Display device

• US 10,707,293 B2
• Filed: 02/28/2019
• Issued: 07/07/2020
• Est. Priority Date: 03/01/2018
• Status: Active Grant

• Current Assignee: Tianma Japan, Ltd. (Tianma Microelectronics Company Limited), Wuhan Tianma Micro-Electronics Company Limited (Wuhan Donghu New Technology Development Zone Production Promotion Centre)
• Original Assignee: Tianman Japan Limited
• Inventors: Takechi, Kazushige
• Primary Examiner(s): Gheyas, Syed I
• Application Number:
  US16/288,785
• Publication Number:
  US 20190273125A1
• Time in Patent Office: 495 Days
• 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 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 50/818 Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 50/824 combined with auxiliary electrodes
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 59/1201 Manufacture or treatment
• CPC Class Codes: H10K 59/121 characterised by the geometry or disposition of pixel elements
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors
• CPC Class Codes: H10K 59/1315 comprising structures specially adapted for lowering the resistance
• CPC Class Codes: H10K 59/80518 Reflective anodes, e.g. ITO combined with thick metallic layers
• CPC Class Codes: H10K 59/80522 combined with auxiliary electrodes
• CPC Class Codes: H10K 59/80524 Transparent cathodes, e.g. comprising thin metal layers

Abstract

Each of pixels includes: a transparent upper electrode covering at least a part of the first region and at least a part of the second region; a reflective lower electrode disposed in the second region; a light-emitting film disposed between the transparent upper electrode and the reflective lower electrode, the light-emitting film being configured to emit light in response to supplied electric current; a thin film transistor disposed lower than the reflective lower electrode in the second region, the thin film transistor having a channel made of a transparent oxide; and a transparent low-resistive film that is made of the transparent oxide and interconnects the power-source potential supply line and the transparent upper electrode, the transparent low-resistive film being separate from an oxide film that is made of the transparent oxide and includes the channel and having a resistance lower than a resistance of the channel.

Claims

1. A display device comprising:

a substrate;

a plurality of pixels formed on the substrate, each of the plurality of pixels including a transparent first region and a second region different from the first region; and

a power-source potential supply line lying through the second regions of the plurality of pixels and connected with a power line at outside of the plurality of pixels,

wherein each of the plurality of pixels includes;

a transparent upper electrode covering at least a part of the first region and at least a part of the second region;

a reflective lower electrode disposed in the second region;

a light-emitting film disposed between the transparent upper electrode and the reflective lower electrode, the light-emitting film being configured to emit light in response to supplied electric current;

a thin film transistor disposed lower than the reflective lower electrode in the second region, the thin film transistor having a channel made of a transparent oxide; and

a transparent low-resistive film consisting of the transparent oxide and interconnects the power-source potential supply line and the transparent upper electrode, the transparent low-resistive film being separate from an oxide film consisting of the transparent oxide and includes the channel and having a resistance lower than a resistance of the channel,

wherein the transparent low-resistive film is connected with the transparent upper electrode in the first region, and

wherein the transparent low-resistive film is connected with the power-source potential supply line in the second region.

2. The display device according to claim 1, wherein the transparent upper electrode is a part of a transparent conductive film covering the plurality of pixels and connected with the power line at outside of the plurality of pixels and covers the whole area of the first region and the second region.

3. The display device according to claim 1,

wherein each of the plurality of pixels includes a storage capacitor between a gate electrode of the thin film transistor and a second electrode that is either a source electrode or a drain electrode of the thin film transistor,

wherein the storage capacitor includes:

a first transparent capacitor electrode connected with the gate electrode in the second region and extending into the first region;

a second transparent capacitor electrode that is a part of the oxide film including the channel, extends continuously from a contact region of the oxide film with the second electrode into the first region, and has a resistance lower than the resistance of the channel; and

an insulating film between the first transparent capacitor electrode and the second transparent capacitor electrode, and

wherein at least a part of the first transparent capacitor electrode and at least a part of the second transparent capacitor electrode are opposed to each other across the insulating film in the first region.

4. The display device according to claim 3, wherein one of the following conditions is satisfied:

that peaks of X-ray Photoelectron Spectroscopy (XPS) spectra originating the indium 3d_5/2 orbital of the transparent low-resistive film and the second transparent capacitor electrode are shifted to lower energy than peaks of XPS spectra originating the indium 3d_5/2 orbital of the channel made of the transparent oxide;

that peaks of XPS spectra originating the gallium 2p_3/2 orbital of the transparent low-resistive film and the second transparent capacitor electrode are shifted to lower energy than peaks of XPS spectra originating the gallium 2p_3/2 orbital of the channel made of the transparent oxide; and

that peaks of XPS spectra originating the zinc 2p_3/2 orbital of the transparent low-resistive film and the second transparent capacitor electrode are shifted to lower energy than peaks of XPS spectra originating the zinc 2p_3/2 orbital of the channel made of the transparent oxide.

5. The display device according to claim 3, wherein peaks of XPS spectra originating the indium 3d_5/2 orbital of the transparent low-resistive film and the second transparent capacitor electrode are located at energies lower than 444.5 eV.

6. The display device according to claim 3, wherein XPS spectra originating the indium 3d_5/2 orbital of the transparent low-resistive film and the second transparent capacitor electrode have sub-peaks at energies lower than 444.0 eV.

7. The display device according to claim 1,

wherein the transparent oxide is IGZO, and

wherein the transparent low-resistive film is more oxygen-deficient than the channel.

8. The display device according to claim 1, wherein the power-source potential supply line is located lower than the reflective lower electrode and lies through a region covered by the reflective lower electrode.

9. The display device according to claim 8, wherein the power-source potential supply line is made of the same material as the source electrode and the drain electrode of the thin film transistor and provided on the same insulating film on which the source electrode and the drain electrode are provided.

10. The display device according to claim 1, wherein the power-source potential supply line is made of the same metal film as the reflective lower electrode.

11. The display device according to claim 1, wherein the gate electrode of the thin film transistor is provided on a layer between the channel and the reflective lower electrode.

12. The display device according to claim 11, wherein one of the following conditions is satisfied:

that peaks of XPS spectra originating the indium 3d_5/2 orbital of the transparent low-resistive film are shifted to lower energy than peaks of XPS spectra originating the indium 3d_5/2 orbital of the channel made of the transparent oxide covered by the gate electrode and located lower than the gate electrode;

that peaks of XPS spectra originating the gallium 2p_3/2 orbital of the transparent low-resistive film are shifted to lower energy than peaks of XPS spectra originating the gallium 2p_3/2 orbital of the transparent oxide covered by the gate electrode and located lower than the gate electrode; and

that peaks of XPS spectra originating the zinc 2p_3/2 orbital of the transparent low-resistive film are shifted to lower energy than peaks of XPS spectra originating the zinc 2p_3/2 orbital of the transparent oxide covered by the gate electrode and located lower than the gate electrode.

13. The display device according to claim 11, wherein peaks of XPS spectra originating the indium 3d_5/2 orbital of the transparent low-resistive film are located at energies lower than 444.5 eV.

14. The display device according to claim 11, wherein XPS spectra originating the indium 3d_5/2 orbital of the transparent low-resistive film have sub-peaks at energies lower than 444.0 eV.

15. The display device according to claim 1, wherein the transparent low-resistive film has a sheet resistance not more than 1 MΩ

.

16. A display device comprising:

a substrate; and

a plurality of pixels formed on the substrate, each of the plurality of pixels including a first region that transmits light and a second region different from the first region,

wherein each of the plurality of pixels includes;

a transparent upper electrode covering at least a part of the first region and at least a part of the second region;

a reflective lower electrode disposed in the second region;

a light-emitting film disposed between the transparent upper electrode and the reflective lower electrode, the light-emitting film being configured to emit light in response to supplied electric current;

a thin film transistor disposed lower than the reflective lower electrode in the second region, the thin film transistor including a gate electrode, a source electrode, a drain electrode, and an oxide film made of a transparent oxide that includes a channel;

a first transparent capacitor electrode connected with the gate electrode in the second region and extending into the first region;

a second transparent capacitor electrode which is a part of the oxide film, extends continuously from a contact region of the oxide film with a second electrode, which is either the source electrode or the drain electrode, into the first region, and has a resistance lower than a resistance of the channel; and

an insulating film between the first transparent capacitor electrode and the second transparent capacitor electrode, and

wherein at least a part of the first transparent capacitor electrode and at least a part of the second transparent capacitor electrode are opposed to each other across the insulating film in the first region to be a storage capacitor between the gate electrode and the second electrode.

17. The display device according to claim 16, wherein the transparent upper electrode is a part of a transparent conductive film covering the plurality of pixels and connected with a power line at outside of the plurality of pixels and covers the whole area of the first region and the second region.

18. The display device according to claim 17,

wherein each of the plurality of pixels further includes:

an auxiliary line lying through the second region and connected with the power line at outside of the plurality of pixels; and

a transparent interconnector which is made of the same material, provided on the same layer as the first transparent capacitor electrode at a distance from the first transparent capacitor electrode, connected with the transparent upper electrode in the first region, and connected with the auxiliary line in the second region.

19. The display device according to claim 16, wherein the second transparent capacitor electrode has a sheet resistance not more than on-resistance of the channel.

20. The display device according to claim 16, wherein the gate electrode of the thin film transistor is provided on a layer between the channel and the reflective lower electrode.