Patent ID: 8043924
Filing Date: 2011-10-25
Classification: H01L

Abstract:
1. A method of forming a phase-change memory unit, comprising: providing a substrate having a trench; forming a conductive layer on the substrate and on the trench; selectively removing portions of the conductive layer on a lower face of the trench to form a plurality of conductive layer patterns wherein the conductive layer patterns partially expose the lower face of the trench; forming an insulation layer to fill up the trench; planarizing the insulation layer and the conductive layer patterns until an upper surface of the substrate is exposed to form first electrodes having top surfaces that are coplanar with the upper surface of the substrate; forming a spacer layer on the upper surface of the substrate, on the insulation layer, and on the top surfaces of the first electrodes; patterning the spacer layer to form a spacer that partially covers the top surfaces of the first electrodes and that exposes portions of the top surfaces of the first electrodes; forming a phase-change material layer on the exposed portions of the top surfaces of the first electrodes and on the spacer; and forming a second electrode on the phase-change material layer.