A memory device. The device includes first and second electrode members, in spaced relation on a substrate. A phase change element lies in electrical contact with the first and second electrode elements and spans the space separating them. The phase change element includes two segments, each in contact with one of the electrode elements. The segments are fused together at a location between the two electrodes such that the fused area has a smaller cross-sectional area than does the remainder of the phase change element. The electrodes, the substrate and the phase change element define a chamber containing a vacuum.