Method for manufacturing semiconductor device

• US 9,564,457 B2
• Filed: 02/11/2015
• Issued: 02/07/2017
• Est. Priority Date: 01/26/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Patel, Reema
• Application Number:
  US14/619,310
• Publication Number:
  US 20150155312A1
• Time in Patent Office: 727 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: H01L 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/36 characterised by the concentration or distribution of impurities in the bulk material within semiconductor regions H01L29/06
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• CPC Class Codes: H01L 29/78651 Silicon transistors H01L29/78606 - H01L29/78645 take precedence
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

To improve productivity of a transistor that includes an oxide semiconductor and has good electrical characteristics. In a top-gate transistor including a gate insulating film and a gate electrode over an oxide semiconductor film, a metal film is formed over the oxide semiconductor film, oxygen is added to the metal film to form a metal oxide film, and the metal oxide film is used as a gate insulating film. After an oxide insulating film is formed over the oxide semiconductor film, a metal film may be formed over the oxide insulating film. Oxygen is added to the metal film to form a metal oxide film and added also to the oxide semiconductor film or the oxide insulating film.

Claims

1. A semiconductor device comprising:

a first insulating film;

a transistor over the first insulating film; and

,

a second insulating film over the first insulating film and the transistor;

wherein the transistor comprises;

an oxide semiconductor film over the first insulating film;

a gate insulating film over the oxide semiconductor film;

a gate electrode over the oxide semiconductor film with the gate insulating film provided therebetween; and

a pair of electrodes electrically connected with the oxide semiconductor film,

wherein the oxide semiconductor film includes low-resistance regions of which conductivity is higher than or equal to 0.1 S/cm and lower than or equal to 1000 S/cm,

wherein the low-resistance regions being electrically connected with the pair of electrodes,

wherein the second insulating film comprises aluminum oxide of which film density is higher than or equal to 3.2 g/cm³, and

wherein the pair of electrodes are in contact with side surfaces of the oxide semiconductor film.

2. The semiconductor device according to claim 1, wherein the low-resistance regions includes dopant contained at a concentration of greater than or equal to 5×

10¹⁸ atoms/cm³ and smaller than or equal to 1×

10²² atoms/cm³.

3. The semiconductor device according to claim 1, wherein the low-resistance regions includes at least one of the group of boron, nitrogen, phosphorus, and arsenic.

4. The semiconductor device according to claim 1, wherein the low-resistance regions includes at least one of the group of helium, neon, argon, krypton, and xenon.

5. The semiconductor device according to claim 1, wherein the oxide semiconductor film comprises one or more elements selected from the group of In, Ga, Sn, and Zn.

6. The semiconductor device according to claim 1, wherein the oxide semiconductor film comprises a hydrogen of which concentration is lower than 5×

10¹⁸ atoms/cm³.

7. The semiconductor device according to claim 1, wherein the oxide semiconductor film comprises a crystal part of which c-axes are aligned in a direction parallel to a normal vector of a surface of the crystal part.

8. The semiconductor device according to claim 1, wherein the first insulating film includes an oxide insulating film of which released amount of oxygen molecules is greater than or equal to 1×

10¹⁸/cm³ in thermal desorption spectroscopy.

9. The semiconductor device according to claim 1, further comprising a third insulating film between the transistor and the second insulating film, wherein a surface of the third insulating film is flat.

10. A semiconductor device comprising:

a first insulating film;

a first transistor over the first insulating film;

a second transistor electrically connected with the first transistor; and

a second insulating film over the first insulating film and the first transistor;

wherein the first transistor comprises;

an oxide semiconductor film over the first insulating film;

a first gate insulating film over the oxide semiconductor film;

a first gate electrode overlapping the oxide semiconductor film with the first gate insulating film provided therebetween; and

a first source electrode and a first drain electrode electrically connected with the oxide semiconductor film,

wherein the second transistor comprises;

a channel region provided in a semiconductor substrate;

a second gate insulating film over the semiconductor substrate;

a second source electrode and a second drain electrode electrically in connected with the semiconductor substrate; and

a second gate electrode overlapping the channel region with the second gate insulating film provided therebetween,

wherein the oxide semiconductor film includes low-resistance regions of which conductivity is higher than or equal to 0.1 S/cm and lower than or equal to 1000 S/cm,

wherein the low-resistance regions being electrically connected with the first source electrode and the first drain electrode, and

wherein the second insulating film comprises aluminum oxide of which film density is higher than or equal to 3.2 g/cm³.

11. The semiconductor device according to claim 10, wherein the semiconductor substrate contains silicon.

12. The semiconductor device according to claim 10,

wherein the second source electrode or the second drain electrode is electrically connected with the first source electrode or the first drain electrode, and

wherein the second gate electrode is electrically connected with the first gate electrode.

13. The semiconductor device according to claim 10, further comprising a capacitor electrically connected with the first transistor,

wherein the capacitor has a first electrode and a second electrode, and

wherein the first electrode is electrically connected with the first source electrode or the first drain electrode.

14. The semiconductor device according to claim 10, further comprising a capacitor electrically connected with the first transistor,

wherein the capacitor has a first electrode and a second electrode,

wherein the first electrode is electrically connected with the first source electrode or the first drain electrode, and

wherein the first electrode is electrically connected with the second gate electrode.

15. The semiconductor device according to claim 10, wherein the low-resistance regions includes dopant contained at a concentration of greater than or equal to 5×

10¹⁸ atoms/cm³ and smaller than or equal to 1×

10²² atoms/cm³.

16. The semiconductor device according to claim 10, wherein the low-resistance regions includes at least one of the group of boron, nitrogen, phosphorus, and arsenic.

17. The semiconductor device according to claim 10, wherein the low-resistance regions includes at least one of the group of helium, neon, argon, krypton, and xenon.

18. The semiconductor device according to claim 10, wherein the oxide semiconductor film comprises one or more elements selected from the group of In, Ga, Sn, and Zn.

19. The semiconductor device according to claim 10, wherein the oxide semiconductor film comprises a hydrogen of which concentration is lower than 5×

10¹⁸ atoms/cm³.

20. The semiconductor device according to claim 10, wherein the oxide semiconductor film comprises a crystal part of which c-axes are aligned in a direction parallel to a normal vector of a surface of the crystal part.

21. The semiconductor device according to claim 10, wherein the first insulating film includes an oxide insulating film of which released amount of oxygen molecules is greater than or equal to 1×

10¹⁸/cm³ in thermal desorption spectroscopy.

22. The semiconductor device according to claim 10, wherein the first source electrode and the first drain electrode are in contact with side surfaces of the oxide semiconductor film.

23. The semiconductor device according to claim 10, wherein the first transistor is over the second transistor.

24. The semiconductor device according to claim 10, further comprising a third insulating film between the first transistor and the second insulating film, wherein a surface of the third insulating film is flat.