METHOD FOR CONTROLLED FORMATION OF THE RESISTIVE SWITCHING MATERIAL IN A RESISTIVE SWITCHING DEVICE AND DEVICE OBTAINED THEREOF
For improved scalability of resistive switching memories, a cross-point resistive switching structure is disclosed wherein the plug itself is used to store the resistive switching material and where the top electrode layer is self-aligned to the plug using, for example, chemical-mechanical-polishing (CMP) or simply mechanical-polishing.
1 . A method for manufacturing a resistive switching device, the device comprising a bottom electrode, a top electrode, and a layer of resistive switching material contacted by the bottom electrode and the top electrode, wherein the method comprises:
providing a substrate comprising the bottom electrode;
providing on the substrate a dielectric layer comprising an opening exposing the bottom electrode; and
forming, in the opening, the resistive layer.
2 . The method of claim 1 , wherein providing the dielectric layer comprises:
depositing the dielectric layer;
forming a trench in the dielectric layer; and
forming in the trench an opening exposing the bottom electrode.
3 . The method of claim 1 , wherein forming the resistive layer comprises at least partially filling the opening with the resistive layer, further comprising:
forming the top electrode in the at least partially filled opening.
4 . The method of claim 1 , wherein providing the dielectric layer and forming the resistive layer comprise:
forming a first dielectric layer having an opening exposing the bottom electrode; and
forming the resistive layer in the opening;
further comprising:
forming a second dielectric layer comprising a trench that exposes the resistive layer; and
forming the top electrode in the trench.
5 . The method of claim 4 , wherein forming the resistive layer comprises partially filling the opening with the resistive switching material.
6 . The method of claim 1 , wherein the substrate comprises a first metal pattern, and the bottom electrode is provided in the first metal pattern.
7 . The method of claim 1 , wherein the substrate comprises a first metal pattern, and the bottom electrode is provided in a via contacting the first metal pattern, further comprising:
forming the top electrode in a second metal pattern.
8 . The method of claim 1 , wherein the resistive switching material is a charge transfer complex containing an electron donor and an electron acceptor.
9 . The method of claim 8 , wherein the resistive switching material is an organic compound having a pi electron system.
10 . The method of claim 9 , wherein the organic compound is provided by TCNQ or by a derivative of TCNQ.
11 . The method of claim 10 , wherein the electron donor is provided by the metal of the bottom electrode, the metal being selected from the group consisting of Cu, Ag or K.
12 . The method of claim 1 , wherein the resistive switching material is a binary metal oxide.
13 . The method of claim 12 , wherein the bottom electrode comprises copper, and the binary metal oxide is a cuprous metal oxide.
14 . The method of claim 1 , further comprising forming the forming the top electrode, wherein forming the top electrode comprises forming a layer of metal over the substrate, and removing metal in excess of the opening.
15 . The method of claim 1 , wherein the resistive switching device is a non-volatile memory device.
16 . A resistive switching device, comprising:
a bottom electrode;
a top electrode; and
a layer of resistive switching material contacted by the bottom electrode and the top electrode;
wherein the top electrode and the resistive layer are contained in an opening formed in a dielectric layer.
17 . The device of claim 16 , wherein:
the bottom electrode is formed in a first metal pattern;
the top electrode is formed in a second metal pattern;
the dielectric layer comprises at least a first layer and a second layer, the first layer separating the first and the second metal pattern and having an opening for providing a connection between the first metal pattern and the second metal pattern; and
the resistive layer is contained in the first opening.
18 . The device of claim 16 , wherein the resistive switching material is a charge transfer complex containing an electron donor and an electron acceptor.
19 . The device of claim 18 , wherein the resistive switching material is an organic compound having a pi electron system.
20 . The method of claim 19 , wherein the organic compound is provided by TCNQ or by a derivative of TCNQ.
21 . The device of claim 20 , wherein the electron donor is provided by the metal of the bottom electrode, the metal being selected from the group consisting of Cu, Ag or K.
22 . The device of claim 16 , wherein the resistive switching material is a binary metal oxide.
23 . The device of claim 22 , wherein the bottom electrode comprises copper, and the binary metal oxide is a cuprous metal oxide.
24 . The device of claim 16 , wherein the bottom electrode and the top electrode are formed from the same materials.