Low heat loss and small contact area composite electrode for a phase change media memory device

A method of fabricating a low heat loss and small contact area electrode structure for a phase change media memory device, comprising:

• depositing a mask layer on a dielectric layer;
• patterning and then etching the mask layer to define a mandrel mask;
• dry etching the dielectric layer and the mandrel mask with an etch gas comprising a first etch gas for etching the dielectric layer and a second etch gas for etching the mandrel mask;
• continuing the dry etching until the mandrel mask is entirely dissolved and until the dielectric layer comprises a dielectric mandrel having a tapered shape that terminates at a vertex;
• conformally depositing an electrically conductive material on the dielectric mandrel to form a composite electrode including a shape that complements the dielectric mandrel and terminates at a tip;
• depositing a first dielectric layer on the composite electrode until the first dielectric layer completely covers an entirety of the composite electrode including the tip;
• planarizing the first dielectric layer;
• dry etching the first dielectric layer until the first dielectric layer recedes below a predetermined distance from the tip of the composite electrode so that an exposed portion of the composite electrode adjacent to tip is not covered by the first dielectric layer;
• depositing a layer of phase change media on the first dielectric layer and the exposed portion;
• patterning and then etching the layer of phase change media to define an island;
• depositing a second dielectric layer on the first dielectric layer and the island;
• planarizing the second dielectric layer;
• patterning and then etching the second dielectric layer to form a via extending to the island;
• depositing an electrically conductive material on the second dielectric layer and in the via so that the electrically conductive material is in contact with the island;
• and
• patterning and then etching the electrically conductive material to define an electrode.