Embedded heater in a phase change memory material
A phase change memory cell for a semiconductor device that includes a heater element on a first conductive layer with a spacer surrounding sides of the heater element. The phase change memory cell includes a first dielectric layer on the conductive layer and on a bottom portion of the spacer surrounding the heater element and a second dielectric layer on the first dielectric layer surrounding a top portion of the heater element. The phase change memory cell includes a phase change material on a top surface of the heater element and on the second dielectric material.
1. A phase change memory cell comprising:
a cone-shaped heater element on a first conductive layer, wherein the cone-shaped heater element is composed of a solid cone of a heater material;
a dielectric material completely surrounding angled sides of the cone-shaped heater element with a spacer on angled sides of the dielectric material; and
a phase change material over a top surface of the cone-shaped heater element, over the top surface and sides of the spacer on the angled sides of the dielectric material, and over a portion of a top surface of the dielectric material.
2. The phase change memory cell of claim 1 , wherein the cone-shaped heater element has a flat top.
3. The phase change memory cell of claim 2 , wherein the top surface of the spacer contacts the phase change material.
4. The phase change memory cell of claim 1 , wherein a portion of the cone-shaped heater element, the dielectric material on the side of the heater element, and the spacer surrounding the dielectric material extend into a portion of the phase change material.
5. The phase change memory cell of claim 1 , wherein the dielectric material and the spacer material are different materials with a different reactive ion etch selectivity.
6. The phase change memory cell of claim 1 , wherein the dielectric material is composed of silicon nitride surrounding the spacer composed of silicon dioxide when the phase change material is a doped germanium-antimony-tellurium material.
7. The phase change memory cell of claim 1 , wherein the phase change material is composed of Cr 2 Ge 2 Te 6 , and wherein Cr 2 Ge 2 Te 6 is reverse phase change material with a higher resistivity in a crystalline phase than in an amorphous phase.
8. The phase change memory cell of claim 1 , wherein the spacer has a thickness that is less than one half the thickness of the dielectric material that is under the spacer.
9. The phase change memory cell of claim 1 , wherein the cone-shaped heater element is composed of the heater material selected from the group consisting of titanium nitride (TiN), titanium tungsten (TiW), a multilayer heater material (e.g., tantalum nitride/titanium nitride), doped Si, doped silicon germanium (SiGe), and chromium-germanium-tellurium (Cr 2 Ge 2 Te 6 ).