Semiconductor device and method of producing the same

• US 6,673,659 B2
• Filed: 01/30/2001
• Issued: 01/06/2004
• Est. Priority Date: 01/31/2000
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.), Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.), Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Miwa, Masahiko, Iwai, Michinori, Sakama, Mitsunori, Ishimaru, Noriko
• Primary Examiner(s): GEBREMARIAM, SAMUEL A
• Application Number:
  US09/771,625
• Publication Number:
  US 20010011725A1
• Time in Patent Office: 1,071 Days
• Field of Search: 438/150, 438/166, 438/486, 438/149, 257/347
• US Class Current: 438/149
• CPC Class Codes: G02F 1/13454 Drivers integrated on the active matrix substrate G02F1/136277 takes precedence
• CPC Class Codes: H01L 2029/7863 with an LDD consisting of more than one lightly doped zone or having a non-homogeneous dopant distribution, e.g. graded LDD
• CPC Class Codes: H01L 21/67236 the substrates being processed being not semiconductor wafers, e.g. leadframes or chips
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/1218 with a particular composition or structure of the substrate
• CPC Class Codes: H01L 27/1262 with a particular formation, treatment or coating of the substrate
• 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 29/78621 with LDD structure or an extension or an offset region or characterised by the doping profile
• CPC Class Codes: H01L 29/78627 with a significant overlap between the lightly doped drain and the gate electrode, e.g. GOLDD
• CPC Class Codes: H01L 29/78636 with supplementary region or layer for improving the flatness of the device

Abstract

A base film is formed for the TFTs in order to prevent diffusion of impurities from the glass substrate into the active layer, to maintain stability in the characteristics such as Vth and S-value of the TFTs and to maintain enhanced productivity. A film in which the composition ratios of N, O and H are continuously changed by changing the flow rates of H₂ and N₂O, is used as the base film to prevent a change in the TFT characteristics. The base film can be formed by varying the flow rates of H₂ and N₂O in the same film-forming chamber to enhance the productivity.

Claims

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

forming an insulating film comprising a silicon oxynitride film on a substrate; and

forming a semiconductor film on said insulating film,

wherein said insulating film comprises at least a first layer in contact with said substrate and a second layer in contact with said semiconductor film,

wherein said first layer is formed from SiH₄, N₂O, and H₂, and

wherein said second layer is formed from SiH₄ and N₂O.

2. A method according to claim 1 wherein said first layer and said second layer forming steps are performed in a same film-forming chamber of a plasma CVD apparatus.

3. A method according to claim 1 wherein a nitrogen concentration in said silicon oxynitride film decreases continuously toward an interface between said insulating film and said semiconductor film.

4. A method according to claim 1 wherein an oxygen concentration in said silicon oxynitride film increases continuously toward an interface between said insulating film and said semiconductor film.

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

forming an insulating film on a substrate; and

forming a semiconductor film on said insulating film,

wherein said insulating film comprises a silicon oxynitride film formed from SiH₄, N₂O, and H₂, and

wherein said silicon oxynitride film is formed by decreasing a flow rate of said H₂ and increasing a flow rate of said N₂O from a region in contact with said substrate to a region in contact with said semiconductor film.

6. A method according to claim 5 wherein a nitrogen concentration in said silicon oxynitride film decreases continuously toward an interface between said insulating film and said semiconductor film.

7. A method according to claim 5 wherein an oxygen concentration in said silicon oxynitride film increases continuously toward an interface between said insulating film and said semiconductor film.

8. A method of producing a semiconductor device comprising the steps of:

forming an insulating film comprising a silicon oxynitride film on a substrate; and

forming a semiconductor film on said insulating film,

wherein said insulating film comprises at least a first layer in contact with said substrate and a second layer in contact with said semiconductor film,

wherein said first layer is formed at a gas flow rate ratio of Xh (=H₂(SiH₄+N₂O)) from 0.5 to 5, and a gas flow rate ratio of Xg (=N₂O/(SiH₄+N₂O)) from 0.94 to 0.97, and

wherein said second layer is formed at a gas flow rate ratio of Xh (=H₂/(SiH₄+N₂O)) equal to 0, and a gas flow rate ratio of Xg (=N₂O/(SiH₄+N₂O)) from 0.97 to 0.99.

9. A method according to claim 8 wherein said steps of forming said first layer and said second layer are performed in a same film-forming chamber of a plasma CVD apparatus.

10. A method according to claim 8 wherein a nitrogen concentration in said silicon oxynitride film decreases continuously toward an interface between said insulating film and said semiconductor film.

11. A method according to claim 8 wherein an oxygen concentration in said silicon oxynitride film increases continuously toward an interface between said insulating film and said semiconductor film.

12. A method of producing a semiconductor device comprising the steps of:

forming an insulating film comprising a silicon oxynitride film on a substrate; and

forming a semiconductor film on said insulating film,

wherein said insulating film is formed by changing gas flow rate ratios of Xh (=H₂/(SiH₄+N₂O)) from 0.5 to 5, and Xg (=N₂O/(SiH₄+N₂O)) from 0.94 to 0.97 to Xh (=H₂/(SiH₄+N₂O)) equal to 0, and Xg (=N₂O/(SiH₄+N₂O)) from 0.97 to 0.99 from a region in contact with said substrate to a region in contact with said semiconductor film.

13. A method according to claim 12 wherein a nitrogen concentration in said silicon oxynitride film decreases continuously toward an interface between said insulating film and said semiconductor film.

14. A method according to claim 12 wherein an oxygen concentration in said silicon oxynitride film increases continuously toward an interface between said insulating film and said semiconductor film.

15. A method of producing a semiconductor device comprising the steps of:

forming a first silicon oxynitride film in contact with a substrate, said first silicon oxynitride film having hydrogen concentration from 1.5 to 5 atomic %, nitrogen concentration from 2 to 10 atomic %, and oxygen concentration from 50 to 60 atomic %;

forming a second silicon oxynitride film, said second silicon oxynitride film having hydrogen concentration from 0.1 to 2 atomic %, nitrogen concentration from 0.1 to 2 atomic %, and oxygen concentration from 60 to 65 atomic %; and

forming a semiconductor film on said second silicon oxynitride film,

wherein said forming steps are performed continuously in a same film-forming chamber.

16. A method according to claim 15 wherein a nitrogen concentration in said first and second silicon oxynitride films decreases continuously toward an interface between said second silicon oxynitride film and said semiconductor film.

17. A method according to claim 15 wherein an oxygen concentration in said first and second silicon oxynitride films increases continuously toward an interface between said second silicon oxynitride film and said semiconductor film.

18. A method of producing a semiconductor device comprising the steps of:

forming an insulating film comprising a silicon oxynitride film on a substrate; and

forming a semiconductor film on said insulating film,

wherein a region of said silicon oxynitride film in contact with said substrate has hydrogen concentration from 1.5 to 5 atomic %, nitrogen concentration from 2 to 10 atomic %, and oxygen concentration from 50 to 60 atomic %,

wherein a region of said silicon oxynitride film in contact with said semiconductor film has hydrogen concentration from 0.1 to 2 atomic %, nitrogen concentration from 0.1 to 2 atomic %, and oxygen concentration from 60 to 65 atomic %,

wherein said silicon oxynitride film continuously changes a composition thereof, and

wherein said forming steps are performed in a same film-forming chamber.

19. A method according to claim 18 wherein a nitrogen concentration in said silicon oxynitride film decreases continuously toward an interface between said insulating film and said semiconductor film.

20. A method according to claim 18 wherein an oxygen concentration in said silicon oxynitride film increases continuously toward an interface between said insulating film and said semiconductor film.

21. A method of producing a semiconductor device comprising the steps of:

forming a first insulating film comprising a silicon oxynitride film in contact with a substrate, said silicon oxynitride film having an oxygen composition ratio to silicon from 1.4 to 1.8, a nitrogen composition ratio to silicon from 0.05 to 0.5;

forming a second insulating film comprising a silicon oxynitride film on said first insulating film, said silicon oxynitride film having an oxygen composition ratio to silicon from 1.7 to 2, a nitrogen composition ratio to silicon from 0.02 to 0.06; and

forming a semiconductor film on said second insulating film,

wherein said forming steps are performed continuously in a same film-forming chamber.

22. A method according to claim 21 wherein a nitrogen concentration in said silicon oxynitride film decreases continuously toward an interface between said second insulating film and said semiconductor film.

23. A method according to claim 21 wherein an oxygen concentration in said silicon oxynitride film increases continuously toward an interface between said second insulating film and said semiconductor film.

24. A method of producing a semiconductor device comprising the steps of:

forming an insulating film comprising a silicon oxynitride film on a substrate; and

forming a semiconductor film on said insulating film,

wherein a region of said silicon oxynitride film in contact with said substrate has an oxygen composition ratio to silicon from 1.4 to 1.8, and a nitrogen composition ratio to silicon from 0.05 to 0.5,

wherein a region of said silicon oxynitride film in contact with said semiconductor film has an oxygen composition ratio to silicon from 1.7 to 2, and a nitrogen composition ratio to silicon from 0.02 to 0.06,

wherein said silicon oxynitride film continuously changes a composition thereof, and

wherein said forming steps are performed in a same film-forming chamber.

25. A method according to claim 24 wherein a nitrogen concentration in said silicon oxynitride film decreases continuously toward an interface between said insulating film and said semiconductor film.

26. A method according to claim 24 wherein an oxygen concentration in said silicon oxynitride film increases continuously toward an interface between said insulating film and said semiconductor film.

27. A method of producing a semiconductor device comprising the steps of:

forming a first silicon oxynitride film in contact with a substrate, said first silicon oxynitride film having hydrogen concentration from 1.5 to 5 atomic %, nitrogen concentration from 2 to 10 atomic %, and oxygen concentration from 50 to 60 atomic %;

forming a second silicon oxynitride film, said second silicon oxynitride film having hydrogen concentration from 0.1 to 2 atomic %, nitrogen concentration from 0.1 to 2 atomic %, and oxygen concentration from 60 to 65 atomic %; and

forming a semiconductor film on said second silicon oxynitride film.

28. A method according to claim 27 wherein a nitrogen concentration in said first and second silicon oxynitride films decreases continuously toward an interface between said second silicon oxynitride film and said semiconductor film.

29. A method according to claim 27 wherein an oxygen concentration in said first and second silicon oxynitride films increases continuously toward an interface between said second silicon oxynitride film and said semiconductor film.

30. A method of producing a semiconductor device comprising the steps of:

forming a first insulating film comprising a silicon oxynitride film in contact with a substrate, said silicon oxynitride film having an oxygen composition ratio to silicon from 1.4 to 1.8, a nitrogen composition ratio to silicon from 0.05 to 0.5;

forming a second insulating film comprising a silicon oxynitride film on said first insulating film, said silicon oxynitride film having an oxygen composition ratio to silicon from 1.7 to 2, a nitrogen composition ratio to silicon from 0.02 to 0.06; and

forming a semiconductor film on said second insulating film.

31. A method according to claim 30 wherein a nitrogen concentration in said silicon oxynitride film decreases continuously toward an interface between said second insulating film and said semiconductor film.

32. A method according to claim 30 wherein an oxygen concentration in said silicon oxynitride film increases continuously toward an interface between said second insulating film and said semiconductor film.