METHOD FOR MAKING MEMORY CELL BY MELTING PHASE CHANGE MATERIAL IN CONFINED SPACE

摘要

To form a memory cell with a phase change element, a hole is formed through an insulator to a bottom electrode, and a phase change material is deposited on the insulator surface covering the hole. A confining structure is formed over the phase change material so the phase change material expands into the hole when heated to melting to become electrically connected to the bottom electrode. A top electrode is formed over and electrically connects to the phase change material. The bottom electrode can include a main portion and an extension having a reduced lateral dimension. The confining structure can include capping material having a higher melting temperature than the phase change material, and sufficient tensile strength to ensure the phase change material moves into the hole when the phase change material melts and expands. The hole can be a J shaped hole.

主权项

1. A method for forming a memory cell with a phase change element comprising:
forming an insulator over a bottom electrode, having a hole extending from a surface of the insulator to the bottom electrode, the hole defining a void extending from the surface to the bottom electrode, the void having a void volume; confining a volume of phase change material inside a confining structure on a surface of the insulator and covering the hole, the phase change material being characterized by expansion in volume when melted by a characteristic percentage, wherein the void volume is less than said characteristic percentage of the volume of phase change material inside the confining structure; heating the phase change material causing the phase change material to expand into the hole so that upon expansion of the phase change material into the hole, the phase change material becomes electrically connected to the bottom electrode; and forming a top electrode over and electrically connected to the phase change material.