Method of fabrication of a crystalline silicon thin film semiconductor with a thin channel region

• US 6,337,232 B1
• Filed: 06/04/1999
• Issued: 01/08/2002
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Ohtani, Hisashi, Kusumoto, Naoto, Takemura, Yasuhiko
• Primary Examiner(s): Elms, Richard
• Assistant Examiner(s): Owens, Beth E.
• Application Number:
  US09/325,572
• Time in Patent Office: 949 Days
• Field of Search: 438/151, 438/401, 438/166, 438/149
• US Class Current: 438/151
• CPC Class Codes: C30B 1/023 from solids with amorphous structure
• CPC Class Codes: C30B 29/06 Silicon
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02488 Insulating materials
• CPC Class Codes: H01L 21/02491 Conductive materials
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02672 using crystallisation enhancing elements
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 27/1233 with different thicknesses of the active layer in different devices
• CPC Class Codes: H01L 29/0657 characterised by the shape of the body
• 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
• CPC Class Codes: H01L 29/78675 with normal-type structure, e.g. with top gate
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

A method for forming a semiconductor device is disclosed. A semiconductor film comprising silicon is formed on a substrate. The semiconductor film is crystallized. The crystallized semiconductor film is patterned into a marker part for aligning a mask and an insular semiconductor part at the same time. A part of the semiconductor film to become a channel formation region is thinned to a thickness 300 Å or less.

Claims

1. A method for forming a semiconductor device comprising the steps of:

forming a semiconductor film comprising silicon on an insulating surface;

crystallizing said semiconductor film; and

thinning at least a portion of the crystallized semiconductor film to become a channel-forming region to a thickness of 300 Å

or less;

patterning the crystallized semiconductor film into a marker part for aligning a mask and an insular semiconductor part at the same time.

7. The method of claim 1 further comprising the step of thinning the crystallized semiconductor film before said patterning step.

10. The method of the claim 1 wherein the crystallization is promoted by an element for promoting crystallization is promoted by an element for promoting crystallization of silicon.

16. The method of claim 10 wherein said element is nickel, palladium, platinum, cobalt or iron.

2. A method for forming a semiconductor device comprising the steps of:

forming a semiconductor film comprising silicon on an insulating surface;

crystallizing said semiconductor film;

thinning at least a portion of the crystallized semiconductor film to become a channel-forming region to a thickness of 300 Å

or less;

patterning the crystallized semiconductor film into a marker part for aligning a mask and an insular semiconductor part at the same time; and

forming a transistor comprising a source region, a drain region and a channel-forming region formed in said insular semiconductor part, said channel-forming region being formed between said source region and said drain region.

8. The method of claim 2 further comprising the step of the thinning of the crystallized semiconductor film before said patterning step.

11. The method of the claim 2 wherein the crystallization is promoted by an element for promoting crystallization is promoted by an element for promoting crystallization of silicon.

17. The method of claim 11 wherein said element is nickel, palladium, platinum, cobalt or iron.

3. A method for forming a semiconductor device comprising the steps of:

forming a semiconductor film comprising silicon on an insulating surface;

crystallizing said semiconductor film;

thinning at least a portion of the crystallized semiconductor film to become a channel-forming region to a thickness of 300 Å

or less;

patterning the crystallized semiconductor film into a marker part for aligning a mask and an insular semiconductor part at the same time;

forming a gate insulating film over said marker part and said insular semiconductor part;

forming a gate electrode on said gate insulating film; and

forming a source region and a drain region by introducing a dopant into said insular semiconductor part using a mask comprising said gate electrode to thereby form a channel-forming region adjacent to said gate electrode and between said source region and said drain region.

12. The method of the claim 3 wherein the crystallization is promoted by an element for promoting crystallization is promoted by an element for promoting crystallization of silicon.

18. The method of claim 12 wherein said element is nickel, palladium, platinum, cobalt or iron.

4. A method for forming a semiconductor device comprising the steps of:

forming a semiconductor film comprising silicon on an insulating surface;

crystallizing said semiconductor film by heat treatment;

irradiating the crystallized semiconductor film with a laser light;

thinning at least a portion of the crystallized semiconductor film to become a channel-forming region to a thickness of 300 Å

or less after said irradiating step;

patterning the crystallized semiconductor film into a marker part for aligning a mask and an insular semiconductor part at the same time after said irradiating step;

forming a gate insulating film over said marker part and said insular semiconductor part;

forming a gate electrode on said gate insulating film; and

forming a source region and a drain region by introducing a dopant into said insular semiconductor part using a mask comprising said gate electrode to thereby form a channel-forming region adjacent to said gate electrode and between said source region and said drain region.

9. The method of claim 4 further comprising the step of the thinning of the crystallized semiconductor film before said patterning step.

13. The method of the claim 4 wherein the crystallization is promoted by an element for promoting crystallization is promoted by an element for promoting crystallization of silicon.

19. The method of claim 13 wherein said element is nickel, palladium, platinum, cobalt or iron.

5. A method for forming a semiconductor device comprising the steps of:

forming a semiconductor film comprising silicon on an insulating surface;

crystallizing said semiconductor film;

thinning at least a portion of the crystallized semiconductor film to become a channel-forming region to a thickness of 300 Å

or less;

patterning the semiconductor film into a marker part for aligning a mask and an insular semiconductor part which includes said portion to become said channel-forming region, at the same time;

forming a gate insulating film over said marker part and said insular semiconductor part;

forming a gate electrode on said gate insulating film; and

forming a source region and a drain region by introducing a dopant into said insular semiconductor part using a mask comprising said gate electrode to thereby form said channel-forming region adjacent to said gate electrode and between said source region and said drain region.

14. The method of the claim 5 wherein the crystallization is promoted by an element for promoting crystallization is promoted by an element for promoting crystallization of silicon.

20. The method of claim 14 wherein said element is nickel, palladium, platinum, cobalt or iron.

6. A method for forming a semiconductor device comprising the steps of:

forming a semiconductor film comprising silicon on an insulating surface;

crystallizing said semiconductor film;

thinning at least a portion of the crystallized semiconductor film to become a channel-forming region to a thickness of 300 Å

or less;

patterning the semiconductor film into a marker part for aligning a mask and an insular semiconductor part which includes said portion to become said channel-forming region, at the same time;

forming a gate insulating film having a thickness of 500 Å

or less over said marker part and said insular semiconductor part;

forming a gate electrode on said gate insulating film; and

forming a source region and a drain region by introducing a dopant into said insular semiconductor part using a mask comprising said gate electrode to thereby form said channel-forming region adjacent to said gate electrode and between said source region and said drain region.

15. The method of the claim 6 wherein the crystallization is promoted by an element for promoting crystallization is promoted by an element for promoting crystallization of silicon.

21. The method of claim 15 wherein said element is nickel, palladium, platinum, cobalt or iron.