SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20130187152A1
• Filed: 01/16/2013
• Published: 07/25/2013
• Est. Priority Date: 01/23/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Suzuki, Yukie, Noda, Kosei, Oikawa, Yoshiaki
• Granted Patent: US 9,653,614 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

A metal element of a metal film is introduced into the oxide semiconductor film by performing heat treatment in the state where the oxide semiconductor film is in contact with the metal film, so that a low-resistance region having resistance lower than that of a channel formation region is formed. A region of the metal film, which is in contact with the oxide semiconductor film, becomes a metal oxide insulating film by the heat treatment. After that, an unnecessary metal film is removed. Thus, the metal oxide insulating film can be formed over the low-resistance region.

Claims

1. A semiconductor device comprising:

an oxide semiconductor film comprising a channel formation region and a first region;

a gate insulating film over and in contact with the oxide semiconductor film;

a first insulating film over and in contact with the first region, the first insulating film comprising an oxide of a metal element;

a gate electrode over the gate insulating film, the gate electrode overlapping with the channel formation region; and

a second insulating film over and in contact with the gate electrode,

wherein the first region comprises the metal element.

2. The semiconductor device according to claim 1, wherein the oxide semiconductor film comprises an In—

Ga—

Zn-based oxide semiconductor.

3. The semiconductor device according to claim 1, further comprising:

a sidewall insulating film on a side surface of the gate electrode,

wherein the oxide semiconductor film comprises a second region between the first region and the channel formation region, the second region overlapping with the sidewall insulating film, and

wherein a resistance of the first region differs from a resistance of the second region.

4. The semiconductor device according to claim 1, wherein the gate insulating film comprises a first gate insulating film and a second gate insulating film over the first gate insulating film.

5. The semiconductor device according to claim 1,

wherein the oxide semiconductor film comprises chlorine, and

wherein the oxide semiconductor film has a chlorine concentration of 2×

10¹⁸ atoms/cm³ or lower.

6. A semiconductor device comprising:

an oxide film;

an oxide semiconductor film over the oxide film, the oxide semiconductor film comprising a channel formation region and a first region having a resistance lower than the channel formation region;

a gate insulating film over and in contact with the oxide semiconductor film;

a first insulating film over and in contact with the first region, the first insulating film comprising an oxide of a metal element; and

a gate electrode over the gate insulating film, the gate electrode overlapping with the channel formation region,

wherein the first region comprises the metal element.

7. The semiconductor device according to claim 6, wherein the oxide semiconductor film comprises an In—

Ga—

Zn-based oxide semiconductor.

8. The semiconductor device according to claim 6, wherein the gate electrode is in contact with the gate insulating film.

9. The semiconductor device according to claim 6, further comprising:

a sidewall insulating film over the gate insulating film and on a side surface of the gate electrode;

a protective insulating film over the gate insulating film, the sidewall insulating film, and the gate electrode; and

an electrode electrically connected to the first region.

10. The semiconductor device according to claim 9, wherein the electrode is one of a source electrode and a drain electrode.

11. The semiconductor device according to claim 9, wherein the oxide semiconductor film comprises an impurity region between the channel formation region and the first region, the impurity region having a resistance different from a resistance of the first region.

12. The semiconductor device according to claim 6, further comprising:

a sidewall insulating film over the gate insulating film and on a side surface of the gate electrode;

a protective insulating film over the first insulating film, the sidewall insulating film, and the gate electrode; and

an electrode electrically connected to the first region.

13. A semiconductor device according to claim 6, further comprising:

an electrode over the oxide film, wherein the oxide semiconductor film is over the oxide film and the electrode;

a sidewall insulating film over the gate insulating film and on a side surface of the gate electrode; and

a protective insulating film over the first insulating film, the sidewall insulating film, and the gate electrode.

14. The semiconductor device according to claim 13, wherein the oxide semiconductor film comprises an impurity region between the channel formation region and the first region, the impurity region having a resistance different from a resistance of the first region.

15. A semiconductor device according to claim 6, further comprising:

an electrode over the oxide film, wherein the oxide semiconductor film is over the oxide film and the electrode;

a sidewall insulating film over the first insulating film and on a side surface of the gate electrode; and

a protective insulating film over the first insulating film, the sidewall insulating film, and the gate electrode.

16. The semiconductor device according to claim 6, wherein the first insulating film comprises one or more elements selected from aluminum, indium, titanium, tin, tungsten, nickel, molybdenum, and zinc.

17. The semiconductor device according to claim 6,

wherein the oxide semiconductor film comprises a second region,

wherein the channel formation region is interposed between the first region and the second region, and

wherein each of the first region and the second region comprises one or more elements selected from aluminum, indium, titanium, tin, tungsten, nickel, molybdenum, zinc, phosphorus, arsenic, antimony, boron, nitrogen, helium, neon, argon, fluorine, and chlorine.

18. The semiconductor device according to claim 6, wherein the oxide semiconductor film comprises an oxide comprising one or more elements selected from indium, zinc, gallium, tin, hafnium, zirconium, titanium, scandium, yttrium, cerium, neodymium, and gadolinium.

19. The semiconductor device according to claim 6,

wherein the channel formation region comprises a crystal portion, and

wherein a c-axis of the crystal portion is aligned in a direction parallel to a normal vector of a surface where the oxide semiconductor film is formed.

20. A method for manufacturing a semiconductor device, comprising:

forming an oxide semiconductor film;

forming a gate insulating film over the oxide semiconductor film;

forming a gate electrode over the gate insulating film, the gate electrode overlapping with the oxide semiconductor film;

forming a metal film in contact with the oxide semiconductor film, the metal film comprising a metal element;

forming a first region comprising the metal element in the oxide semiconductor film and a metal oxide insulating film in contact with the first region by heat treatment performed in a state where the oxide semiconductor film is in contact with the metal film, wherein a part of the metal film remains unoxidized; and

removing the part.

21. The method for manufacturing a semiconductor device according to claim 20, further comprising:

introducing dopant into the oxide semiconductor film through the gate insulating film by using the gate electrode as a mask;

forming a sidewall insulating film on a side surface of the gate electrode; and

removing a part of the gate insulating film by using the gate electrode and the sidewall insulating film as masks to expose a surface of the oxide semiconductor film,

wherein the oxide semiconductor film is formed over an oxide film.

22. The method for manufacturing a semiconductor device according to claim 20, further comprising:

removing a part of the gate insulating film by using the gate electrode as a mask to expose a surface of the oxide semiconductor film;

forming a sidewall insulating film on a side surface of the gate electrode; and

introducing dopant into the oxide semiconductor film through the metal oxide insulating film by using the gate electrode and the sidewall insulating film as masks,

wherein the oxide semiconductor film is formed over an oxide film.

23. The method for manufacturing a semiconductor device according to claim 21, further comprising:

forming a protective insulating film and an interlayer insulating film over the metal oxide insulating film, the sidewall insulating film, and the gate electrode;

forming an opening portion reaching the first region in the interlayer insulating film; and

forming an electrode in the opening portion.

24. The method for manufacturing a semiconductor device according to claim 20, further comprising:

forming an electrode over an oxide film;

introducing dopant into the oxide semiconductor film through the gate insulating film by using the gate electrode as a mask;

forming a sidewall insulating film on a side surface of the gate electrode; and

removing a part of the gate insulating film by using the gate electrode and the sidewall insulating film as masks to expose a surface of the oxide semiconductor film,

wherein the oxide semiconductor film is formed over the electrode.

25. The method for manufacturing a semiconductor device according to claim 20, further comprising:

forming an electrode over an oxide film;

removing a part of the gate insulating film by using the gate electrode as a mask to expose a surface of the oxide semiconductor film;

forming a sidewall insulating film on a side surface of the gate electrode; and

introducing dopant into the oxide semiconductor film through the metal oxide insulating film by using the gate electrode and the sidewall insulating film as masks,

wherein the oxide semiconductor film is formed over the electrode.

26. The method for manufacturing a semiconductor device according to claim 20, wherein the heat treatment is performed in an inert gas atmosphere.

27. The method for manufacturing a semiconductor device according to claim 26, wherein one or more of nitrogen, helium, neon, and argon are used as the inert gas atmosphere.

28. The method for manufacturing a semiconductor device according to claim 20, wherein the metal film comprises one or more elements selected from aluminum, indium, titanium, tin, tungsten, nickel, molybdenum, and zinc.

29. The method for manufacturing a semiconductor device according to claim 21, wherein one or more elements selected from aluminum, indium, titanium, tin, tungsten, nickel, molybdenum, zinc, phosphorus, arsenic, antimony, boron, nitrogen, helium, neon, argon, fluorine, and chlorine are used as the dopant.