Method of forming semiconductor device having self-aligned plug
A conductive pattern on a substrate is formed. An insulating layer having an opening exposing the conductive pattern is formed. A bottom electrode is formed on the conductive pattern and a first sidewall of the opening. A spacer is formed on the bottom electrode and a second sidewall of the opening. The spacer and the bottom electrode are formed to be lower than a top surface of the insulating layer. A data storage plug is formed on the bottom electrode and the spacer. The data storage plug has a first sidewall aligned with a sidewall of the bottom electrode and a second sidewall aligned with a sidewall of the spacer. A bit line is formed on the data storage plug.
1. A method of fabricating a semiconductor device, comprising:
forming a conductive pattern on a substrate;
forming an insulating layer on the conductive pattern and having an opening exposing the conductive pattern;
forming a bottom electrode on the conductive pattern and a first sidewall of the opening;
forming a spacer on the bottom electrode and a second sidewall of the opening, the spacer and the bottom electrode being formed to be lower than a top surface of the insulating layer;
forming a data storage plug on the bottom electrode and the spacer, the data storage plug having a first sidewall aligned with a sidewall of the bottom electrode and a second sidewall aligned with a sidewall of the spacer; and
forming a bit line on the data storage plug.
2. The method of claim 1 , wherein the bottom electrode comprises an upper part and a lower part so as to have an L-shaped cross section.
3. The method of claim 2 , wherein the upper part of the bottom electrode has a vertical length longer than a horizontal length and the lower part of the bottom electrode has a horizontal length longer than a vertical length.
4. The method of claim 2 , wherein the spacer is formed on a sidewall of the upper part of the bottom electrode and a top surface of the lower part of the bottom electrode.
5. The method of claim 1 , wherein the bottom electrode entirely covers a top surface of the conductive pattern.
6. The method of claim 1 , wherein the spacer is formed of a material layer having an etch selectivity with respect to the insulating layer, and the spacer has a higher electrical resistance than the bottom electrode.
7. The method of claim 1 , wherein the bottom electrode and the spacer constitute a bottom electrode structure, and a distance between the first sidewall of the data storage plug and the second sidewall of the data storage plug is the same as a width of the bottom electrode structure.
8. The method of claim 1 , wherein the data storage plug has a top surface having a same surface level as the top surface of the insulating layer.
9. The method of claim 1 , wherein the data storage plug comprises a phase-change plug, a polymer plug, a nanoparticle plug, or a resistance-change plug.
10. The method of claim 1 , wherein forming the bottom electrode and the spacer comprises:
forming the spacer on the second sidewall of the opening;
forming a bottom electrode layer on the substrate having the spacer, the bottom electrode layer being in contact with a sidewall of the spacer;
etching the bottom electrode layer using an anisotropic etching process to form the bottom electrode; and
etching the spacer and the bottom electrode.
11. The method of claim 1 , wherein forming the bottom electrode and the spacer comprises:
forming a bottom electrode layer covering the first sidewall of the opening and a bottom of the opening and the insulating layer;
forming a spacer layer covering the bottom electrode layer;
etching the spacer layer, and exposing the bottom electrode layer on the insulating layer and the bottom of the opening; and
removing the exposed bottom electrode layer.