ReRAM device structure
A resistive random access memory (ReRAM) includes a first metal layer having a first metal and a metal-oxide layer on the first metal layer. The metal-oxide layer includes the first metal. The ReRAM further includes a second metal layer over the metal-oxide layer and a first continuous conductive barrier layer in physical contact with sidewalls of the first metal layer and of the metal-oxide layer.
1. A method of forming a resistive random access memory (ReRAM) comprising:
forming a first opening in a first dielectric layer;
forming a continuous barrier layer within the first opening, wherein the continuous barrier layer is in physical contact with a sidewall of the first opening and a bottom of the first opening;
forming a first metal layer within the first opening;
oxidizing a top portion of the first metal layer to form a metal-oxide layer within the first opening, wherein the continuous barrier layer within the first opening is in physical contact with sidewalls of the metal-oxide layer and the first metal layer; and
forming a second metal layer over the metal-oxide layer, wherein the second metal layer is located within a perimeter of a major surface of the metal-oxide layer.
2. The method of claim 1 , wherein the step of forming the second metal layer over the metal-oxide layer comprises:
forming a second dielectric layer over the first dielectric layer;
forming a second opening in the second dielectric layer which exposes the metal-oxide layer and does not expose the first dielectric layer;
forming a second continuous barrier layer in physical contact with a sidewall of the second opening; and
forming the second metal layer within the second opening and in physical contact with the second continuous barrier layer.
3. The method of claim 2 , wherein the step of forming the second continuous barrier layer in physical contact with the sidewall of the second opening is performed such that the second continuous barrier layer is also formed along a bottom of the second opening in physical contact with the exposed metal-oxide layer, wherein the step of forming the second metal layer within the opening is performed such that the second continuous barrier layer is between the second metal layer and the major surface of the metal-oxide layer.
4. The method of claim 2 , wherein the step of forming the second metal layer within the second opening is performed such that the second metal layer is in physical contact with the exposed metal-oxide layer.
5. The method of claim 2 , wherein each of the first and the second continuous barrier layers are conductive.
6. The method of claim 5 , wherein each of the first and second continuous barrier layers comprise nitride.
7. The method of claim 1 , wherein the first and second metal layers comprise copper, and the metal-oxide layer comprises copper oxide.
8. The method of claim 7 , wherein the first continuous barrier layer is conductive.
9. The method of claim 8 , wherein the first continuous barrier layer comprises a nitride.