In some embodiments, the dielectric layer 110 has a first pair sidewalls 110a that are aligned with outer sidewalls of the bottom electrode 106. A sidewall spacer 116 surrounds the outer sidewalls of the top electrode 114, the outer sidewalls of the metal layer 112 and the second pair of outer sidewalls 110b of the dielectric layer 110. The first pair of outer sidewalls 110a has a greater width than a second pair of outer sidewalls 110b. A bottom surface of the sidewall spacer 116 contacts a top surface of the dielectric layer 110. Outer sidewalls of the top electrode via 120 are within the outer sidewalls of the top electrode 114. In some embodiments, the first conductive via 122 and the first conductive wire 124 may be comprised of copper or aluminum, for example. Outer sidewalls of the bottom electrode 106 are aligned with the first pair of outer sidewalls 110a of the dielectric layer 110. Outer sidewalls of the top electrode 114 and outer sidewalls of the metal layer 112 are aligned with the second pair of outer sidewalls 110b of the dielectric layer 110. In some embodiments, the first pair of outer sidewalls 110a and the second pair of outer sidewalls 110b are defined from a cross-sectional view. For example, if when viewed from above the programmable metallization cell 119 is circular/elliptical then the first pair of outer sidewalls 110a is a single continuous sidewall when viewed from above, therefore the first “pair” of outer sidewalls 110a refers to the nature of this single continuous sidewall when depicted in in a cross-sectional view. Additionally, if when viewed from above the programmable metallization cell 119 is circular or elliptical then any length associated with a cross-sectional view of the layers comprising the programmable metallization cell 119 respectively correspond to diameters of a circle or lengths defined between two vertices on the major axis of an ellipse.