Method of manufacturing a phase change memory device

A method of manufacturing a phase change memory device, the method comprising:

• forming an insulating interlayer on a substrate, the insulating interlayer having an opening therethrough;
• forming a plurality of phase change material layers each on a surface defining sides of the opening and atop the insulating interlayer, the plurality of phase change material layers having different compositions from each other;
• planarizing the phase change material layers until a top surface of the insulating interlayer is exposed to form a plurality of preliminary phase change material layer patterns in the opening;
• and
• applying energy to the plurality of preliminary phase change material layer patterns to form a phase change material layer pattern having a composition different from each of those of the preliminary phase change material layer patterns, the phase change material layer pattern including elements from the plurality of preliminary phase change material layer patterns.

A method of manufacturing a phase change memory device, the method comprising:

• forming an insulating interlayer, having openings passing therethrough, on a substrate, wherein the openings are spaced apart from each other in at least one direction parallel to an upper surface of the substrate;
• forming at least one conformal layer comprising phase change material on the insulating interlayer such that each said at least one conformal layer extends within the openings and the at least one conformal layer leaves a portion of each of the openings unfilled;
• forming a blanket layer comprising phase change material directly on the at least one conformal layer to fill what remains of the openings, the phase change material of the blanket layer having a composition different from that of the first phase change material of each said at least one conformal layer;
• planarizing the at least one conformal layer and the blanket layer until a top surface of the interlayer insulating layer is exposed, thereby forming a plurality of patterns of phase change material in each of the openings;
• and
• applying energy to the phase change material layer patterns to form, within each of the openings, a pattern of phase change material having a composition different from that of the phase change material of each of the layers of phase change material and including a mixture of elements of phase change material from the at least one conformal and blanket layers.