Semiconductor device and method of manufacturing the same

• US 9,666,720 B2
• Filed: 05/05/2014
• Issued: 05/30/2017
• Est. Priority Date: 07/27/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Noda, Kosei, Endo, Yuta, Imai, Keitaro, Isobe, Atsuo, Sato, Hitomi, Okazaki, Yutaka, Sasaki, Toshinari, Ikarashi, Mizuho
• Primary Examiner(s): Smith, Zandra
• Assistant Examiner(s): TYNES JR., LAWRENCE C
• Application Number:
  US14/269,819
• Publication Number:
  US 20140239297A1
• Time in Patent Office: 1,121 Days
• Field of Search: 257 52
• 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 29/78603 characterised by the insulating substrate or support H01L29/78657 takes precedence
• 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

It is an object to manufacture a semiconductor device in which a transistor including an oxide semiconductor has normally-off characteristics, small fluctuation in electric characteristics, and high reliability. First, first heat treatment is performed on a substrate, a base insulating layer is formed over the substrate, an oxide semiconductor layer is formed over the base insulating layer, and the step of performing the first heat treatment to the step of forming the oxide semiconductor layer are performed without exposure to the air. Next, after the oxide semiconductor layer is formed, second heat treatment is performed. An insulating layer from which oxygen is released by heating is used as the base insulating layer.

Claims

1. A semiconductor device comprising:

a first insulating layer over a substrate, the first insulating layer including a first region adjacent to the substrate;

an oxide semiconductor layer over and in direct contact with the first insulating layer;

a gate electrode wherein the oxide semiconductor layer and the gate electrode overlap with each other; and

a gate insulating layer between the oxide semiconductor layer and the gate electrode,

wherein a hydrogen concentration in the first region is less than or equal to 1.1×

10²⁰ atoms/cm³,

wherein the oxide semiconductor layer includes a channel formation region, a second region and a third region,

wherein resistances of the second region and the third region are lower than a resistance of the channel formation region, and

wherein the second region and the third region are formed in a self-aligned manner with respect to the gate insulating layer.

2. The semiconductor device according to claim 1, wherein, in the first insulating layer, a released amount of oxygen which is converted to an oxygen atom is greater than or equal to 1.0×

10¹⁸ atoms/cm³ in thermal desorption spectroscopy.

3. The semiconductor device according to claim 2, wherein the first insulating layer comprises at least one of silicon oxide, silicon oxynitride, silicon nitride oxide, and aluminum oxide.

4. The semiconductor device according to claim 1, wherein the first insulating layer is in direct contact with the substrate.

5. The semiconductor device according to claim 1,

wherein the gate insulating layer is in direct contact with the oxide semiconductor layer and the gate electrode, and

wherein the semiconductor device comprises a second insulating layer over and in direct contact with the oxide semiconductor layer, the gate insulating layer and the gate electrode.

6. A semiconductor device comprising:

a first insulating layer over a substrate, the first insulating layer including a first region adjacent to the substrate;

an oxide semiconductor layer over and in direct contact with the first insulating layer;

a gate insulating layer over the oxide semiconductor layer; and

a gate electrode over the gate insulating layer,

wherein a hydrogen concentration in the first region is less than or equal to 1.1×

10²⁰ atoms/cm³,

wherein the oxide semiconductor layer includes a channel formation region, a second region and a third region,

wherein resistances of the second region and the third region are lower than a resistance of the channel formation region, and

wherein the second region and the third region are formed in a self-aligned manner with respect to the gate insulating layer.

7. The semiconductor device according to claim 6, wherein, in the first insulating layer, a released amount of oxygen which is converted to an oxygen atom is greater than or equal to 1.0×

10¹⁸ atoms/cm³ in thermal desorption spectroscopy.

8. The semiconductor device according to claim 6, wherein the first insulating layer is silicon oxide in which the number of oxygen atoms per unit volume is more than twice the number of silicon atoms per unit volume.

9. The semiconductor device according to claim 6, wherein the first insulating layer comprises at least one of silicon oxide, silicon oxynitride, silicon nitride oxide, and aluminum oxide.

10. The semiconductor device according to claim 6, wherein the first insulating layer is in direct contact with the substrate.

11. The semiconductor device according to claim 6,

wherein the gate insulating layer is in direct contact with the oxide semiconductor layer and the gate electrode, and

wherein the semiconductor device comprises a second insulating layer over and in direct contact with the oxide semiconductor layer, the gate insulating layer and the gate electrode.

12. A semiconductor device comprising:

a first insulating layer over a substrate, the first insulating layer including a first region adjacent to the substrate;

an oxide semiconductor layer over and in direct contact with the first insulating layer;

a gate electrode over the oxide semiconductor layer; and

a gate insulating layer between the oxide semiconductor layer and the gate electrode,

wherein a hydrogen concentration in the first region is less than or equal to 1.1×

10²⁰ atoms/cm³,

wherein the oxide semiconductor layer includes a channel formation region, a second region and a third region,

wherein resistances of the second region and the third region are lower than a resistance of the channel formation region,

wherein an end portion of the second region and a first end portion of the gate insulating layer are aligned, and

wherein an end portion of the third region and a second end portion of the gate insulating layer are aligned.

13. The semiconductor device according to claim 12, wherein, in the first insulating layer, a released amount of oxygen which is converted to an oxygen atom is greater than or equal to 1.0×

10¹⁸ atoms/cm³ in thermal desorption spectroscopy.

14. The semiconductor device according to claim 12, wherein the first insulating layer comprises at least one of silicon oxide, silicon oxynitride, silicon nitride oxide, and aluminum oxide.

15. The semiconductor device according to claim 12, wherein the first insulating layer is in direct contact with the substrate.

16. The semiconductor device according to claim 12,

wherein the gate insulating layer is in direct contact with the oxide semiconductor layer and the gate electrode, and

wherein the semiconductor device comprises a second insulating layer over and in direct contact with the oxide semiconductor layer, the gate insulating layer and the gate electrode.