Method for manufacturing semiconductor device

• US 9,299,807 B2
• Filed: 09/28/2015
• Issued: 03/29/2016
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Sasaki, Toshinari, Sakata, Junichiro, Ohara, Hiroki, Yamazaki, Shunpei
• Primary Examiner(s): Lee, Kyoung
• Application Number:
  US14/867,636
• Publication Number:
  US 20160020332A1
• Time in Patent Office: 183 Days
• US Class Current: 1/1
• 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 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/42356 Disposition, e.g. buried gate electrode H01L29/42324 and H01L29/4234 take precedence
• CPC Class Codes: H01L 29/42384 for thin film field effect transistors, e.g. characterised by the thickness or the shape of the insulator or the dimensions, the shape or the lay-out of the conductor
• 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 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• 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

It is an object to provide a highly reliable semiconductor device which includes a thin film transistor having stable electric characteristics. It is another object to manufacture a highly reliable semiconductor device at lower cost with high productivity. In a method for manufacturing a semiconductor device which includes a thin film transistor where a semiconductor layer having a channel formation region, a source region, and a drain region are formed using an oxide semiconductor layer, heat treatment (heat treatment for dehydration or dehydrogenation) is performed so as to improve the purity of the oxide semiconductor layer and reduce impurities such as moisture. Moreover, the oxide semiconductor layer subjected to the heat treatment is slowly cooled under an oxygen atmosphere.

Claims

1. A semiconductor device comprising:

a first conductive film over a substrate;

a first insulating film over the first conductive film;

a first oxide semiconductor film over the first insulating film;

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

a second conductive film and a third conductive film over the first oxide semiconductor film and the second oxide semiconductor film;

an oxide insulating film over the second conductive film and the third conductive film;

a second insulating film over the oxide insulating film; and

a fourth conductive film and a fifth conductive film over the second insulating film,

wherein the fourth conductive film is electrically connected to the third conductive film,

wherein a region of the fifth conductive film overlaps the first conductive film, the first oxide semiconductor film and the second oxide semiconductor film, and

wherein the fourth conductive film and the fifth conductive film comprise the same material.

2. The semiconductor device according to claim 1,

wherein the first oxide semiconductor film contains indium, gallium and zinc, and

wherein the second oxide semiconductor film contains indium, gallium and zinc.

3. The semiconductor device according to claim 1,

wherein the second oxide semiconductor film comprises nanocrystals.

4. The semiconductor device according to claim 1,

wherein each of the second conductive film and the third conductive film has a stacked structure.

5. The semiconductor device according to claim 1,

wherein the second insulating film is a nitride film which is in contact with the oxide insulating film.

6. The semiconductor device according to claim 1,

wherein each of the fourth conductive film and the fifth conductive film comprises a transparent conductive film.

7. A display device comprising the semiconductor device according to claim 1.

8. An electronic equipment comprising the display device according to claim 7.

9. A semiconductor device comprising:

a first conductive film over a substrate;

a first insulating film over the first conductive film;

a first oxide semiconductor film over the first insulating film;

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

a second conductive film and a third conductive film over the first oxide semiconductor film and the second oxide semiconductor film;

an oxide insulating film over the second conductive film and the third conductive film;

a second insulating film over the oxide insulating film; and

a fourth conductive film and a fifth conductive film over the second insulating film,

wherein the first oxide semiconductor film is thicker than the second oxide semiconductor film,

wherein the fourth conductive film is electrically connected to the third conductive film,

wherein a region of the fifth conductive film overlaps the first conductive film, the first oxide semiconductor film and the second oxide semiconductor film, and

wherein the fourth conductive film and the fifth conductive film comprise the same material.

10. The semiconductor device according to claim 9,

wherein the first oxide semiconductor film contains indium, gallium and zinc, and

wherein the second oxide semiconductor film contains indium, gallium and zinc.

11. The semiconductor device according to claim 9,

wherein the second oxide semiconductor film comprises nanocrystals.

12. The semiconductor device according to claim 9,

wherein each of the second conductive film and the third conductive film has a stacked structure.

13. The semiconductor device according to claim 9,

wherein the second insulating film is a nitride film which is in contact with the oxide insulating film.

14. The semiconductor device according to claims 9,

wherein each of the fourth conductive film and the fifth conductive film comprises a transparent conductive film.

15. A display device comprising the semiconductor device according to claim 9.

16. An electronic equipment comprising the display device according to claim 15.