A phase change memory device with improve thermal isolation. The device includes an electrode stack, including a first and second electrode elements, generally planar in form, separated by and in mutual contact with a dielectric spacer element, wherein the electrode stack includes a side surface; a phase change element having a bottom surface in contact with the electrode stack side surface, including electrical contact with the first and second electrode elements; and dielectric fill material surrounding and encasing the memory device, wherein the dielectric fill material is spaced from the phase change element, such that the phase change element and the dielectric fill material define a cavity adjacent the phase change element, and wherein the cavity contains a low pressure environment.