Bottom-gate transistor including an oxide semiconductor layer contacting an oxygen-rich insulating layer

• US 9,502,572 B2
• Filed: 12/20/2012
• Issued: 11/22/2016
• Est. Priority Date: 12/27/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): PIZARRO CRESPO, MARCOS D
• Application Number:
  US13/721,967
• Publication Number:
  US 20130161610A1
• Time in Patent Office: 1,433 Days
• Field of Search: 438/104, 438/158
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02244 of a metallic layer
• CPC Class Codes: H01L 21/02614 Transformation of metal, e.g. oxidation, nitridation
• 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 27/14612 involving a transistor
• CPC Class Codes: H01L 27/14692 Thin film technologies, e.g. amorphous, poly, micro- or nanocrystalline silicon
• 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 29/78693 the semiconducting oxide being amorphous
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays

Abstract

A highly reliable semiconductor device which includes a transistor including an oxide semiconductor is provided. In a semiconductor device including a bottom-gate transistor including an oxide semiconductor layer, a stacked layer of an insulating layer and a metal film is provided in contact with the oxide semiconductor layer. Oxygen doping treatment is performed in a manner such that oxygen is introduced into the insulating layer and the metal film from a position above the metal film. Thus, a region containing oxygen in excess of the stoichiometric composition is formed in the insulating layer, and the metal film is oxidized to form a metal oxide film. Further, resistivity of the metal oxide film is greater than or equal to 1×10¹⁰ Ωm and less than or equal to 1×10¹⁹ Ωm.

Claims

1. A semiconductor device comprising:

a gate electrode layer;

a gate insulating layer over the gate electrode layer;

an oxide semiconductor layer over the gate insulating layer, the oxide semiconductor layer overlapping with the gate electrode layer;

a source electrode layer over the oxide semiconductor layer, the source electrode layer being electrically connected to the oxide semiconductor layer;

a drain electrode layer over the oxide semiconductor layer, the drain electrode layer being electrically connected to the oxide semiconductor layer;

an insulating layer comprising silicon oxide over and in contact with the oxide semiconductor layer; and

an aluminum oxide film over and in contact with the insulating layer,

wherein the aluminum oxide film comprises magnesium or titanium,

wherein the insulating layer comprises a region containing oxygen in excess of a stoichiometric composition,

wherein the aluminum oxide film has a resistivity greater than or equal to 1×

10¹⁰ Ω

m and less than or equal to 1×

10¹⁹ Ω

m, and

wherein a thickness of the aluminum oxide film is greater than or equal to 3 nm and less than or equal to 10 nm.

2. The semiconductor device according to claim 1,

wherein the insulating layer is over the source electrode layer and the drain electrode layer, and

wherein the insulating layer between the source electrode layer and the drain electrode layer is in contact with the oxide semiconductor layer.

3. The semiconductor device according to claim 1,

wherein the source electrode layer is over the insulating layer,

wherein the drain electrode layer is over the insulating layer,

wherein the insulating layer has a first opening and a second opening,

wherein the source electrode layer is in contact with the oxide semiconductor layer through the first opening, and

wherein the drain electrode layer is in contact with the oxide semiconductor layer through the second opening.

4. The semiconductor device according to claim 1, wherein the insulating layer is a silicon oxide film containing nitrogen.

5. A display device comprising:

a gate electrode layer;

a gate insulating layer over the gate electrode layer;

an oxide semiconductor layer over the gate insulating layer, the oxide semiconductor layer overlapping with the gate electrode layer;

a source electrode layer over the oxide semiconductor layer, the source electrode layer being electrically connected to the oxide semiconductor layer;

a drain electrode layer over the oxide semiconductor layer, the drain electrode layer being electrically connected to the oxide semiconductor layer;

an insulating layer comprising silicon oxide over and in contact with the oxide semiconductor layer;

an aluminum oxide film over and in contact with the insulating layer;

an interlayer insulating layer over the aluminum oxide film; and

a light-emitting element over the interlayer insulating layer,

wherein the aluminum oxide film comprises magnesium or titanium,

wherein the insulating layer comprises a region containing oxygen in excess of a stoichiometric composition,

wherein the aluminum oxide film has a resistivity greater than or equal to 1×

10¹⁰ Ω

m and less than or equal to 1×

10¹⁹ Ω

m, and

wherein a thickness of the aluminum oxide film is greater than or equal to 3 nm and less than or equal to 10 nm.

6. The display device according to claim 5,

wherein the insulating layer is over the source electrode layer and the drain electrode layer, and

wherein the insulating layer between the source electrode layer and the drain electrode layer is in contact with the oxide semiconductor layer.

7. The display device according to claim 5,

wherein the source electrode layer is over the insulating layer,

wherein the drain electrode layer is over the insulating layer,

wherein the insulating layer has a first opening and a second opening,

wherein the source electrode layer is in contact with the oxide semiconductor layer through the first opening, and

wherein the drain electrode layer is in contact with the oxide semiconductor layer through the second opening.

8. The display device according to claim 5, wherein the insulating layer is a silicon oxide film containing nitrogen.