Chalcogenide containing semiconductors with chalcogenide gradient

1. A method comprising:

forming a chalcogenide containing semiconductor device with a gradient film between a chalcogenide and non-chalcogenide film, such that the concentration of chalcogenide changes across the thickness of the gradient film, wherein said gradient film includes both chalcogenide and non-chalcogenide material.

2. The method of claim 1 including forming said device with a gradient film with opposed sides, one side being adjacent the chalcogenide such that the concentration of chalcogenide decreases across the thickness of the film, moving away from the chalcogenide.

3. The method of claim 1 including forming a phase change memory.

4. The method of claim 1 including forming an ovonic threshold switch.

5. The method of claim 1 including forming the chalcogenide on one side of said gradient film and an electrode on the other side of said gradient film.

6. The method of claim 1 including forming the chalcogenide on one side of said gradient film and an insulator on the other side.

7. The method of claim 1 including forming the chalcogenide on one side of said gradient film and another film on the other side of said gradient film, the gradient film including a concentration of the material forming said another film, said concentration increasing across the thickness of the gradient film moving from the chalcogenide to the another film.

8. An apparatus comprising:

a chalcogenide layer;

a second layer in contact with said chalcogenide layer; and

a third layer, being non-chalcogenide, in contact with said second layer, the second layer including chalcogenide and material also forming said third layer, the concentration of said chalcogenide decreasing moving through the second layer and away from the chalcogenide layer.

9. The apparatus of claim 8 wherein said apparatus is a phase change memory.

10. The apparatus of claim 8 wherein said apparatus is an ovonic threshold switch.

11. The apparatus of claim 8 wherein the concentration of said material increases in the second layer moving from the chalcogenide to said third layer.

12. The apparatus of claim 8 wherein the atomic percent of chalcogenide in said second layer decreases linearly from the chalcogenide to the third layer.

13. The apparatus of claim 8 including a fourth layer on said chalcogenide layer on the opposite side of said chalcogenide layer from said second layer, said apparatus including a fifth layer on said fourth layer, the concentration of chalcogenide in said fourth layer decreasing across the thickness of said fourth layer moving from said chalcogenide layer to said fifth layer.

14. The apparatus of claim 8 wherein the thickness of said second layer is less than five nanometers.

15. The apparatus of claim 14 wherein the thickness of said second layer is less than ten Angstroms.

16. A chalcogenide containing semiconductor comprising:

a chalcogenide layer;

a non-chalcogenide layer; and

an intervening layer between said non-chalcogenide layer and said chalcogenide layer, said intervening layer including a mixture of chalcogenide and material making up the non-chalcogenide layer.

17. The device of claim 16 wherein said non-chalcogenide layer is an insulator.

18. The device of claim 16 wherein said non-chalcogenide is a conductor.

19. The device of claim 16 wherein the concentration of chalcogenide decreases linearly across said intervening layer moving from said chalcogenide layer to said non-chalcogenide layer.

20. The device of claim 19 wherein the concentration of non-chalcogenide increases linearly moving from said chalcogenide layer to said non-chalcogenide layer across said intervening layer.