Method for forming polycrystalline silicon film

• US 6,391,747 B1
• Filed: 02/07/2000
• Issued: 05/21/2002
• Est. Priority Date: 02/09/1999
• Status: Expired due to Term

• Current Assignee: Gold Charm Limited (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Okumura, Hiroshi, Sera, Kenji
• Primary Examiner(s): Nelms, David
• Assistant Examiner(s): LE, DUNG ANH
• Application Number:
  US09/498,619
• Time in Patent Office: 834 Days
• Field of Search: 438/478, 438/159-162, 438/166, 438/486-488
• US Class Current: 438/478
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02672 using crystallisation enhancing elements
• CPC Class Codes: H01L 21/02675 using laser beams

Abstract

In a method for forming a polycrystalline silicon (poly-Si) thin film on an inexpensive glass substrate, a cap film doped with a catalyst element is provided on an amorphous silicon (a-Si) film formed on the substrate. The a-Si film is transformed into the poly-Si film by irradiating an excimer laser beam on the a-Si film through the cap film. Thereafter, the cap film is removed from the poly-Si film together with the catalyst element precipitated therein.

Claims

1. A semiconductor-thin-film forming method comprising:

a step of forming a non-single-crystal semiconductor film on a substrate having an insulation surface;

a step of forming a cap film of a transparent insulating material on said semiconductor film, said cap film containing a catalyst element for accelerating crystallization of said semiconductor film;

a step of irradiating a laser beam on said semiconductor film through said cap film; and

a step of removing said cap film after said step of irradiating said laser beam.

2. The semiconductor-thin-film forming method according to claim 1, wherein said catalyst element is added to said cap film after said step of forming said cap film.

3. The semiconductor-thin-film forming method according to claim 1, wherein said catalyst element is added to said cap film during said step of forming said cap film.

4. The semiconductor-thin-film forming method according to claim 2, wherein said catalyst element is added to said cap film by using an ion implantation.

5. The semiconductor-thin-film forming method according to claim 3, wherein said catalyst element is added to said cap film simultaneously when said cap film is formed by using a sputtering method.

6. The semiconductor-thin-film forming method according to claim 3, wherein said catalyst element is added to said cap film by using a hot wire CVD method.

7. The semiconductor-thin-film forming method according to claim 1, wherein said cap film has a thickness of at least 10 nm.

8. The semiconductor-thin-film forming method according to claim 1, wherein said cap film is removed by using a dry etching method provided with an etching gas containing halogen.

9. The semiconductor-thin-film forming method according to claim 1, wherein said step of removing said cap film includes a RCA cleaning.

10. The semiconductor-thin-film forming method according to claim 1, said catalyst element is selected from a group consisting of Ni, Pt, Pd, Co, Fe, Cu, Au, Ag, Cr, and mixture thereof.

11. The semiconductor-thin-film forming method according to claim 1, wherein said cap film is a silicon oxide film.

12. The semiconductor-thin-film forming method according to claim 1, wherein said laser beam is an excimer laser beam.

13. A method of making a semiconductor thin film, comprising the steps of:

forming a cap film that is at least 10 nm thick on a non-single-crystal semiconductor film that is on a substrate having an insulation surface, the cap film being a transparent electrical insulator and containing a catalyst that accelerates crystallization of the semiconductor film;

irradiating a laser beam through the cap film onto the semiconductor film to crystallize the semiconductor film; and

removing the cap film after the irradiating step.

14. The method of claim 13, wherein the cap film is silicon oxide to which the catalyst is added after the cap film is formed.

15. The method of claim 13, wherein the cap film is silicon oxide to which the catalyst is added while forming the cap film.

16. A method of making a semiconductor thin film, comprising the steps of:

forming a silicon oxide cap film on a non-single-crystal semiconductor film that is on a substrate having an insulation surface, the silicon oxide cap film containing a catalyst that accelerates crystallization of the semiconductor film;

irradiating a laser beam through the silicon oxide cap film onto the semiconductor film to crystallize the semiconductor film; and

removing the silicon oxide cap film after the irradiating step.

17. The method of claim 16, wherein the catalyst is added after the cap film is formed.

18. The method of claim 16, wherein the catalyst is added while forming the cap film.

19. The method of claim 16, wherein the silicon oxide cap film is at least 10 nm thick.