A non-volatile memory device that limits the temperature excursion of a selector during operation to enhance the cycling life of the non-volatile memory device. A selector, in line with a memory element, may be degraded with repeated temperature excursions as current passes through a stack during the read/write process. The selector changes from an amorphous state to become crystalline thus reducing the life of a memory device. The memory device includes a word line, a bit line disposed perpendicular to the word line, a stack—including a memory element, a selector, and a spacer—disposed between the word line and bit line, and one or more insulating layers surrounding an outer surface of the stack disposed between the word line and bit line. By surrounding the selector with a high thermal conductive heat-sink material, heat is directed away from the selector helping maintain the selector's amorphous state longer.
