Method for manufacturing semiconductor device

• US 9,450,080 B2
• Filed: 12/15/2014
• Issued: 09/20/2016
• Est. Priority Date: 12/20/2013
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Yamade, Naoto, Yamamoto, Yoshitaka, Suzawa, Hideomi, Sakakura, Masayuki, Sato, Yuhei, Yamane, Yasumasa
• Primary Examiner(s): Nguyen, Thanh T
• Application Number:
  US14/570,422
• Publication Number:
  US 20150179774A1
• Time in Patent Office: 645 Days
• Field of Search: 438/104
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 21/383 using diffusion into or out of a solid from or into a gaseous phase
• CPC Class Codes: H01L 21/425 producing ion implantation
• CPC Class Codes: H01L 21/441 Deposition of conductive or insulating materials for electrodes
• CPC Class Codes: H01L 21/465 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/469
• CPC Class Codes: H01L 21/477 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/38 - H01L21/449 and H01L21/461 - H01L21/475 take precedence
• 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 29/78648 arranged on opposing sides of the channel
• 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 29/78696 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

The semiconductor device is manufactured by the following method. A first oxide semiconductor film is formed over a first gate electrode and a first insulating film, oxygen is added to the first oxide semiconductor film, and then a second oxide semiconductor film is formed over the first oxide semiconductor film. Then, heat treatment is performed. Next, part of the first insulating film, part of the first oxide semiconductor film, and part of the second oxide semiconductor film are etched to form a first gate insulating film having a projection. Next, a pair of electrodes is formed over the second oxide semiconductor film, and a third oxide semiconductor film is formed over the second oxide semiconductor film and the pair of electrodes. Then, a second gate insulating film is formed over the third oxide semiconductor film, and a second gate electrode is formed over the second gate insulating film.

Claims

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

forming a first gate electrode;

forming a first insulating film over the first gate electrode;

forming a first oxide semiconductor film over the first insulating film;

adding oxygen to the first oxide semiconductor film;

forming a second oxide semiconductor film over the first oxide semiconductor film after adding the oxygen;

performing a heat treatment on the first oxide semiconductor film and the second oxide semiconductor film;

etching a part of the first insulating film, a part of the first oxide semiconductor film, and a part of the second oxide semiconductor film to form a first gate insulating film having a projection after performing the heat treatment;

forming a pair of electrodes in contact with the second oxide semiconductor film after etching the part of the second oxide semiconductor film;

forming a third oxide semiconductor film over the second oxide semiconductor film and the pair of electrodes;

forming a second gate insulating film over the third oxide semiconductor film; and

forming a second gate electrode over the second gate insulating film.

2. The method for manufacturing a semiconductor device according to claim 1, wherein the oxygen is added to the first oxide semiconductor film by an ion implantation method, an ion doping method, or plasma treatment.

3. The method for manufacturing a semiconductor device according to claim 1, wherein the first oxide semiconductor film, the second oxide semiconductor film, and the third oxide semiconductor film include indium or gallium.

4. The method for manufacturing a semiconductor device according to claim 1, wherein conduction band minimums of the first oxide semiconductor film and the third oxide semiconductor film are closer to a vacuum level than a conduction band minimum of the second oxide semiconductor film is.

5. The method for manufacturing a semiconductor device according to claim 1, wherein a difference in energy level between a conduction band minimum of the second oxide semiconductor film and each of conduction band minimums of the first oxide semiconductor film and the third oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV.

6. The method for manufacturing a semiconductor device according to claim 1, further comprising a step of forming a second insulating film under the first gate electrode and the first insulating film,

wherein the second insulating film is in contact with the pair of electrodes.

7. The method for manufacturing a semiconductor device according to claim 1,

wherein the second oxide semiconductor film includes a low resistance region, and

wherein each of the pair of electrodes includes a region having high oxygen concentration.

8. A method for manufacturing a semiconductor device, comprising the steps of:

forming a first gate electrode;

forming a first insulating film over the first gate electrode;

forming a first oxide semiconductor film over the first insulating film;

forming a second oxide semiconductor film over the first oxide semiconductor film;

etching a part of the first insulating film, a part of the first oxide semiconductor film, and a part of the second oxide semiconductor film to form a first gate insulating film having a projection;

forming a pair of electrodes in contact with the second oxide semiconductor film after etching the part of the second oxide semiconductor film;

forming a third oxide semiconductor film over the second oxide semiconductor film and the pair of electrodes;

adding oxygen to the third oxide semiconductor film;

performing a heat treatment on the third oxide semiconductor film after adding the oxygen;

forming a second gate insulating film over the third oxide semiconductor film after performing the heat treatment; and

forming a second gate electrode over the second gate insulating film.

9. The method for manufacturing a semiconductor device according to claim 8, wherein the oxygen is added to the third oxide semiconductor film by an ion implantation method, an ion doping method, or plasma treatment.

10. The method for manufacturing a semiconductor device according to claim 8, wherein the first oxide semiconductor film, the second oxide semiconductor film, and the third oxide semiconductor film include indium or gallium.

11. The method for manufacturing a semiconductor device according to claim 8, wherein conduction band minimums of the first oxide semiconductor film and the third oxide semiconductor film are closer to a vacuum level than a conduction band minimum of the second oxide semiconductor film is.

12. The method for manufacturing a semiconductor device according to claim 8, wherein a difference in energy level between a conduction band minimum of the second oxide semiconductor film and each of conduction band minimums of the first oxide semiconductor film and the third oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV.

13. The method for manufacturing a semiconductor device according to claim 8, further comprising a step of forming a second insulating film under the first gate electrode and the first insulating film,

wherein the second insulating film is in contact with the pair of electrodes.

14. The method for manufacturing a semiconductor device according to claim 8,

wherein the second oxide semiconductor film includes a low resistance region, and

wherein each of the pair of electrodes includes a region having high oxygen concentration.

15. A method for manufacturing a semiconductor device, comprising the steps of:

forming a first gate electrode;

forming a first insulating film over the first gate electrode;

forming a first oxide semiconductor film over the first insulating film;

adding oxygen to the first oxide semiconductor film;

forming a second oxide semiconductor film over the first oxide semiconductor film after adding the oxygen to the first oxide semiconductor film;

performing a first heat treatment on the first oxide semiconductor film and the second oxide semiconductor film;

etching a part of the first insulating film, a part of the first oxide semiconductor film, and a part of the second oxide semiconductor film to form a first gate insulating film having a projection after performing the first heat treatment;

forming a pair of electrodes in contact with the second oxide semiconductor film after etching the part of the second oxide semiconductor film;

forming a third oxide semiconductor film over the second oxide semiconductor film and the pair of electrodes;

adding oxygen to the third oxide semiconductor film;

performing a second heat treatment on the third oxide semiconductor film after adding the oxygen to the third oxide semiconductor film;

forming a second gate insulating film over the third oxide semiconductor film after performing the second heat treatment; and

forming a second gate electrode over the second gate insulating film.

16. The method for manufacturing a semiconductor device according to claim 15, wherein the oxygen is added to the first oxide semiconductor film and the third oxide semiconductor film by an ion implantation method, an ion doping method, or plasma treatment.

17. The method for manufacturing a semiconductor device according to claim 15, wherein the first oxide semiconductor film, the second oxide semiconductor film, and the third oxide semiconductor film include indium or gallium.

18. The method for manufacturing a semiconductor device according to claim 15,

wherein conduction band minimums of the first oxide semiconductor film and the third oxide semiconductor film are closer to a vacuum level than a conduction band minimum of the second oxide semiconductor film is, and

wherein a difference in energy level between the conduction band minimum of the second oxide semiconductor film and each of the conduction band minimums of the first oxide semiconductor film and the third oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV.

19. The method for manufacturing a semiconductor device according to claim 15, further comprising a step of forming a second insulating film under the first gate electrode and the first insulating film,

wherein the second insulating film is in contact with the pair of electrodes.

20. The method for manufacturing a semiconductor device according to claim 15,

wherein the second oxide semiconductor film includes a low resistance region, and

wherein each of the pair of electrodes includes a region having high oxygen concentration.