SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20140110705A1
• Filed: 10/23/2013
• Published: 04/24/2014
• Est. Priority Date: 10/24/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Koezuka, Junichi, Shima, Yukinori, Tokunaga, Hajime, Sasaki, Toshinari, Murayama, Keisuke, Matsubayashi, Daisuke
• Granted Patent: US 9,349,869 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 21/022 the layer being a laminate, i.e. composed of sublayers, e.g. stacks of alternating high-k metal oxides adhesion layers or buffer layers H01L21/02304, H01L21/02362
• CPC Class Codes: H01L 21/02263 deposition from the gas or vapour phase
• 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 29/513 the variation being perpendicular to the channel plane
• 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 29/78609 for preventing leakage current H01L29/78618 takes precedence
• 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

To reduce defects in an oxide semiconductor film in a semiconductor device. To improve the electrical characteristics and the reliability of a semiconductor device including an oxide semiconductor film. In a semiconductor device including a transistor including a gate electrode formed over a substrate, a gate insulating film covering the gate electrode, a multilayer film overlapping with the gate electrode with the gate insulating film provided therebetween, and a pair of electrodes in contact with the multilayer film, a first oxide insulating film covering the transistor, and a second oxide insulating film formed over the first oxide insulating film, the multilayer film includes an oxide semiconductor film and an oxide film containing In or Ga, the first oxide insulating film is an oxide insulating film through which oxygen is permeated, and the second oxide insulating film is an oxide insulating film containing more oxygen than that in the stoichiometric composition.

Claims

1. A semiconductor device comprising a transistor, the transistor comprising:

a gate electrode over a substrate;

a gate insulating film over the gate electrode;

a multilayer film over the gate insulating film;

a pair of electrodes in electrical contact with the multilayer film;

a first oxide insulating film over the gate insulating film, the multilayer film, and the pair of electrodes; and

a second oxide insulating film over the first oxide insulating film,

wherein the multilayer film includes an oxide semiconductor film and an oxide film containing at least one of In and Ga,

wherein the first oxide insulating film is an oxide insulating film through which oxygen is permeated,

wherein the second oxide insulating film is an oxide insulating film containing more oxygen than that in a stoichiometric composition, and

wherein a threshold voltage of the transistor does not change or changes in a negative direction or a positive direction, and an amount of change is less than or equal to 1.0 V by a bias-temperature stress test.

2. The semiconductor device according to claim 1, wherein the oxide semiconductor film contains at least one of In and Ga.

3. The semiconductor device according to claim 1, wherein a conduction band bottom of the oxide film is closer to a vacuum level than a conduction band bottom of the oxide semiconductor film is.

4. The semiconductor device according to claim 3, wherein an energy difference between the conduction band bottom of the oxide film and the conduction band bottom of the oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV.

5. The semiconductor device according to claim 1,

wherein each of the oxide semiconductor film and the oxide film is In-M-Zn oxide,

wherein the M represents Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf, and

wherein a proportion of M atoms in the oxide film is higher than a proportion of M atoms in the oxide semiconductor film.

6. The semiconductor device according to claim 1, wherein an absorption coefficient of the multilayer film derived from a constant photocurrent method is lower than 1×

10<sup>−

3</sup>/cm in an energy range from 1.5 eV to 2.3 eV.

7. The semiconductor device according to claim 1, wherein a concentration of silicon between the oxide semiconductor film and the oxide film is lower than 2×

10¹⁸ atoms/cm³.

8. The semiconductor device according to claim 1, wherein the semiconductor device is one selected from the group consisting of a television device, a computer, and a tablet terminal.

9. A semiconductor device comprising a transistor, the transistor comprising:

a gate electrode over a substrate;

a gate insulating film over the gate electrode;

a multilayer film over the gate insulating film;

a pair of electrodes in electrical contact with the multilayer film;

a first oxide insulating film over the gate insulating film, the multilayer film, and the pair of electrodes; and

a second oxide insulating film over the first oxide insulating film,

wherein the multilayer film includes an oxide semiconductor film and an oxide film containing at least one of In and Ga, and

wherein the second oxide insulating film is an oxide insulating film containing more oxygen than that in a stoichiometric composition.

10. The semiconductor device according to claim 9, wherein the oxide semiconductor film contains at least one of In and Ga.

11. The semiconductor device according to claim 9, wherein a conduction band bottom of the oxide film is closer to a vacuum level than a conduction band bottom of the oxide semiconductor film is.

12. The semiconductor device according to claim 11, wherein an energy difference between the conduction band bottom of the oxide film and the conduction band bottom of the oxide semiconductor film is greater than or equal to 0.05 eV and less than or equal to 2 eV.

13. The semiconductor device according to claim 9,

wherein each of the oxide semiconductor film and the oxide film is In-M-Zn oxide,

wherein the M represents Al, Ti, Ga, Y, Zr, La, Ce, Nd, or Hf, and

wherein a proportion of M atoms in the oxide film is higher than a proportion of M atoms in the oxide semiconductor film.

14. The semiconductor device according to claim 9, wherein an absorption coefficient of the multilayer film derived from a constant photocurrent method is lower than 1×

10<sup>−

3</sup>/cm in an energy range from 1.5 eV to 2.3 eV.

15. The semiconductor device according to claim 9, wherein a concentration of silicon between the oxide semiconductor film and the oxide film is lower than 2×

10¹⁸ atoms/cm³.

16. The semiconductor device according to claim 9, wherein the semiconductor device is one selected from the group consisting of a television device, a computer, and a tablet terminal.

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

forming a gate electrode over a substrate;

forming a gate insulating film over the gate electrode;

forming a multilayer film including an oxide semiconductor film and an oxide film containing at least one of In and Ga, over the gate insulating film;

forming a pair of electrodes in electrical contact with the multilayer film;

forming a first oxide insulating film over the multilayer film and the pair of electrodes; and

forming a second oxide insulating film over the first oxide insulating film,

wherein the substrate placed in a treatment chamber which is vacuum-evacuated is held at a temperature higher than or equal to 180°

C. and lower than or equal to 400°

C., pressure in the treatment chamber is set to be greater than or equal to 20 Pa and less than or equal to 250 Pa with introduction of a source gas into the treatment chamber, and a high-frequency power is supplied to an electrode provided in the treatment chamber to form the first oxide insulating film, and

wherein the substrate placed in a treatment chamber which is vacuum-evacuated is held at a temperature higher than or equal to 180°

C. and lower than or equal to 260°

C., pressure in the treatment chamber is set to be greater than or equal to 100 Pa and less than or equal to 250 Pa with introduction of a source gas into the treatment chamber, and a high-frequency power higher than or equal to 0.17 W/cm² and lower than or equal to 0.5 W/cm² is supplied to an electrode provided in the treatment chamber to form the second oxide insulating film.

18. The method for manufacturing a semiconductor device according to claim 17, wherein, as the first oxide insulating film and the second oxide insulating film, a silicon oxide film or a silicon oxynitride film is formed using a deposition gas containing silicon and an oxidizing gas as a source gas.

19. The method for manufacturing a semiconductor device according to claim 17, wherein, as the first oxide insulating film and the second oxide insulating film, a silicon oxynitride film is formed using silane and dinitrogen monoxide as a source gas.