1. A phase change memory device comprising: an array of memory cells, memory cells in the array comprising respectively, a first electrode and second electrode, and a body of phase change memory material between the first and second electrodes, wherein the body of phase change memory material comprises a combination of Ge, Sb, and Te with a dielectric additive in amounts effective to provide a crystallization transition temperature greater than to 160° C.; wherein the combination of Ge, Sb, and Te comprises Ge x Sb y Te z , wherein x, y and z are atomic percentages, with a Ge atomic concentration x within a range from 13% to 18%, an Sb atomic concentration y within a range from 18% to 32% and a Te atomic concentration z within a range from 34% to 50%, and further comprising the dielectric additive with an atomic concentration within a range of 10% to 30%; and a controller coupled to the array, and configured to execute set operations and reset operations for memory cells in the array.