A memory device includes a plurality of side-wall electrodes formed on a first side-wall of a trench within an insulating layer over a first plurality of contacts in an array of contacts in a substrate. The plurality of side-wall electrodes contact respective top surfaces of the first plurality of contacts. The side-wall electrodes respectively comprise a layer of tantalum nitride, having a composition TaxNy, where y is greater than x, and a layer of electrode material having a lower electrical resistivity and a lower thermal resistivity than the layer of tantalum nitride. Top surfaces of the plurality of side-wall electrodes contact memory material. A second plurality of side-wall electrodes may be formed on a second side-wall of the trench over a second plurality of contacts in the array of contacts.