Tone inversion integration for phase change memory
Embodiments of the invention are directed to methods and resulting structures for forming a storage element using phase change memory (PCM). In a non-limiting embodiment of the invention, a PCM layer is formed over a surface of a bottom electrode. A top electrode is formed over the PCM layer using a tone inversion process that includes a sacrificial layer. A PCM pillar is then formed by patterning the PCM layer to expose a surface of the bottom electrode. The tone inversion process enables a sub-50 nm PCM pillar diameter.
1. A semiconductor device comprising:
a bottom electrode
a phase change memory (PCM) pillar formed over a surface of the bottom electrode;
an etch stop layer formed over the PCM pillar; and
a ring electrode formed over the etch stop layer, the ring electrode comprising three stacked electrode layers;
wherein the PCM pillar comprises a diameter of about 10 nm to about 50 nm.
2. The semiconductor device of claim 1 , wherein the PCM pillar comprises a germanium-antimony-tellurium (GST) ternary compound.
3. The semiconductor device of claim 1 , wherein the bottom electrode is electrically isolated between two portions of a dielectric layer.