A thermally insulated memory device includes a memory cell, the memory cell having electrodes with a via extending therebetween, a thermal insulator within the via and defining a void extending between the electrode surfaces. A memory material, such as a phase change material, is within the void and electrically couples the electrodes to create a memory material element. The thermal insulator helps to reduce the power required to operate the memory material element. An electrode may contact the outer surface of a plug to accommodate any imperfections, such as the void-type imperfections, at the plug surface. Methods for making the device and accommodating plug surface imperfections are also disclosed.