阅读说明：本技术 一种高效深紫外led光源封装结构及其封装方法 (Efficient deep ultraviolet LED light source packaging structure and packaging method thereof ) 是由 程寅山 何至年 周波 吴学坚 徐钊 郑朝曦 于 2021-09-01 设计创作，主要内容包括：本发明提供了一种高效深紫外LED光源封装结构及其封装方法,所述封装结构包括基板、深紫外LED晶片和玻璃罩,所述深紫外LED晶片安装于所述基板上,所述玻璃罩密封地盖在所述基板上使得所述深紫外LED晶片处于密闭空间内,所述深紫外LED晶片发出的光线通过所述玻璃罩射出,所述玻璃罩包括框体和窗体,所述框体上设有反射涂层,所述窗体上设有透镜面；所述深紫外LED晶片直接发出的光线以及经所述反射涂层反射的光线经透镜面后会以接近平行的方向从所述玻璃罩射出,提高了发光效率,所述深紫外LED中p型接触层的厚度设置为500nm以上,提高了平坦度,继而提高了LED晶片的使用寿命。(The invention provides a high-efficiency deep ultraviolet LED light source packaging structure and a packaging method thereof, wherein the packaging structure comprises a substrate, a deep ultraviolet LED wafer and a glass cover, the deep ultraviolet LED wafer is arranged on the substrate, the glass cover is hermetically covered on the substrate to enable the deep ultraviolet LED wafer to be positioned in a closed space, light emitted by the deep ultraviolet LED wafer is emitted out through the glass cover, the glass cover comprises a frame body and a window body, a reflection coating is arranged on the frame body, and a lens surface is arranged on the window body; the light that the deep ultraviolet LED wafer directly sent and through the reflection coating reflection can follow in the direction of being close parallel behind the lens face the glass cover jets out, has improved luminous efficiency, the thickness of p type contact layer sets up to more than 500nm in the deep ultraviolet LED, has improved the flatness, has then improved the life of LED wafer.)

1. A high-efficiency deep ultraviolet LED light source packaging structure is characterized by comprising a substrate, a deep ultraviolet LED wafer and a glass cover, wherein the deep ultraviolet LED wafer is arranged on the substrate, the glass cover is hermetically covered on the substrate to enable the deep ultraviolet LED wafer to be located in a closed space, and light rays emitted by the deep ultraviolet LED wafer are emitted through the glass cover;

the glass cover comprises a frame body and a window body, the window body is connected with the frame body in a sealing mode, an inclined wall surface is arranged inside the frame body, an inner concave surface is arranged on the inclined wall surface, a DUV (deep ultraviolet) reflecting coating is arranged on the inner concave surface, the inner concave surface is a part of a rotating ellipsoid, and a light-emitting central point of the deep ultraviolet LED wafer is located at one focus of the ellipsoid where the rotating ellipsoid is located;

the formula of the concave surface is as follows:

wherein a and b are ellipse parameters, and c is the thickness of the frame body;

the lower surface of the window body is a curved surface and is used for emitting the light emitted by the deep ultraviolet LED wafer and the reflected light of the reflecting coating out of the window body at an angle close to parallel light;

the deep ultraviolet LED chip comprises an n-type coating layer, an active layer, a p-type coating layer, a p-type contact layer, a p-side electrode and an n-side electrode, wherein the p-type coating layer is arranged on the active layer and is made of a p-type aluminum gallium nitride-based semiconductor material or a p-type aluminum nitride-based semiconductor material with the aluminum nitride ratio of 50% or more, the p-type contact layer is arranged in contact with the p-type coating layer and is made of a p-type aluminum gallium nitride-based semiconductor material or a p-type gallium nitride-based semiconductor material with the aluminum nitride ratio of 20% or less, the difference between the aluminum nitride ratio of the p-type coating layer and the aluminum nitride ratio of the p-type contact layer is 50% or more, and the thickness of the p-type contact layer is larger than 500 nm.

2. The package structure of claim 1, wherein the ellipse parameter a has a value range of [2.5, 3.8] mm, and the ellipse parameter b has a value range of [8.4, 10.6] mm.

3. The high-efficiency deep ultraviolet LED light source package structure of claim 2, wherein the curved surface of the lower surface of the window body comprises a convex surface in the middle and a concave surface around the convex surface, the convex surface is a part of the convex lens surface, the concave surface is a part of the concave lens surface, a connection line between the inner concave surface on the inclined wall surface and the other focus of the ellipsoid intersects with the concave surface of the window body, light emitted from the deep ultraviolet LED chip is emitted after passing through the convex surface of the window body, and light reflected by the reflective coating is emitted after passing through the concave surface of the window body.

4. The package structure of claim 3, wherein the frame and the window are made of borosilicate glass with DUV light transmittance, and the reflective coating is made of aluminum or an alloy material containing aluminum as a main component.

5. The packaging method of the high-efficiency deep ultraviolet LED light source packaging structure as claimed in one of claims 1 to 4, wherein the method comprises the following steps:

s1, preparing a glass cover: selecting a plane borosilicate glass sheet as a window body, printing a glass slurry ring on the window body by a screen printing technology, forming a glass cavity structure on a glass cover plate by a sintering process, pouring high-temperature borosilicate glass liquid into a mould, paving the window body on the mould, waiting for the window body to be cooled, and after cooling, arranging a corresponding convex lens surface and a concave lens surface on the window body, wherein the borosilicate glass liquid is a mixture of glass powder, ceramic powder and a binder, and the components are set as follows: selecting a low-melting-point glass material with the glass transition temperature lower than 600 ℃ as glass powder, wherein the mixing amount of the glass material is 65-75% of the total weight of the sizing agent, selecting an alumina material as ceramic powder, the mixing amount of the alumina material is 15-25% of the total weight of the sizing agent, the grain diameters of the glass powder and the ceramic powder are 2-8 microns, selecting a binder as a mixture of ethyl cellulose and terpineol, the mixing amounts of the ethyl cellulose and the terpineol are 3-4% and 8-14% of the total weight of the sizing agent respectively, selecting a borosilicate glass sheet with the same size, cutting off a plurality of terraces in the borosilicate glass sheet to be used as a frame body, polishing an elliptic curved surface on an inclined wall formed by cutting off the terraces, adding a reflective coating material on the elliptic curved surface, and sealing and connecting the window body and the frame body to form a glass cover after the reflective coating is formed;

s2, forming a metal layer on the lower bottom surface of the frame of the glass cover for welding with the substrate;

s3, attaching a plurality of deep ultraviolet LED chips on a substrate, forming a metal layer on the periphery of the chips on the substrate, and coating Au-Sn wax material on the metal layer to be used as a solder layer;

s4, aligning and pressurizing the glass cover metal layer and the solder layer on the substrate to enable the ultraviolet LED chip to be positioned in the glass cavity, and realizing the melting of the solder layer through the integral heating or local heating technology, thereby forming the ultraviolet LED sealing structure;

and S5, cutting and slicing the ultraviolet LED packaging wafer with the sealing structure formed in the step S4 to obtain the high-efficiency deep ultraviolet LED light source packaging product.

Technical Field

The invention relates to the technical field of chip packaging, in particular to a high-efficiency deep ultraviolet LED light source packaging structure and a packaging method thereof.

Background

Due to the technical development of the blue light LED, most of the deep ultraviolet LEDs imitate the blue light LED packaging form to package the blue light LED, the blue light LED basically packages the blue light LED by adopting organic materials such as silica gel and resin, the deep ultraviolet LEDs emit deep ultraviolet rays which can damage the organic materials, and the organic materials are not suitable for packaging the deep ultraviolet LEDs at all. In addition, the current deep ultraviolet LED has low photoelectric conversion efficiency, so that the heat productivity of the deep ultraviolet LED is large, and the heat conducting performance of the current substrate for packaging the blue light LED is poor, so that the heat emitted by the deep ultraviolet LED chip cannot be conducted out in time, the junction temperature of the deep ultraviolet LED device is high, the deep ultraviolet LED chip is damaged, and the light emitting efficiency and the reliability of the deep ultraviolet LED device are reduced.

Now, a plurality of package structures have been developed, and through a large number of searches and references, it is found that the existing package is a system disclosed as KR101648079B1, KR100926898B1, CN106299087B and KR101715839B1, the system comprises a support, an LED chip and a transparent cover plate, the support comprises a reflective cup, the LED chip is fixed in the reflective cup, the support further comprises a support table surrounding the reflective cup, a groove surrounding the reflective cup is formed in the upper surface of the support table, a reflective layer corresponding to the groove is formed in the lower surface of the transparent cover plate, and the transparent cover plate is fixedly connected with the support through a colloid arranged in the groove. The deep ultraviolet LED packaging structure can avoid damage of deep ultraviolet light to organic materials, avoid loose contact between the light-transmitting cover plate and the support, and improve the service life and the luminous efficiency of the deep ultraviolet LED. However, the reflective efficiency of the reflective cup with this structure needs to be improved, the package structure is complicated, the light emitting chip is not improved, and the light emitting efficiency and the lifetime of the light source need to be improved.

Disclosure of Invention

The invention aims to provide a high-efficiency deep ultraviolet LED light source packaging structure and a packaging method thereof,

the invention adopts the following technical scheme:

a high-efficiency deep ultraviolet LED light source packaging structure comprises a substrate, a deep ultraviolet LED wafer and a glass cover, wherein the deep ultraviolet LED wafer is mounted on the substrate, the glass cover is hermetically covered on the substrate to enable the deep ultraviolet LED wafer to be located in a closed space, and light rays emitted by the deep ultraviolet LED wafer are emitted through the glass cover;

the glass cover comprises a frame body and a window body, the window body is connected with the frame body in a sealing mode, an inclined wall surface is arranged inside the frame body, an inner concave surface is arranged on the inclined wall surface, a DUV (deep ultraviolet) reflecting coating is arranged on the inner concave surface, the inner concave surface is a part of a rotating ellipsoid, and a light-emitting central point of the deep ultraviolet LED wafer is located at one focus of the ellipsoid where the rotating ellipsoid is located;

the formula of the concave surface is as follows:

wherein a and b are ellipse parameters, and c is the thickness of the frame body;

the lower surface of the window body is a curved surface and is used for emitting the light emitted by the deep ultraviolet LED wafer and the reflected light of the reflecting coating out of the window body at an angle close to parallel light;

the deep ultraviolet LED chip comprises an n-type coating layer, an active layer, a p-type coating layer, a p-type contact layer, a p-side electrode and an n-side electrode, wherein the p-type coating layer is arranged on the active layer and is made of a p-type aluminum gallium nitride-based semiconductor material or a p-type aluminum nitride-based semiconductor material with the aluminum nitride ratio of 50% or more, the p-type contact layer is arranged in contact with the p-type coating layer and is made of a p-type aluminum gallium nitride-based semiconductor material or a p-type gallium nitride-based semiconductor material with the aluminum nitride ratio of 20% or less, the difference between the aluminum nitride ratio of the p-type coating layer and the aluminum nitride ratio of the p-type contact layer is 50% or more, and the thickness of the p-type contact layer is more than 500 nm;

further, the value range of the ellipse parameter a is [2.5, 3.8] mm, and the value range of the ellipse parameter b is [8.4, 10.6] mm;

furthermore, the curved surface of the lower surface of the window body comprises a convex surface positioned in the middle and concave surfaces positioned at the periphery, the convex surface is a part of a convex lens surface, the concave surface is a part of a concave lens surface, a connecting line of an inner concave surface on the inclined wall surface and the other focus of the ellipsoid is intersected with the concave surface of the window body, light emitted by the deep ultraviolet LED wafer is emitted after passing through the convex surface of the window body, and light reflected by the reflecting coating is emitted after passing through the concave surface of the window body;

furthermore, the frame body and the window body are both made of borosilicate glass with DUV light transmission, and the reflective coating is made of aluminum or an alloy material taking aluminum as a main component;

a packaging method of a high-efficiency deep ultraviolet LED light source packaging structure comprises the following steps:

s1, preparing a glass cover: selecting a plane borosilicate glass sheet as a window body, printing a glass slurry ring on the window body by a screen printing technology, forming a glass cavity structure on a glass cover plate by a sintering process, pouring high-temperature borosilicate glass liquid into a mould, paving the window body on the mould, waiting for the window body to be cooled, and after cooling, arranging a corresponding convex lens surface and a concave lens surface on the window body, wherein the borosilicate glass liquid is a mixture of glass powder, ceramic powder and a binder, and the components are set as follows: selecting a low-melting-point glass material with the glass transition temperature lower than 600 ℃ as glass powder, wherein the mixing amount of the glass material is 65-75% of the total weight of the sizing agent, selecting an alumina material as ceramic powder, the mixing amount of the alumina material is 15-25% of the total weight of the sizing agent, the grain diameters of the glass powder and the ceramic powder are 2-8 microns, selecting a binder as a mixture of ethyl cellulose and terpineol, the mixing amounts of the ethyl cellulose and the terpineol are 3-4% and 8-14% of the total weight of the sizing agent respectively, selecting a borosilicate glass sheet with the same size, cutting off a plurality of terraces in the borosilicate glass sheet to be used as a frame body, polishing an elliptic curved surface on an inclined wall formed by cutting off the terraces, adding a reflective coating material on the elliptic curved surface, and sealing and connecting the window body and the frame body to form a glass cover after the reflective coating is formed;

s2, forming a metal layer on the lower bottom surface of the frame of the glass cover for welding with the substrate;

s3, attaching a plurality of deep ultraviolet LED chips on a substrate, forming a metal layer on the periphery of the chips on the substrate, and coating Au-Sn wax material on the metal layer to be used as a solder layer;

s4, aligning and pressurizing the glass cover metal layer and the solder layer on the substrate to enable the ultraviolet LED chip to be positioned in the glass cavity, and realizing the melting of the solder layer through the integral heating or local heating technology, thereby forming the ultraviolet LED sealing structure;

and S5, cutting and slicing the ultraviolet LED packaging wafer with the sealing structure formed in the step S4 to obtain the high-efficiency deep ultraviolet LED light source packaging product.

The beneficial effects obtained by the invention are as follows:

the glass cover is divided into the frame body and the window body, the reflecting surface is arranged on the frame body, the transmission surface is arranged on the window body, the utilization rate of light is improved, the window body and the frame body can be spliced after curved surfaces are machined, the sealing and packaging difficulty is reduced, meanwhile, the reflecting surface is designed into an ellipsoid surface, the direction of the reflected light is controlled, the transmission surface is divided into a convex lens surface and a concave lens surface and is used for respectively processing the directly emitted light and the reflected light, the utilization rate of the light is further improved, meanwhile, the thickness and the components of each layer of the light-emitting wafer are controlled, the service life of the light-emitting wafer is prolonged, the whole packaging structure is made of inorganic materials, the heat conduction is enhanced, and the damage to a chip is reduced.

Drawings

The invention will be further understood from the following description in conjunction with the accompanying drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the embodiments. Like reference numerals designate corresponding parts throughout the different views.

FIG. 1 is a schematic overall frame diagram;

FIG. 2 is a schematic diagram of a package structure;

FIG. 3 is a schematic diagram of deep ultraviolet LED wafer layering;

FIG. 4 is a schematic diagram showing the relationship between the thickness of the p-type contact layer and the luminous intensity of the deep ultraviolet LED wafer;

FIG. 5 is a graph showing the relationship between the lifetime of a deep ultraviolet LED wafer and the thickness of a p-type contact layer.

In the figure, a substrate 11, a deep ultraviolet LED chip 12, a frame 13, a window 14, a substrate 20, a base layer 21, an n-type cladding layer 22, an active layer 23, a p-type cladding layer 24, a p-type contact layer 25, a p-side electrode 26 and an n-side electrode 27 are shown.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to embodiments thereof; it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Other systems, methods, and/or features of the present embodiments will become apparent to those skilled in the art upon review of the following detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. Additional features of the disclosed embodiments are described in, and will be apparent from, the detailed description that follows.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not indicated or implied that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limitations of the present patent, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.

The first embodiment.

The embodiment provides a high-efficiency deep ultraviolet LED light source packaging structure, which comprises a substrate, a deep ultraviolet LED wafer and a glass cover, wherein the deep ultraviolet LED wafer is arranged on the substrate, the glass cover is hermetically covered on the substrate to enable the deep ultraviolet LED wafer to be located in a closed space, and light emitted by the deep ultraviolet LED wafer is emitted through the glass cover;

the glass cover comprises a frame body and a window body, the window body is connected with the frame body in a sealing mode, an inclined wall surface is arranged inside the frame body, an inner concave surface is arranged on the inclined wall surface, a DUV (deep ultraviolet) reflecting coating is arranged on the inner concave surface, the inner concave surface is a part of a rotating ellipsoid, and a light-emitting central point of the deep ultraviolet LED wafer is located at one focus of the ellipsoid where the rotating ellipsoid is located;

the formula of the concave surface is as follows:

wherein a and b are ellipse parameters, and c is the thickness of the frame body;

the lower surface of the window body is a curved surface and is used for emitting the light emitted by the deep ultraviolet LED wafer and the reflected light of the reflecting coating out of the window body at an angle close to parallel light;

the deep ultraviolet LED chip comprises an n-type coating layer, an active layer, a p-type coating layer, a p-type contact layer, a p-side electrode and an n-side electrode, wherein the p-type coating layer is arranged on the active layer and is made of a p-type aluminum gallium nitride-based semiconductor material or a p-type aluminum nitride-based semiconductor material with the aluminum nitride ratio of 50% or more, the p-type contact layer is arranged in contact with the p-type coating layer and is made of a p-type aluminum gallium nitride-based semiconductor material or a p-type gallium nitride-based semiconductor material with the aluminum nitride ratio of 20% or less, the difference between the aluminum nitride ratio of the p-type coating layer and the aluminum nitride ratio of the p-type contact layer is 50% or more, and the thickness of the p-type contact layer is more than 500 nm;

the value range of the ellipse parameter a is [2.5, 3.8] mm, and the value range of the ellipse parameter b is [8.4, 10.6] mm;

the curved surface of the lower surface of the window body comprises a convex surface positioned in the middle and a concave surface positioned on the periphery, the convex surface is a part of a convex lens surface, the concave surface is a part of a concave lens surface, a connecting line of an inner concave surface on the inclined wall surface and the other focus of the ellipsoid is intersected with the concave surface of the window body, light emitted by the deep ultraviolet LED wafer is emitted after passing through the convex surface of the window body, and light reflected by the reflecting coating is emitted after passing through the concave surface of the window body;

the frame body and the window body are both made of borosilicate glass with DUV light transmission, and the reflective coating is made of aluminum or an alloy material taking aluminum as a main component;

a packaging method of a high-efficiency deep ultraviolet LED light source packaging structure comprises the following steps:

s1, preparing a glass cover: selecting a plane borosilicate glass sheet as a window body, printing a glass slurry ring on the window body by a screen printing technology, forming a glass cavity structure on a glass cover plate by a sintering process, pouring high-temperature borosilicate glass liquid into a mould, paving the window body on the mould, waiting for the window body to be cooled, and after cooling, arranging a corresponding convex lens surface and a concave lens surface on the window body, wherein the borosilicate glass liquid is a mixture of glass powder, ceramic powder and a binder, and the components are set as follows: selecting a low-melting-point glass material with the glass transition temperature lower than 600 ℃ as glass powder, wherein the mixing amount of the glass material is 65-75% of the total weight of the sizing agent, selecting an alumina material as ceramic powder, the mixing amount of the alumina material is 15-25% of the total weight of the sizing agent, the grain diameters of the glass powder and the ceramic powder are 2-8 microns, selecting a binder as a mixture of ethyl cellulose and terpineol, the mixing amounts of the ethyl cellulose and the terpineol are 3-4% and 8-14% of the total weight of the sizing agent respectively, selecting a borosilicate glass sheet with the same size, cutting off a plurality of terraces in the borosilicate glass sheet to be used as a frame body, polishing an elliptic curved surface on an inclined wall formed by cutting off the terraces, adding a reflective coating material on the elliptic curved surface, and sealing and connecting the window body and the frame body to form a glass cover after the reflective coating is formed;

s2, forming a metal layer on the lower bottom surface of the frame of the glass cover for welding with the substrate;

s3, attaching a plurality of deep ultraviolet LED chips on a substrate, forming a metal layer on the periphery of the chips on the substrate, and coating Au-Sn wax material on the metal layer to be used as a solder layer;

s4, aligning and pressurizing the glass cover metal layer and the solder layer on the substrate to enable the ultraviolet LED chip to be positioned in the glass cavity, and realizing the melting of the solder layer through the integral heating or local heating technology, thereby forming the ultraviolet LED sealing structure;

and S5, cutting and slicing the ultraviolet LED packaging wafer with the sealing structure formed in the step S4 to obtain the high-efficiency deep ultraviolet LED light source packaging product.

Example two.

The substrate of the embodiment is made of high-thermal-conductivity materials such as aluminum nitride and silicon nitride, a plurality of wiring electrodes are arranged on the substrate, and the deep ultraviolet LED chip is electrically connected with the wiring electrodes;

the glass cover comprises a frame body and a window body, wherein the frame body and the window body are both made of borosilicate glass with DUV light transmission performance, the window body covers an opening of the frame body and is in sealing fit with the frame body, an inclined wall surface is arranged in the frame body, a DUV reflection coating is arranged on the inclined wall surface, an angle formed by the inclined wall surface and the lower end surface of the frame body is beta, the value range of the beta is [45 degrees ] and 85 degrees ], and the DUV reflection coating can be connected with the lower end surface of the window body and the lower end surface of the frame body according to requirements;

an inner concave surface is arranged on the inclined wall surface, the reflection coating is positioned in the inner concave surface, and the formula of the inner concave surface is as follows:

wherein a and b are ellipse parameters, and c is the thickness of the frame body;

the DUV reflective coating may be formed by any film forming method including, but not limited to, plating, spray coating, and vapor deposition;

the DUV reflecting coating can be made of any material with the property of reflecting DUV, and preferably, an alloy material containing aluminum or taking the aluminum as a main component is used as the material of the DUV reflecting coating;

the lower end face of the window body is provided with HfO by adding₂、ZrO₂Or SiO₂To prevent the window from reflecting against the DUV;

in order to prevent the deterioration of the constituent materials in the deep ultraviolet LED light source device, inert gas such as nitrogen, helium or argon is filled in the sealed space formed by the glass cover and the substrate, the melting point of the sealing material between the glass cover and the substrate is required to be lower than that of the DUV reflecting coating material, and preferably, the glass cover is sealed on the substrate by using Au-Sn wax material with the melting point of 217 ℃;

referring to fig. 3, the deep ultraviolet LED wafer includes a substrate, a base layer, an n-type cladding layer, an active layer, a p-type cladding layer, a p-type contact layer, a p-side electrode, and an n-side electrode;

the substrate is transparent to deep ultraviolet light emitted by the semiconductor light emitting chip, such as a sapphire substrate;

a substrate including a first principal surface as a principal surface in contact with the foundation layer and a second principal surface opposite to the first principal surface, the first principal surface having a fine concave-convex pattern of submicron depth and pitch thereon, is referred to as a patterned sapphire substrate;

the second main surface is a light-transmitting surface that emits deep ultraviolet light to the outside;

the base layer is arranged on the first main surface of the substrate, the base layer is a template layer forming an n-type cladding layer, and the base layer comprises an undoped aluminum nitride layer or an aluminum gallium nitride layer formed at high temperature;

the n-type clad layer is provided on the base layer, and is an n-type aluminum gallium nitride-based semiconductor material layer, for example, an aluminum gallium nitride layer doped with silicon as an n-type impurity;

the component proportion of the n-type coating layer is set to be capable of transmitting the deep ultraviolet light emitted by the active layer, for example, the mole fraction of aluminum nitride in the coating layer is more than 40%;

the n-type cladding layer has a band gap larger than a wavelength of deep ultraviolet light emitted from the active layer, for example, the n-type cladding layer has a band gap of 3.85eV or more;

preferably, the mole fraction of aluminum nitride in the n-type cladding layer is between 40% and 80% and the band gap is between 3.85eV and 5.5eV, more preferably, the mole fraction of aluminum nitride in the n-type cladding layer is between 50% and 70% and the band gap is between 4.2eV and 5.2 eV;

the thickness range of the n-type coating layer is 1-3 mu m;

the concentration of impurity silicon in the n-type cladding layer ranges from 1 to 10¹⁸cm³To 5 x 10¹⁹cm³Preferably, the concentration of impurity silicon in the n-type cladding layer is in the range of 5 x 10¹⁸cm³To 3 x 10¹⁹cm³More preferably, the concentration of impurity silicon in the n-type cladding layer is in the range of 7 x 10¹⁸cm³To 2 x 10¹⁹cm³To (c) to (d);

the n-type cladding layer comprises a first upper surface and a second upper surface, wherein an active layer is formed on the first upper surface, and an n-side electrode is formed on the second upper surface;

the active layer is provided on a first upper surface of the n-type cladding layer, the active layer is made of an aluminum gallium nitride-based semiconductor material and has a double heterojunction structure by being sandwiched by the n-type cladding layer and the p-type cladding layer, the active layer having a band gap of 3.4eV or more;

the active layer has a single-layer or multi-layer quantum well structure, and is composed of a barrier layer made of undoped aluminum gallium nitride-based semiconductor material and a well layer laminated layer made of doped aluminum gallium nitride-based semiconductor material;

the active layer comprises a first barrier layer directly contacted with the n-type cladding layer and a first well layer arranged on the first barrier layer, one or more pairs of well layers and barrier layers are additionally arranged between the first barrier layer and the first well layer, and the thicknesses of the barrier layer and the well layer are both between 1nm and 20 nm;

the active layer comprises an electron blocking layer in direct contact with the p-type cladding layer, the electron blocking layer is an undoped aluminum gallium nitride-based semiconductor material layer, the mole fraction of aluminum nitride in the electron blocking layer is 80% or more, and the thickness of the electron blocking layer is between 1nm and 10 nm;

the p-type clad layer is provided on the active layer, the p-type clad layer being a p-type aluminum gallium nitride-based semiconductor material layer, for example, the p-type clad layer being an aluminum gallium nitride layer doped with magnesium as a p-type impurity;

the p-type cladding layer has a higher aluminum nitride ratio than the p-type contact layer, and the mole fraction of aluminum nitride in the p-type cladding layer is 50% or more, preferably 60% or more;

the thickness of the p-type cladding layer is between 10nm and 100 nm;

the p-type contact layer is provided on and in direct contact with the p-type cladding layer, the p-type contact layer is a p-type aluminum gallium nitride-based semiconductor material layer or a p-type gallium nitride-based semiconductor material layer, the ratio of aluminum nitride in the p-type contact layer is different from that in the p-type cladding layer by 50% or more, preferably 60% or more, the p-type contact layer is configured to a ratio of aluminum nitride of 20% or less to obtain an appropriate ohmic contact with the p-side electrode, the ratio of aluminum nitride in the p-type contact layer is 10% or less, and the p-type contact layer may be a p-type gallium nitride layer containing no aluminum nitride;

the thickness of the p-type contact layer exceeds 500 nm;

the p-side electrode is disposed on and in ohmic contact with the US bridge contact layer, and is configured such that the p-side electrode has an ohmic contact resistance of 1 x 10 with respect to the p-contact layer^-2Ω·cm²Or less, the p-side electrode is made of a transparent conductive oxide such as indium tin oxide, a platinum group metal such as rhodium, or a stacked structure of nickel and gold;

the n-side electrode is arranged on the second upper surface of the n-type cladding layer, and is made of a material which can be in ohmic contact with the n-type cladding layer and has high reflectivity to deep ultraviolet light emitted by the active layer, for example, the n-side electrode is composed of a titanium layer and an aluminum layer;

the flatness of the upper surface of the p-type contact layer is improved by configuring the thickness of the p-type contact layer to be large, the in-plane uniformity of the density of current flowing to the active layer through the p-side electrode is improved by forming the p-side electrode on the highly flat upper surface, the local concentration of current and the non-uniformity of current density in-plane due to the rugged structure at the interface between the p-type contact layer and the p-side electrode are prevented, and the influence of the reduction in the lifetime of the wafer due to the excessive current flowing in a part of the deep ultraviolet LED wafer is prevented;

through experiments, the flatness of the upper surface of the p-type contact layer is greatly improved by increasing the thickness of the p-type contact layer to a degree exceeding 500 nm;

referring to fig. 4, the light emission intensity of the deep ultraviolet LED chip is shown when the p-type contact layer has a thickness of 16nm, 300nm, 500nm, 700nm, 1000nm, the wavelength of the light emitted from the active layer is about 280nm-285nm, the aluminum nitride ratio of the p-type cladding layer is 75%, the aluminum nitride ratio of the p-type contact layer is 0%, and the aluminum nitride ratio of the n-type cladding layer is 55%;

as can be seen from fig. 4, the emission intensity at a thickness of 16nm of the p-type contact layer decreased to 75% after 24 hours and 70% after 48 hours;

the emission intensity at a thickness of 300nm of the p-type contact layer decreased to 81% after 200 hours and 70% after 950 hours;

on the other hand, the emission intensity of the p-type contact layer at a thickness of 500nm is 90% or more after 200 hours and 80% or more after 1000 hours;

similarly, the emission intensity of the p-type contact layer at a thickness of 700nm is 90% or more after 200 hours and 85% or more after 1000 hours;

further, the emission intensity generated when the thickness of the p-type contact layer was 1000nm was about 90% after 200 hours and about 85% after 1000 hours;

therefore, increasing the thickness of the p-type contact layer can slow down the decrease in the emission intensity and extend the time in which the emission intensity can be maintained at a certain level or higher, i.e., the wafer life;

referring to fig. 5, a relationship between the lifetime of the deep ultraviolet LED wafer, which is the time elapsed before the emission intensity of the deep ultraviolet LED wafer decreases to 70%, and the thickness of the p-type contact layer is shown;

as shown, the greater the thickness of the p-type contact layer 30, the longer the wafer lifetime;

the graph shows that when the thickness of the p-type contact layer exceeds 500nm, the wafer lifetime is significantly extended;

more specifically, when the thickness of the p-type contact layer exceeds 500nm, the wafer lifetime exceeds 5000 hours;

the wafer life is 6500 hours when the thickness of the p-type contact layer is 520nm, and 8000 hours when the thickness of the p-type contact layer is 550 nm;

when the thickness of the p-type contact layer is 590nm or more, the wafer lifetime is 10000 hours or more;

further, when the thickness of the p-type contact layer is not less than 700nm and not more than 1000nm, a wafer lifetime of 20000 hours or more can be achieved.

Although the invention has been described above with reference to various embodiments, it should be understood that many changes and modifications may be made without departing from the scope of the invention. That is, the methods, systems, and devices discussed above are examples. Various configurations may omit, substitute, or add various procedures or components as appropriate. For example, in alternative configurations, the methods may be performed in an order different than that described, and/or various components may be added, omitted, and/or combined. Moreover, features described with respect to certain configurations may be combined in various other configurations, as different aspects and elements of the configurations may be combined in a similar manner. Further, elements therein may be updated as technology evolves, i.e., many elements are examples and do not limit the scope of the disclosure or claims.

Specific details are given in the description to provide a thorough understanding of the exemplary configurations including implementations. However, configurations may be practiced without these specific details, for example, well-known circuits, processes, algorithms, structures, and techniques have been shown without unnecessary detail in order to avoid obscuring the configurations. This description provides example configurations only, and does not limit the scope, applicability, or configuration of the claims. Rather, the foregoing description of the configurations will provide those skilled in the art with an enabling description for implementing the described techniques. Various changes may be made in the function and arrangement of the wafers without departing from the spirit or scope of the disclosure.

In conclusion, it is intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that these examples are illustrative only and are not intended to limit the scope of the invention. After reading the description of the invention, the skilled person can make various changes or modifications to the invention, and these equivalent changes and modifications also fall into the scope of the invention defined by the claims.