Method of making phase change memory device employing thermally insulating voids and sloped trench
View Patent ↗A phase change memory device, and method of making the same, that includes a trench formed in insulation material having opposing sidewalls that are inwardly sloping with trench depth. A first electrode is formed in the trench. Phase change memory material is formed in electrical contact with the first electrode. A second electrode is formed in electrical contact with the phase change memory material. Voids are formed in the insulation material to impede heat from the phase change memory material from conducting away therefrom. The voids are formed in pairs, with either a portion of the phase change memory material or the second electrode disposed between the voids.
1. A method of making a phase change memory device, comprising:
forming a first insulation layer;
forming a first layer of phase change memory material over the first insulation layer;
forming a second insulation layer over the first layer of phase change memory material;
forming a trench that extends into the first and second insulation layers and the first layer of phase change memory material;
forming a first void in a portion of one of the first or second insulation layers;
forming a first electrode in the trench that is disposed in electrical contact with the first layer of phase change memory material; and
forming a second electrode in electrical contact with the layer of phase change memory material;
wherein electrical current passing through the first and second electrodes and the phase change memory material generates heat for heating the phase change memory material, and wherein the first void impedes the heat from the phase change memory material from conducting away therefrom.
2. The method of claim 1 , wherein the trench includes opposing sidewalls that are inwardly sloping with trench depth.
3. The method of claim 1 , further comprising:
forming a second void in a portion of the other one of the first or second insulation layers, wherein a portion of the phase change memory material layer is disposed between the first and second voids, and wherein the first and second voids impede the heat from the phase change memory material from conducting away therefrom.
4. The method of claim 3 , wherein the phase change memory material layer extends from a sidewall of the first electrode at a non-orthogonal angle.
5. The method of claim 3 , further comprising:
forming a second phase change memory material layer over and in electrical contact with a portion of the first phase change memory material layer, wherein the second phase change memory material layer is disposed in electrical contact with the second electrode and does not extend between the pair of voids.
6. The method of claim 5 , wherein the first and second layers of phase change memory material form a current path between the first and second electrodes, and wherein the current path has a minimum cross sectional area directly adjacent the first electrode.
7. The method of claim 5 , wherein the first and second layers of phase change memory material form a current path between the first and second electrodes, and wherein the current path has a minimum cross sectional area between the first and second voids.