxide layer, the certain element being at least one element included in the certain electrode, and
• a thermal conductivity of the interface oxide is lower than a thermal conductivity of the certain electrode.

A variable resistive element comprising:

• a metal oxide layer between a first electrode and a second electrode where an electrical resistance between the first and second electrodes reversibly changes in accordance with a application of an electrical stress across the first and second electrodes, wherein
• the metal oxide layer has a filament which is a current path where a density of a current flowing between the first and second electrodes is locally high,
• a portion including at least a vicinity of an interface between a certain electrode, which is one or both of the first and second electrodes, and the filament, on an interface between the certain electrode and the metal oxide layer is provided with an interface oxide which is an oxide of a certain element and different from an oxide of the metal oxide layer, the certain element being at least one element included in the certain electrode, and
• free energy for generating an oxide in the certain element is less than free energy for generating an oxide in a metal element that forms the metal oxide layer.

A manufacturing method for a variable resistive element, the manufacturing method comprising:

• forming an original structure for the variable resistive element having the a metal oxide layer between a first electrode and a second electrode where an electrical resistance between the first and second electrodes reversibly changes in accordance with application of an electrical stress across the first and second electrodes;
• forming a filament which is a current path where a density of a current flowing through the metal oxide layer between the first and second elements is locally high by applying a first forming voltage across the first and second electrodes in the original structure;
• and
• forming an interface oxide in a portion including at least a vicinity of an interface between a certain electrode, which is one or both of the first and second electrodes, and the filament, on an interface between the certain electrode and the metal oxide layer, the interface oxide being an oxide of a certain element which is at least one element included in the certain electrode and being different from an oxide in the metal oxide layer, wherein
• the original structure forming step, the filament forming step and the interface oxide forming step are carried out in sequence, and
• the interface oxide is generated when the certain element in the certain electrode grabs oxygen in the metal oxide layer through the interface in the interface oxide forming step.