Phase change memory cell with constriction structure

Abstract

Some embodiments include methods of forming memory cells. Such methods can include forming a first electrode, a second electrode, and a memory element directly contacting the first and second electrodes. Forming the memory element can include forming a programmable portion of the memory element isolated from the first electrode by a first portion of the memory element and isolated from the second electrode by a second portion of the memory element, Other embodiments are described.

What is claimed is: 
     
         1 . A device comprising:
 a first electrode and a second electrode; and   a memory element including a programmable portion, the memory element including:   a first portion coupled to the first electrode and having a first cross-section;   a second portion coupled to the second electrode and having a second cross-section, wherein the programmable portion is between the first and second portions, the programmable portion includes a part of the first portion and a part of the second portion, the part of the first portion directly contacts the part of the second portion, the first portion includes a tapered part, the tapered part is included in the part of the first portion, and the programmable portion includes the tapered part, and wherein,   the first portion includes a first width adjacent the part of the second portion, the first width extending in a direction perpendicular to a direction between the first and second electrodes, and a second width adjacent the first electrode, the second width extending in the direction perpendicular to the direction between the first and second electrodes, and the first width is less than the second width; and   the second portion includes a third width adjacent the part of the first portion, the third width extending in the direction perpendicular to the direction between the first and second electrodes, and a fourth width adjacent the second electrode, the fourth width extending in the direction perpendicular to the direction between the first and second electrodes, and the third width is equal to the fourth width.