Resistive memory with core and shell oxides and interface dipoles

A method of forming a ReRAM device, the method comprising:

• depositing a bottom electrode layer on a substrate;
• patterning the bottom electrode layer into at least a first bottom electrode and a second bottom electrode;
• forming a mandrel over a portion of each of the first bottom electrode and the second bottom electrode, and over a portion of the substrate in between the first bottom electrode and the second bottom electrode;
• forming first spacers along vertical sidewall surfaces of the mandrel;
• forming cores along the vertical sidewall surfaces of the mandrel over the first spacers;
• forming second spacers along the vertical sidewall surfaces of the mandrel over the cores and the first spacers to form at least a first ReRAM cell over the first bottom electrode and a second ReRAM cell over the second bottom electrode;
• surrounding the first ReRAM cell and the second ReRAM cell in an isolation layer comprising a material selected from the group consisting of:
• SiOx, SiOC, SiOCN, SiN, and combinations thereof;
• depositing a top electrode layer on the isolation layer and exposed top surfaces of the first ReRAM cell and the second ReRAM cell;
• and
• patterning the top electrode layer into at least a first top electrode over the first ReRAM cell and a second top electrode over the second ReRAM cell, wherein the first spacers and the second spacers each comprise a low group electron negativity material, and the cores comprise a high group electron negativity material, and wherein a combination of the low group electron negativity material for the spacers and the high group electron negativity material for the cores generates an interface dipole in the first ReRAM cell and the second ReRAM cell pointing toward the cores.

A method of operating a ReRAM device, the method comprising:

• providing the ReRAM device having at least one ReRAM cell comprising:
• a substrate;
• a bottom electrode disposed on the substrate;
• spacers comprising a low group electron negativity material disposed on the bottom electrode;
• a core comprising a high group electron negativity material present between the spacers;
• and a top electrode over and in contact with the spacers and the core, wherein a combination of the low group electron negativity material for the spacers and the high group electron negativity material for the core generates an interface dipole pointing toward the core;
• applying an electric field between the top electrode and the bottom electrode to form a filament which, based on the interface dipole, is in a center of the ReRAM cell;
• and
• applying an opposite polarity electric field between the top electrode and the bottom electrode to break the filament.