Light emitting device

• US 7,851,989 B2
• Filed: 03/22/2006
• Issued: 12/14/2010
• Est. Priority Date: 03/25/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Noda, Takeshi
• Primary Examiner(s): Patel; Ashok
• Application Number:
  US11/386,187
• Publication Number:
  US 20060232203A1
• Time in Patent Office: 1,728 Days
• Field of Search: None
• US Class Current: 313/503
• CPC Class Codes: H01L 33/26 Materials of the light emitting region
• CPC Class Codes: H05B 33/24 of metallic reflective layers H05B33/26 takes precedence
• CPC Class Codes: H10K 50/14 Carrier transporting layers
• CPC Class Codes: H10K 50/805 Electrodes
• CPC Class Codes: H10K 50/813 characterised by their shape
• CPC Class Codes: H10K 59/805 Electrodes

Abstract

It is an object of the present invention to provide a light-emitting device in which, even when a material with high reflectivity such as aluminum is used for an electrode, a layer containing oxygen can be formed over the electrode without increasing contact resistance and a manufacturing method thereof. According to the present invention, a feature thereof is a light-emitting element having an electrode composed of a stacked structure where a conductive film having high reflectivity such as aluminum, silver, and an alloy containing aluminum or an alloy containing silver, and a conductive film composed of a refractory metal material is provided over the conductive film, or a light-emitting device having the light-emitting element.

Claims

1. A light-emitting device comprising:

a first electrode comprising a first conductive film and a second conductive film;

a layer formed over the first electrode; and

a second electrode formed over the layer,

wherein the first conductive film is formed over the second conductive film,

wherein the layer comprises a mixture region comprising a metal oxide,

wherein the mixture region is in contact with the first conductive film,

wherein the first conductive film comprises a refractory metal material, and

wherein the second conductive film corn rises a metal material having high reflectiveness.

2. A light-emitting device according to claim 1, wherein the metal oxide comprises at least one selected from the group consisting of vanadium oxide, molybdenum oxide, niobium oxide, rhenium oxide, tungsten oxide, ruthenium oxide, titanium oxide, chromium oxide, zirconium oxide, hafnium oxide, and tantalum oxide.

3. A light-emitting device according to claim 1, wherein light is emitted from the layer through the second electrode.

4. A light-emitting device according to claim 1, wherein the metal material having high reflectiveness comprises aluminum, silver, an alloy comprising aluminum, and an alloy comprising silver.

5. A light-emitting device according to claim 1, wherein the refractory metal material comprises titanium nitride.

6. A light-emitting device according to claim 1, wherein the refractory metal material comprises at least one selected from the group consisting of titanium, tungsten, molybdenum, and a compound containing these metals.

7. A light-emitting device comprising:

a first electrode comprising a first conductive film and a second conductive film;

a layer formed over the first electrode; and

a second electrode having reflectiveness formed over the layer,

wherein the first conductive film is formed over the second conductive film,

wherein the layer comprises a mixture region comprising a metal oxide,

wherein the mixture region is in contact with the first conductive film,

wherein the first conductive film comprises a refractory metal material,

wherein the second conductive film comprises a metal material having high reflectiveness, and

wherein the second electrode has a film thickness that transmits light from the layer.

8. A light-emitting device according to claim 7, wherein the metal material having high reflectiveness comprises aluminum, silver, an alloy comprising aluminum, and an alloy comprising silver.

9. A light-emitting device according to claim 7, wherein the metal oxide comprises at least one selected from the group consisting of vanadium oxide, molybdenum oxide, niobium oxide, rhenium oxide, tungsten oxide, ruthenium oxide, titanium oxide, chromium oxide, zirconium oxide, hafnium oxide, and tantalum oxide.

10. A light-emitting device according to claim 7, wherein light is emitted from the layer through the second electrode.

11. A light-emitting device according to claim 7, wherein the refractory metal material comprises at least one selected from the group consisting of titanium, tungsten, molybdenum, and a compound containing these metals.

12. A light-emitting device according to claim 7, wherein the refractory metal material comprises titanium nitride.

13. A light-emitting device having at least first, second and third light-emitting elements, each of the first, second and third light-emitting elements comprising:

a first electrode comprising a first conductive film and a second conductive film;

a layer formed over the first electrode; and

a second electrode formed over the layer,

wherein the first conductive film is formed over the second conductive film,

wherein the layer comprises a mixture region comprising a metal oxide,

wherein the mixture region is in contact with the first conductive film,

wherein the first conductive film comprises a refractory metal material,

wherein the first light-emitting element emits red light, the second light-emitting element emits green light and the third light-emitting element emits blue light,

wherein the second conductive film comprises a metal material having high reflectiveness, and

wherein a film thickness of the mixture region of each of the first, second and third light-emitting elements is different.

14. A light-emitting device according to claim 13, wherein the metal material having high reflectiveness comprises aluminum, silver, an alloy comprising aluminum, and an alloy comprising silver.

15. A light-emitting device according to claim 13, wherein the refractory metal material comprises at least one selected from the group consisting of titanium, tungsten, molybdenum, and a compound containing these metals.

16. A light-emitting device according to claim 13, wherein the metal oxide comprises at least one selected from the group consisting of vanadium oxide, molybdenum oxide, niobium oxide, rhenium oxide, tungsten oxide, ruthenium oxide, titanium oxide, chromium oxide, zirconium oxide, hafnium oxide, and tantalum oxide.

17. A light-emitting device according to claim 13, wherein light is emitted from the layer through the second electrode.

18. A light-emitting device according to claim 13, wherein the refractory metal material comprises titanium nitride.

19. A light-emitting device comprising:

a semiconductor film formed over an insulating substrate;

a wiring connected to an impurity region in the semiconductor film;

a first electrode comprising a first conductive film and a second conductive film, the first electrode being connected to the wiring;

,

a layer formed over the first electrode; and

a second electrode formed over the layer,

wherein the first conductive film is formed over the second conductive film,

wherein the layer comprises a mixture region comprising a metal oxide,

wherein the mixture region is in contact with the first conductive film,

wherein the first conductive film comprises a refractory metal material, and

wherein the second conductive film comprises a metal material having high reflectiveness.

20. A light-emitting device according to claim 19, wherein the impurity region is an n-type impurity region.

21. A light-emitting device according to claim 19, wherein the impurity region is a p-type impurity region.

22. A light-emitting device according to claim 19, wherein the metal material having high reflectiveness comprises aluminum, silver, an alloy comprising aluminum, and an alloy comprising silver.

23. A light-emitting device according to claim 19, wherein the metal oxide comprises at least one selected from the group consisting of vanadium oxide, molybdenum oxide, niobium oxide, rhenium oxide, tungsten oxide, ruthenium oxide, titanium oxide, chromium oxide, zirconium oxide, hafnium oxide, and tantalum oxide.

24. A light-emitting device according to claim 19, wherein light is emitted from the layer through the second electrode.

25. A light-emitting device according to claim 19, wherein the refractory metal material comprises at least one selected from the group consisting of titanium, tungsten, molybdenum, and a compound containing these metals.

26. A light-emitting device according to claim 19, wherein the refractory metal material comprises titanium nitride.