Method for forming self-aligned thermal isolation cell for a variable resistance memory array

A method of fabricating a memory device, comprising:

• providing a dielectric layer;
• etching the dielectric layer to form a via;
• forming a first electrode in the via;
• depositing a sidewall element in the via;
• depositing a memory element over the sidewall element;
• and
• forming a second electrode over the memory element;
• wherein the sidewall element is spaced away from the first electrode having inner surface which with a top surface of the bottom electrode defines an opening within the via on the first electrode.

A method of fabricating a memory device, comprising the steps of:

• providing a substrate of insulating material;
• depositing successively a lower electrode layer, a spandrel layer and a sacrificial layer on the substrate, trimming those layers to form a lower electrode element, a spandrel element and a sacrificial element, and depositing an insulating layer to enclose and surround the same;
• etching the sacrificial element to form a void over the lower electrode element and spandrel element in the insulating layer surface;
• forming a sidewall spacer element having a generally funnel-shaped opening in the void, having a terminal edge at the bottom of the opening, thereby exposing the spandrel layer;
• selectively isotropically etching the spandrel element to extend the opening through the spandrel element to the lower electrode, such that a spandrel element inner surface is defined, recessed from the terminal edge of the sidewall spacer element;
• depositing a programmable resistive material into the opening, such that a portion of the programmable resistive material is in contact with the sidewall spacer element inner surface and a portion extends from the sidewall spacer element terminal edge to make contact with the lower electrode;
• and
• forming an upper electrode in contact with the programmable resistive material;
• whereby the spandrel element inner surface and the programmable resistive material define a thermal isolation cell.