Method of forming phase-change memory layers on recessed electrodes

A method comprising:

• forming a conductive feature over a substrate;
• forming a first dielectric layer over the conductive feature;
• etching the first dielectric layer to form an opening in the first dielectric layer, wherein the opening exposes the conductive feature;
• forming a first spacer on a first sidewall of the opening and in physical contact with the conductive feature;
• forming a second spacer on a second sidewall of the opening and in physical contact with the conductive feature, wherein the second sidewall of the opening is opposite the first sidewall of the opening;
• depositing a first conductive material in the opening to form a bottom electrode in the opening, wherein the bottom electrode is in physical contact with conductive feature;
• removing a top portion of the bottom electrode to form a recess;
• depositing a phase-change material in the recess and over the first dielectric layer, the first spacer, and the second spacer;
• depositing a second conductive material over the phase-change material;
• etching the phase-change material and the second conductive material, wherein a remaining portion of the phase-change material forms a phase-change layer and a remaining portion of the second conductive material forms a top electrode;
• and
• forming a second dielectric layer over the first dielectric layer, wherein the second dielectric layer extends along and is in physical contact with sidewalls of the phase-change layer and sidewalls of the top electrode, and wherein the second dielectric layer is in physical contact with the first spacer and the second spacer.

A method comprising:

• forming a first dielectric layer over a substrate;
• forming a first conductive feature in the first dielectric layer;
• forming a second dielectric layer over the first dielectric layer and the first conductive feature;
• forming an opening in the second dielectric layer, wherein the opening exposes a portion of a top surface of the first conductive feature;
• forming spacers on sidewalls of the opening;
• filling the opening with a first conductive material to form a bottom electrode in the opening;
• recessing the bottom electrode below a top surface of the second dielectric layer to form a recess, wherein the recess extends into the bottom electrode, and wherein a width of the recess decreases as the recess extends into the bottom electrode toward the substrate;
• depositing a phase-change material in the recess and over the second dielectric layer;
• depositing a second conductive material over the phase-change material;
• and
• performing a patterning process to remove portions of the phase-change material and the second conductive material and to expose the top surface of the second dielectric layer and top surfaces of the spacers, wherein a remaining portion of the phase-change material forms a phase-change layer, and wherein a remaining portion of the second conductive material forms a top electrode.