Methods of fabricating phase changeable semiconductor memory devices including multi-plug conductive structures and related devices

摘要

In fabricating a phase changeable memory device, an insulating layer with an opening extending therethrough is formed on a substrate. A conductive structure is formed in the opening. The conductive structure includes a first conductive plug on opposing sidewalls of the opening and a surface therebetween and a second plug on the first conductive plug. The first conductive plug is between the second plug and the sidewalls of the opening and between the second plug and the surface therebetween. A lower electrode is formed on the first conductive plug, on the second plug, and on the insulating layer. The lower electrode extends outside the opening in the insulating layer. A phase changeable material layer is formed on the lower electrode, and an upper electrode is formed on the phase changeable material layer opposite the lower electrode.