CN116565083A

CN116565083A - Ultraviolet light-emitting diode and light-emitting device

Info

Publication number: CN116565083A
Application number: CN202210108059.7A
Authority: CN
Inventors: 臧雅姝; 陈思河; 卓佳利; 贺春兰; 张中英; 江宾; 曾炜竣
Original assignee: Xiamen Sanan Optoelectronics Technology Co Ltd
Current assignee: Xiamen Sanan Optoelectronics Technology Co Ltd
Priority date: 2022-01-28
Filing date: 2022-01-28
Publication date: 2023-08-08

Abstract

The invention provides an ultraviolet light-emitting diode, which comprises an epitaxial structure, a first contact electrode, a second contact electrode and an insulating dimming structure, wherein the epitaxial structure comprises a first semiconductor layer, a light-emitting layer and a second semiconductor layer which are sequentially stacked, the first contact electrode is positioned on the epitaxial structure and is electrically connected with the first semiconductor layer, the second contact electrode is positioned on the epitaxial structure and is electrically connected with the second semiconductor layer, and the insulating dimming structure is positioned on the epitaxial structure and covers the second contact electrode and is used for modulating light rays emitted by the light-emitting layer. Therefore, the light emitting angle can be improved, the reflection of ultraviolet light is enhanced, and the light emitting performance of the ultraviolet light emitting diode is improved.

Description

Ultraviolet light-emitting diode and light-emitting device

Technical Field

The present invention relates to the field of semiconductor manufacturing technology, and in particular, to an ultraviolet light emitting diode and a light emitting device.

Background

An ultraviolet light emitting diode (UV Light Emitting Diode, UV-LED) is a solid state semiconductor device capable of directly converting electrical energy into ultraviolet light. With the development of technology, the ultraviolet light emitting diode has wide market application prospect in the fields of biomedical treatment, anti-counterfeiting identification, purification (water, air and the like), computer data storage, military and the like. In recent years, as the demands of people for drinking water, daily sterilization, disinfection and the like are increasingly increased, the application of ultraviolet LEDs is becoming a research hotspot. In order to improve the disinfection efficiency of the ultraviolet LED, various competing manufacturers do not penetrate through various means, and the aim is to extract light from the deep ultraviolet LED as much as possible so as to realize the maximum luminous efficiency of the deep ultraviolet LED.

Therefore, how to effectively improve the light emitting effect of the ultraviolet LED and enhance the disinfection and sterilization performance has become a technical problem to be solved by those skilled in the art.

Disclosure of Invention

The invention provides an ultraviolet light-emitting diode, which comprises an epitaxial structure, a first contact electrode, a second contact electrode and an insulating dimming structure, wherein the epitaxial structure comprises a first semiconductor layer, a light-emitting layer and a second semiconductor layer which are sequentially stacked, the first contact electrode is positioned on the epitaxial structure and is electrically connected with the first semiconductor layer, the second contact electrode is positioned on the epitaxial structure and is electrically connected with the second semiconductor layer, and the insulating dimming structure is positioned on the epitaxial structure and covers the second contact electrode and is used for modulating light rays emitted by the light-emitting layer.

The invention also provides a light-emitting device comprising the ultraviolet light-emitting diode in the previous embodiment.

The invention has the advantages that the ultraviolet light-emitting diode and the light-emitting device are provided, through the arrangement of the insulating dimming structure, the light-emitting angle can be improved, the reflection of ultraviolet light is enhanced, and the light-emitting efficiency of the ultraviolet light-emitting diode is improved; the insulating dimming structure can also play a role of an optical resonant cavity, so that the resonant wave band of the optical resonant cavity is matched with the luminous wave band of the luminous layer, and the light emitting performance of the ultraviolet light emitting diode is further improved.

The ultraviolet light-emitting diode and the light-emitting device can be provided, and the first contact electrode can be protected from being damaged due to factors such as corrosion in the stage of forming the insulating dimming structure through the arrangement of the first protection electrode; and on the basis of playing a role in protecting the first contact electrode, the height of the first electrode region can be supplemented, the height difference between the first electrode region and the second electrode region is reduced, the bonding degree of the pad electrode and a subsequent packaging substrate is enhanced, and meanwhile, the effect of expanding current and improving electrical property is also achieved.

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.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description will be given below of the drawings required for the embodiments or the prior art descriptions, it being obvious that the drawings in the following description are some embodiments of the present invention, and that other drawings may be obtained according to these drawings without the need for inventive effort for a person of ordinary skill in the art; the positional relationships described in the drawings in the following description are based on the orientation of the elements shown in the drawings unless otherwise specified.

Fig. 1 is a schematic top view of an ultraviolet light emitting diode according to a first embodiment of the present invention;

FIG. 2 is a schematic longitudinal cross-sectional view taken along line A-A of FIG. 1;

FIG. 3 is a schematic diagram of an insulated dimming structure according to the present invention;

FIG. 4 is a schematic diagram of a modulated light at different thicknesses for an insulated dimming structure;

FIG. 5 is a schematic top view of the various structures of the UV LED shown in FIG. 1;

fig. 6 is a schematic top view of an ultraviolet led according to a second embodiment of the present invention;

FIG. 7 is a schematic longitudinal cross-sectional view taken along line A-A of FIG. 6;

FIG. 8 is a schematic top view of the various structures of the UV LED shown in FIG. 6;

fig. 9 is a schematic top view of an ultraviolet led according to a third embodiment of the present invention;

FIG. 10 is a schematic longitudinal cross-sectional view taken along line A-A of FIG. 9;

FIG. 11 is a schematic top view of the various structures of the UV LED shown in FIG. 9;

fig. 12 is a schematic top view of an ultraviolet led according to a second embodiment of the present invention;

FIG. 13 is a schematic longitudinal cross-sectional view taken along line A-A of FIG. 12;

fig. 14 is a schematic top view of the structures of the uv led shown in fig. 12.

Reference numerals:

1. 2, 3, 4-ultraviolet light emitting diodes; 10-a substrate; 12. 52-an epitaxial structure; 121. 521-a first semiconductor layer; 122. 522-a light emitting layer; 123. 523-a second semiconductor layer; 124-mesa; 524-via holes; 14. 54-a first contact electrode; 16. 56-a second contact electrode; 18. 74-insulating dimming structure; 181-a first insulating layer; 182-a reflective layer; 183-a second insulating layer; 184. 741-first conductive vias; 185. 742-second conductive via; 20. 72-a first guard electrode; 21. 58-a first connection electrode; 22. 60-a second connection electrode; 24. 62-a first insulating structure; 241. 621—a first opening; 242. 622-a second opening; 26. 68-first pads; 28. 70-a second bonding pad; 30-a first current blocking layer; 303-a third conductive via; 304-fourth conductive vias; 64-a third connection electrode; 641-fifth opening; 66-a second insulating structure; 663-a third opening; 664-fourth opening; l1-a first distance; d1, D2, D3-horizontal spacing; d4-horizontal distance.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention; the technical features designed in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other; all other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be understood that the terms "center," "lateral," "upper," "lower," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, merely to facilitate describing the present invention and simplify the description, and do not indicate or imply that the devices or components referred to must have a specific orientation or be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more. In addition, the term "comprising" and any variations thereof are meant to be "at least inclusive".

Referring to fig. 1 to 5, fig. 1 is a schematic top view of an ultraviolet light emitting diode 1 according to a first embodiment of the present invention, fig. 2 is a schematic longitudinal cross-sectional view taken along a line A-A of fig. 1, fig. 3 is a schematic structure of an insulating dimming structure 18 according to the present invention, fig. 4 is a schematic light modulating view of the insulating dimming structure 18 at different thicknesses, and fig. 5 is a schematic top view of each structure of the ultraviolet light emitting diode 1 shown in fig. 1. To achieve at least one of the advantages and other advantages, an embodiment of the present invention provides an ultraviolet light emitting diode 1. As shown in the drawing, the ultraviolet light emitting diode 1 may include at least an epitaxial structure 12, a first contact electrode 14, a second contact electrode 16, an insulating dimming structure 18, a first connection electrode 21, a second connection electrode 22, a first insulating structure 24, a first pad 26, and a second pad 28.

An epitaxial structure 12 is disposed on an upper surface of the substrate 10. The substrate 10 may be an insulating substrate, and preferably, the substrate 10 may be made of a transparent material or a translucent material. In the illustrated embodiment, the substrate 10 is a sapphire substrate. In some embodiments, substrate 10 may be a patterned sapphire substrate, but the present patent is not limited thereto. The substrate 10 may also be made of a conductive material or a semiconductor material. For example: the substrate 10 material may include silicon carbide (SiC), silicon (Si), magnesium aluminum oxide (MgAl) ₂ O ₄ ) Magnesium oxide (MgO), lithium aluminum oxide (LiAlO) ₂ ) Aluminum gallium oxide (LiGaO) ₂ ) And at least one of gallium nitride (GaN). In order to enhance the light extraction efficiency of the substrate 10, particularly the effect of light extraction from the substrate face, the thickness of the substrate 10 may be appropriately increased, and the thickness thereof may be increased to 200 μm to 900 μm, such as 250 μm to 400 μm, or 400 to 550 μm, or 550 to 750 μm.

Epitaxial structure 12 is formed over the upper surface of substrate 10. The epitaxial structure 12 includes a first semiconductor layer 121, a light emitting layer 122, and a second semiconductor layer 123 stacked in this order in the stacking direction. The stacking direction refers to a direction in which the components are stacked on the upper surface of the substrate 10, and is a direction from the substrate 10 to the pads (the first pad 26 and the second pad 28) in this embodiment. Epitaxial structure 12 may provide light of a particular center emission wavelength, such as ultraviolet light, deep ultraviolet light, and the like. The present illustrated embodiment is described with the example of the epitaxial structure 12 providing ultraviolet light. Optionally, the epitaxial structure 12 may further include an aluminum nitride underlayer (not shown in the figure) disposed between the upper surface of the substrate 10 and the first semiconductor layer 121, the underlayer being in contact with the upper surface of the substrate 10, and preferably having a thickness of 1 μm or less. Further, the aluminum nitride underlayer includes a low temperature layer, an intermediate layer, and a high temperature layer in this order from the side near the substrate 10, facilitating the growth of the epitaxial structure 12 excellent in crystallinity. In other preferred embodiments, a series of hole structures may also be formed in the aluminum nitride bottom layer to facilitate stress relief within epitaxial structure 12. The series of holes is preferably a series of elongated holes extending along the thickness of the aluminum nitride, which may be, for example, 0.5-1.5 μm deep.

In the illustrated embodiment, a first semiconductor layer 121 in the epitaxial structure 12 is formed over the substrate 10. The first semiconductor layer 121 may be an N-type semiconductor layer, and may supply electrons to the light emitting layer 122 under the power supply. In some embodiments, the first semiconductor layer 121 includes an N-type doped nitride layer. The N-doped nitride layer may include one or more N-type impurities of a group IV element. The N-type impurity may include one of Si, ge, sn, or a combination thereof. In some embodiments, a further buffer layer is provided between the first semiconductor layer 121 and the substrate 10 to mitigate lattice mismatch between the substrate 10 and the first semiconductor layer 121. The buffer layer may include an unintentionally doped GaN layer (u-GaN for short) or an unintentionally doped AlGaN layer (u-AlGaN for short). The first semiconductor layer 121 may be bonded to the substrate 10 by an adhesive layer.

The light emitting layer 122 may be a Quantum Well (QW) structure. In some embodiments, the light emitting layer 122 may also be a multiple quantum Well structure (Multiple Quantum Well, abbreviated as MQW), wherein the multiple quantum Well structure includes a plurality of quantum Well layers (Well) and a plurality of quantum Barrier layers (Barrier) alternately arranged in a repetitive manner, such as a multiple quantum Well structure that may be GaN/AlGaN, inAlGaN/InAlGaN or InGaN/AlGaN. The composition and thickness of the well layer in the light-emitting layer 122 determine the wavelength of the generated light. To increase the light emitting efficiency of the light emitting layer 122, this may be achieved by varying the depth of the quantum wells, the number of layers, thickness, and/or other characteristics of the pairs of quantum wells and quantum barriers in the light emitting layer 122. In the present embodiment, the light emission wavelength range of the ultraviolet light emitting diode 1 is 200nm to 420nm, that is, the light emission wavelength range of the light emitting layer 122 is 200nm to 420nm.

In the illustrated embodiment, the second semiconductor layer 123 in the epitaxial structure 12 is a P-type semiconductor layer that can provide holes to the light emitting layer 122 under power. In some embodiments, the second semiconductor layer 123 includes a P-type doped nitride layer. The P-doped nitride layer may include one or more P-type impurities of a group II element. The P-type impurity may include one of Mg, zn, be, or a combination thereof. The second semiconductor layer 123 may have a single-layer structure or a multi-layer structure having different compositions. In addition, the arrangement of the epitaxial structure 12 is not limited thereto, and other types of epitaxial structures 12 may be selected according to actual requirements.

In a specific embodiment, the first semiconductor layer 121 is an n-type AlGaN layer, the light emitting layer 122 is an ultraviolet light emitting layer, and has a well layer and a barrier layer, the number of repetitions of the well layer and the barrier layer may be between 1 and 10, the well layer may be an AlGaN layer, and the barrier layer may be an AlGaN layer, but the Al composition of the well layer is lower than that of the barrier layer. The second semiconductor layer 123 may be a p-type AlGaN layer or a p-type GaN layer, or a layer structure in which a p-type AlGaN layer and a p-type GaN layer are sequentially stacked. In this embodiment, the second semiconductor layer 123 includes a p-type GaN surface layer, where the p-type GaN surface layer is connected to the second contact electrode 16 to form a good ohmic contact, and is an upper surface layer of the second semiconductor layer 123, and the thickness of the p-type GaN surface layer is 5-50 nm, and by providing a thin film type p-type GaN surface layer, both the internal quantum light-emitting efficiency and the external quantum light-emitting efficiency of the ultraviolet light-emitting diode 1 can be considered, and in particular, the p-type GaN surface layer within the thickness range contributes to the lateral expansion of the p-side current, and does not cause too serious light absorption. In some embodiments, the edge of the first semiconductor layer 121 has a certain horizontal distance D4 from the edge of the substrate 10, and as shown in fig. 2, the sidewall of the first semiconductor layer 121 is located inside the sidewall of the substrate 10. In the uv led 1 chip, the thickness of the substrate 10 is increased to facilitate the improvement of the light emitting efficiency, but the thickness of the substrate 10 is increased and the dicing difficulty of the substrate 10 is also increased, so in this embodiment, a certain distance is reserved between the edge of the first semiconductor layer 121 and the edge of the substrate 10, and thus the semiconductor layer sequence (such as the first semiconductor layer 121) is not damaged when the substrate 10 is diced, thereby improving the reliability of the uv led 1. Alternatively, the horizontal distance D4 between the edge of the first semiconductor layer 121 and the edge of the substrate 10 is 1 μm or more, and preferably, the horizontal distance D4 is 2 μm or more, for example, 4 to 10 μm.

In some embodiments, a portion of the second semiconductor layer 123 and the light-emitting layer 122 of the epitaxial structure 12 is removed to expose the first semiconductor layer 121, and one or more mesas 124 are formed, that is, the mesas 124 are the surface of the first semiconductor layer 121 not covered by the second semiconductor layer 123 and the light-emitting layer 122, as shown in fig. 5 (a). In this embodiment, it is preferable to form a whole mesa 124, the mesa 124 is used for disposing the first contact electrode 54, the distribution of the mesa 124 is not limited to that shown in fig. 5 (a), and the mesa 124 may be designed according to the actual chip size and shape, and the mesas 124 may be connected together or separated from each other. In the ultraviolet light emitting diode 1, the Al content of the n-type semiconductor layer (e.g., the first semiconductor layer 121) is generally high, so that it is difficult for the current to spread, and thus the current cannot flow uniformly in the light emitting layer 122 and the p-type semiconductor layer (e.g., the second semiconductor layer 123), preferably, the area of the mesa 124 occupies 20% to 65% of the area of the epitaxial structure 12 in a plan view from above the ultraviolet light emitting diode 1 toward the epitaxial structure 12, and is relatively uniformly distributed in the epitaxial structure 12. Optionally, the closest distance between each region of the light emitting layer 122 and the mesa 124 is preferably 4-15 μm, so that the current spreading of the n-type semiconductor layer (such as the first semiconductor layer 121) can be protected, which is beneficial to improving the internal quantum efficiency of the uv light emitting diode 1, thereby helping to reduce the forward voltage of the uv light emitting diode 1. If the area of the mesa 124 is too large, the area of the light emitting region 122 of the uv led 1 will be too large, which is not beneficial to improving the light emitting efficiency of the uv led 1.

The first contact electrode 14 is electrically connected to the first semiconductor layer 121. Specifically, the first contact electrode 14 is disposed on the upper surface of the first semiconductor layer 121, and forms good ohmic contact with the first semiconductor layer 121; the second contact electrode 16 is located on the epitaxial structure 12, and the second contact electrode 16 is disposed on the upper surface of the second semiconductor layer 123, and forms good ohmic contact with the second semiconductor layer 123. The first contact electrode 14 may be of a single layer, a double layer or a multi-layer structure, for example: laminated structures such as Ti/Al, ti/Al/Ti/Au, ti/Al/Ni/Au, V/Al/Pt/Au, etc. In some embodiments, the first contact electrode 14 may be formed directly on the mesa 124 of the epitaxial structure 12, the first semiconductor layer 121 has a higher Al composition, and the first contact electrode 14 is alloyed with the first semiconductor layer 121 after being deposited on the mesa 124 by high temperature fusion, so as to form a good ohmic contact, for example, the first contact electrode 14 may be a Ti/Al/Ti/Au alloy structure, a Ti/Al/Ti/Pt alloy structure, a Ti/Al/Ni/Pt alloy structure, a Ti/Al/Au alloy structure, a Ti/Al/Ni/Au alloy structure, a Cr/Al/Ti/Au alloy structure, a Ti/Al/Au/Pt alloy structure, or the like.

The second contact electrode 16 is located on the second semiconductor layer 123, and may be made of a transparent conductive material or a metal material, and may be adaptively selected according to the doping condition of the surface layer (such as a p-type GaN surface layer) of the second semiconductor layer 123. In some embodiments, the second contact electrode 16 is made of a transparent conductive material, and the material may include Indium Tin Oxide (ITO), zinc indium oxide (indium zinc oxide, IZO), indium oxide (InO), tin oxide (tin oxide, snO), cadmium tin oxide (cadmium tin oxide, CTO), tin antimony oxide (antimony tin oxide, ATO), aluminum zinc oxide (aluminum zinc oxide, AZO), zinc tin oxide (zinc tin oxide, ZTO), zinc oxide doped gallium (gallium doped zinc oxide, GZO), indium oxide doped tungsten (tungsten doped indium oxide, IWO), or zinc oxide (zinc oxide, znO), but the embodiments of the present disclosure are not limited thereto. Preferably, the light transmittance of the second contact electrode 16 is greater than 25%; more preferably, the transmittance of the second contact electrode 16 is greater than 40%.

In some embodiments, the edge of the second contact electrode 16 and the edge of the second semiconductor layer 123 have a horizontal distance D1, and the horizontal distance D1 is preferably 2 to 15 μm, for example, may be 5 to 10 μm. This arrangement can reduce the risk of occurrence of leakage (also referred to as reverse leakage; abbreviated as IR) and electrostatic discharge (ESD) abnormality in the ultraviolet light emitting diode 1. Further, the horizontal distance D2 between the end point or edge of the upper surface of the second contact electrode 16 and the edge of the first contact electrode 14 is 4 μm or more, preferably 6 μm or more, and when the distance is too small, leakage tends to occur. The horizontal distance D2 between the end point or edge of the upper surface of the second contact electrode 16 and the edge of the first contact electrode 14 includes a horizontal distance D3 (2 μm or more) between the edge of the first contact electrode 14 and the edge of the lower surface of the second semiconductor layer 123, and a horizontal distance D2 (2 μm or more) between the edge of the second contact electrode 16 and the edge of the lower surface of the second semiconductor layer 123. By this configuration, the second contact electrode 16 and the mesa 124 on the epitaxial structure 12 can have a certain distance, so as to prevent the occurrence of electric leakage and ESD abnormality of the uv led 1. Meanwhile, a certain distance between the edge of the first insulating structure 24 and the table board 124 on the epitaxial structure 12 can be ensured, so that the first insulating structure 24 with enough thickness is etched on the side wall of the epitaxial structure 12, and the ultraviolet light emitting diode 1 is ensured to have better insulation protection and anti-leakage performance.

The insulating dimming structure 18 covers the epitaxial structure 12, and has a refractive index smaller than that of the second contact electrode 16, and can be used for modulating the light with a specific wavelength band emitted by the light emitting layer 122, so that more light can be emitted, and the light emitting efficiency of the ultraviolet light emitting diode 1 is further improved. Specifically, the insulating dimming structure 18 covers a portion of the upper surface of the substrate 10, a sidewall and a portion of the upper surface of the first semiconductor layer 121, a sidewall of the light emitting layer 122, a sidewall and a portion of the upper surface of the second semiconductor layer 123, and a sidewall and a portion of the upper surface of the second contact electrode 16. The insulating dimming structure 18 has a first conductive hole 184 and a second conductive hole 185, the first conductive hole 184 is located on the first semiconductor layer 121 and is used for exposing the first contact electrode 14, so that the first connection electrode 21 is electrically connected to the first contact electrode 14 through the first conductive hole 184; the second conductive via 185 is located on the second semiconductor layer 123 to expose the second contact electrode 16, such that the second connection electrode 22 is electrically connected to the second contact electrode 16 through the second conductive via 185. Preferably, the material of the insulating dimming structure 18 includes a dielectric material having a refractive index lower than that of the second contact electrode 16, and the second contact electrode 16 is made of a transparent conductive material; And the dielectric material has lower absorption coefficient in ultraviolet light band, such as SiO ₂ Etc.

By means of the arrangement of the insulating dimming structure 18, the light emitting angle can be improved, the reflection of ultraviolet light is enhanced, and the light emitting efficiency of the ultraviolet light emitting diode 1 is improved; the insulating dimming structure 18 can also function as an optical resonant cavity, so that the resonant wave band is matched with the light-emitting wave band of the light-emitting layer 122, and the light-emitting performance of the ultraviolet light-emitting diode 1 is further improved. The following examples illustrate two embodiments of the insulating dimming structure 18, but the disclosure is not limited thereto.

First kind: as shown in fig. 3 and 4, the insulating dimming structure 18 includes at least a first insulating layer 181 and a reflective layer 182 in a stacking direction. The first insulating layer 181 is disposed on the second contact electrode 16, and the reflective layer 182 is disposed on a surface of the first insulating layer 181 remote from the second contact electrode 16. The reflective layer 182 may be a metallic reflective layer, for example: the reflectance of the Al metal reflective layer, the Rh metal reflective layer, or the like is higher than that of the second contact electrode 16, and preferably the reflectance is 70 to 100%. The refractive index of the first insulating layer 181 is lower than that of the second contact electrode 16. Light emitted by the light emitting layer 122 passes through the second contact electrode 16 and enters the first insulating layer 181, and is reflected back and forth by the reflecting layer 182 on the upper side and the lower side of the first insulating layer 181 and the second contact electrode 16, and during the continuous reflection process of the light, part of ultraviolet light is continuously transmitted to the direction of the substrate 10 by the second contact electrode 16, and then is emitted to the outside.

The insulating dimming structure 18 may further include a second insulating layer 183, the reflective layer 182 being located between the first insulating layer 181 and the second insulating layer 183. The first insulating layer 181 and the second insulating layer 183 cover the reflective layer 182, and the reflective layer 182 of metal is completely covered by the first insulating layer 181 and the second insulating layer 183 through the first insulating layer 181 and the second insulating layer 183 so as not to participate in conduction, so that the reflective layer 182 is prevented from migrating after being electrified to cause electrical abnormality. The materials of the first insulating layer 181 and the second insulating layer 183 may include SiO ₂ 、SiN、SiO _x N _y 、Si ₃ N ₄ 、Al ₂ O ₃ 、TiN、AlN、ZrO ₂ 、TiAlN、TiSiN、HfO ₂ 、TaO ₂ And MgF ₂ At least one of them or a combination thereof.

Further, as shown in fig. 4, the thickness of the first insulating layer 181 is one of important factors affecting the modulated wavelength light. GAN/ITO in fig. 4 is a surface layer corresponding to the second semiconductor layer 123 and the second contact electrode 16, wo and w are no SiO, respectively ₂ First insulating layer 181 and SiO ₂ In the case of the first insulating layer 181, numerals 600, 1500, and the like represent thicknesses. As shown in FIG. 4, when SiO is not provided ₂ The reflectivity of the first insulating layer 181 of (a) is about 15% to 27% for deep ultraviolet light having a wavelength of 260 nm to 280 nm; when SiO is arranged ₂ When the thickness of the first insulating layer 181 is 600 Emi, the reflectivity of the deep ultraviolet light with the wavelength of 260-280 nm is increased to 65-75%, and the resonance peak is relatively wide corresponding to the wave band range; when SiO is arranged ₂ When the thickness of the first insulating layer 181 is 1500 Emi, the reflectivity for the deep ultraviolet light with the wavelength of 260-280 nm is 62% -68%; when SiO is arranged ₂ When the thickness of the first insulating layer 181 is 3300 meter, the reflectivity of the deep ultraviolet light with the wavelength of 260-280 nm is changed more severely, the reflectivity of 265-280 nm can reach more than 50%, the reflectivity of 260-265 nm is reduced to about 40%, high-order resonance is formed, and the resonance peak corresponds to a narrower wave band range; when SiO is arranged ₂ When the thickness of the first insulating layer 181 is 5200. Mu.m, the reflectance for deep ultraviolet light having a wavelength of 260 to 280nm is 13 to 38%.

Specifically, the insulating dimming structure 18 may be used to modulate the light path of the light emitted from the light emitting layer 122, thereby increasing the light extraction. Wherein the first insulating layers 181 having different thicknesses are different in adjusting the optical path as follows: when the thickness of the first insulating layer 181 reaches a certain basic value, a resonant cavity is formed, the resonant wave band of the resonant cavity is matched with the light emitting wave band of the light emitting layer, so that the light emitting performance of the ultraviolet light emitting diode 1 is improved, but when the thickness exceeds a certain limit, the higher-order resonance is more obvious when the thickness is larger. Therefore, limiting the upper limit of the thickness of the first insulating layer 181 can prevent higher-order resonance (e.g., curve of a thickness 5200 a/m) from occurring due to the excessive thickness of the first insulating layer 181: wavelengths emitted from the light emitting layer 122 are generally distributed in a wavelength range (e.g., 260-280 nm), and when the thickness of the first insulating layer 181 is too large, high-order resonance is formed between the first insulating layer 181 and the second contact electrode 16. The higher-order resonance means that the difference of the reflection effects on the light within a band is large, so that the range of the target band corresponding to the resonance peak is relatively narrow, and at this time, part of the wavelength light emitted by the light emitting layer 122 may exceed, even deviate from, the resonance peak, resulting in a decrease in reflectivity. If low-order resonance (such as curve trend with thickness of 600 and 1500 meter) is formed, the range of the target wave band corresponding to the resonance peak is wider, the light in the wave band range has higher reflectivity and stronger reflectivity. The reason why the lower limit of the thickness of the first insulating layer 181 is limited is as follows: the first insulating layer 181 with a certain thickness can better protect the metal reflecting layer 182 thereon, and avoid electrical anomalies caused by diffusion or migration of the metal reflecting layer 182.

Preferably, when the refractive index of the dielectric material of the first insulating layer 181 is smaller than that of the second contact electrode 16, the thickness of the first insulating layer 181 is 500 to 5000 a/m, preferably 1200 to 5000 a/m, for example 1500 a/m, 3000 a/m, etc., and the thickness of the first insulating layer 181 may be 600 a/m, which will form a superior low-order resonant cavity, and the overall light-emitting performance is superior.

Second kind: the insulating dimming structure 18 may be an insulating layer, and does not need to have high reflection characteristics, but rather, the reflecting characteristics of the reflecting electrode of the second connecting electrode 22 (i.e. the second connecting electrode 22 includes a reflecting metal layer, such as an Al metal layer, an Rh metal layer, etc.) function as an optical resonant cavity, so that the resonant band is matched with the light emitting band of the light emitting layer 122, thereby improving the light emitting performance of the uv light emitting diode 1. In other words, the light emitted from the light emitting layer 122 passes through the second contact electrode 16 and enters the insulating dimming structure 18, and is reflected back and forth by the second connection electrode 22 and the second contact electrode 16 on the upper and lower sides of the insulating dimming structure 18, and during the continuous reflection process of the light, the second contact electrode 16 continuously transmits part of the ultraviolet light to the direction of the substrate 10, and then to the outside. In this case, the thickness of the insulating dimming structure 18 is one of the important factors affecting the modulated wavelength light. For details of the adjusting light path by the different thicknesses of the insulating dimming structure 18, reference is made to fig. 4 and the content of the first insulating layer 181. Preferably, the thickness of the insulating dimming structure 18 is 500 to 5000 a, preferably 1200 to 5000 a, for example 1500 a, 3000 a, etc., which will form a superior low-order resonant cavity with better overall light output.

The first connection electrode 21 is connected to the first contact electrode 14 through the first conductive hole 184, and it can protect the underlying first contact electrode 14, and can support, raise, and the like, in addition to the current spreading function. Preferably, the first connection electrode 21 completely covers the first contact electrode 14 to avoid metal precipitation in the first contact electrode 14, for example, to avoid Al metal precipitation. The material of the first connection electrode 21 may be selected from one or more of Cr, pt, au, ni, ti, al. Preferably, the surface metal of the first connection electrode 21 contacting the first insulating structure 24 and the insulating dimming structure 18 is a Ti metal layer or a Cr metal layer, so that a stable adhesion relationship is formed between the first connection electrode 21 and the first insulating structure 24 and the insulating dimming structure 18.

The second connection electrode 22 is connected to the second contact electrode 16 through the second conductive via 185. The material of the second connection electrode 22 may be selected from one or more of Cr, pt, au, ni, ti, al. Preferably, the surface metal of the second connection electrode 22 contacting the first insulating structure 24 and the insulating dimming structure 18 is a Ti metal layer or a Cr metal layer, so that a stable adhesion relationship is formed between the second connection electrode 22 and the first insulating structure 24 and the insulating dimming structure 18.

The first insulating structure 24 covers the epitaxial structure 12, the insulating dimming structure 18, the first connection electrode 21, and the second connection electrode 22. The first insulating structure 24 has a first opening 241 and a second opening 242, the first opening 241 being located on the first connection electrode 21 for exposing the first connection electrode 21; the second opening 242 is located on the second connection electrode 22 for exposing the second connection electrode 22. The first insulating structure 24 has different functions according to the related location, for example, covering the sidewall of the epitaxial structure 12 to prevent the conductive material from leaking to electrically connect the first semiconductor layer 121 and the second semiconductor layer 123, so as to reduce the short-circuit abnormality of the uv led 1, but the embodiment of the disclosure is not limited thereto. The material of the first insulating structure 24 comprises a non-conductive material. The non-conductive material is preferably an inorganic material or a dielectric material. The inorganic material may comprise silica gel. The dielectric material comprises an electrically insulating material such as aluminum oxide, silicon nitride, silicon oxide, titanium oxide, or magnesium fluoride. For example, the insulating layer may be silicon dioxide, silicon nitride, titanium oxide, tantalum oxide, niobium oxide, barium titanate, or a combination thereof, which may be, for example, a bragg reflector (DBR) formed by repeatedly stacking two materials.

The first pad 26 is located on the first insulating structure 24, and is connected to the first connection electrode 21 through the first opening 241. The second pad 28 is located on the first insulating structure 24 and is connected to the second connection electrode 22 through the second opening 242. The first pad 26 and the second pad 28 may be formed together using the same material in the same process, and thus may have the same layer configuration.

Optionally, in an embodiment, in order to protect the first contact electrode 14 from damage caused by corrosion or other factors during the stage of forming the insulating dimming structure 18, a first protection electrode 20 is disposed on the first contact electrode 14, and the first protection electrode 20 is formed on the epitaxial structure 12 prior to the insulating dimming structure 18. That is, as shown in fig. 1 and 2, the uv light emitting diode 1 further includes a first protection electrode 20, and the first protection electrode 20 completely covers the first contact electrode 14 to protect the first contact electrode 14, thereby improving stability and reliability of the uv light emitting diode 1. In one embodiment, the first protection electrode 20 may have a single-layer structure, such as a Ti metal layer structure, for protecting the first contact electrode 14, and may have a thickness of 10nm or more, for example, 30-50 nm; the first protection electrode 20 may also have a multi-layer structure, such as a plurality of structures selected from Cr, pt, au, ni, ti, al, and on the basis of protecting, the heights of the first electrode regions (such as the first contact electrode 14 and the first connection electrode 21) may be further supplemented, so as to reduce the height difference between the first electrode regions and the second electrode regions (such as the second contact electrode 16 and the second connection electrode 22), enhance the bonding degree between the pad electrode (the first pad 26 and the second pad 28) and the subsequent package substrate, and also have the effects of expanding current and improving electrical properties.

As shown in fig. 5, the ultraviolet light emitting diode 1 may be formed by the following manufacturing method:

first, as shown in fig. 5 (a), an epitaxial structure 12 including a first semiconductor layer 121, a light emitting layer 122, and a second semiconductor layer 123 is grown on a substrate 10. Next, etching is performed downward from the second semiconductor layer 123 until the first semiconductor layer 121 is etched to expose the first semiconductor layer 121, and the electrode pad 124 is used. As shown in fig. 5 (a), the second semiconductor layer 123 after etching has an "E" shape, and the electrode mesa 124 on the first semiconductor layer 121 is entirely connected, it should be understood that the present invention is not limited to this pattern, different patterns may be selected according to the requirement, and the electrode mesa 124 on the first semiconductor layer 121 may not be entirely connected. In addition, the edge portion of the epitaxial structure 12 may be selectively removed to further expose the substrate 10 for subsequent dicing and the like.

Next, as shown in fig. 5 (b) and (c), the first contact electrode 14 is formed on the first semiconductor layer 121, and the second contact electrode 16 is formed on the second semiconductor layer 123. Preferably, the materials of the first contact electrode 14 and the second contact electrode 16 are different. Optionally, considering that in the current process of the uv led 1, the N-side electrode is usually annealed at high temperature to form an alloy electrode, and then directly subjected to subsequent wet etching or dry etching to form an insulating layer or other structures, so that the N-side electrode is very susceptible to be damaged by etching corrosion to destroy the overall performance of the uv led 1, and therefore the first contact electrode 14 is formed first and then the second contact electrode 16 is formed. Preferably, the first contact electrode 14 includes a plurality of metals, and a metal alloy is formed after high temperature annealing, thereby forming a good ohmic contact with the first semiconductor layer 121.

Next, as shown in fig. 5 (d), before the insulating dimming structure 18 is formed, the first protection electrode 20 is formed on the first contact electrode 14, so as to prevent the first contact electrode 14 from being damaged in a subsequent process. Subsequently, as shown in fig. 5 (e), after the first guard electrode 20 is formed, the insulating dimming structure 18 starts to be prepared. Preferably, the insulating dimming structure 18 has a plurality of second conductive holes 185, and the second conductive holes 185 are distributed on the second contact electrode 16 in an array shape, so that the current can be dispersed and flowed into the second contact electrode 16 below through the second conductive holes 185, thereby achieving the effect of uniformly distributing the current.

As shown in fig. 5 (f), a first connection electrode 21 is formed above the first protection electrode 20, and a second connection electrode 22 is formed on the insulating dimming structure 18, wherein the first connection electrode 21 is connected to the first protection electrode 20 through a first conductive hole 184, and the second connection electrode 22 is connected to the second contact electrode 16 through a second conductive hole 185. Subsequently, as shown in fig. 5 (g), a first insulating structure 24 is formed to cover the first connection electrode 21, the second connection electrode 22, and the insulating dimming structure 18.

Finally, as shown in fig. 5 (h), the first pad 26 and the second pad 28 are formed on the first insulating structure 24, the first pad 26 being connected to the first connection electrode 21 through the first opening 241, and the second pad 28 being connected to the second connection electrode 22 through the second opening 242.

Referring to fig. 6, 7 and 8, fig. 6 is a schematic top view of the uv led 2 according to the second embodiment of the present invention, fig. 7 is a schematic longitudinal cross-sectional view taken along the line A-A of fig. 6, and fig. 8 is a schematic top view of each structure of the uv led 2 shown in fig. 6. To achieve at least one of the advantages or other advantages, a second embodiment of the present invention further provides an ultraviolet light emitting diode 2. Compared to the ultraviolet light emitting diode 1 shown in fig. 1, the ultraviolet light emitting diode 2 of the present embodiment further includes a first current blocking layer 30. The first current blocking layer 30 covers the insulating dimming structure 18 to further enhance insulation protection and anti-leakage performance. The first current blocking layer 30 has a third conductive via 303 and a fourth conductive via 304. The third conductive hole 303 is located in the first conductive hole 184 and is used for exposing the first protection electrode 20, as shown in fig. 6 and 8, when the epitaxial structure 12 is seen from above the uv led 2; the fourth conductive via 304 is located in the second conductive via 185 for exposing the second contact electrode 16. Wherein, the first current blocking layer 30 is formed on the insulating dimming structure 18 after the insulating dimming structure 18 is prepared; next, after the first current blocking layer 30 is prepared, the first connection electrode 21 and the second connection electrode 22 are disposed on the first current blocking layer 30.

Referring to fig. 9, 10 and 11, fig. 9 is a schematic top view of an ultraviolet light emitting diode 3 according to a third embodiment of the present invention, fig. 10 is a schematic longitudinal cross-sectional view taken along a line A-A of fig. 9, and fig. 11 is a schematic top view of each structure of the ultraviolet light emitting diode 3 shown in fig. 9. As shown in the drawing, the ultraviolet light emitting diode 3 may include at least an epitaxial structure 52, a first contact electrode 54, a second contact electrode 56, a first connection electrode 58, a second connection electrode 60, a first insulating structure 62, a third connection electrode 64, a second insulating structure 66, a first pad 68, and a second pad 70.

Epitaxial structure 52 is disposed on the upper surface of substrate 10. The lamination and material selection of epitaxial structure 52 may be referred to in the first embodiment described above. The epitaxial structure 52 includes a first semiconductor layer 521, a light emitting layer 522, and a second semiconductor layer 523, which are sequentially stacked in the stacking direction. The stacking direction refers to a direction in which the components are stacked on the upper surface of the substrate 10, and is a direction from the substrate 10 to the pads (the first pad 68 and the second pad 70) in this embodiment. In the illustrated embodiment, a first semiconductor layer 521 in the epitaxial structure 52 is formed on the substrate 10. The first semiconductor layer 521 may be an N-type semiconductor layer, and may supply electrons to the light emitting layer 522 under the power supply. In the illustrated embodiment, the second semiconductor layer 523 in the epitaxial structure 52 is a P-type semiconductor layer that can provide holes to the light emitting layer 522 under power.

Compared to the uv led 1 shown in fig. 1, the epitaxial structure 52 of the uv led 3 in the present embodiment has a plurality of vias 524 (i.e. the mesas of the first semiconductor layer 521 are not completely connected), and the plurality of vias 524 penetrate from the upper surface of the second semiconductor layer 523 down to the upper surface of the first semiconductor layer 521 to expose the first semiconductor layer 521. The through holes 524 are located in the second semiconductor layer 523 at a first distance L1 from the top of the uv led 3 toward the epitaxial structure 52, so that the current flows into the first semiconductor layer 521 below through the through holes 524 in a dispersed manner, thereby achieving a uniform current distribution effect. Further, in the epitaxial structure 12 of the uv led 1 shown in fig. 1, the second semiconductor layer 123 and the light emitting layer 122 are etched in a large area to form the connected mesa 124, and the connected mesa 124 is located outside the second semiconductor layer 123, in contrast to the embodiment, the uv led 3 is formed with the plurality of via holes 524 spaced by the first distance L1 inside the second semiconductor layer 523, which can more uniformly disperse the current, ensure the effect of current expansion, improve the light emitting effect of the uv led 3, and also retain the larger area of the light emitting layer 522, and improve the light emitting amount of the light emitting layer 522. Preferably, the sum of the areas of the plurality of vias 524 is less than or equal to 50% of the area of the epitaxial structure 52 in a plan view. The sum of the areas of the plurality of via holes 524 refers to the sum of the areas of the first semiconductor layer 521 exposed by the respective via holes 524. As shown in the figure, the vias 524 are circular, but the shape and number of the vias 524 are not particularly limited, and the vias 524 can be distributed with uniform spacing or non-uniform spacing according to practical requirements. If the distribution pattern is a non-uniform pitch, the first distance L1 between each two adjacent vias 524 is different.

The first distance L1 refers to the distance between the center points of two adjacent vias 524. Preferably, the first distance L1 ranges from 100 μm to 150 μm, i.e. the distance between the center points of two adjacent vias 524 ranges from 100 μm to 150 μm. The size of each via hole 524 ranges from 20 to 100 μm, preferably from 40 to 60 μm. For example, the via hole 524 of the present embodiment is circular, and its size is the diameter of the circular via hole.

The first contact electrode 54 and the second contact electrode 56 are both located on the epitaxial structure 52 and electrically connect the first semiconductor layer 521 and the second semiconductor layer 523, respectively. Specifically, the first contact electrode 54 is disposed on the upper surface of the first semiconductor layer 521 through a plurality of via holes 524, and forms good ohmic contact with the first semiconductor layer 521; the second contact electrode 56 is provided on the upper surface of the second semiconductor layer 523, and forms a good ohmic contact with the second semiconductor layer 523. The first contact electrode 54 may have a single-layer, double-layer or multi-layer structure, for example: laminated structures such as Ti/Al, ti/Al/Ti/Au, ti/Al/Ni/Au, V/Al/Pt/Au, etc. In some embodiments, the first contact electrode 54 may be formed directly on the mesa of the epitaxial structure 52, the first semiconductor layer 521 has a higher Al composition, the first contact electrode 54 is alloyed with the first semiconductor layer 521 after being deposited on the first semiconductor layer 521, so as to form a good ohmic contact with the first semiconductor layer 521, for example, the first contact electrode 54 may be a Ti/Al/Ti/Au alloy structure, a Ti/Al/Ti/Pt alloy structure, a Ti/Al/Ni/Pt alloy structure, a Ti/Al/Au alloy structure, a Ti/Al/Ni/Au alloy structure, a Cr/Al/Ti/Au alloy structure, a Ti/Al/Au/Pt alloy structure, or the like.

The second contact electrode 56 may be made of a transparent conductive material or a metal material, and may be adaptively selected according to the doping condition of the surface layer (e.g., p-type GaN surface layer) of the second semiconductor layer 523. The transparent conductive material may include Indium Tin Oxide (ITO), zinc indium oxide (indium zinc oxide, IZO), indium oxide (InO), tin oxide (tin oxide, snO), cadmium tin oxide (cadmium tin oxide, CTO), tin antimony oxide (antimony tin oxide, ATO), aluminum zinc oxide (aluminum zinc oxide, AZO), zinc tin oxide (zinc tin oxide, ZTO), zinc oxide doped gallium (gallium doped zinc oxide, GZO), indium oxide doped tungsten (tungsten doped indium oxide, IWO), or zinc oxide (zinc oxide, znO); the metal material may be selected from Ni/Au alloy, ni/Rh alloy, ni/Al/Au alloy, etc., but the embodiment of the present disclosure is not limited thereto. Preferably, the second contact electrode 56 has a light transmittance of greater than 25%. More preferably, the transmittance of the second contact electrode 56 is greater than 40%.

The first connection electrode 58 is located on the first contact electrode 54, and can protect the underlying first contact electrode 54 from being corroded by the corrosive solution or gas during the subsequent wet etching and dry etching processes. The first connection electrode 58 may also function as a support, a spacer, a current spreading, etc. Preferably, the first connecting electrode 58 completely covers the first contact electrode 54 to avoid metal precipitation in the first contact electrode 54, for example, to avoid Al metal precipitation. The material of the first connection electrode 58 may be selected from one or more of Cr, pt, au, ni, ti, al. Preferably, the first connection electrode 58 contacts the first insulation structure 62 with a surface metal layer of Ti metal layer or Cr metal layer, so that a stable adhesion relationship is formed between the first connection electrode 58 and the first insulation structure 62. In addition, the surface metal of the first connection electrode 58 contacting the first insulating structure 62 may be a Ni metal layer, a Pt metal layer, or the like.

The second connection electrode 60 is positioned on the second contact electrode 56, and the material of the second connection electrode 60 may be selected from one or more of Cr, pt, au, ni, ti, al. Preferably, the surface metal of the second connection electrode 60 contacting the first insulation structure 62 is a Ti metal layer or a Cr metal layer, so that a stable adhesion relationship is formed between the second connection electrode 60 and the first insulation structure 62. The surface metal of the second connection electrode 60 contacting the first insulating structure 62 may be a Ni metal layer, a Pt metal layer, or the like.

The first insulating structure 62 covers the epitaxial structure 52, the first connection electrode 58 and the second connection electrode 60. The first insulating structure 62 has a first opening 621 and a second opening 622, the first opening 621 is located on the first connection electrode 58 for exposing the first connection electrode 58; the second opening 622 is located on the second connection electrode 60 for exposing the second connection electrode 60. Preferably, the number of the first openings 621 is plural, and the number of the first openings 621 is the same as the number of the via holes 524. The first opening 621 is located inside the via hole 524 in a plan view from above the uv led 3 toward the epitaxial structure 52.

The third connection electrode 64 is disposed on the first insulating structure 62 and is electrically connected to the first connection electrode 58 through the first opening 621. The third connection electrode 64 has a fifth opening 641, the fifth opening 641 exposing a portion of the second connection electrode 60, and the second opening 622 being located inside the fifth opening 641 such that the second pad 70 can be electrically connected to the second connection electrode 60 through the fifth opening 641.

The second insulating structure 66 covers the third connection electrode 64 and the first insulating structure 62. The second insulating structure 66 has a third opening 663 and a fourth opening 664, the third opening 663 being located on the third connection electrode 64 for exposing the third connection electrode 64; the fourth opening 664 is located inside the second opening 622, i.e., the fourth opening 664 is smaller than the second opening 622 and smaller than the fifth opening 641, for exposing the second connection electrode 60 such that the second pad 70 may be electrically connected to the second connection electrode 60 through the fourth opening 664.

The first insulating structure 62 and the second insulating structure 66 have different functions according to the related positions, for example, the sidewall of the epitaxial structure 52 is covered to prevent the conductive material from leaking to electrically connect the first semiconductor layer 521 and the second semiconductor layer 523, so as to reduce the abnormal short circuit of the uv led 3, but the embodiment of the disclosure is not limited thereto. The material of the first insulating structure 62 and the second insulating structure 66 comprises a non-conductive material. The non-conductive material is preferably an inorganic material or a dielectric material. The inorganic material may comprise silica gel. The dielectric material comprising aluminum oxide, silicon nitride, silicon oxide, titanium oxide, or magnesium fluoride may be an electrically insulating material. For example, the insulating layer may be silicon dioxide, silicon nitride, titanium oxide, tantalum oxide, niobium oxide, barium titanate, or a combination thereof, for example, a bragg reflector (DBR) formed by repeatedly stacking two materials, so as to enhance the selection effect of ultraviolet light and improve the light emitting performance of the ultraviolet light emitting diode 3. In addition, the first insulating structure 62 may also adopt a similar structural design as the insulating dimming structure 18 shown in fig. 3 and 4, that is, the first insulating structure 62 includes two insulating layers (a first insulating layer and a second insulating layer) and a reflective layer interposed between the first insulating layer and the second insulating layer, so as to achieve the function of an optical resonant cavity, and make the resonant band match with the light-emitting band of the light-emitting layer 522, so as to further increase the light intensity of the ultraviolet light-emitting diode 3.

The first pad 68 is located on the second insulating structure 66, and is connected to the third connection electrode 64 through the third opening 663. The second pad 70 is located on the second insulating structure 66, and is connected to the second connection electrode 60 through the fourth opening 664. The first and second pads 68 and 70 may be formed together using the same material in the same process, and thus may have the same layer configuration.

Further, the uv led 3 of the present embodiment is designed with a plurality of vias 524, which can be used to distinguish the arrangement positions of the first pads 68 and the second pads 70 by means of the dual insulation layer arrangement of the first insulation structure 62 and the second insulation structure 66. In addition, the shapes of the first bonding pad 68 and the second bonding pad 70 do not need to be specially designed, so that the distance between the first bonding pad 68 and the second bonding pad 70 can be ensured, and the problem in the subsequent installation and use can be avoided. By providing dual insulation layers for the first insulation structure 62 and the second insulation structure 66, the risk of short circuits due to breakage of the insulation structures can also be reduced. In addition, by means of the arrangement of the first connection electrode 58, the first contact electrode 54 below can be protected, the first contact electrode 54 is prevented from being corroded by corrosive solution or gas in the subsequent wet etching, dry etching and other processes, and stability and reliability of the ultraviolet light emitting diode 3 are improved.

As shown in fig. 11, the manufacturing process of the ultraviolet light emitting diode 3 is as follows:

first, as shown in fig. 11 (a), an epitaxial structure 52 including a first semiconductor layer 521, a light emitting layer 522, and a second semiconductor layer 523 is grown on a substrate 10. Then, the second semiconductor layer 523 starts to be etched down until the first semiconductor layer 521 is etched to form a plurality of via holes 524 exposing the first semiconductor layer 521. In addition, the edge portions of the epitaxial structure 52 may be selectively removed to further expose the substrate 10 for subsequent dicing and the like.

Next, as shown in fig. 11 (b), a first contact electrode 54 is formed on the first semiconductor layer 521, and the first contact electrode 54 is connected to the first semiconductor layer 521 through a via hole 524; as shown in fig. 11 (c), a second contact electrode 56 is formed on the second semiconductor layer 523. Alternatively, considering that in the current process of the uv led 3, the N-side electrode is usually annealed at high temperature to form an alloy electrode, and then directly subjected to subsequent wet etching or dry etching to form an insulating layer or other structures, so that the N-side electrode is very susceptible to be damaged by etching corrosion to destroy the overall performance of the uv led 3, and therefore the first contact electrode 54 may be formed first and then the second contact electrode 56 may be formed.

Next, as shown in fig. 11 (d), a first connection electrode 58 and a second connection electrode 60 are formed on the first contact electrode 54 and the second contact electrode 56, respectively. Preferably, the first connecting electrode 58 completely encloses the first contact electrode 54. Then, as shown in fig. 11 (e), a first insulating structure 62 is formed to cover the first connection electrode 58, the second connection electrode 60, and the epitaxial structure 52.

Subsequently, as shown in fig. 11 (f), a third connection electrode 64 is formed on the first insulating structure 62. The third connection electrode 64 is connected to the first connection electrode 58 through the first opening 621 of the first insulating structure 62. Then, as shown in fig. 11 (g), a second insulating structure 66 is formed on the third connection electrode 64 and the first insulating structure 62.

Finally, as shown in fig. 11 (h), a first pad 68 and a second pad 70 are formed on the second insulating structure 66, the first pad 68 being connected to the third connection electrode 64 through the third opening 663, the second pad 70 being connected to the second connection electrode 60 through the fourth opening 664.

Referring to fig. 12, 13 and 14, fig. 12 is a schematic top view of an led 4 according to a second embodiment of the present invention, fig. 13 is a schematic longitudinal cross-sectional view taken along a line A-A of fig. 12, and fig. 14 is a schematic top view of each structure of the led 4 shown in fig. 12. To achieve at least one of the advantages or other advantages, a fourth embodiment of the present invention further provides an ultraviolet light emitting diode 4. Compared to the ultraviolet light emitting diode 3 shown in fig. 9, the ultraviolet light emitting diode 4 of the present embodiment further includes a first protection electrode 72 and an insulating dimming structure 74.

The first protection electrode 72 is located between the first contact electrode 54 and the first connection electrode 58, completely covers the first contact electrode 54, and is formed on the first contact electrode 54 before the insulating dimming structure 74, so as to protect the first contact electrode 54, prevent the first contact electrode 54 from being damaged due to corrosion and other factors in the process of forming the insulating dimming structure 74, and improve the stability and reliability of the ultraviolet light emitting diode 4. The thickness of the first guard electrode 72 is 10nm or more. In an embodiment, the first protection electrode 72 may have a single-layer structure, such as a Ti metal layer structure, and serves to protect the first contact electrode 54; the first protection electrode 72 may be one or more metal structures selected from Cr, pt, au, ni, ti, al, and on the basis of protecting, the height of the first electrode region may be further supplemented, the height difference between the first electrode region and the second electrode region may be reduced, the bonding degree between the pad electrode and the package substrate may be enhanced, and the effect of expanding the current and improving the electrical property may be further provided.

The insulating dimming structure 74 covers the epitaxial structure 52, and has a refractive index smaller than that of the second contact electrode 54, and can be used for modulating the light with a specific wavelength band emitted by the light emitting layer 522, so that more light can be emitted, and the light emitting efficiency of the ultraviolet light emitting diode 4 is further improved. By controlling the thickness of the insulating dimming structure 74, a relatively suitable resonant cavity can be formed, so that the resonant wave band is matched with the light-emitting wave band of the light-emitting layer 522, and the light-emitting efficiency of the ultraviolet light-emitting diode 4 is further improved. Specifically, the insulating dimming structure 74 covers a portion of the upper surface of the substrate 10, the sidewall and a portion of the upper surface of the first semiconductor layer 521, the sidewall of the light emitting layer 522, the sidewall and a portion of the upper surface of the second semiconductor layer 523, and the sidewall and a portion of the upper surface of the second contact electrode 56. The insulating dimming structure 74 has a first conductive hole 741 and a second conductive hole 742, the first conductive hole 741 being located on the first semiconductor layer 521 for exposing the first protection electrode 72 such that the first connection electrode 58 is electrically connected to the first protection electrode 72 through the first conductive hole 741; the second conductive via 742 is located on the second semiconductor layer 523 to expose the second contact electrode 56 such that the second connection electrode 60 is electrically connected to the second contact electrode 56 through the second conductive via 742. The first insulating structure 62 covers the insulating dimming structure 74. The second contact electrode 56 is made of a transparent conductive material, and the material of the insulating dimming structure 74 includes a dielectric material having a lower refractive index than the second contact electrode 56.

By means of the arrangement of the insulating dimming structure 74, the light emitting angle can be improved, the reflection of ultraviolet light is enhanced, and the light emitting efficiency of the ultraviolet light emitting diode 4 is improved; the insulating dimming structure 74 can also function as an optical resonant cavity, so that the resonant wave band is matched with the light-emitting wave band of the light-emitting layer 522, and the light-emitting performance of the ultraviolet light-emitting diode 4 is further improved. The specific structure and modulated light of the insulating dimming structure 74 can be described with reference to the foregoing embodiments of fig. 1 to 4 regarding the insulating dimming structure 18, wherein both implementations of the insulating dimming structure 18 can be applied to the insulating dimming structure 74 of the present embodiment, for example: the insulating dimming structure 74 of the present embodiment may be a reflective layer including a first insulating layer, a second insulating layer, and interposed between the first insulating layer and the second insulating layer; the different thicknesses of the first insulating layer are different in the adjustment light path, preferably, when the refractive index of the dielectric material of the first insulating layer is smaller than that of the second contact electrode 56, the thickness of the first insulating layer is 500-5000 a/m, preferably 1200-5000 a/m, and a better low-order resonant cavity is formed by the thickness, so that the overall light emitting performance is better; the refractive index of the dielectric material of the first insulating layer is smaller than that of the second contact electrode; the reflectivity of the reflecting layer is higher than that of the second contact electrode; the insulating dimming structure 74 may not have a reflective property, but may function as an optical resonant cavity by virtue of the reflective property of the second connection electrode 60. With this understanding, the remainder will not be described in detail.

An embodiment of the present invention proposes a light emitting device employing the ultraviolet light emitting diodes 1, 2, 3, 4 as described in any of the previous embodiments. The light-emitting device has good photoelectric performance.

In summary, compared with the prior art, the ultraviolet light emitting diodes 1, 2, 3, 4 and the light emitting device provided by the invention have good photoelectric characteristics.

In addition, it should be understood by those skilled in the art that although many problems exist in the prior art, each embodiment or technical solution of the present invention may be modified in only one or several respects, without having to solve all technical problems listed in the prior art or the background art at the same time. Those skilled in the art will understand that nothing in one claim should be taken as a limitation on that claim.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims

1. An ultraviolet light emitting diode, characterized in that: the ultraviolet light emitting diode includes:

the epitaxial structure comprises a first semiconductor layer, a light-emitting layer and a second semiconductor layer which are sequentially stacked;

a first contact electrode located over the epitaxial structure and electrically connected to the first semiconductor layer;

a second contact electrode located over the epitaxial structure and electrically connected to the second semiconductor layer;

and the insulating dimming structure is positioned on the epitaxial structure and covers the second contact electrode and is used for modulating the light rays emitted by the light-emitting layer.

2. The ultraviolet light emitting diode of claim 1, wherein: the insulating dimming structure comprises a first insulating layer and a reflecting layer, wherein the first insulating layer is positioned above the second contact electrode, and the reflecting layer is positioned on one side surface of the first insulating layer, which is far away from the second contact electrode.

3. The ultraviolet light emitting diode of claim 2, wherein: the thickness of the first insulating layer ranges from 500 to 5000 angstroms.

4. The ultraviolet light emitting diode of claim 2, wherein: the reflectivity of the reflective layer is higher than the reflectivity of the second contact electrode.

5. The ultraviolet light emitting diode of claim 2, wherein: the insulating dimming structure further comprises a second insulating layer, wherein the reflecting layer is located between the first insulating layer and the second insulating layer, and the first insulating layer and the second insulating layer cover the reflecting layer.

6. The ultraviolet light emitting diode of claim 1, wherein: the second contact electrode is made of transparent conductive material, and the material of the insulating dimming structure comprises a dielectric material with refractive index lower than that of the second contact electrode.

7. The ultraviolet light emitting diode of claim 6, wherein: the thickness range of the insulating dimming structure is 500-5000 angstroms.

8. The ultraviolet light emitting diode of claim 1, wherein: the ultraviolet light emitting diode further comprises a first connecting electrode and a second connecting electrode, wherein the first connecting electrode is electrically connected with the first contact electrode, and the second connecting electrode is electrically connected with the second contact electrode.

9. The ultraviolet light emitting diode of claim 8, wherein: the second connection electrode includes a reflective metal layer.

10. The ultraviolet light emitting diode of claim 8, wherein: the ultraviolet light emitting diode further comprises a first insulation structure, a first bonding pad and a second bonding pad, wherein the first insulation structure covers the epitaxial structure, the insulation dimming structure, the first connecting electrode and the second connecting electrode, the first insulation structure is provided with a first opening and a second opening, the first bonding pad is located on the first insulation structure and is connected with the first connecting electrode through the first opening, and the second bonding pad is located on the second insulation structure and is connected with the second connecting electrode through the second opening.

11. An ultraviolet light emitting diode according to claim 1, wherein: the ultraviolet light emitting diode further comprises a first protection electrode, and the first protection electrode coats the first contact electrode.

12. The ultraviolet light emitting diode of claim 11, wherein: the first protection electrode is formed on the epitaxial structure before the insulating dimming structure.

13. The ultraviolet light emitting diode of claim 11, wherein: the first guard electrode may be a single layer structure or a multi-layer structure.

14. The ultraviolet light emitting diode of claim 11, wherein: the thickness of the first protection electrode is more than or equal to 10nm.

15. An ultraviolet light emitting diode according to claim 1, wherein: the light transmittance of the second contact electrode is greater than 25%.

16. An ultraviolet light emitting diode according to claim 1, wherein: the second semiconductor layer comprises a p-type GaN surface layer, the p-type GaN surface layer is connected with the second contact electrode, and the thickness of the p-type GaN surface layer ranges from 5 nm to 50nm.

17. An ultraviolet light emitting diode according to claim 1, wherein: the epitaxial structure is arranged on the substrate, and a horizontal distance is arranged between the edge of the first semiconductor layer and the edge of the substrate, wherein the horizontal distance is more than or equal to 1 mu m.

18. An ultraviolet light emitting diode according to claim 1, wherein: the epitaxial structure further comprises a mesa, the mesa is the surface of the first semiconductor layer which is not covered by the second semiconductor layer and the light-emitting layer, and the area of the mesa accounts for 20% -65% of the area of the epitaxial structure.

19. An ultraviolet light emitting diode according to claim 1, wherein: the first contact electrode may be a Ti/Al/Ti/Au alloy structure, a Ti/Al/Ti/Pt alloy structure, a Ti/Al/Ni/Pt alloy structure, a Ti/Al/Au alloy structure, a Ti/Al/Ni/Au alloy structure, a Cr/Al/Ti/Au alloy structure, or a Ti/Al/Au/Pt alloy structure.

20. A light emitting device, characterized in that: use of an ultraviolet light emitting diode according to any one of claims 1-19.