Semiconductor device having an oxide film on an oxide semiconductor film

• US 10,304,859 B2
• Filed: 04/08/2014
• Issued: 05/28/2019
• Est. Priority Date: 04/12/2013
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Koezuka, Junichi, Nakazawa, Yasutaka, Shima, Yukinori, Jintyou, Masami, Sakakura, Masayuki, Nakashima, Motoki
• Primary Examiner(s): Chen, Yu
• Assistant Examiner(s): Roland, Christopher M
• Application Number:
  US14/247,676
• Publication Number:
  US 20140306221A1
• Time in Patent Office: 1,876 Days
• CPC Class Codes: H01L 21/02609 Crystal orientation
• 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 27/1229 with different crystal properties within a device or between different devices
• CPC Class Codes: H01L 29/04 characterised by their crystalline structure, e.g. polycrystalline, cubic or particular orientation of crystalline planes characterised by physical imperfections H01L29/30
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• 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 29/7869 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 stability of a step of processing a wiring formed using copper, aluminum, gold, silver, molybdenum, or the like is increased. Moreover, the concentration of impurities in a semiconductor film is reduced. Moreover, the electrical characteristics of a semiconductor device are improved. In a transistor including an oxide semiconductor film, an oxide film in contact with the oxide semiconductor film, and a pair of conductive films being in contact with the oxide film and including copper, aluminum, gold, silver, molybdenum, or the like, the oxide film has a plurality of crystal parts and has c-axis alignment in the crystal parts, and the c-axes are aligned in a direction parallel to a normal vector of a top surface of the oxide semiconductor film or the oxide film.

Claims

1. A semiconductor device comprising:

a first insulating film over a substrate;

a second insulating film over the first insulating film;

an oxide semiconductor film over and in contact with the second insulating film, the oxide semiconductor film including a channel region, wherein the oxide semiconductor film comprises In, M and Zn where M is an element selected from Ga, Y, Zr, La, Ce and Nd;

an oxide film over and in contact with the oxide semiconductor film, wherein the oxide film is non-single crystalline and comprises In, M and Zn where M is an element selected from Ga, Y, Zr, La, Ce and Nd;

a pair of conductive films over and in contact with the oxide film, the pair of conductive films including copper, aluminum, gold, silver, or molybdenum; and

a third insulating film over the pair of conductive films,

wherein the third insulating film is in contact with an upper surface of the oxide film at least in a region between the pair of conductive films,

wherein the oxide film includes a plurality of crystal parts and has c-axis alignment in the plurality of crystal parts,

wherein the pair of conductive films is in contact with a top surface of the first insulating film,

wherein an atomic ratio of M with respect to In in the oxide film is larger than an atomic ratio of M with respect to In in the oxide semiconductor film, and

wherein, in an atomic ratio of the oxide film, M is larger than In, and Zn is larger than M.

2. The semiconductor device according to claim 1, further comprising a gate electrode between the substrate and the first insulating film.

3. The semiconductor device according to claim 1, further comprising:

a gate electrode over the third insulating film.

4. The semiconductor device according to claim 1, wherein the first insulating film is a nitride insulating film.

5. The semiconductor device according to claim 1, wherein the second insulating film is an oxide insulating film.

6. The semiconductor device according to claim 1, wherein in the plurality of crystal parts of the oxide film, directions of a-axes and b-axes are irregular.

7. The semiconductor device according to claim 1, wherein the pair of conductive films has a single-layer structure.

8. The semiconductor device according to claim 1,

wherein side surfaces of the second insulating film are aligned with side surfaces of the oxide semiconductor film.

9. A semiconductor device comprising:

a substrate;

a gate electrode over the substrate;

a gate insulating film over the gate electrode;

a non-single crystalline oxide semiconductor film over the gate electrode with the gate insulating film therebetween, the non-single crystalline oxide semiconductor film comprising In, Ga and Zn;

an oxide film over and in contact with the non-single crystalline oxide semiconductor film, the oxide film comprising In, Ga and Zn;

a pair of conductive films over the oxide film; and

an insulating film over the pair of conductive films, the insulating film being in contact with an upper surface of the oxide film at least in a region between the pair of conductive films,

wherein the oxide film has a c-axis alignment and includes a plurality of crystal parts,

wherein an atomic ratio of Ga with respect to In in the oxide film is larger than an atomic ratio of Ga with respect to In in the non-single crystalline oxide semiconductor film, and

wherein, in an atomic ratio of In, Ga and Zn in the oxide film, Ga is larger than In, and Zn is larger than Ga.

10. The semiconductor device according to claim 9, wherein the pair of conductive films is in contact with the oxide film.

11. The semiconductor device according to claim 9, wherein the gate insulating film comprises a first insulating film comprising a nitride and a second insulating film comprising an oxide formed on the first insulating film.

12. The semiconductor device according to claim 9, wherein the pair of conductive films has a single-layer structure.

13. The semiconductor device according to claim 9, wherein the pair of conductive films includes copper.

14. A semiconductor device comprising:

a substrate;

a gate electrode over the substrate;

a gate insulating film over the gate electrode;

an oxide semiconductor film over the gate insulating film, wherein the oxide semiconductor film comprises In, M and Zn where M is an element selected from Ga, Y, Zr, La, Ce and Nd;

an oxide film over and in contact with the oxide semiconductor film, wherein the oxide film comprises In, M and Zn where M is an element selected from Ga, Y, Zr, La, Ce and Nd;

a pair of conductive films over the oxide film, wherein the pair of conductive films comprises copper;

wherein the oxide semiconductor film including a channel formation region,

wherein the pair of conductive films is electrically connected to the oxide semiconductor film via the oxide film,

wherein the oxide film includes a plurality of crystal parts having c-axis alignment,

wherein an atomic ratio of M with respect to In in the oxide film is larger than an atomic ratio of M with respect to In in the oxide semiconductor film, and

wherein, in an atomic ratio of the oxide film, M is larger than In, and Zn is larger than M.

15. The semiconductor device according to claim 14, wherein the gate insulating film comprises a first insulating film comprising a nitride and a second insulating film comprising an oxide formed on the first insulating film.

16. The semiconductor device according to claim 15, wherein side surfaces of the second insulating film are aligned with side surfaces of the oxide semiconductor film.

17. The semiconductor device according to claim 14,

wherein the oxide semiconductor film has a first region including silicon, and

wherein silicon concentration in the first region of the oxide semiconductor film is 2×

10¹⁸ atoms/cm³ or lower.

18. The semiconductor device according to claim 14, wherein the oxide semiconductor film has a second region including copper.

19. The semiconductor device according to claim 18, wherein copper concentration of the second region of the oxide semiconductor film is lower than 1×

10¹⁸ atoms/cm³.

20. The semiconductor device according to claim 14, wherein the pair of conductive films has a single-layer structure.