Systems and methods for creating crystallographic-orientation controlled poly-Silicon films

• US 20060102901A1
• Filed: 11/18/2004
• Published: 05/18/2006
• Est. Priority Date: 11/18/2004
• Status: Active Grant

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Im, James S., van der Wilt, Paul Christian
• Granted Patent: US 7,645,337 B2
• Time in Patent Office: Days
• US Class Current: 257/64
• CPC Class Codes: C30B 13/22 by irradiation or electric discharge
• CPC Class Codes: C30B 29/605 Products containing multiple oriented crystallites, e.g. columnar crystallites
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02595 polycrystalline
• CPC Class Codes: H01L 21/02609 Crystal orientation
• CPC Class Codes: H01L 21/02672 using crystallisation enhancing elements
• CPC Class Codes: H01L 21/0268 Shape of mask
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/02691 Scanning of a beam
• CPC Class Codes: H01L 27/1285 using control of the annealing or irradiation parameters, e.g. using different scanning direction or intensity for different transistors
• CPC Class Codes: H01L 27/1296 adapted to increase the uniformity of device parameters
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: Y10S 117/904 Laser beam
• CPC Class Codes: Y10T 117/10 Apparatus
• CPC Class Codes: Y10T 117/1004 with means for measuring, testing, or sensing

Abstract

In accordance with one aspect, the present invention provides a method for providing polycrystalline films having a controlled microstructure as well as a crystallographic texture. The methods provide elongated grains or single-crystal islands of a specified crystallographic orientation. In particular, a method of processing a film on a substrate includes generating a textured film having crystal grains oriented predominantly in one preferred crystallographic orientation; and then generating a microstructure using sequential lateral solidification crystallization that provides a location-controlled growth of the grains orientated in the preferred crystallographic orientation.

Claims

1. A method of processing a film on a substrate, the method comprising:

providing a textured film comprising crystal grains having a crystallographic orientation predominantly in one direction; and

generating a microstructure using sequential lateral solidification crystallization for providing a location-controlled growth of said crystal grains orientated in said crystallographic orientation.

2. The method of claim 1, wherein sequential lateral solidification crystallization comprises:

generating a plurality of laser beam pulses;

directing the plurality of laser beam pulses through a mask to generate a plurality of patterned laser beams;

irradiating a portion of a film with one of the plurality of patterned beams, said beam having an intensity that is sufficient to melt through the entire thickness of the irradiated portion of the film, wherein the irradiated portion of the film laterally crystallizes upon cooling; and

repositioning the film to irradiate a subsequent portion with patterned beams, such that the subsequent portion of the film overlaps with the previously irradiated portion permitting further lateral growth of the crystal grains.

3. The method of claim 1, wherein sequential lateral solidification crystallization comprises:

generating a plurality of laser beam pulses;

directing the plurality of laser beam pulses through a mask to generate a plurality of patterned laser beams;

irradiating a portion of a selected region of a film with one of the plurality of patterned beams, said beam having an intensity that is sufficient to melt the irradiated portion of the film, wherein the irradiated portion of the film crystallizes upon cooling,

moving the film along a first translation pathway and moving the mask along a second translation pathway while successive portions of the selected region are irradiated with patterned beams, such that the selected region of the film is substantially completely crystallized in a single traversal of the patterned beams over the selected region of the film.

4. The method of claim 2, wherein the mask comprises a dot-patterned mask.

5. The method according to claim 4, wherein the mask includes opaque array patterns which include at least one of dot-shaped areas, hexagonal-shaped areas and rectangular-shaped areas.

6. The method of claim 1, wherein the textured film is generated by one of zone melt recrystallization, solid phase recrystallization, direct deposition methods, surface-energy driven secondary grain growth methods and pulsed laser crystallization methods.

7. The method of claim 6, wherein the direct deposition methods comprise one of chemical vapor deposition, sputtering and evaporation.

8. The method of claim 6, wherein the pulsed laser crystallization methods comprise one of sequential lateral solidification and multiple-pulse ELA processes.

9. The method of claim 1, wherein the film is a semiconductor film.

10. The method of claim 1, wherein the film is a metallic film.

11. The method of claim 1, wherein the one direction is preferably a direction normal to the surface of the film.

12. The method according to claim 1, wherein the predominant crystallographic orientation is a <

111>

orientation.

13. The method according to claim 1, wherein the predominant crystallographic orientation is a <

100>

orientation.

14. A system for processing a film on a substrate, comprising:

at least one laser for generating a plurality of laser beam pulses;

a film support for positioning the film that is capable of movement in at least one direction;

a mask support;

optics for directing a first set of laser beam pulses through a first mask to generate a textured film;

optics for directing a second set of laser beam pulses through a second mask onto the textured film; and

a controller for controlling the movement of the film support and mask support in conjunction with frequency of the first set of and second set of laser beam pulses.

15. The system of claim 14, wherein the textured film is generated by one of zone melt recrystallization, solid phase recrystallization, direct deposition methods, surface-energy driven secondary grain growth methods and pulsed laser crystallization methods.

16. The system of claim 14, wherein the direct deposition methods comprise one of chemical vapor deposition, sputtering, and evaporation.

17. The system of claim 14, wherein the pulsed laser crystallization methods comprise one of sequential lateral solidification and multiple-pulse ELA processes.

18. The system of claim 14, wherein the film is a semiconductor film.

19. The system of claim 14, wherein the film is a metallic film.

20. A device comprising a polycrystalline thin film, comprising:

a polycrystalline thin film having periodically located grains in which each of the grains are predominantly of one crystallographic orientation.

21. The device of claim 20, wherein the film is a semiconductor film.

22. The device of claim 20, wherein the film is a metallic film.

23. The device of claim 20, wherein the predominant crystallographic orientation is a <

111>

orientation.

24. The device of claim 20, wherein the predominant crystallographic orientation is a <

100>

orientation.

25. The device of claim 20, wherein the microstructure of the periodically located grains is a hexagonal pattern, a round pattern, a rectangular pattern, or a square pattern.

26. The device of claim 20, wherein the periodically located grains form columns of elongated grains.