A method for making a memory device, includes: forming a first dielectric layer over a bottom electrode; forming a first void extending through the first dielectric layer to expose a portion of an upper boundary of the bottom electrode; forming a first conductive structure lining along respective sidewalls of the first void and the exposed portion of the upper boundary of the bottom electrode; filling the first void with the first dielectric layer; and forming a phase change material layer over the first dielectric layer to cause the phase change material layer to contact at least a portion of a sidewall of the first conductive structure.