CN212517229U

CN212517229U - Light emitting element

Info

Publication number: CN212517229U
Application number: CN201921953244.6U
Authority: CN
Inventors: 邱柏顺; 蒋宗勋; 纪喨胜; 谢静; 赵欣
Original assignee: Epistar Corp
Current assignee: Epistar Corp
Priority date: 2019-11-13
Filing date: 2019-11-13
Publication date: 2021-02-09
Anticipated expiration: 2029-11-13

Abstract

The utility model provides a light-emitting element, which comprises a substrate; a light emitting stack comprising a first semiconductor stack, an active layer on the first semiconductor stack, and a second semiconductor stack on the active layer; a first electrode on the first semiconductor stack; a second electrode on the second semiconductor stack; and an insulating layer located on the light-emitting laminated layer, wherein the first semiconductor laminated layer comprises a first table-board and a second table-board, the first electrode is located on the first table-board, and a first step difference is formed between the first table-board and the second table-board.

Description

Light emitting element

Technical Field

The present invention relates to a light emitting device, and more particularly, to a light emitting device having a plurality of panels.

Background

Light Emitting Diodes (LEDs) are a widely used solid state light emitting element. A Light Emitting Diode (LED) includes a p-type semiconductor layer, an n-type semiconductor layer, and an active layer between the p-type semiconductor layer and the n-type semiconductor layer to emit a light. The principle of the LED is to provide a current to the LED to inject electrons and holes into the active layer, so that the electric energy is converted into light energy. The electrons and holes combine in the active layer to emit light.

SUMMERY OF THE UTILITY MODEL

Drawings

Fig. 1 is a top view of a light emitting element 1 disclosed in the present invention.

Fig. 2 is a cross-sectional view of the light emitting element 1 of fig. 1 taken along line X-X'.

Fig. 3 is a partial electron microscope (SEM) image of the light-emitting element 1 disclosed in the present invention.

Fig. 4 is a cross-sectional view of a light emitting device 2 according to the present invention.

Fig. 5 is a schematic view of a light emitting device 3 according to an embodiment of the present invention.

Fig. 6 is a schematic view of a light emitting device 4 according to an embodiment of the present invention.

List of reference numerals

1, 2 light emitting element

10 base plate

10d side wall

10S face

20 light emitting laminate

21 first semiconductor stack

210 first doped semiconductor layer

211 first undoped semiconductor layer

21S first inclined plane

211S side surface

22 active layer

23 second semiconductor stack

23S second inclined plane

3 light emitting device

31 first electrode

311 first electrode pad

312 first extension electrode

32 second electrode

321 second electrode pad

322 second extended electrode

4 light emitting device

40 insulating layer

50 lower reflecting layer

51 packaging substrate

511 first gasket

512 second gasket

52 transparent conductive layer

53 insulating part

54 reflective structure

60 third electrode

601 extension

602 lampshade

604 reflecting mirror

606 bearing part

608 luminous unit

610 luminous module

612 lamp holder

614 Heat sink

616 connection part

618 electric connection element

70 fourth electrode

80 current confinement region

S1 first table top

S2 second table top

S3 third table top

Thickness of T

First order difference of T1

Second order difference of T2

Detailed Description

For a more complete and complete description of the present invention, reference is made to the following description of the embodiments, taken in conjunction with the accompanying drawings. However, the following examples are provided to illustrate the light emitting element of the present invention, and the present invention is not limited to the following examples. The dimensions, materials, shapes, relative arrangements and the like of the constituent elements described in the embodiments of the present invention are not limited to the above description, and the scope of the present invention is not limited to these, but is merely illustrative. The sizes and positional relationships of the members shown in the drawings are exaggerated for clarity. In the following description, the same or similar members are denoted by the same reference numerals and signs so as to appropriately omit detailed description.

Fig. 1 is a top view of a light emitting element 1 disclosed in the present invention. Fig. 2 is a cross-sectional view of the light emitting element 1 of fig. 1 taken along line X-X'. Fig. 3 is a partial electron microscope (SEM) image of the light-emitting element 1 disclosed in the present invention. A light emitting device 1 including a substrate 10; a light emitting stack 20 comprising a first semiconductor stack 21, an active layer 22 on the first semiconductor stack 21, and a second semiconductor stack 23 on the active layer 22; a first electrode 31 on the first semiconductor stack 21; a second electrode 32 on the second semiconductor stack 23; and an insulating layer 40 disposed on the light emitting stack 20, wherein the first semiconductor stack 21 includes a first mesa S1 and a second mesa S2, the first electrode 31 is disposed on the first mesa S1, and a first step T1 is formed between the first mesa S1 and the second mesa S2.

In an embodiment of the present invention, the second semiconductor stack 23 of the light emitting device 1 includes a third mesa S3, wherein a second step T2 is provided between the first mesa S1 and the third mesa S3.

In an embodiment of the present invention, the first step T1 is between 2 μm and 3 μm. The second step T2 is between 0.2 μm and 2 μm, preferably between 0.8 μm and 1.8 μm.

In an embodiment of the present invention, the light emitting device 1 further includes a first inclined plane 21S connecting the first mesa S1 and the second mesa S2, wherein the first inclined plane 21S includes a first angle between 15 degrees and 75 degrees, preferably between 25 degrees and 65 degrees, and more preferably between 35 degrees and 55 degrees, relative to the first mesa S1 or the second mesa S2.

In an embodiment of the present invention, the light emitting device 1 further includes a second inclined plane 23S connecting the first mesa S1 and the third mesa S3, wherein the second inclined plane 23S includes a second angle between 15 degrees and 75 degrees, preferably between 25 degrees and 65 degrees, more preferably between 35 degrees and 55 degrees, relative to the first mesa S1 or the third mesa S3.

The substrate 10 may be a growth substrate including a gallium arsenide (GaAs) wafer for epitaxially growing aluminum gallium indium phosphide (AlGaInP), or a sapphire (Al2O3) wafer, gallium nitride (GaN) wafer, or silicon carbide (SiC) wafer for growing indium gallium nitride (InGaN). In another embodiment, the substrate 10 may be a supporting substrate, the light emitting stack 20 that was epitaxially grown on the growth substrate may be transferred to the supporting substrate, and the growth substrate that was used for the epitaxial growth may be selectively removed according to the application requirements.

The surface 10S of the substrate 10 in contact with the first semiconductor stack 21 may have a surface with increased roughening, and the roughened surface may be a surface having an irregular form or a surface having a regular form, for example, a surface having a plurality of hemispherical shapes, a surface having a plurality of conical shapes, or a surface having a plurality of polygonal pyramid shapes.

The support substrate includes a conductive material such as silicon (Si), aluminum (Al), copper (Cu), tungsten (W), molybdenum (Mo), gold (Au), silver (Ag), silicon carbide (SiC), or an alloy thereof, or a thermally conductive material such as diamond (diamond), graphite (graphite), or aluminum nitride (aln).

In an embodiment of the present invention, a semiconductor stack having electro-optical characteristics, such as a light-emitting (light-emitting) stack, is formed on the substrate 10 by a Metal Organic Chemical Vapor Deposition (MOCVD), a Molecular Beam Epitaxy (MBE), a hydride vapor deposition (HVPE), a Physical Vapor Deposition (PVD) or an ion plating method, wherein the PVD method includes a Sputtering (Sputtering) or an evaporation (evaporation) method.

In an embodiment of the present invention, the light emitting stack 20 may further include a buffer layer (not shown) located between the first semiconductor stack 21 and the substrate 10 for releasing stress generated between the substrate 10 and the first semiconductor stack 21 due to lattice mismatch of materials, so as to reduce dislocation and lattice defects, thereby improving epitaxial quality. The buffer layer may be a single layer or a structure including a plurality of layers. In one embodiment, PVD aluminum nitride (AlN) may be used as a buffer layer formed between the first semiconductor stack 21 and the substrate 10 to improve the epitaxial quality of the first semiconductor stack 21. In one embodiment, the target material used to form PVD aluminum nitride (AlN) is comprised of aluminum nitride. In another embodiment, a target comprised of aluminum is used to reactively form aluminum nitride with the aluminum target in the presence of a nitrogen source.

The wavelength of the light emitted from the light emitting device 1 can be adjusted by changing the physical and chemical composition of one or more layers of the light emitting stack 20. The material of the light emitting stack 20 comprises a group III-V semiconductor material, such as Al_xIn_yGa_(1-x-y)N or Al_xIn_yGa_(1-x-y)P, wherein 0 ≦ x, y ≦ 1; (x + y) ≦ 1. When the material of the light emitting stack 20 is AlInGaP series material, it can emit red light with a wavelength between 610nm and 650nm, or green light with a wavelength between 530nm and 570 nm. When the light emitting stack 20 is an InGaN-based material, it can emit blue light with a wavelength between 400nm and 490 nm. When the light emitting stack 20 is made of AlGaN or AlInGaN, ultraviolet light having a wavelength between 400nm and 250nm can be emitted.

The first semiconductor layer 21 and the second semiconductor layer 23 each include a cladding layer (cladding layer) having different conductivity types, electrical properties, polarities, or doped elements for providing electrons or holes, for example, the first semiconductor layer 21 is an n-type semiconductor layer, and the second semiconductor layer 23 is a p-type semiconductor layer. The active layer 22 is formed between the first semiconductor layer 21 and the second semiconductor layer 23, and electrons and holes are driven by a current to recombine in the active layer 22, so as to convert the electric energy into light energy and emit light. The active layer 22 may be a Single Heterostructure (SH), a Double Heterostructure (DH), a double-side double heterostructure (DDH), or a multi-quantum well (MQW). The material of the active layer 22 may be a neutral, p-type or n-type conductivity semiconductor. The first semiconductor stack 21, the active layer 22, or the second semiconductor stack 23 includes a structure of a plurality of layers.

In an embodiment of the present invention, the first semiconductor layer 21 of the light emitting device 1 includes a first doped semiconductor layer 210 having a first mesa S1 and a first undoped semiconductor layer 211 having a second mesa S2, wherein the first undoped semiconductor layer 211 is located between the substrate 10 and the first doped semiconductor layer 210.

In an embodiment of the present invention, the first undoped semiconductor layer 211 includes a thickness T between 2 μm and 3 μm.

In an embodiment of the present invention, the substrate 10 of the light emitting device 1 includes a sidewall 10d connected to a side 211S of the first undoped semiconductor layer 211.

In an embodiment of the present invention, the first inclined plane 21S and the side 211S of the first undoped semiconductor layer 211 include a distance between 0.5 μm and 10 μm, preferably between 1 μm and 5 μm, and more preferably between 2 μm and 3 μm.

In one embodiment of the present invention, the light emitting device 1 includes one or more current confinement regions 80 on the second semiconductor stack 23 to prevent the current injected into the light emitting device 1 from being concentrated under the second electrode 32. The material of the current confinement region 80 comprises an insulating material such as silicon oxide, silicon nitride, or aluminum oxide. In another embodiment of the present invention, the current confinement region 80 may be a single layer or a multi-layer stack, such as a Bragg reflector (DBR).

In an embodiment of the present invention, the light emitting device 1 includes the transparent conductive layer 52 on the current confinement region 80 and/or on the third mesa S3 of the second semiconductor stack 23, so that the current injected into the second electrode 32 is uniformly diffused to the entire surface of the light emitting device 1. In order to form a good ohmic contact with the second semiconductor stacked layer 23 of the light emitting device 1, the transparent conductive layer 52 is preferably a metal oxide containing at least one element selected from zinc, indium, and tin, such as zinc oxide (ZnO), indium oxide (InO), tin oxide (SnO), Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), or Gallium Zinc Oxide (GZO). A metal film may also be used as the transparent conductive layer 52.

As shown in fig. 1, the light emitting device 1 includes a rectangle in a top view, for example, having two long sides and two short sides. The first electrode 31 includes a first electrode pad 311, and one or more first extending electrodes 312 extend from the first electrode pad 311 and extend in a direction along the long side of the light emitting device 1. The second electrode 32 includes a second electrode pad 321, and one or more second extending electrodes 322 extend from the second electrode pad 321 and extend in a direction along the long side of the light emitting device 1. The first electrode 31 and the second electrode 32 may be configured in a symmetrical structure with respect to a horizontal line, a vertical line, or a diagonal line passing through the center point of the light emitting element 1.

In one embodiment of the present invention, the insulating layer 40 of the light emitting device 1 may include more than two materials with different refractive indexes alternately stacked to form a bragg reflector (DBR) structure. In one embodiment, the insulating layer 40 may comprise a laminated SiO₂And TiO₂Or SiO₂And Nb₂O₅The layer selectively reflects light of a specific wavelength, increasing the light extraction efficiency of the light-emitting element 1. When the peak emission wavelength (peak emission wavelength) of the light emitting element 1 is λ, the optical thickness of the insulating layer 40 may be set to an integral multiple of λ/4. The peak wavelength is a wavelength having the strongest intensity in the light emission spectrum of the light emitting element 1. The thickness of the insulating layer 40 may have a deviation of ± 30% on the basis of an integral multiple of λ/4.

In one embodiment, the insulating layer 40 is made of a non-conductive material, and includes an organic material, such as Su8, benzocyclobutene (BCB), Perfluorocyclobutane (PFCB), Epoxy (Epoxy), Acrylic Resin (Acrylic Resin), cyclic olefin Polymer (COC), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), Polycarbonate (PC), Polyetherimide (Polyetherimide), or Fluorocarbon Polymer (Fluorocarbon Polymer), or an inorganic material, such as silicon gel (Silicone) or Glass (Glass), or a dielectric material, such as aluminum oxide (Al2O3), silicon nitride (SiOx), silicon oxide (SiOx), titanium oxide (TiOx), or magnesium fluoride (MgFx).

In one embodiment, the thickness of the insulating layer 40 may be 1000 to 40000 angstroms.

In an embodiment of the present invention, the light emitting device 1 further includes a third electrode 60 located on the third mesa S3 and covering the first mesa S1 and the second mesa S2. As shown in fig. 1 and 2, the third electrode 60 includes an extension 601 contacting the first electrode pad 311; and a fourth electrode 70 on the third mesa S3, the fourth electrode 70 contacting the second electrode pad 321.

In one embodiment of the present invention, the third electrode 60 includes a dimension that is the same as or different from a dimension of the fourth electrode 70, which may be a width or an area. For example, the upper viewing area of the third electrode 60 or the fourth electrode 70 may be 0.8 times or more and less than 1 time the sum of the upper viewing areas of the third electrode 60 and the fourth electrode 70.

In one embodiment of the present invention, the third electrode 60 or the fourth electrode 70 has a thickness between 1 μm and 100 μm, preferably between 1.5 μm and 50 μm, and more preferably between 1.5 μm and 4 μm.

In one embodiment of the present invention, the third electrode 60 or the fourth electrode 70 comprises a gap between 1 μm and 100 μm, preferably between 5 μm and 50 μm, and more preferably between 10 μm and 30 μm.

In an embodiment of the present invention, the first electrode 31, the second electrode 32, the third electrode 60, and the fourth electrode 70 include a metal material, such as chromium (Cr), titanium (Ti), tungsten (W), gold (Au), aluminum (Al), indium (In), tin (Sn), nickel (Ni), platinum (Pt), or an alloy thereof. The first electrode 31, the second electrode 32, the third electrode 60, and the fourth electrode 70 may be composed of a single layer or a plurality of layers. For example, the first electrode 31, the second electrode 32, the third electrode 60, and the fourth electrode 70 may include a Ti/Au layer, a Ti/Pt/Au layer, a Cr/Pt/Au layer, a Ni/Pt/Au layer, or a Cr/Al/Cr/Ni/Au layer.

Fig. 4 is a cross-sectional view of a light emitting device 2 according to the present invention. Since the light emitting element 2 and the light emitting element 1 have substantially the same structure, the light emitting element 2 in fig. 4 and the light emitting element 1 in fig. 1 to 3 have the same structure, the same material, or the same function, and therefore the description thereof will be omitted or omitted.

A light emitting device 2 including a substrate 10; a light emitting stack 20 comprising a first semiconductor stack 21, an active layer 22 on the first semiconductor stack 21, and a second semiconductor stack 23 on the active layer 22; a first electrode 31 on the first semiconductor stack 21; a second electrode 32 on the second semiconductor stack 23; and an insulating layer 40 disposed on the light emitting stack 20, wherein the first semiconductor stack 21 includes a first mesa S1 and a second mesa S2, the first electrode 31 is disposed on the first mesa S1, and a first step T1 is formed between the first mesa S1 and the second mesa S2.

In an embodiment of the present invention, the second semiconductor stack 23 of the light emitting device 2 includes a third mesa S3, wherein a second step T2 is provided between the first mesa S1 and the third mesa S3.

In an embodiment of the present invention, the light emitting device 2 further includes a first inclined plane 21S connecting the first mesa S1 and the second mesa S2, wherein the first inclined plane 21S includes a first angle between 15 degrees and 75 degrees, preferably between 25 degrees and 65 degrees, more preferably between 35 degrees and 55 degrees, relative to the first mesa S1 or the second mesa S2.

In an embodiment of the present invention, the light emitting device 2 further includes a second inclined plane 23S connecting the first mesa S1 and the third mesa S3, wherein the second inclined plane 23S includes a second angle between 15 degrees and 75 degrees, preferably between 25 degrees and 65 degrees, more preferably between 35 degrees and 55 degrees, relative to the first mesa S1 or the third mesa S3.

In an embodiment of the present invention, the first semiconductor layer 21 of the light emitting device 2 includes a first doped semiconductor layer 210 having a first mesa S1 and a first undoped semiconductor layer 211 having a second mesa S2, wherein the first undoped semiconductor layer 211 is located between the substrate 10 and the first doped semiconductor layer 210.

In an embodiment of the present invention, the substrate 10 of the light emitting device 2 includes a sidewall 10d connected to a side 211S of the first undoped semiconductor layer 211.

In an embodiment of the present invention, the light emitting device 2 includes a lower reflective layer 50 located below the substrate 10 for selectively reflecting light with a specific wavelength, thereby increasing the light extraction efficiency of the light emitting device 2. The lower reflective layer 50 may be a Bragg reflector (DBR) structure comprising laminated SiO₂And TiO₂Or SiO₂And Nb₂O₅And the like. When the peak wavelength (peak emission wavelength) of the light emitting element 2 is λ, the optical thickness of the lower reflective layer 50 may be set to an integral multiple of λ/4. The peak wavelength is a wavelength having the strongest intensity in the light emission spectrum of the light emitting element 2. The thickness of the lower reflection layer 50 may have a deviation of ± 30% on the basis of an integral multiple of λ/4.

In another embodiment of the present invention, the material of the lower reflective layer 50 includes metal such as aluminum (Al), silver (Ag), rhodium (Rh), or platinum (Pt), or an alloy of the above materials. The lower reflective layer 50 is used for reflecting light and emitting the reflected light outward toward the substrate 10, wherein the reflected light is generated by the active layer 22.

Fig. 5 is a schematic diagram of a light emitting device 3 according to an embodiment of the present invention. The light emitting element 1 in the foregoing embodiment is mounted on the first pad 511 and the second pad 512 of the package substrate 51 in a flip chip manner or the light emitting element 2 in a flip chip manner. The first pad 511 and the second pad 512 are electrically insulated by an insulating portion 53 containing an insulating material. Flip chip mounting is a light extraction surface mainly formed on the growth substrate side facing the electrode pad formation surface. In order to increase the light extraction efficiency of the light emitting device 3, a reflective structure 54 may be disposed around the light emitting element 1 or the light emitting element 2.

Fig. 6 is a schematic diagram of a light emitting device 4 according to an embodiment of the present invention. The light emitting device 4 is a bulb lamp including a lampshade 602, a reflector 604, a light emitting module 610, a lamp holder 612, a heat sink 614, a connecting portion 616 and an electrical connecting element 618. The light emitting module 610 includes a carrying portion 606, and a plurality of light emitting units 608 located on the carrying portion 606, wherein the plurality of light emitting units 608 may be the

light emitting elements

1 and 2 or the light emitting devices 3 in the foregoing embodiments.

Claims

1. A light emitting element comprising:

a substrate;

a light emitting stack comprising a first semiconductor stack, an active layer on the first semiconductor stack, and a second semiconductor stack on the active layer;

a first electrode on the first semiconductor stack;

a second electrode on the second semiconductor stack; and

an insulating layer on the light emitting stack layer,

the first semiconductor lamination includes a first mesa and a second mesa, the first electrode is located on the first mesa, and a first step difference is formed between the first mesa and the second mesa.

2. The light-emitting device according to claim 1, wherein the first semiconductor layer comprises a first doped semiconductor layer having the first mesa and a first undoped semiconductor layer having the second mesa.

3. The light-emitting device according to claim 2, wherein the substrate comprises a sidewall connected to a side of the first undoped semiconductor layer.

4. The light-emitting element according to claim 2, wherein the first undoped semiconductor layer is located between the substrate and the first doped semiconductor layer.

5. The light-emitting element according to claim 1, wherein the first step is between 2 μm and 3 μm.

6. The light-emitting device according to claim 1, wherein the second semiconductor stack comprises a third mesa, and wherein the first mesa and the third mesa have a second step therebetween.

7. The light-emitting element according to claim 6, wherein the second step difference is between 0.2 μm and 2 μm.

8. The light-emitting element according to claim 1, wherein the insulating layer comprises a Bragg reflector (DBR) structure.

9. The light-emitting device according to claim 1, further comprising a first slope connecting the first mesa and the second mesa, wherein the first slope has an angle of 35-55 degrees with respect to the first mesa or the second mesa.

10. The light-emitting device according to claim 6, further comprising a third electrode on the third mesa, the third electrode comprising an extension contacting the first electrode; and a fourth electrode on the third mesa and contacting the second electrode.