Method for manufacturing polycrystalline semiconductor layers and thin-film transistors, and laser annealing apparatus

• US 20020142567A1
• Filed: 02/22/2002
• Published: 10/03/2002
• Est. Priority Date: 02/22/2001
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Imao, Kazuhiro, Wakita, Ken, Ogata, Hidenori, Nakanishi, Shiro, Morimoto, Yoshihiro, Hagino, Takashi, Monzen, Toshio
• Granted Patent: US 6,797,651 B2
• Time in Patent Office: Days
• US Class Current: 438/487
• 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 21/02595 polycrystalline
• CPC Class Codes: H01L 21/02675 using laser beams
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 21/268 using electromagnetic radiation, e.g. laser radiation

Abstract

A laser annealing apparatus is provided in which laser light is irradiated onto an amorphous semiconductor layer placed inside an annealing chamber (100) through a chamber window (120), thereby poly-crystallizing the amorphous semiconductor film. Inside the annealing chamber 100 a low degree vacuum (about 1.3×10³ Pa to about 1.3 Pa) is maintained at a room temperature. An inert gas such as nitrogen, hydrogen, or argon is introduced into the atmosphere while maintaining the low degree vacuum. As a result, the surface smoothness of the polycrystalline semiconductor layer is comparable to that resulting from high degree vacuum annealing, while, unlike high degree vacuum annealing, there is less contamination of the chamber window (120) and productivity is improved.

Claims

1. A method for manufacturing a polycrystalline semiconductor layer, comprising the step of laser annealing an amorphous semiconductor layer in a low degree vacuum atmosphere.

2. The method defined in claim 1, wherein said annealing is performed under a pressure between about 1.3×

10³ Pa and about 1.3 Pa.

3. The method defined in claim 2, wherein said annealing is performed in an annealing atmosphere containing an inert gas.

4. The method defined in claim 3, wherein said inert gas includes a gas selected from the group consisting of nitrogen, hydrogen, argon, and neon.

5. The method defined in claim 1, wherein said annealing is performed in an annealing atmosphere containing an inert gas.

6. The method defined in claim 5, wherein said inert gas includes a gas selected from the group consisting of nitrogen, hydrogen, argon, and neon.

7. A method of manufacturing a thin-film transistor, comprising the steps of:

forming an amorphous silicon layer on a substrate;

disposing said substrate inside an annealing chamber;

creating a low degree vacuum atmosphere within said annealing chamber; and

irradiating focused laser light onto the amorphous silicon layer overlying said substrate through a chamber window built in said annealing chamber to anneal and poly-crystallize said amorphous silicon, whereby a polycrystalline silicon layer is formed as an active layer of said thin-film transistor.

8. The method defined in claim 7, wherein said annealing is performed under a pressure between about 1.3×

10³ Pa and about 1.3 Pa.

9. The method defined in claim 7, wherein said annealing is performed in an annealing atmosphere containing an inert gas.

10. The method defined in claim 9, wherein said inert gas includes a gas selected from the group consisting of nitrogen, hydrogen, argon, and neon.

11. A laser annealing apparatus, wherein focused laser light is irradiated through a chamber window onto an object to be processed placed inside a annealing chamber, comprising:

an introducer for introducing an inert gas into said annealing chamber during annealing;

a pump for reducing the pressure in said annealing chamber; and

a pressure controller for controlling the pressure in said annealing chamber to maintain a pressure between about 1.3×

10³ Pa and about 1.3 Pa.