Phase change memory cell sidewall heater

A phase change memory element structure, comprising:

• a bottom electrode;
• a phase change material layer;
• a bilayer dielectric, including a base layer dielectric and a phase change element layer dielectric located on top of the base layer dielectric;
• and
• a sidewall heater with an upper section and a lower section, wherein the upper section extends vertically through the phase change element layer dielectric of the bilayer dielectric to contact the phase change material layer and the lower section of the sidewall heater has a plurality of conductive layers in contact with the bottom electrode, and wherein a dimension of the upper section of the sidewall heater in contact with the phase change material layer is substantially smaller than a dimension of the lower section of the sidewall heater in contact with the bottom electrode, resulting in an inverted T-shape,
• wherein the sidewall heater is composed of a multilayer stack of metal including alternating layers of at least two materials selected from the group consisting of TiN, TaN, TaAlN, TiSiN, TiAlN, and TaSiN.