Method of making a nonvolatile phase change memory cell having a reduced contact area

A method is described to form a nonvolatile memory cell having a contact area between a phase-change material such as a chalcogenide and a heat source which is smaller than photolithographic limits. A conductive or semiconductor pillar is exposed at a dielectric surface and recessed by selective etch. A thin, conformal layer of a spacer material is deposited on the dielectric top surface, the pillar top surface, and the sidewalls of the recess, then removed from horizontal surfaces by anistropic etch, leaving a spacer on the sidewalls defining a reduced volume within the recess. The phase change material is deposited within the spacer, having a reduced contact area to the underlying conductive or semiconductor pillar.