Semiconductor device forming method

• US 7,391,051 B2
• Filed: 12/30/2005
• Issued: 06/24/2008
• Est. Priority Date: 03/12/1993
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ohtani, Hisashi, Takayama, Toru, Takemura, Yasuhiko, Zhang, Hongyong, Miyanaga, Akiharu
• Primary Examiner(s): POTTER, ROY KARL
• Application Number:
  US11/321,640
• Publication Number:
  US 20060192202A1
• Time in Patent Office: 907 Days
• Field of Search: 257/57, 257/347, 257/59
• US Class Current: 257/57
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02672 using crystallisation enhancing elements
• CPC Class Codes: H01L 27/1277 using a crystallisation promoting species, e.g. local introduction of Ni catalyst
• CPC Class Codes: H01L 27/1296 adapted to increase the uniformity of device parameters
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/66757 Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate

Abstract

In thin film transistors (TFTs) having an active layer of crystalline silicon adapted for mass production, a catalytic element is introduced into doped regions of an amorphous silicon film by ion implantation or other means. This film is crystallized at a temperature below the strain point of the glass substrate. Further, a gate insulating film and a gate electrode are formed. Impurities are introduced by a self-aligning process. Then, the laminate is annealed below the strain point of the substrate to activate the dopant impurities. On the other hand, Neckel or other element is also used as a catalytic element for promoting crystallization of an amorphous silicon film. First, this catalytic element is applied in contact with the surface of the amorphous silicon film. The film is heated at 450 to 650° C. to create crystal nuclei. The film is further heated at a higher temperature to grow the crystal grains. In this way, a crystalline silicon film having improved crystallinity is formed.

Claims

1. A semiconductor device, comprising:

a substrate;

an active matrix portion formed over the substrate; and

a CPU formed over the substrate and operationally connected to the active matrix portion, each of the active matrix portion and the CPU comprising at least one thin film transistor comprising a semiconductor island as an active layer,

wherein said semiconductor island comprises crystalline silicon and has a crystal growth direction approximately aligned with <

111>

axis of the crystalline silicon.

2. The semiconductor device according to claim 1, wherein said semiconductor island contains a metal for promoting crystallization of silicon.

3. The semiconductor device according to claim 1, wherein said semiconductor island contains a material for promoting crystallization of silicon, said material comprising at least one element selected from the group consisting of nickel, cobalt, iron and platinum.

4. A semiconductor device, comprising:

a substrate;

an active matrix portion formed over the substrate; and

a CPU formed over the substrate and operationally connected to the active matrix portion, each of the active matrix portion and the CPU comprising at least one thin film transistor comprising a semiconductor island as an active layer,

wherein said semiconductor island comprises crystalline silicon and has a <

111>

axis extending in parallel with a surface of the substrate.

5. The semiconductor device according to claim 4, wherein said semiconductor island contains a metal for promoting crystallization of silicon.

6. The semiconductor device according to claim 4, wherein said semiconductor island contains a material for promoting crystallization of silicon, said material comprising at least one element selected from the group consisting of nickel, cobalt, iron and platinum.

7. A semiconductor device, comprising:

a substrate;

an active matrix portion formed over the substrate; and

a correction memory formed over the substrate for storing information regarding characteristics of the active matrix portion, each of the active matrix portion and the correction memory comprising at least one thin film transistor comprising a semiconductor island as an active layer,

wherein said semiconductor island comprises crystalline silicon and contains a metal for promoting crystallization of silicon.

8. The semiconductor device according to claim 7, wherein said metal comprises at least one element selected from the group consisting of nickel, cobalt, iron and platinum.

9. A semiconductor device, comprising:

a substrate;

an active matrix portion formed over the substrate; and

a correction memory formed over the substrate for storing information regarding characteristics of the active matrix portion, each of the active matrix portion and the correction memory comprising at least one thin film transistor comprising a semiconductor island as an active layer,

wherein said semiconductor island comprises crystalline silicon and has a crystal growth direction approximately parallel with a major surface of the substrate.

10. The semiconductor device according to claim 9, wherein said semiconductor island contains a metal for promoting crystallization of silicon.

11. The semiconductor device according to claim 9, wherein said semiconductor island contains a material for promoting crystallization of silicon, said material comprising at least one element selected from the group consisting of nickel, cobalt, iron and platinum.

12. A semiconductor device, comprising:

a substrate;

an active matrix portion formed over the substrate; and

a correction memory formed over the substrate for storing information regarding characteristics of the active matrix portion, each of the active matrix portion and the correction memory comprising at least one thin film transistor comprising a semiconductor island as an active layer,

wherein said semiconductor island comprises crystalline silicon and has a crystal growth direction approximately aligned with <

111>

axis of the crystalline silicon.

13. The semiconductor device according to claim 12, wherein said semiconductor island contains a metal for promoting crystallization of silicon.

14. The semiconductor device according to claim 12, wherein said semiconductor island contains a material for promoting crystallization of silicon, said material comprising at least one element selected from the group consisting of nickel, cobalt, iron and platinum.

15. A semiconductor device, comprising:

a substrate;

an active matrix portion formed over the substrate; and

a correction memory formed over the substrate for storing information regarding characteristics of the active matrix portion, each of the active matrix portion and the correction memory comprising at least one thin film transistor comprising a semiconductor island as an active layer,

wherein said semiconductor island comprises crystalline silicon and has a <

111>

axis extending in parallel with a surface of the substrate.

16. The semiconductor device according to claim 15, wherein said semiconductor island contains a metal for promoting crystallization of silicon.

17. The semiconductor device according to claim 15, wherein said semiconductor island contains a material for promoting crystallization of silicon, said material comprising at least one element selected from the group consisting of nickel, cobalt iron and platinum.