Semiconductor device

• US 9,806,201 B2
• Filed: 03/03/2015
• Issued: 10/31/2017
• Est. Priority Date: 03/07/2014
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Yamada, Yoshinori, Nonaka, Yusuke, Oota, Masashi, Kurosawa, Yoichi, Ishihara, Noritaka, Hamada, Takashi, Ichijo, Mitsuhiro, Egi, Yuji
• Primary Examiner(s): Monbleau, Davienne
• Assistant Examiner(s): Wilson, Scott R
• Application Number:
  US14/636,477
• Publication Number:
  US 20150255534A1
• Time in Patent Office: 973 Days
• Field of Search: None
• 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 29/78693 the semiconducting oxide being amorphous
• 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
• CPC Class Codes: H10B 41/70 the floating gate being an electrode shared by two or more components

Abstract

A method for forming an oxide that can be used as a semiconductor of a transistor or the like is provided. In particular, a method for forming an oxide with fewer defects such as grain boundaries is provided. One embodiment of the present invention is a semiconductor device including an oxide semiconductor, an insulator, and a conductor. The oxide semiconductor includes a region overlapping with the conductor with the insulator therebetween. The oxide semiconductor includes a crystal grain with an equivalent circle diameter of 1 nm or more and a crystal grain with an equivalent circle diameter less than 1 nm.

Claims

1. A semiconductor device comprising:

a first insulating film having a projection;

a first oxide semiconductor film;

a first conductor film over the first oxide semiconductor film;

a second conductor film over the first oxide semiconductor film;

a second oxide semiconductor film over the first conductor film, the second conductor film, and the first oxide semiconductor film;

a second insulating film over the second oxide semiconductor film; and

a third conductor film over the second insulating film,

wherein the first oxide semiconductor film is located over the projection of the first insulating film,

wherein each of the second oxide semiconductor film, the first conductor film, and the second conductor film is in contact with a top surface and a side surface of the first oxide semiconductor film, and a side surface of the projection of the first insulating film,

wherein the first oxide semiconductor film comprises a crystal grain with an equivalent circle diameter of 1 nm or more and a crystal grain with an equivalent circle diameter less than 1 nm, and

wherein the first oxide semiconductor film comprises a region in which hydrogen concentration measured by secondary ion mass spectrometry is lower than 1×

10¹⁹ atoms/cm³.

3. The semiconductor device according to claim 1, wherein the third conductor film overlaps with the first conductor film and the second conductor film.

4. The semiconductor device according to claim 1, further comprising a fourth conductor film under the first insulating film,

wherein the third conductor film overlaps with the fourth conductor film.

5. The semiconductor device according to claim 4, wherein the third conductor film overlaps with the first conductor film, the second conductor film, and the forth conductor film.

2. A semiconductor device comprising:

a first insulating film having a projection;

a first oxide semiconductor film;

a first conductor film over the first oxide semiconductor film;

a second conductor film over the first oxide semiconductor film;

a second oxide semiconductor film over the first conductor film, the second conductor film, and the first oxide semiconductor film;

a second insulating film over the second oxide semiconductor film; and

a third conductor film over the second insulating film,

wherein the first oxide semiconductor film is located over the projection of the first insulating film,

wherein each of the second oxide semiconductor film, the first conductor film, and the second conductor film is in contact with a top surface and a side surface of the first oxide semiconductor film, and a side surface of the projection of the first insulating film, and

wherein the first oxide semiconductor film comprises a crystal grain with an equivalent circle diameter of 1 nm or more and a crystal grain with an equivalent circle diameter less than 1 nm.

6. A semiconductor device comprising:

a first insulating film having a projection;

a first oxide semiconductor film;

a first conductor film over the first oxide semiconductor film;

a second conductor film over the first oxide semiconductor film;

a second oxide semiconductor film over the first conductor film, the second conductor film, and the first oxide semiconductor film;

a second insulating film over the second oxide semiconductor film; and

a third conductor film over the second insulating film,

wherein the first oxide semiconductor film is located over the projection of the first insulating film,

wherein each of the second oxide semiconductor film, the first conductor film, and the second conductor film is in contact with a top surface and a side surface of the first oxide semiconductor film, and a side surface of the projection of the first insulating film, and

wherein the first oxide semiconductor film comprises a crystal grain with an equivalent circle diameter of 1 nm or more and a crystal grain with an equivalent circle diameter less than 1 nm.

7. The semiconductor device according to claim 6, wherein the first oxide semiconductor film comprises a region in which carbon concentration measured by secondary ion mass spectrometry is lower than 1×

10²⁰ atoms/cm³.

8. The semiconductor device according to claim 6, wherein the third conductor film overlaps with the first conductor film and the second conductor film.

9. The semiconductor device according to claim 6, further comprising a fourth conductor film under the first insulating film,

wherein the third conductor film overlaps with the fourth conductor film.

10. The semiconductor device according to claim 9, wherein the third conductor film overlaps with the first conductor film, the second conductor film, and the forth conductor film.

11. A semiconductor device comprising:

a first insulating film having a projection;

a first oxide semiconductor film;

a first conductor film over the first oxide semiconductor film;

a second conductor film over the first oxide semiconductor film;

a second oxide semiconductor film over the first conductor film, the second conductor film, and the first oxide semiconductor film;

a second insulating film over the second oxide semiconductor film; and

a third conductor film over the second insulating film,

wherein the first oxide semiconductor film is located over the projection of the first insulating film,

wherein each of the second oxide semiconductor film, the first conductor film, and the second conductor film is in contact with a top surface and a side surface of the first oxide semiconductor film, and a side surface of the projection of the first insulating film, and

wherein the first oxide semiconductor film comprises a crystal grain with an equivalent circle diameter of 1 nm or more.

12. The semiconductor device according to claim 11, wherein the first oxide semiconductor film comprises a region in which carbon concentration measured by secondary ion mass spectrometry is lower than 1×

10²⁰ atoms/cm³.

13. The semiconductor device according to claim 11, wherein the third conductor film overlaps with the first conductor film and the second conductor film.

14. The semiconductor device according to claim 11, further comprising a fourth conductor film under the first insulating film,

wherein the third conductor film overlaps with the fourth conductor film.

15. The semiconductor device according to claim 14, wherein the third conductor film overlaps with the first conductor film, the second conductor film, and the forth conductor film.