Methods of forming crystallized materials from amorphous materials

1. A method, comprising:

forming a first amorphous material comprising at least one element selected from the group consisting of silicon and germanium;

forming a second amorphous material over and in contact with the first amorphous material, the second amorphous material comprising at least one element selected from the group consisting of silicon and germanium, wherein the second amorphous material exhibits a crystallization temperature different than a crystallization temperature of the first amorphous material;

removing a portion of the second amorphous material and the first amorphous material to form pillars, each pillar comprising a portion of the second amorphous material over and in contact with a portion of the first amorphous material; and

exposing the pillars of the first amorphous material and the second amorphous material to a temperature between the crystallization temperature of the first amorphous material and the crystallization temperature of the second amorphous material to convert the pillars to a crystalline form.

2. The method of claim 1 , wherein exposing the pillars of the first amorphous material and the second amorphous material to a temperature between the crystallization temperature of the first amorphous material and the crystallization temperature of the second amorphous material comprises forming single-crystal pillars from the first amorphous material.

3. The method of claim 1 , wherein exposing the pillars of the first amorphous material and the second amorphous material to a temperature between the crystallization temperature of the first amorphous material and the crystallization temperature of the second amorphous material comprises subjecting the pillars of the first amorphous material and the second amorphous material to a temperature of less than about 650° C.

4. The method of claim 1 , wherein exposing the pillars of the first amorphous material and the second amorphous material to a temperature between the crystallization temperature of the first amorphous material and the crystallization temperature of the second amorphous material comprises subjecting the pillars of the first amorphous material and the second amorphous material to a temperature of less than about 500° C.

5. The method of claim 1 , further comprising forming at least one dopant in the second amorphous material.

6. The method of claim 5 , wherein forming at least one dopant in the second amorphous material comprises forming a dopant selected from the group consisting of boron, arsenic, and phosphorus in the second amorphous material.

7. The method of claim 1 , wherein exposing the pillars of the first amorphous material and the second amorphous material to a temperature between the crystallization temperature of the first amorphous material and the crystallization temperature of the second amorphous material comprises forming a crystalline material from the second amorphous material and propagating a crystalline structure from the crystalline material into the first amorphous material.

8. The method of claim 1 , further comprising forming a blocking material between adjacent pillars.

9. The method of claim 8 , wherein forming a blocking material between adjacent pillars comprises forming a material selected from the group consisting of an oxide, a nitride, and a carbon-containing material between adjacent pillars.

10. The method of claim 8 , wherein forming a blocking material comprises oxidizing a surface of the pillars.

11. The method of claim 1 , wherein forming a second amorphous material comprises forming the second amorphous material having a thickness between about 25 Å and about 5 μm over the first amorphous material.

12. The method of claim 1 , wherein removing a portion of the second amorphous material and the first amorphous material comprises forming an opening between two adjacent pillars, the opening having a width between about 5 Å and about 1,000 Å.

13. A method, comprising:

forming a structure comprising pillars, each pillar comprising a first amorphous material and a second amorphous material; and

subjecting the structure to a temperature between a crystallization temperature of the first amorphous material and a crystallization temperature of the second amorphous material to form the pillars comprising a single crystalline structure,

wherein the first amorphous material and the second amorphous material each comprise at least one element selected from the group consisting of silicon and germanium.

14. A method, comprising:

forming a first amorphous material comprising silicon, germanium, or silicon-germanium;

forming a second amorphous material over and in contact with the first amorphous material, the second amorphous material comprising silicon, germanium, or silicon-germanium, wherein the second amorphous material exhibits a crystallization temperature different than a crystallization temperature of the first amorphous material;

removing a portion of the second amorphous material and the first amorphous material to form pillars, each pillar comprising a portion of the second amorphous material over and in contact with a portion of the first amorphous material; and

exposing the pillars of the first amorphous material and the second amorphous material to a temperature between the crystallization temperature of the first amorphous material and the crystallization temperature of the second amorphous material to form the pillars comprising a continuous crystallized material.