Phase change memory including ovonic threshold switch with layered electrode and methods for forming the same

摘要

Erosion of chalcogenides in phase change memories using ovonic threshold switch selectors can be reduced by controlling columnar morphology in electrodes used in the ovonic threshold switch. The columnar morphology may cause cracks to occur which allow etchants used to etch the ovonic threshold switch to sneak through the ovonic threshold switch and to attack chalcogenides, either in the switch or in the memory element. In one embodiment, the electrode may be split into two metal nitride layers separated by an intervening metal layer.

主权项

1. A method comprising:
forming a phase change memory element including a phase change memory material in contact with a plurality of heaters, wherein a first one of the plurality of heaters having a cross-sectional area different than a cross-sectional area of a second one of the plurality of heaters; forming a first electrode having a layer of a metal nitride material over the phase change memory material, wherein a first portion of the layer of the metal nitride material contacts a portion of the phase change memory material; forming a chalcogenide material over the first electrode, wherein a portion of the chalcogenide material contacts a second portion of the layer of the metal nitride material of the first electrode; forming a carbon layer overlaying the chalcogenide material; and forming a second electrode overlaying the carbon layer, the second electrode including at least two metal nitride layers separated by an intervening metal layer.