Semiconductor device and display device having the same

• US 9,768,315 B2
• Filed: 04/08/2015
• Issued: 09/19/2017
• Est. Priority Date: 04/18/2014
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koezuka, Junichi, Jintyou, Masami, Kurosaki, Daisuke
• Primary Examiner(s): Vu, David
• Application Number:
  US14/681,383
• Publication Number:
  US 20150303309A1
• Time in Patent Office: 895 Days
• 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 29/66969 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 29/78648 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

Abstract

A change in electrical characteristics can be inhibited and reliability can be improved in a semiconductor device using a transistor including an oxide semiconductor. A semiconductor device includes a transistor which includes a gate electrode, a first insulating film over the gate electrode, an oxide semiconductor film over the first insulating film, a source electrode electrically connected to the oxide semiconductor film, and a drain electrode electrically connected to the oxide semiconductor film. A second insulating film is provided over the transistor, and a protective film is provided over the second insulating film. The second insulating film includes oxygen. The protective film includes at least one of metal elements used for the oxide semiconductor film.

Claims

1. A semiconductor device comprising:

a gate electrode;

a first insulating film over the gate electrode;

an oxide semiconductor film over the first insulating film;

a source electrode electrically connected to the oxide semiconductor film;

a drain electrode electrically connected to the oxide semiconductor film;

a second insulating film over the oxide semiconductor film; and

a protective film over the second insulating film,

wherein the protective film comprises In, Sn, Si and oxygen.

2. The semiconductor device according to claim 1,

wherein the second insulating film includes a top surface, side surface and curved surface between the top surface and the side surface, and

wherein the protective film covers the curved surface.

3. The semiconductor device according to claim 1, wherein the thickness of the protective film is greater than or equal to 3 nm and less than or equal to 30 nm.

4. The semiconductor device according to claim 1, wherein the oxide semiconductor film includes In, Zn, and M (M is Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or Hf).

5. The semiconductor device according to claim 1,

wherein the oxide semiconductor film comprises a crystal, and

wherein the crystal has c-axis alignment.

6. A display device comprising:

the semiconductor device according to claim 1; and

a display element.

7. A display module comprising:

the display device according to claim 6; and

a touch sensor.

8. An electronic appliance comprising:

the display module according to claim 7; and

an operation key or a battery.

9. The semiconductor device according to claim 1,

wherein the second insulating film is configured to release oxygen when heat treatment is performed, and

wherein a part of oxygen in the second insulating film is added through the protective film.

10. The semiconductor device according to claim 9, wherein the part of oxygen in the second insulating film is added by plasma treatment, ion doping method or ion implantation method.

11. A semiconductor device comprising:

a first gate electrode;

a first insulating film over the first gate electrode;

an oxide semiconductor film over the first insulating film;

a source electrode electrically connected to the oxide semiconductor film;

a drain electrode electrically connected to the oxide semiconductor film;

a second insulating film over the oxide semiconductor film, the source electrode, and the drain electrode;

a protective film over the second insulating film;

a third insulating film over the protective film; and

a second gate electrode over the third insulating film,

wherein the protective film comprises In, Sn, Si and oxygen.

12. The semiconductor device according to claim 11,

wherein the second insulating film includes an uneven surface, and

wherein the protective film covers the uneven surface of the second insulating film.

13. The semiconductor device according to claim 11, wherein the thickness of the protective film is greater than or equal to 3 nm and less than or equal to 30 nm.

14. The semiconductor device according to claim 11, wherein the oxide semiconductor film includes In, Zn, and M (M is Ti, Ga, Sn, Y, Zr, La, Ce, Nd, or Hf).

15. The semiconductor device according to claim 11,

wherein the oxide semiconductor film comprises a crystal part, and

wherein a c-axis of the crystal is perpendicular to an upper surface of the oxide semiconductor film.

16. The semiconductor device according to claim 11,

wherein the second gate electrode is in contact with a side surface of the second insulating film in a channel width direction, a side surface of the protective film in the channel width direction, and a side surface of the third insulating film in the channel width direction.

17. The semiconductor device according to claim 11,

wherein the second gate electrode comprises depression reflecting a gap between the source electrode and the drain electrode.

18. The semiconductor device according to claim 11,

wherein the second insulating film is configured to release oxygen when heat treatment is performed, and

wherein a part of oxygen in the second insulating film is added through the protective film.

19. The semiconductor device according to claim 18, wherein the part of oxygen in the second insulating film is added by plasma treatment, ion doping method or ion implantation method.