Resistive switching device and fabrication method thereof
A resistive switching device includes a substrate; a first dielectric layer on the substrate; a conductive via in the first dielectric layer; a bottom electrode on the conductive via and the first dielectric layer, a resistive switching layer on the bottom electrode; and a cone-shaped top electrode on the resistive switching layer. The cone-shaped top electrode can produce increased and concentrated electric field during operation, which facilitates the filament forming process.
1 . A resistive switching device, comprising:
a substrate;
a first dielectric layer on the substrate;
a conductive via in the first dielectric layer;
a bottom electrode on the conductive via and the first dielectric layer;
a resistive switching layer on the bottom electrode; and
a cone-shaped top electrode on the resistive switching layer and comprising a tip, wherein a bottom width of the cone-shaped top electrode is wider than a width of the tip.
2 . The resistive switching device according to claim 1 , wherein the conductive via comprises tungsten.
3 . The resistive switching device according to claim 1 , further comprising a spacer layer covering the cone-shaped top electrode, wherein the pointed tip of the cone-shaped top electrode protrudes from an upper surface of the spacer layer.
4 . The resistive switching device according to claim 3 , wherein the spacer layer further covers a sidewall of the resistive switching layer and a top surface of the first dielectric layer.
5 . The resistive switching device according to claim 3 further comprising:
a second dielectric layer on the spacer layer; and
a contact penetrating through the second dielectric layer and the spacer layer and being electrically connected with the cone-shaped top electrode.
6 . The resistive switching device according to claim 1 , wherein the bottom electrode comprises TaN and the cone-shaped top electrode comprises TiN.
7 . The resistive switching device according to claim 1 , wherein the bottom electrode comprises a recessed sidewall.
8 . The resistive switching device according to claim 7 , wherein the spacer layer covering the recessed sidewall of the bottom electrode.
9 . The resistive switching device according to claim 1 , wherein a bottom width of the resistive switching layer connecting to the bottom electrode is greater than a bottom width of the bottom electrode away from the resistive switching layer.
10 . The resistive switching device according to claim 1 , wherein a width of the resistive switching layer is greater than a bottom width of the cone-shaped top electrode.
11 . A method for forming a resistive switching device, comprising:
providing a substrate;
forming a first dielectric layer on the substrate;
forming a conductive via in the first dielectric layer;
forming a bottom electrode on the conductive via and the first dielectric layer;
forming a resistive switching layer on the bottom electrode; and
forming a cone-shaped top electrode on the resistive switching layer, wherein the cone-shaped top electrode comprises a tip, and wherein a bottom width of the cone-shaped top electrode is wider than a width of the tip.
12 . The method according to claim 11 , wherein the conductive via comprises tungsten.
13 . The method according to claim 11 , further comprising a spacer layer covering the cone-shaped top electrode, wherein the pointed tip of the cone-shaped top electrode protrudes from an upper surface of the spacer layer.
14 . The method according to claim 13 , wherein the spacer layer further covers a sidewall of the resistive switching layer and a top surface of the first dielectric layer.
15 . The method according to claim 13 further comprising:
forming a second dielectric layer on the spacer layer; and
forming a contact penetrating through the second dielectric layer and the spacer layer and being electrically connected with the cone-shaped top electrode.
16 . The method according to claim 11 , wherein the bottom electrode comprises TaN and the cone-shaped top electrode comprises TiN.
17 . The method according to claim 11 , wherein the bottom electrode comprises a recessed sidewall.
18 . The method according to claim 17 , wherein the spacer layer covering the recessed sidewall of the bottom electrode.
19 . The method according to claim 11 , wherein a bottom width of the resistive switching layer connecting to the bottom electrode is greater than a bottom width of the bottom electrode away from the resistive switching layer.
20 . The method according to claim 11 , wherein a width of the resistive switching layer is greater than a bottom width of the cone-shaped top electrode.