阅读说明：本技术 发光二极管 (Light emitting diode ) 是由 郭贵田 朱立钦 蔡琳榕 杨力勋 于 2018-11-13 设计创作，主要内容包括：本发明公开了一种发光二极管。在一些实施例中,发光二极管包括：发光外延叠层,包含第一半导体层、有源层和第二半导体层,具有对应的第一表面和第二表面；透光层,形成于所述发光外延叠层的第二表面上；第一金属层,形成于所述透光层之远离所述发光外延叠层的表面上；第二金属层,形成于所述第一金属层之远离所述发光外延叠层的表面上；所述第一金属层和第二金属层构成镜面结构。(The invention discloses a light emitting diode. In some embodiments, a light emitting diode includes: a light emitting epitaxial stack comprising a first semiconductor layer, an active layer and a second semiconductor layer having corresponding first and second surfaces; a light-transmitting layer formed on the second surface of the light-emitting epitaxial stacked layer; the first metal layer is formed on the surface, far away from the light-emitting epitaxial lamination layer, of the light-transmitting layer; a second metal layer formed on a surface of the first metal layer remote from the light-emitting epitaxial stack; the first metal layer and the second metal layer form a mirror structure.)

1. A light emitting diode, comprising:

a light emitting epitaxial stack comprising a first semiconductor layer, an active layer and a second semiconductor layer having corresponding first and second surfaces;

a light-transmitting layer formed on the second surface of the light-emitting epitaxial stacked layer;

the first metal layer is formed on the surface, far away from the light-emitting epitaxial lamination layer, of the light-transmitting layer;

a second metal layer formed on a surface of the first metal layer remote from the light-emitting epitaxial stack;

the method is characterized in that: the first metal layer and the second metal layer form a mirror structure, and the reflectivity of the first metal layer to the light emitted by the light-emitting epitaxial lamination is defined as R1, the reflectivity of the second metal layer to the light emitted by the light-emitting epitaxial lamination is defined as R2, and the composite reflectivity of the first metal layer and the second metal layer to the light emitted by the light-emitting epitaxial lamination is defined as R3, then R1 is less than R2, and (R2-R3)/R2 is less than 4%.

2. The LED of claim 1 wherein said light-emitting epitaxial stack emits light at a wavelength of 360 ~ 450 nm.

3. The light-emitting diode according to claim 1, wherein the light-emitting epitaxial stack has an emission wavelength of 385 ~ 450nm, and the combined reflectance of the first metal layer and the second metal layer is 90% or more.

4. The LED according to claim 1 wherein the light emitting epitaxial stack emits light at a wavelength of 365 ~ 450nm and the combined reflectance of the first and second metal layers is 85% or more.

5. The led of claim 1, wherein: the euphotic layer is an insulating material layer.

6. The light-emitting diode according to claim 3, wherein: the light-transmitting layer has a thickness of 5000 angstroms or less.

7. The led of claim 1, wherein: the first metal layer is in a state of not being formed.

8. The led of claim 1, wherein: the first metal layer has a thickness of 50 angstroms or less.

9. The LED of claim 1, wherein the second metal layer has a thickness of 100 ~ 5000 angstroms.

10. The led of claim 1, wherein: the first metal layer is an aluminum layer or a rhodium layer, and the second metal layer is a silver layer.

11. The led of claim 1, wherein: the edge of the second metal layer exceeds the edge of the light emitting epitaxial stack.

12. The led of claim 1, wherein: defining the luminous epitaxial lamination layer as an upper part, wherein a structure below the second surface of the luminous epitaxial lamination layer is a lower part, the lower part is provided with an edge part exceeding the edge of the luminous epitaxial lamination layer, and the edge part at least comprises a first insulating layer, a metal material layer and a second insulating layer from top to bottom.

13. The led of claim 12, wherein: the metal protective layer is formed between the second metal layer and the insulating layer and covers the second metal layer, and the metal material layer of the edge part is made of the same material as the metal protective layer.

14. The led of claim 12, wherein: the metal material layer of the edge portion is located on the outermost side of the outer edge portion.

15. The led of claim 1, wherein: also comprises

The insulating layer is formed on the surface, far away from the light-emitting epitaxial lamination layer, of the second metal layer;

the conductive connecting layer is formed on the surface of the insulating layer far away from the light-emitting epitaxial lamination layer;

the light-emitting epitaxial lamination layer is provided with at least one concave part, the concave part starts from the second surface of the light-emitting epitaxial lamination layer, penetrates through the second semiconductor layer and the active layer and extends to the first type semiconductor layer, the light-transmitting layer is made of insulating materials and covers the side wall of the concave part, and the conductive connecting layer fills the concave part and is electrically connected with the first semiconductor layer.

16. The led of claim 15, wherein: defining the light-emitting epitaxial lamination layer as an upper part, wherein the structure below the second surface of the light-emitting epitaxial lamination layer is a lower part, the lower part is provided with an edge part exceeding the edge of the light-emitting epitaxial lamination layer, and the edge part at least comprises a light-transmitting layer, a metal material layer and an insulating layer from top to bottom.

17. The led of claim 16, wherein: the metal protective layer is formed between the second metal layer and the insulating layer and covers the second metal layer, and the metal material layer of the edge part is made of the same material as the metal protective layer.

18. An ultraviolet light emitting diode comprising:

a light emitting epitaxial stack comprising a first semiconductor layer, an active layer and a second semiconductor layer having corresponding first and second surfaces;

a light-transmitting layer formed on the second surface of the light-emitting epitaxial stacked layer;

the first conducting layer is formed on the surface, far away from the light-emitting epitaxial lamination layer, of the light-transmitting layer;

a second conductive layer formed on a surface of the first conductive layer remote from the light emitting epitaxial stack;

the method is characterized in that: the first conductive layer and the second conductive layer constitute a mirror structure, and the reflectivity of the first conductive layer to the light emitted by the light-emitting epitaxial stack is defined as R2, the reflectivity of the second conductive layer to the light emitted by the light-emitting epitaxial stack is defined as R2, and the composite reflectivity of the first conductive layer and the second conductive layer to the light emitted by the light-emitting epitaxial stack is defined as R3, then R1< R2, and (R2-R3)/R2< 4%.

19. The led of claim 18, wherein: the euphotic layer is an insulating material layer.

20. The led of claim 18, wherein: the light-transmitting layer has a thickness of 5000 angstroms or less.

21. The led of claim 18, wherein: the first conductive layer is in an uncoated state.

22. The led of claim 18, wherein: the first conductive layer has a thickness of 50 angstroms or less.

23. The LED of claim 18, wherein said second conductive layer has a thickness of 100 ~ 5000 angstroms.

24. The led of claim 18, wherein: the first conducting layer is an aluminum layer or a rhodium layer, and the second conducting layer is a silver layer.

25. The led of claim 18, wherein: defining the luminous epitaxial lamination layer as an upper part, wherein a structure below the second surface of the luminous epitaxial lamination layer is a lower part, the lower part is provided with an edge part exceeding the edge of the luminous epitaxial lamination layer, and the edge part at least comprises a first insulating layer, a metal material layer and a second insulating layer from top to bottom.

26. The led of claim 25, wherein: the metal protective layer is formed between the second metal layer and the insulating layer and covers the second metal layer, and the metal material layer of the edge part is made of the same material as the metal protective layer.

27. The led of claim 25, wherein: the metal material layer of the edge portion is located on the outermost side of the outer edge portion.

28. The led of claim 18, wherein: also comprises

The insulating layer is formed on the surface, far away from the light-emitting epitaxial lamination layer, of the second metal layer;

the conductive connecting layer is formed on the surface of the insulating layer far away from the light-emitting epitaxial lamination layer;

the light-emitting epitaxial lamination layer is provided with at least one concave part, the concave part starts from the second surface of the light-emitting epitaxial lamination layer, penetrates through the second semiconductor layer and the active layer and extends to the first type semiconductor layer, the light-transmitting layer is made of insulating materials and covers the side wall of the concave part, and the conductive connecting layer fills the concave part and is electrically connected with the first semiconductor layer.

29. The led of claim 28, wherein: defining the light-emitting epitaxial lamination layer as an upper part, wherein the structure below the second surface of the light-emitting epitaxial lamination layer is a lower part, the lower part is provided with an edge part exceeding the edge of the light-emitting epitaxial lamination layer, and the edge part at least comprises a light-transmitting layer, a metal material layer and an insulating layer from top to bottom.

30. The led of claim 29, wherein: the metal protective layer is formed between the second metal layer and the insulating layer and covers the second metal layer, and the metal material layer of the edge part is made of the same material as the metal protective layer.

Technical Field

The invention relates to the field of semiconductor photoelectricity, in particular to a light-emitting diode structure.

Background

Light emitting diodes are widely used as solid state lighting sources. Compared with the traditional incandescent bulb and fluorescent lamp, the light emitting diode has the advantages of low power consumption, long service life and the like, so the light emitting diode gradually replaces the traditional light source and is applied to various fields such as traffic signs, backlight modules, street lamp illumination, medical equipment and the like. In order to improve the light emitting efficiency of the light emitting diode, a reflective layer is usually disposed below the epitaxial lamination layer, so that light emitted downward from the active layer is reflected back by the reflective layer, thereby increasing the light emitting efficiency.

Disclosure of Invention

The invention provides a light emitting diode which effectively improves the external light extraction efficiency of the light emitting diode.

A light emitting diode according to a first aspect of the present invention comprises: a light emitting epitaxial stack comprising a first semiconductor layer, an active layer and a second semiconductor layer having corresponding first and second surfaces; a light-transmitting layer formed on the second surface of the light-emitting epitaxial stacked layer; the first metal layer is formed on the surface, far away from the light-emitting epitaxial lamination layer, of the light-transmitting layer; a second metal layer formed on a surface of the first metal layer remote from the light-emitting epitaxial stack; the first metal layer and the second metal layer form a mirror structure, and the reflectivity of the first metal layer to the light emitted by the light-emitting epitaxial lamination is defined as R1, the reflectivity of the second metal layer to the light emitted by the light-emitting epitaxial lamination is defined as R2, and the composite reflectivity of the first metal layer and the second metal layer to the light emitted by the light-emitting epitaxial lamination is defined as R3, then R1 is less than R2, and (R2-R3)/R2 is less than 4%.

In some embodiments, the light emitting epitaxial stack has a light emitting wavelength of 385 ~ 450nm, and the first metal layer and the second metal layer have a combined reflectance of 90% or more.

In some embodiments, the luminescent epitaxial stack has a luminescent wavelength of 365 ~ 450nm, and the first metal layer and the second metal layer have a combined reflectance of 85% or more.

According to a second aspect of the present invention, an ultraviolet light emitting diode includes: a light emitting epitaxial stack comprising a first semiconductor layer, an active layer and a second semiconductor layer having corresponding first and second surfaces; a light-transmitting layer formed on the second surface of the light-emitting epitaxial stacked layer; the first conducting layer is formed on the surface, far away from the light-emitting epitaxial lamination layer, of the light-transmitting layer; a second conductive layer formed on a surface of the first conductive layer remote from the light emitting epitaxial stack; the first conductive layer and the second conductive layer constitute a mirror structure, and it is defined that the reflectivity of the first conductive layer for light emitted by the light emitting epitaxial stack is R2, the reflectivity of the second conductive layer for light emitted by the light emitting epitaxial stack is R2, and the composite reflectivity of the first conductive layer and the second conductive layer for light emitted by the light emitting epitaxial stack is R3, then R1< R2, and (R2-R3)/R2< 4%.

According to a third aspect of the present invention, a light emitting diode comprises an upper portion and a lower portion, wherein the upper portion is a semiconductor laminated layer and comprises a first semiconductor layer, an active layer and a second semiconductor layer in sequence from top to bottom, the lower portion comprises an insulating material layer, an adhesive layer and a substrate in sequence, the lower portion has an edge portion exceeding an edge of the upper portion, and the edge portion comprises at least a first insulating layer, a metal material layer and a second insulating layer, an adhesive layer and a substrate in sequence from top to bottom.

In some embodiments, the first insulating layer, the metal reflective layer, the metal protection layer and the second insulating layer are sequentially disposed on the lower surface of the semiconductor stack.

Preferably, the metal protective layer is made of the same material as the metal material layer of the edge portion. In other embodiments, the metal protective layer and the metal material layer of the edge portion may also be different in material.

In some embodiments, the metal protection layer is electrically isolated from the metal material layer of the edge portion.

Preferably, the metal material layer of the edge portion is located outermost of the outer edge portion.

In some embodiments, the semiconductor stack has at least one recess extending from a lower surface of the semiconductor stack, through the second semiconductor layer, the active layer, to the first type semiconductor layer, the first insulating layer covering sidewalls of the recess.

Further, the light emitting diode further comprises a first conductive connecting layer which is formed on the surface of the first insulating layer, fills the concave part and is electrically connected with the first semiconductor layer; a second conductive connection layer formed between the first insulating layer and the second insulating layer and electrically connected to the second semiconductor layer; the second conductive connecting layer comprises a metal reflecting layer and a metal protecting layer. Preferably, the metal protective layer is made of the same material as the metal material layer of the edge portion.

In some embodiments, the second conductive connecting layer further comprises a conductive adhesion layer between the metal reflective layer and the first insulating layer.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. Furthermore, the drawing figures are for a descriptive summary and are not drawn to scale.

Fig. 1 is a schematic structural diagram of a light emitting diode according to a first embodiment of the invention.

Fig. 2 shows a graph of the reflectivity for different materials for different wavelengths of light.

Fig. 3 is a schematic structural diagram of a light emitting diode according to a second embodiment of the invention.

Fig. 4 is a schematic diagram illustrating that the edge of the metal reflective layer of the light emitting diode according to the second preferred embodiment exceeds the edge of the epitaxial stack.

Fig. 5 is a schematic structural diagram of a light emitting diode according to a third embodiment of the invention.

Fig. 6 is a diagram illustrating a manufacturing process of a light emitting diode chip according to a fourth embodiment of the present invention.

Fig. 7 to 19 are schematic structural diagrams showing steps in a light emitting diode manufacturing process according to a fourth embodiment of the present invention.

Fig. 20-25 are schematic views showing a structure of a part of steps in a process for manufacturing a light emitting diode according to a fifth embodiment of the present invention, wherein fig. 23 shows a cut-off photograph in the process for manufacturing the light emitting diode according to the fourth and fifth embodiments, respectively.

Fig. 26 is a schematic structural diagram of a light emitting diode according to a sixth embodiment of the invention.

Fig. 27 is a schematic structural diagram of a light emitting diode according to a seventh embodiment of the invention.

Detailed Description

The structures, proportions, sizes, and other dimensions shown in the drawings of the present specification are for understanding and reading the content of the present disclosure, and are not intended to limit the scope of the present disclosure, which is defined by the claims, and therefore, they are not essential to the technology, and any structural modifications, changes in proportions, or adjustments in size, without affecting the efficacy and attainment of the same, are intended to be included within the scope of the present disclosure. Meanwhile, the terms such as "upper", "lower", "left", "right", "middle", and "a" used in the present specification are for clarity of description, and are not intended to limit the scope of the present invention, and changes or modifications of the relative relationship may be considered as the scope of the present invention without substantial technical changes.

The following describes the led structure in detail with reference to the accompanying drawings, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented. It should be noted that, as long as there is no conflict, the embodiments and the features of the embodiments of the present invention may be combined with each other, and the technical solutions formed are within the scope of the present invention.