Electrode structure for a non-volatile memory device and method

A resistive switching device for a non-volatile memory device, comprising:

• a substrate having a surface region;
• a first dielectric layer overlying the surface region of the substrate;
• a first wiring structure overlying the first dielectric layer;
• a junction layer overlying the first wiring structure;
• a resistive switching layer overlying the junction layer;
• an active metal layer overlying the resistive switching layer;
• an adhesion layer comprising a tungsten material overlying and in contact with the active metal layer;
• a diffusion barrier layer overlying and in contact with the adhesion layer, the diffusion barrier layer not including tungsten;
• a stack of material comprising the junction layer, the resistive switching layer, the active metal layer, and the adhesion layer, wherein the stack of material is characterized by a side wall with a reduced gap region between the diffusion barrier layer and the resistive switching layer;
• and
• a second wiring structure overlying the stack of material including the diffusion barrier layer.