WO2020040304A1

WO2020040304A1 - Deep ultraviolet led device and method for manufacturing same

Info

Publication number: WO2020040304A1
Application number: PCT/JP2019/033110
Authority: WO
Inventors: 行雄鹿嶋; 恵里子松浦; 小久保　光典; 田代　貴晴; 秀樹平山; 哲利前田; 隆一郎上村; 大和長田; 寛治古田; 武岩井; 洋平青山; 祝迫　恭; 丞益長野; 高木　秀樹; 優一倉島; 貴司松前
Original assignee: 丸文株式会社; 東芝機械株式会社; 国立研究開発法人理化学研究所; 株式会社アルバック; 東京応化工業株式会社; 日本タングステン株式会社; 大日本印刷株式会社; 国立研究開発法人産業技術総合研究所
Priority date: 2018-08-24
Filing date: 2019-08-23
Publication date: 2020-02-27
Also published as: TW202027304A

Abstract

Provided is a deep ultraviolet LED device comprising: a surface mount-type aluminum nitride ceramic package in which an inorganic coating film having a reflectivity of at least 91% at a deep ultraviolet LED element design wavelength λ (200-355 nm) is coated on the inner bottom surface and inner side walls thereof, the inner side wall angle thereof is 45-60 degrees, and the outermost surface thereof is sealed with a quartz window; and a deep ultraviolet LED element mounted in the package, wherein the deep ultraviolet LED element has a reflective electrode layer (Au), a metal layer (Ni), a p-type GaN contact layer, a p-type AlGaN layer, a multi-quantum barrier layer (or electron block layer), a multi-quantum well layer, an n-type AlGaN layer, an AlN buffer layer, and a sapphire substrate in this order from the opposite side from the sapphire substrate, and has a reflective two-dimensional photonic crystal which is located within the range of the metal layer and the p-type GaN contact layer in the thickness direction and which has a plurality vacancies disposed in locations that are not beyond the boundaries of the p-type GaN contact layer and the p-type AlGaN layer. The periodic structure of the reflective two-dimensional photonic crystal has a photonic band gap that opens to a TE-polarized component, wherein the period a of the reflective two-dimensional photonic crystal periodic structure satisfies the Bragg condition for light having the design wavelength λ, the order m in the Bragg equation, mλ/n_eff=2a (m: order, λ: design wavelength, n_eff: effective refractive index of two-dimensional photonic crystal, and a: period of two-dimensional photonic crystal) satisfies 3≤m≤4, and the ratio of R/a (R is the radius of the vacancies) satisfies 0.30≤R/a≤0.40.

Description

Deep ultraviolet LED device and method of manufacturing the same

The present invention relates to a deep ultraviolet LED device and a method for manufacturing the same.

深 Deep UV LEDs with an emission wavelength of 200 nm to 355 nm are used in a wide variety of applications, including sterilization, water purification, sterilization for hospital infections, medical use for vitiligo and atopic dermatitis, and industrial use for resin curing. However, the power conversion efficiency (WPE) is several percent, which is low as compared with 20% of a mercury lamp, and there are many problems in practical use. The reason is that the light emitted from the quantum well layer is absorbed and lost by the p-type GaN contact layer and the Ni / Au electrode, and the light can be extracted to the outside by the total internal reflection caused by the refractive index difference between the LED element and air. Light extraction efficiency (Light Extraction Efficiency: LEE) is as low as 6% or less because it is not easy. Furthermore, when an LED element is mounted on a package, there is no effective material for suppressing absorption of deep ultraviolet light.

Therefore, Patent Document 1 reports that LEE has been improved more than twice by forming a reflective photonic crystal on the p-type GaN contact layer or the p-type AlGaN contact layer. In addition, Patent Document 2 reports that the LEE has been improved up to about three times at the maximum by bonding a sapphire hemispherical lens transparent to the above wavelength on the back surface of the sapphire substrate.

Japanese Patent No. 6156898 Japanese Patent No. 6230038

表 In Table 1 of Patent Document 1, the reflection type photonic crystal is formed on the p-type AlGaN contact layer transparent to the emission wavelength, and the LEE is improved 1.82 times at the maximum to 23.8%. In this case, it is assumed that the inner wall of the aluminum nitride ceramic package on which the deep ultraviolet LED element is mounted is covered with aluminum having a reflectance of 92% at a wavelength of 280 nm. However, when the inner wall of the package is deposited with aluminum in an actual process, excited electrons on the aluminum nitride surface weaken an electric field inside aluminum, so that deep ultraviolet light enters and disappears inside, and a desired reflectance cannot be obtained. (See FIG. 1E of the present application described below).

Further, in Table 7 of Patent Document 2, LEE is further improved to 57.1% at the maximum by bonding a sapphire hemispherical lens to the back surface of the sapphire substrate of the deep ultraviolet LED element having the reflective photonic crystal, The process involves polishing the back surface of the sapphire substrate to reduce the thickness from 400 μm to 100 μm, which is costly and impractical. Further, when this deep ultraviolet LED element is mounted on a commercially available aluminum nitride ceramic package having excellent heat radiation characteristics, all deep ultraviolet light is absorbed / dissipated on the inner wall of the package, causing a problem that LEE deteriorates by 30% or more. Therefore, LEE decreases from 57.1% to about 40%.

The present invention aims to improve LEE of a deep ultraviolet LED device. Another object of the present invention is to realize a deep ultraviolet LED device with improved LEE at low cost.

According to a first aspect of the present invention, an inorganic paint having a reflectance of 91% or more at a design wavelength λ (200 nm to 355 nm) of a deep ultraviolet LED element is coated on an inner bottom surface and an inner side wall and cured (hereinafter referred to as “hardening treatment”). The act of coating and curing the inorganic paint is collectively referred to as "coating", and the coating obtained by coating the inorganic paint is referred to as "inorganic paint coating film." Wherein the inner side wall angle of the package is not less than 45 degrees and not more than 60 degrees, and the outermost surface of the package is a package sealed with a quartz window, and a deep ultraviolet LED element mounted in the package, A reflective electrode layer (Au), a metal layer (Ni), a p-type GaN contact layer, a p-type AlGaN layer, A barrier layer (or an electron block layer), a multiple quantum well layer, an n-type AlGaN layer, an AlN buffer layer, and a sapphire substrate are arranged in this order from the side opposite to the sapphire substrate. A reflection type two-dimensional photo having a plurality of holes provided in a range in a thickness direction of the p-type GaN contact layer and not exceeding an interface between the p-type GaN contact layer and the p-type AlGaN layer. Nic crystal, the reflective two-dimensional photonic crystal periodic structure has a photonic band gap opened for a TE polarization component, and the reflective two-dimensional photonic crystal has a photonic band gap for light of the design wavelength λ. period a crystal periodic structure satisfies the Bragg condition, and the Bragg condition mλ _{/ n} eff = 2a (where, m: order, lambda: design _{wavelength, n eff:} 2-dimensional photonic The effective refractive index of the crystal, a: the period of the two-dimensional photonic crystal) satisfies 3 ≦ m ≦ 4, and when the radius of the hole is R, the R / a ratio is 0.30 ≦ And a deep ultraviolet LED element satisfying R / a ≦ 0.40.
The reflectance of the inorganic paint may be at least 91% at a design wavelength λ (200 nm to 355 nm) when the ultraviolet LED device is used. Even if the inorganic paint itself has a reflectance of less than 91%, An inorganic paint that has a reflectance of 91% after coating, or an inorganic paint that has a reflectance of 91% or more by an additional process involving a chemical change after coating may be used.

According to a second aspect of the present invention, the inorganic paint is a surface-mounted aluminum nitride ceramic package coated on an inner bottom surface and an inner side wall, and the inner side wall angle of the package is 45 degrees or more and 60 degrees. The package is a package sealed with a quartz window on the outermost surface, and a deep ultraviolet LED element mounted in the package. The package includes a reflective electrode layer (Au) and a metal layer (Ni). , A p-type AlGaN contact layer, a multiple quantum barrier layer (or an electron blocking layer), a multiple quantum well layer, an n-type AlGaN layer, an AlN buffer layer, and a sapphire substrate from the opposite side to the sapphire substrate. The metal layer and the p-type AlGaN contact layer in the thickness direction, and the p-type AlGaN contact layer and the p-type AlGaN contact layer. A reflection type two-dimensional photonic crystal having a plurality of holes provided at a position not exceeding an interface with a quantum barrier layer (or an electron block layer); It has a photonic band gap opened to the polarization component, and the period a of the reflection type two-dimensional photonic crystal periodic structure satisfies the Bragg condition for light of the design wavelength λ, and the Bragg condition formula The order m in mλ / n _eff = 2a (where m: order, λ: design wavelength, n _eff : effective refractive index of the two-dimensional photonic crystal, a: period of the two-dimensional photonic crystal) is 2 ≦ m ≦ 3. A deep ultraviolet LED device comprising: a deep ultraviolet LED element that satisfies the condition 3 and the radius of the hole is R, and the R / a ratio satisfies 0.30 ≦ R / a ≦ 0.35. I will provide a.

According to the third aspect of the present invention, the reflective electrode (Au) is replaced with the reflective electrode (Rh) and the metal layer (Ni) is eliminated from the structure of the deep ultraviolet LED device of the second aspect. A deep ultraviolet LED device having a structure is provided.

According to a fourth aspect of the present invention, the structure of the deep ultraviolet LED device according to the first aspect further includes a sapphire or quartz hemispherical lens transparent to a wavelength λ bonded to the back surface of the sapphire substrate. In addition, the present invention provides a deep ultraviolet LED device comprising a deep ultraviolet LED element having a radius of the hemispheric lens equal to or larger than a radius of a circumcircle of the sapphire substrate.

According to a fifth aspect of the present invention, the structure of the deep ultraviolet LED device according to the second aspect further includes a sapphire or quartz hemispherical lens transparent to a wavelength λ bonded to the back surface of the sapphire substrate. The radius of the hemispherical lens is equal to or larger than the radius of a circumcircle of the sapphire substrate.

According to a sixth aspect of the present invention, in the structure of the deep ultraviolet LED device according to the third aspect, there is further provided a sapphire or quartz hemispherical lens transparent to a wavelength λ to be bonded to the back surface of the sapphire substrate. The radius of the hemispherical lens is equal to or larger than the radius of a circumcircle of the sapphire substrate.

According to a seventh aspect of the present invention, the inorganic paint is a surface-mounted aluminum nitride ceramic package coated on an inner bottom surface and an inner side wall, and the inner side wall angle of the package is 60 degrees or more and 75 degrees. A package having the following structure, and a deep ultraviolet LED element mounted in the package, wherein a reflective electrode layer (Au), a metal layer (Ni), a p-type GaN contact layer, and a p-type AlGaN layer are multiplexed. It has a quantum barrier layer (or an electron blocking layer), a multiple quantum well layer, an n-type AlGaN layer, an AlN buffer layer, and a sapphire substrate in this order from the side opposite to the sapphire substrate. The p-type GaN contact layer is provided at a position within the thickness direction of the p-type GaN contact layer and at a position not exceeding the interface between the p-type GaN contact layer and the p-type AlGaN layer. Reflective two-dimensional photonic crystal having a plurality of holes, the reflective two-dimensional photonic crystal periodic structure has a photonic band gap opened to a TE polarized light component, and the design wavelength λ , The period a of the reflection type two-dimensional photonic crystal periodic structure satisfies the Bragg condition, and the Bragg condition mλ / n _eff = 2a (where m: order, λ: design wavelength, n _eff : the effective refractive index of the two-dimensional photonic crystal, a: the order m in the period of the two-dimensional photonic crystal satisfies 3 ≦ m ≦ 4, and when the radius of the hole is R, the R / a ratio Satisfies 0.30 ≦ R / a ≦ 0.40, and further has a sapphire or quartz hemispherical lens transparent to the wavelength λ bonded to the back surface of the sapphire substrate, and the radius of the hemispherical lens is the inner wall of the package. of It has more than contact yen, provides a deep ultraviolet LED device, wherein the transparent resin film with respect to the wavelength λ completely covering sealing the hemispherical lens surface and the top surface of the package.

According to an eighth aspect of the present invention, the inorganic paint is a surface mount type aluminum nitride ceramic package coated on an inner bottom surface and an inner side wall, and the inner side wall angle of the package is 60 degrees or more and 75 degrees. A package and a deep ultraviolet LED element mounted in the package, wherein the package includes a reflective electrode layer (Au), a metal layer (Ni), a p-type AlGaN contact layer, and a multiple quantum barrier layer (or an electron A block layer), a multiple quantum well layer, an n-type AlGaN layer, an AlN buffer layer, and a sapphire substrate in this order from the side opposite to the sapphire substrate, wherein the metal layer and the p-type AlGaN contact layer Within the range of the thickness direction, and not exceeding the interface between the p-type AlGaN contact layer and the multiple quantum barrier layer (or electron blocking layer). A reflective two-dimensional photonic crystal having a plurality of holes provided at positions, wherein the reflective two-dimensional photonic crystal periodic structure has a photonic band gap opened to a TE polarization component; For the light of the design wavelength λ, the period a of the reflective two-dimensional photonic crystal periodic structure satisfies the Bragg condition, and the Bragg condition mλ / n _eff = 2a (where m: order, λ: The order m in the design wavelength, n _eff : the effective refractive index of the two-dimensional photonic crystal, a: the period of the two-dimensional photonic crystal) satisfies 2 ≦ m ≦ 3, and when the radius of the hole is R, A deep ultraviolet LED element satisfying an R / a ratio of 0.30 ≦ R / a ≦ 0.35, further comprising a sapphire or quartz hemispherical lens transparent to a wavelength λ to be bonded to the back surface of the sapphire substrate. Having A deep ultraviolet LED device, wherein a radius of the hemispheric lens is equal to or larger than a circumcircle of the inner wall of the package, and a resin film transparent to a wavelength λ completely covers and seals the surface of the hemispheric lens and the upper surface of the package. I do.

According to the ninth aspect of the present invention, the reflective electrode (Au) is replaced with the reflective electrode (Rh) and the metal layer (Ni) is eliminated from the structure of the deep ultraviolet LED device of the eighth aspect. A deep ultraviolet LED device having a structure is provided.

According to a tenth aspect of the present invention, there is provided a method of manufacturing a deep ultraviolet LED device having a design wavelength of λ (200 nm to 355 nm), the method including a step of forming a laminated structure using a sapphire substrate as a growth substrate. Reflective electrode layer (Au), metal layer (Ni), p-type GaN contact layer, p-type AlGaN layer, multiple quantum barrier layer (or electron blocking layer), multiple quantum well layer, n-type AlGaN Forming a layered structure including a layer, an AlN buffer layer, and a sapphire substrate in this order from a side opposite to the sapphire substrate, in a thickness direction range of the metal layer and the p-type GaN contact layer. Reflective two-dimensional photonic crystal periodic structure having a plurality of vacancies provided in a position not exceeding an interface between the p-type GaN contact layer and the p-type AlGaN layer Forming, forming a mold for forming the reflective two-dimensional photonic crystal periodic structure, forming a resist layer on the p-type GaN contact layer, and nanoimprinting the structure of the mold. Transferring by a method, etching the p-type GaN contact layer using the resist layer to which the structure has been transferred as a mask to form a two-dimensional photonic crystal periodic structure, and the reflection type two-dimensional photonic crystal. Forming a metal layer and a reflective electrode layer in this order by an oblique vapor deposition method, dicing the sapphire substrate to form a deep ultraviolet LED element, and an inner side wall angle of 45 degrees. Preparing a surface-mount type aluminum nitride ceramic package having a temperature of not less than 60 degrees and not more than 60 degrees; A deep ultraviolet LED device, a step of mounting the deep ultraviolet LED element on the package, and a step of sealing the outermost surface of the package with a quartz window.

According to an eleventh aspect of the present invention, in the method for manufacturing a deep ultraviolet LED device according to the tenth aspect, the p-type contact layer is changed from a p-type GaN contact layer to a p-type AlGaN contact layer. The position of forming the reflective photonic crystal periodic structure is different from that of the sixteenth aspect, that is, within the range of the metal layer and the p-type AlGaN contact layer in the thickness direction, and in the p-type AlGaN contact layer. A deep ultraviolet LED device comprising the step of providing a plurality of holes at positions not exceeding the interface between the contact layer and the multiple quantum barrier layer (or the electron blocking layer), and otherwise having the same steps as the tenth aspect. A manufacturing method is provided.

According to a twelfth aspect of the present invention, in the method for manufacturing a deep ultraviolet LED device according to the eleventh aspect, a step of changing the reflective electrode from Au to Rh and using no metal layer (Ni), The eleventh aspect provides a method of manufacturing a deep ultraviolet LED device having the same steps except for this point.

According to a thirteenth aspect of the present invention, in the method for manufacturing a deep ultraviolet LED device according to the tenth aspect, further comprising: preparing a sapphire or quartz hemispherical lens having a radius equal to or larger than the circumcircle of the LED element substrate; A step of flattening the back surface of the LED element substrate and the back surface of the hemispheric lens, a step of surface-activating the back surface of the hemispheric lens and the back surface of the LED element substrate with an ion beam or atmospheric pressure plasma, and the hemispheric lens subjected to the surface activation processing Bonding a back surface to the back surface of the LED element substrate, preparing a surface-mounted aluminum nitride ceramic package having an inner side wall angle of 45 degrees or more and 60 degrees or less, and forming the inorganic bottom surface and the inner side wall of the package on the inner bottom surface and the inner side wall. A step of coating a paint, and a step of mounting the hemispherical lens junction LED element on the package. The package top surface to provide a method of manufacturing a deep-ultraviolet LED device having a step of sealing with a quartz window.

According to a fourteenth aspect of the present invention, in the method for manufacturing a deep ultraviolet LED device according to the eleventh aspect, further comprising: preparing a sapphire or quartz hemispherical lens having a radius equal to or larger than the circumcircle of the LED element substrate; A step of flattening the back surface of the LED element substrate and the back surface of the hemispheric lens, a step of surface-activating the back surface of the hemispheric lens and the back surface of the LED element substrate with an ion beam or atmospheric pressure plasma, and the hemispheric lens subjected to the surface activation processing Bonding a back surface to the back surface of the LED element substrate, preparing a surface-mounted aluminum nitride ceramic package having an inner side wall angle of 45 degrees or more and 60 degrees or less, and forming the inorganic bottom surface and the inner side wall of the package on the inner bottom surface and the inner side wall. A step of coating a paint, and a step of mounting the hemispherical lens junction LED element on the package. The package top surface to provide a method of manufacturing a deep-ultraviolet LED device having a step of sealing with a quartz window.

According to a fifteenth aspect of the present invention, in the method for manufacturing a deep ultraviolet LED device according to the twelfth aspect, further comprising: preparing a sapphire or quartz hemispherical lens having a radius equal to or larger than the circumcircle of the LED element substrate; A step of flattening the back surface of the LED element substrate and the back surface of the hemispheric lens, a step of surface-activating the back surface of the hemispheric lens and the back surface of the LED element substrate with an ion beam or atmospheric pressure plasma, and the hemispheric lens subjected to the surface activation processing Bonding a back surface to the back surface of the LED element substrate, preparing a surface-mounted aluminum nitride ceramic package having an inner side wall angle of 45 degrees or more and 60 degrees or less, and forming the inorganic bottom surface and the inner side wall of the package on the inner bottom surface and the inner side wall. A step of coating a paint, and a step of mounting the hemispherical lens junction LED element on the package. The package top surface to provide a method of manufacturing a deep-ultraviolet LED device having a step of sealing with a quartz window.

According to a sixteenth aspect of the present invention, in the method for manufacturing a deep ultraviolet LED device according to the tenth aspect, further comprising: preparing a sapphire or quartz hemispherical lens having a radius equal to or larger than a circumcircle of the package inner wall; A step of flattening the back surface of the LED element substrate and the back surface of the hemispheric lens, a step of surface-activating the back surface of the hemispheric lens and the back surface of the LED element substrate with an ion beam or atmospheric pressure plasma, and the hemispheric lens subjected to the surface activation processing Bonding the back surface to the LED device substrate back surface, mounting the hemispherical lens bonded LED device to the package, and simultaneously covering the hemispherical lens surface and the package top surface with a resin film transparent to a wavelength λ. Provided is a method for manufacturing a deep ultraviolet LED device having a sealing step.

According to a seventeenth aspect of the present invention, in the method for manufacturing a deep ultraviolet LED device according to the eleventh aspect, further comprising: preparing a sapphire or quartz hemispherical lens having a radius equal to or larger than a circumcircle of the package inner wall; A step of flattening the back surface of the LED element substrate and the back surface of the hemispheric lens, a step of surface-activating the back surface of the hemispheric lens and the back surface of the LED element substrate with an ion beam or atmospheric pressure plasma, and the hemispheric lens subjected to the surface activation processing Bonding the back surface to the LED device substrate back surface, mounting the hemispherical lens bonded LED device to the package, and simultaneously covering the hemispherical lens surface and the package top surface with a resin film transparent to a wavelength λ. Provided is a method for manufacturing a deep ultraviolet LED device having a sealing step.

According to an eighteenth aspect of the present invention, in the method for manufacturing a deep ultraviolet LED device according to the twelfth aspect, further comprising: preparing a sapphire or quartz hemispheric lens having a radius equal to or larger than a circumcircle of the package inner wall; A step of flattening the back surface of the LED element substrate and the back surface of the hemispheric lens, a step of surface-activating the back surface of the hemispheric lens and the back surface of the LED element substrate with an ion beam or atmospheric pressure plasma, and the hemispheric lens subjected to the surface activation processing Bonding the back surface to the LED device substrate back surface, mounting the hemispherical lens bonded LED device to the package, and simultaneously covering the hemispherical lens surface and the package top surface with a resin film transparent to a wavelength λ. Provided is a method for manufacturing a deep ultraviolet LED device having a sealing step.
This description includes part or all of the disclosure content of Japanese Patent Application No. 2018-157332, which is a priority document of the present application.

According to the present invention, LEE of a deep ultraviolet LED device can be improved at low cost.

FIG. 2 is a cross-sectional view and a plan view of the deep ultraviolet LED device according to the first embodiment of the present invention. FIG. 9 is a diagram illustrating a photonic band structure and a relationship between R / a and a PBG value in a TE polarization component incident on a two-dimensional photonic crystal formed on a p-type GaN contact layer, obtained by a plane wave expansion method. 4 is a calculation model in the ray tracing method of the deep ultraviolet LED device according to the first embodiment. 5 is a calculation model in the FDTD method of the deep ultraviolet LED device according to the first embodiment. An AlN package coated with an inorganic paint NC-RC manufactured by Nippon Tungsten Co., Ltd. (hereinafter referred to as "NC-RC reflector") as an inorganic paint satisfying the characteristic conditions of the inorganic paint, and an aluminum coat film. FIG. 7 is a diagram illustrating a wavelength characteristic of the reflectance in the case where the reflection is performed. FIG. 5 is an LEE analysis result in the case where the inorganic paint coating film according to the first embodiment is an NC-RC reflector, an Al reflection film, an Au reflection film, and no reflection film. 5 is an LEE increase factor analysis result using a distance G from Well of the multiple quantum well layer of the first embodiment to the shortest end face of 2D-PhC as a variable. It is an LEE increase factor analysis result of the calculation model of 2D-PhC of the first embodiment. It is sectional drawing and a top view of the deep ultraviolet LED device of 2nd Embodiment. FIG. 9 is a diagram illustrating a photonic band structure and a relationship between R / a and a PBG value in a TE polarization component incident on a two-dimensional photonic crystal formed on a p-type AlGaN contact layer, obtained by a plane wave expansion method. FIG. 10 is an LEE analysis result in the case of an NC-RC reflective material, an Al reflective film, an Au reflective film, and no reflective film, which are the inorganic paint coating films of the second embodiment. 10 is an LEE increase factor analysis result using the distance G from Well of the multiple quantum well layer of the second embodiment to the shortest end face of 2D-PhC as a variable. It is an LEE increase factor analysis result of the calculation model of 2D-PhC of the second embodiment. It is sectional drawing and a top view of the deep ultraviolet LED device of 3rd Embodiment. FIG. 14 is an LEE analysis result in the case where the inorganic paint coating film according to the third embodiment is an NC-RC reflector, an Al reflection film, an Au reflection film, and no reflection film. It is an LEE increase factor analysis result of the calculation model of 2D-PhC of the third embodiment. It is the sectional view and top view of the deep ultraviolet LED device of a 4th embodiment. 16 is a calculation model in the ray tracing method of the deep ultraviolet LED device according to the fourth embodiment. 14 is a calculation model of the deep ultraviolet LED device according to the fourth embodiment in the FDTD method. It is an LEE analysis result in the case of an NC-RC reflector, an Al reflector, an Au reflector, and no reflector, which are inorganic coating films according to the fourth embodiment. It is an LEE increase factor analysis result of the calculation model of 2D-PhC of the fourth embodiment. It is the sectional view and top view of the deep ultraviolet LED device of a 5th embodiment. It is an LEE analysis result in the case of an NC-RC reflective material, an Al reflective film, an Au reflective film, and no reflective film, which are the inorganic paint coating films of the fifth embodiment. It is an LEE increase factor analysis result of the calculation model of 2D-PhC of the fifth embodiment. It is the sectional view and top view of the deep ultraviolet LED device of a 6th embodiment. It is an LEE analysis result in the case of an NC-RC reflective material, an Al reflective film, an Au reflective film, and no reflective film, which are the inorganic paint coating films of the sixth embodiment. It is an LEE increase factor analysis result of the calculation model of 2D-PhC of the sixth embodiment. It is the sectional view and top view of the deep ultraviolet LED device of a 7th embodiment. 16 is a calculation model of the deep ultraviolet LED device according to the seventh embodiment by a ray tracing method. It is a calculation model by the FDTD method of the deep ultraviolet LED device of the seventh embodiment. It is the LEE analysis result in the case of the NC-RC reflective material, the Al reflective film, the Au reflective film, and no reflective film which are the inorganic paint coating films of the seventh embodiment. It is the LEE increase factor analysis result of the calculation model of 2D-PhC of the seventh embodiment. It is sectional drawing and a top view of the deep ultraviolet LED device of 8th Embodiment. It is an LEE analysis result in the case of an NC-RC reflector, an Al reflector, an Au reflector, and no reflector, which are the inorganic paint coating films of the eighth embodiment. It is an LEE increase factor analysis result of the calculation model of 2D-PhC of the eighth embodiment. It is the sectional view and top view of the deep ultraviolet LED device of a 9th embodiment. It is an LEE analysis result in the case of an NC-RC reflective material, an Al reflective film, an Au reflective film, and no reflective film, which are the inorganic paint coating films of the ninth embodiment. It is an LEE increase factor analysis result of the calculation model of 2D-PhC of the ninth embodiment. It is the sectional view and top view of the deep ultraviolet LED device of a 10th embodiment. It is an LEE analysis result in the case of an NC-RC reflective material, an Al reflective film, an Au reflective film, and no reflective film, which are the inorganic paint coating films of the tenth embodiment. It is an LEE increase factor analysis result of the 2D-PhC calculation model of the tenth embodiment. It is the sectional view and top view of the deep ultraviolet LED device of an eleventh embodiment. It is an LEE analysis result in the case of an NC-RC reflective material, an Al reflective film, an Au reflective film, and no reflective film which are the inorganic paint coating films of the eleventh embodiment. It is an LEE increase factor analysis result of the calculation model of 2D-PhC of the eleventh embodiment. It is sectional drawing and a top view of the deep ultraviolet LED device of the twelfth embodiment. It is the LEE analysis result in the case of the NC-RC reflection material, the Al reflection film, the Au reflection film, and no reflection film which are the inorganic paint coating films of the twelfth embodiment. FIG. 39 shows LEE increase factor analysis results of the 2D-PhC calculation model of the twelfth embodiment. It is the sectional view and top view of the deep ultraviolet LED device of a 13th embodiment. It is an LEE analysis result in the case of an NC-RC reflector, an Al reflector, an Au reflector, and no reflector, which are inorganic paint coating films of the thirteenth embodiment. FIG. 37 shows LEE increase factor analysis results of the 2D-PhC calculation model according to the thirteenth embodiment. It is the sectional view and top view of the deep ultraviolet LED device of a 14th embodiment. It is an LEE analysis result in the case of an NC-RC reflective material, an Al reflective film, an Au reflective film, and no reflective film, which are the inorganic paint coating films of the fourteenth embodiment. FIG. 39 shows LEE increase factor analysis results of the 2D-PhC calculation model of the fourteenth embodiment. It is the sectional view and top view of the deep ultraviolet LED device of a 15th embodiment. It is an LEE analysis result in the case of an NC-RC reflective material, an Al reflective film, an Au reflective film, and no reflective film, which are the inorganic paint coating films of the fifteenth embodiment. FIG. 39 shows LEE increase factor analysis results of the 2D-PhC calculation model of the fifteenth embodiment. As a comparative example, the thickness of the sapphire substrate was changed to 130 μm, 280 μm, and 430 μm, and analysis was performed by the ray tracing method to determine the relationship between the sapphire substrate thickness and LEE of the LED without PhC. It is an LEE analysis result when using a sapphire lens with a quartz window and a quartz lens shown as a comparative example. 9 is an analysis result of light extraction efficiency when a sapphire lens with a transparent resin film and a quartz lens are used as comparative examples. It is the sectional view and top view of the deep ultraviolet LED device of a 31st embodiment.

Hereinafter, a deep ultraviolet LED device according to an embodiment of the present invention will be described in detail with reference to the drawings.
In carrying out the present invention, an inorganic paint NC-RC manufactured by Nippon Tungsten Co., Ltd. was used as an inorganic paint satisfying a reflectance of 91% or more at a design wavelength λ (200 nm to 355 nm) of a deep ultraviolet LED element. The process was performed to obtain an NC-RC reflector. The inorganic paint NC-RC is a paint mainly composed of an organopolysiloxane composition and hexagonal boron nitride, and has a reflectance of 91% or more at a design wavelength λ (200 nm to 355 nm) after coating.

(First Embodiment)
FIG. 1A (a-1) shows a structure (a cross-sectional view and a plan view) of an AlGaN-based deep ultraviolet LED device having a wavelength of 280 nm as an example of a design wavelength λ as a deep ultraviolet LED device according to the first embodiment of the present invention. , (A-2).

Specifically, the quartz window 1, the sapphire substrate 2, the AlN buffer layer 3, the n-type AlGaN layer 4, the multiple quantum well layer 5, and the multiple quantum barrier layer are arranged in this order from the top of the sectional view of FIG. (Or electron block layer) 6, p-type AlGaN layer 7, p-type GaN contact layer 8, metal layer (hereinafter Ni layer) 9, reflective electrode layer (hereinafter Au reflective electrode layer) 10, surface mount type aluminum nitride package (hereinafter AlN package) 15, NC-RC reflector 17 coated on the inner bottom surface and inner side wall surface of AlN package, inner side wall angle θ15a of AlN package 15, reflection type two-dimensional photonic crystal periodic structure 100, hole 101 (h) Having.

As shown in FIG. 1A (a-1), a sapphire substrate 2, an AlN buffer layer 3, an n-type AlGaN layer 4, a multiple quantum well layer 5, a multiple quantum barrier layer (or electron block layer) 6, p-type AlGaN layer 7, p-type GaN contact layer 8, metal layer (hereinafter Ni layer) 9, reflection electrode layer (hereinafter Au reflection electrode layer) 10, reflection type two-dimensional photonic crystal periodic structure 100, hole 101 (h ) Is mounted. When the angle of the inner side wall angle θ15a of the AlN package 15 is not less than 45 degrees and not more than 60 degrees, light emitted from the side surface of the deep ultraviolet LED element can be reflected upward, so that LEE is improved. The upper part of the AlN package 15 is sealed with the quartz window 1. This is to prevent the aging of the deep ultraviolet LED element.

Next, in the deep ultraviolet LED element, at a position within the thickness direction of the Ni layer 9 and the p-type GaN contact layer 8 and not exceeding the interface between the p-type GaN contact layer 8 and the p-type AlGaN layer 7, A reflective two-dimensional photonic crystal periodic structure 100 having a plurality of holes 101 (h) is formed.

As shown as an xy plan view in FIG. 1A (a-2), the reflection type two-dimensional photonic crystal periodic structure 100 is a column-shaped air having a smaller refractive index than the p-type GaN contact layer 8 and having a radius of R. The hole 101 (h) having a cross section has a hole structure formed in a triangular lattice shape with a period a along the x direction and the y direction.

In the above structure, the deep ultraviolet light having a wavelength of 280 nm emitted from the quantum well layer 5 is transmitted in the medium while elliptically polarized as TE light and TM light are radiated in all directions. The two-dimensional photonic crystal periodic structure 100 provided near the quantum well layer 5 has a Bragg conditional expression (mλ / n _eff = 2a, where m: order, λ: emission wavelength, n _eff : two-dimensional photonic crystal). , A: the period of the two-dimensional photonic crystal) and the photonic band gap (PBG) opens for the TE polarization component, the deep ultraviolet light incident on the two-dimensional photonic crystal becomes 2 A standing wave is formed in the plane of the two-dimensional photonic crystal and is reflected toward the sapphire substrate 2.

FIG. 1B (b-1) shows the photonic in the TE polarization component when deep ultraviolet light having a wavelength of 280 nm is incident on the two-dimensional photonic crystal (R / a = 0.4) formed on the p-type GaN contact layer. The band structure is shown in (b-2) by finding the relationship between R / a and the PBG value by the plane wave expansion method. The PBG value is a value indicating the size of the gap between the first photonic band (ω1TE) and the second photonic band (ω2TE), and is (the minimum value of the second photonic band (ωa / 2πc)) − (The maximum value of the first photonic band (ωa / 2πc)). From this figure, it can be seen that R / a and the PBG value are in a proportional relationship.

The parameters required for the calculation of the plane wave expansion method are calculated as follows. The filling factor f of the two-dimensional photonic crystal is calculated by the equation f = (2π / 3) ^0.5 × (R / a) ² . Further, the equivalent refractive index n _eff of the two-dimensional photonic crystal is calculated by the following equation: n _eff = (n2 ² + (n1 ² −n2 ² ) × f) ^0.5 . Therefore, assuming that the refractive index of air is n1 = 1 and the refractive index of the p-type GaN contact layer 8 is n2 = 2.618, the equivalent refractive indices of R / a = 0.2, 0.3 and 0.4 are expressed by the above two equations. Thus, they are 2.45, 2.223 and 1.859, respectively.

(4) Next, LEE due to the reflection effect of the two-dimensional photonic crystal is determined by simulation analysis using the FDTD method. The FDTD method converts the Maxwell equation into a difference equation in space and time and directly calculates the electromagnetic field strength. Therefore, the FDTD method is suitable for wave analysis of a photonic crystal having a nm structure, but cannot directly calculate LEE. On the other hand, in the ray tracing method, since tens of thousands of rays are randomly emitted and the number of rays reaching the detector is directly calculated, it is possible to directly obtain the LEE in the mm structure. However, wave analysis of nm structure is not possible. Therefore, in order to obtain LEE due to the reflection effect of the photonic crystal, a cross simulation of the FDTD method and the ray tracing method is required.

Therefore, Table 1 shows a calculation model of the ray tracing method of the deep ultraviolet LED device, Table 2 shows a calculation model of the FDTD method of the deep ultraviolet LED device, and Table 3 shows a calculation model of the FDTD method of the reflection type two-dimensional photonic crystal. Indicates parameters. FIG. 1C shows a calculation model of the ray tracing method, FIG. 1D shows a calculation model of the FDTD method, and FIG. 1E shows the wavelength characteristics of the reflectance of the NC-RC reflector 17 and the aluminum coat film coated on the AlN package 15. As is clear from the figure, the reflectance of the NC-RC reflector 17 is excellent. The element shown in FIG. 1D is similar to FIG. 1A and corresponds to Table 2.

(Calculation of LEE by ray tracing method)
In the calculation model of the ray tracing method of FIG. 1C, the inner bottom surface and the inner side wall are changed to 45 °, 60 °, 75 °, and 90 ° with the inner side wall angle θ of the AlN package as a variable, and the NC-RC reflector 17 ( LEE of the deep ultraviolet LED device was calculated as an inorganic paint coating film). In addition, as a comparison of the NC-RC reflector 17, the LEE in the case of the Al reflection film, the Au reflection film, and the absence of the reflection film was analyzed, and the results are shown in FIG.

より From the above results, the LEE of the deep ultraviolet LED device having the NC-RC reflector 17 shows a higher LEE than other cases. Further, as for the inner side wall angle, a high LEE is shown between 45 degrees and 60 degrees.

(Calculation of LEE by FDTD method)
In the calculation model of FIG. 1D, first, an analysis was performed on the formation position of the two-dimensional photonic crystal (2D-PhC) in which the LEE increase factor (output with 2D-PhC / output without 2D-PhC) is maximized. The calculation model of 2D-PhC selected from Table 3 has R / a = 0.4, order m = 3, diameter 181 nm, and period 226 nm. With respect to the formation position, the LEE increase factor was analyzed by changing the distance G from the well of the multiple quantum well layer to the shortest end face of 2D-PhC in 4 nm steps at 29 nm ≦ G ≦ 69 nm. The rearmost end face of 2D-PhC was always the interface between the p-type GaN contact layer 8 and the Ni layer 9. The angle of the NC-RC reflector 17 was selected to be 60 degrees based on the result of the ray tracing method. The results are shown in FIG. 1G and Table 5.

より From the above results, the LEE increase factor becomes maximum when G = 61 nm at the position where 2D-PhC is formed. Since the depth when G = 61 nm, which is the formation position of 2D-PhC, is 150 nm, this depth is fixed, and R / a = 0.3 (order m = 3) and R / a in Table 3 are set. = 0.3 (order m = 4) and R / a = 0.4 (order m = 4) A 2D-PhC calculation model was used to analyze the LEE increase factor. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (4.5%) of the NC-RC reflector 17 and the angle of 60 degrees obtained by the ray tracing method. The results are shown in FIG.

(Second embodiment)
As the deep ultraviolet LED device according to the second embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

Specifically, the quartz window 1, the sapphire substrate 2, the AlN buffer layer 3, the n-type AlGaN layer 4, the multiple quantum well layer 5, and the multiple quantum barrier layer are arranged in this order from the top of the cross-sectional view of FIG. (Or electron block layer) 6, p-type AlGaN contact layer 8a, Ni layer 9, Au reflective electrode layer 10, AlN package 15, NC-RC reflector 17, inner side wall angle θ15a of AlN package 15, reflection type two-dimensional photo The nick crystal has a periodic structure 100 and holes 101 (h).

The first embodiment is different from the first embodiment in that the p-type contact layer of the structure of the deep ultraviolet LED element is changed from the p-type GaN contact layer to the p-type AlGaN contact layer, and the other structure is the same.

Further, in the present embodiment, the interface between the Ni layer 9 and the p-type AlGaN contact layer 8a in the thickness direction and the interface between the p-type AlGaN contact layer 8a and the multiple quantum barrier layer (or electron block layer) 6 are set. A reflection type two-dimensional photonic crystal periodic structure 100 having a plurality of holes 101 (h) is formed at a position not exceeding.

FIG. 2B (b-1) shows the photo in the TE polarization component when deep ultraviolet light having a wavelength of 280 nm is incident on the two-dimensional photonic crystal (R / a = 0.4) formed on the p-type AlGaN contact layer 8a. The nick band structure is shown in (b-2) by finding the relationship between R / a and the PBG value by the plane wave expansion method. From this figure, it can be seen that R / a and the PBG value are in a proportional relationship.

The parameters required for the calculation of the plane wave expansion method are calculated as follows. The filling factor f of the two-dimensional photonic crystal is calculated by the equation f = (2π / 3) ^0.5 × (R / a) ² . Further, the equivalent refractive index n _eff of the two-dimensional photonic crystal is calculated by the following equation: n _eff = (n2 ² + (n1 ² −n2 ² ) × f) ^0.5 . Therefore, assuming that the refractive index of air n1 = 1 and the refractive index of the p-type AlGaN contact layer 8a is n2 = 2.622, the equivalent refractive indices of R / a = 0.2, 0.3 and 0.4 are expressed by the above two equations. Thus, they are 2.454, 2.226 and 1.861, respectively.

(4) Next, LEE due to the reflection effect of the two-dimensional photonic crystal is determined by simulation analysis using the FDTD method. Therefore, Table 7 shows a calculation model of the ray tracing method of the deep ultraviolet LED device, Table 8 shows a calculation model of the FDTD method of the deep ultraviolet LED device, and Table 9 shows a calculation model of the FDTD method of the reflection type two-dimensional photonic crystal. Indicates parameters. Further, the calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 1C and 1D in the first embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
The LEE of the deep ultraviolet LED device was calculated using the inner bottom surface and the inner side wall as the NC-RC reflector 17 by changing the inner side wall angle θ of the AlN package to 45 °, 60 °, 75 °, and 90 ° as variables. As a comparison of the NC-RC reflector 17 (inorganic paint coating), the LEE in the case of an Al coating film, an Au reflection film, and no reflection film was analyzed, and the results are shown in FIG.

(Calculation of LEE by FDTD method)
First, the formation position of 2D-PhC at which the LEE increase factor is maximized was analyzed. The calculation model of 2D-PhC selected from Table 9 has R / a = 0.3, order m = 3, diameter 113 nm, and period 189 nm. With respect to the formation position, the LEE increase factor was analyzed by changing the distance G from the Well of the multiple quantum well layer 5 to the shortest end face of 2D-PhC in 4 nm steps at 29 nm ≦ G ≦ 73 nm. The rearmost end face of 2DPhC was always the interface between the p-type AlGaN contact layer 8a and the Ni layer 9. The angle of the NC-RC reflector 17 was selected to be 60 degrees based on the result of the ray tracing method. The results are shown in FIG.

より From the above results, in the formation position of 2D-PhC, the LEE increase factor becomes maximum when G = 69 nm. Since the depth when G = 69 nm, which is the formation position of 2D-PhC, is 60 nm, this depth is fixed, and R / a = 0.3 (order m = 2) and R / a in Table 9 are set. The LEE increase factor was analyzed using a calculation model of 2D-PhC where = 0.35 (order m = 2) and R / a = 0.35 (order m = 3). Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (14.7%) of the NC-RC reflector 17 and the angle of 60 degrees obtained by the ray tracing method. The results are shown in FIG. 2E and Table 12.

(Third embodiment)
As the deep ultraviolet LED device according to the third embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. 3A (a-1) and (a). -2).

The present embodiment has the same structure as the second embodiment except that the Ni layer 9 and the Au reflective electrode layer 10 are replaced with the Rh reflective electrode layer 16. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as those in the second embodiment. Therefore, in order to obtain LEE due to the reflection effect of the photonic crystal, a cross simulation of the FDTD method and the ray tracing method is performed.

Table 13 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 14 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. Each parameter of the calculation model of the reflection type two-dimensional photonic crystal by the FDTD method is the same as in Table 9. The calculation model of the ray tracing method and the calculation model of the FDTD method are not particularly illustrated.

(Calculation of LEE by ray tracing method)
First, the inner side wall angle θ of the AlN package is changed to 45 degrees, 60 degrees, 75 degrees, and 90 degrees as variables, and the inner bottom surface and the inner side walls are used as NC-RC reflectors 17 (inorganic paint coating) for a deep ultraviolet LED device. LEE was calculated. In addition, as a comparison of the NC-RC reflector 17, LEE in the case of the Al reflection film, the Au reflection film, and the absence of the reflection film was analyzed, and the results are shown in FIG.

(Calculation of LEE by FDTD method)
As in the second embodiment, the formation position of the 2D-PhC at which the LEE increase factor is the maximum has the maximum LEE increase factor when G = 69 nm. Since the depth when G = 69 nm, which is the formation position of 2D-PhC, is 60 nm, this depth is fixed, and R / a = 0.3 (order m = 2) and R / a in Table 9 are set. = 0.3 (order m = 3) R / a = 0.35 (order m = 2), R / a = 0.35 (order m = 3) 2D-PhC calculation model to analyze LEE increase factor did. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (16.3%) of the NC-RC reflector 17 and the angle of 60 degrees obtained by the ray tracing method. The results are shown in FIG.

(Fourth embodiment)
As the deep ultraviolet LED device according to the fourth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

Specifically, the quartz window 1, the sapphire hemispherical lens 20a, the sapphire substrate 2, the AlN buffer layer 3, the n-type AlGaN layer 4, and the multiple quantum well layer 5 are arranged in this order from the top of the sectional view of FIG. , Multiple quantum barrier layer (or electron block layer) 6, p-type AlGaN layer 7, p-type GaN contact layer 8, Ni layer 9, Au reflective electrode layer 10, AlN package 15, NC-RC reflector 17, AlN package 15. , A reflective two-dimensional photonic crystal periodic structure 100, and holes 101 (h).

ＡAs shown in FIG. 4A (a-1), a sapphire hemispherical lens 20a having a radius equal to or larger than the circumcircle of the sapphire substrate 2 is bonded to the back surface of the sapphire substrate 2. When the deep ultraviolet light emitted from the multiple quantum well layer 5 is incident on the sapphire substrate 2, the deep ultraviolet light is emitted to the outside from the normal direction of the surface of the sapphire hemispherical lens 20a, so that multiple internal total reflection is reduced. Therefore, LEE is improved.

The structure other than the sapphire hemispherical lens 20a is the same as that of the first embodiment. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as in the first embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Therefore, Table 17 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 18 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. The parameters of the FDTD calculation model of the reflection type two-dimensional photonic crystal are the same as in Table 3. FIG. 4B shows a calculation model of the ray tracing method, and FIG. 4C shows a calculation model of the FDTD method. The elements shown in FIG. 4C are the same as those in FIG. 4A and correspond to Table 18.

(Calculation of LEE by ray tracing method)
In the calculation model of the ray tracing method of FIG. 4B, the inner side wall angle θ of the AlN package is changed to 45 degrees, 60 degrees, 75 degrees, and 90 degrees as variables, and the inner bottom surface and the inner side walls are used as the NC-RC reflector 17. The LEE of the deep ultraviolet LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), the LEE in the case of an Al coat film, an Au reflection film, and no reflection film was analyzed, and the results are shown in FIG.

(Calculation of LEE by FDTD method)
In the calculation model of FIG. 4C, the angle of the NC-RC reflector 17 is set to 60 degrees as in the first embodiment. Further, the depth of 150 nm when G = 61 nm, which is the formation position of 2D-PhC, was fixed. Then, R / a = 0.3 (order m = 3), R / a = 0.3 (order m = 4), R / a = 0.4 (order m = 3), R selected from Table 3. The LEE increase factor was analyzed using a calculation model of 2DPhC where /a=0.4 (order m = 4). Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (10.2%) of the NC-RC reflector 17 and the angle of 60 degrees obtained by the ray tracing method. The results are shown in FIG.

(Fifth embodiment)
As a deep ultraviolet LED device according to a fifth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

More specifically, the quartz window 1, the sapphire hemispherical lens 20a, the sapphire substrate 2, the AlN buffer layer 3, the n-type AlGaN layer 4, the multiple quantum well layer 5 Multi-quantum barrier layer (or electron blocking layer) 6, p-type AlGaN contact layer 8a, Ni layer 9, Au reflective electrode layer 10, AlN package 15, NC-RC reflector 17, inner side wall angle θ15a of AlN package 15, It has a reflective two-dimensional photonic crystal periodic structure 100 and holes 101 (h).

ＡAs shown in FIG. 5A (a-1), a sapphire hemispherical lens 20a having a radius equal to or larger than the circumcircle of the sapphire substrate 2 is bonded to the back surface of the sapphire substrate 2. When the deep ultraviolet light emitted from the multiple quantum well layer 5 is incident on the sapphire substrate 2, the deep ultraviolet light is emitted to the outside from the normal direction of the surface of the sapphire hemispherical lens 20a, so that multiple internal total reflection is reduced. Therefore, LEE is improved.

The structure other than the sapphire hemispherical lens 20a is the same as that of the second embodiment. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as those in the second embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Therefore, Table 21 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 22 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. Table 9 is referred to for the parameters of the calculation model of the reflection type two-dimensional photonic crystal by the FDTD method. The calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 4B and 4C in the fourth embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
Similarly to the second embodiment, the inner side wall angle θ of the AlN package is changed to 45 degrees, 60 degrees, 75 degrees, and 90 degrees with the inner side wall angle θ as a variable, and the inner bottom surface and the inner side wall are used as NC-RC reflectors 17 for deep ultraviolet. The LEE of the LED device was calculated. In addition, as a comparison of the NC-RC reflector 17 (inorganic paint coating), LEE was analyzed in the case of an Al coat film, an Au reflection film, and no reflection film, and the results are shown in FIG.

(Calculation of LEE by FDTD method)
As in the second embodiment, in the position where 2D-PhC is formed, the LEE increase factor becomes maximum when G = 69 nm. Since the depth when G = 69 nm, which is the position where 2D-PhC is formed, is 150 nm, this depth is fixed and R / a = 0.3 (order m = 2) and R / a in Table 9. = 0.35 (order m = 2), R / a = 0.3 (order m = 3), R / a = 0.35 (order m = 3) Analyzed. The LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (25.5%) of the NC-RC reflector 17 and the angle of 60 degrees obtained by the ray tracing method. The results are shown in FIG. 5C and Table 24.

(Sixth embodiment)
As the deep ultraviolet LED device according to the sixth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. 6A (a-1) and (a). -2).

In this embodiment, the Ni layer 9 and the Au reflective electrode layer 10 in the fifth embodiment are replaced with the Rh reflective electrode layer 16. Other structures are the same as in the fifth embodiment. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as in the fifth embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Therefore, Table 25 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 26 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. Table 9 is referred to for the parameters of the calculation model of the reflection type two-dimensional photonic crystal by the FDTD method. The calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 4B and 4C in the fourth embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
Similarly to the fifth embodiment, the inner side wall angle θ of the AlN package is changed to 45 °, 60 °, 75 °, and 90 ° as variables, and the inner bottom surface and the inner side wall are formed as NC-RC reflectors 17 for deep ultraviolet. The LEE of the LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), the LEE in the case of the Al reflective film, the Au reflective film, and the absence of the reflective film was analyzed, and the results are shown in FIG.

(Calculation of LEE by FDTD method)
As in the fifth embodiment, in the formation position of 2D-PhC, when G = 69 nm, the LEE increase factor becomes the maximum. Since the depth when G = 69 nm, which is the formation position of 2D-PhC, is 60 nm, this depth is fixed, and R / a = 0.3 (order m = 2) and R / a in Table 9 are set. = 0.3 (order m = 3), R / a = 0.35 (order m = 2), R / a = 0.35 (order m = 3) 2D-PhC Calculation Model Analyzed. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (27.0%) of the NC-RC reflector and the angle of 60 degrees obtained by the ray tracing method. The results are shown in FIG. 6C and Table 28.

(Seventh embodiment)
As the deep ultraviolet LED device according to the seventh embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. 7A (a-1) and 7 (a). -2).

深 The deep ultraviolet LED element structure of the present embodiment is the same as that of the fourth embodiment,

As shown in FIG. 7A (a-1), a sapphire hemispherical lens 20a is bonded to the back surface of the sapphire substrate 2, the hemispherical lens covers at least the inner side wall of the upper surface of the AlN package 15, and A transparent resin film 21 a is attached to the surface of the lens, and seals the upper outer peripheral portion of the AlN package 15. The reason for sealing with the transparent resin film 21a is to prevent aging of the deep ultraviolet LED element. The radius of the sapphire hemispherical lens 20a is equal to or larger than the radius of a circumcircle of the inner side wall of the AlN package 15.

With this structure, since the quartz window 1 of the fourth embodiment is not used, when deep ultraviolet light is emitted from quartz to air, total internal reflection at the interface is suppressed, so that LEE can be improved. Furthermore, since the surface area of the entire inner side wall of the AlN package 15 is about 1/3 as compared with the deep ultraviolet LED device of the fourth embodiment, restrictions on the reflectivity of the reflection film and the side wall angle are relaxed. .

The reflection effect of the two-dimensional photonic crystal in the deep ultraviolet LED element and the method of optimization are the same as in the first embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is required to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Therefore, Table 29 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 30 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. The parameters of the FDTD calculation model of the reflection type two-dimensional photonic crystal are the same as in Table 3.
FIG. 7B shows a calculation model of the ray tracing method, and FIG. 7C shows a calculation model of the FDTD method. The element shown in FIG. 7C is the same as FIG. 7A and corresponds to Table 30.

(Calculation of LEE by ray tracing method)
In the calculation model of the ray tracing method of FIG. 7B, the inner side wall angle θ of the AlN package is changed to 45 degrees, 60 degrees, 75 degrees, and 90 degrees as variables, and the inner bottom surface and the inner side walls are used as the NC-RC reflector 17. The LEE of the deep ultraviolet LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), the LEE without the Al coat film, the Au reflection film, and without the reflection film was analyzed, and the results are shown in FIG. 7D and Table 31.

より From the above results, the LEE of the deep ultraviolet LED device having the NC-RC reflector 17 shows a slightly higher LEE than the other cases. In addition, the angle of the inner side wall does not depend much on the angle, but shows a high LEE in the range of 45 to 75 degrees.

(Calculation of LEE by FDTD method)
In the calculation model of FIG. 7C, the angle of the NC-RC reflector 17 was set to 75 degrees based on the result of the ray tracing method. Further, the depth of 150 nm when G = 61 nm, which is the formation position of 2D-PhC, was fixed. Then, R / a = 0.3 and order m = 3, R / a = 0.3 and order m = 4, R / a = 0.4 and order m = 3, R / a = The LEE increase factor was analyzed with a 2DPhC calculation model of 0.4 and order m = 4. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (11.4%) of the NC-RC reflector 17 and the angle of 75 degrees obtained by the above ray tracing method. The results are shown in FIG. 7E and Table 32.

(Eighth embodiment)
As the deep ultraviolet LED device according to the eighth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

The deep ultraviolet LED structure of the present embodiment has the same structure as that of the fifth embodiment. However, as shown in FIG. 8A (a-1), a sapphire hemispherical lens 20a is bonded to the back surface of the sapphire substrate 2. The hemispherical lens covers at least the inner side wall of the upper surface of the AlN package 15, the transparent resin film 21a is adhered to the surface of the hemispherical lens, and the upper outer peripheral portion of the AlN package 15 is sealed. are doing. The reason for sealing with the transparent resin film 21a is to prevent aging of the deep ultraviolet LED element. The radius of the sapphire hemispherical lens 20a is equal to or larger than the radius of a circumcircle of the inner side wall of the AlN package 15.

Note that the structure of the deep ultraviolet LED element from the sapphire substrate 2 to the Au reflective electrode layer 10 is the same as that of the second embodiment. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as those in the second embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Table 33 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 34 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. Table 9 is referred to for the parameters of the calculation model of the reflection type two-dimensional photonic crystal by the FDTD method. The calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 7B and 7C in the seventh embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
Similarly to the fifth embodiment, the inner side wall angle θ of the AlN package is changed to 45 °, 60 °, 75 °, and 90 ° as variables, and the inner bottom surface and the inner side wall are formed as NC-RC reflectors 17 for deep ultraviolet. The LEE of the LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), the LEE in the case of an Al coating film, an Au reflection film, and no reflection film was analyzed, and the results are shown in FIG.

より From the above results, the LEE of the deep ultraviolet LED device having the NC-RC reflector 17 shows a higher LEE than other cases. In addition, the angle of the inner side wall does not depend much on the angle, but shows a high LEE in the range of 45 to 75 degrees.

(Calculation of LEE by FDTD method)
As in the fifth embodiment, in the formation position of 2D-PhC, when G = 69 nm, the LEE increase factor becomes the maximum. Since the depth when G = 69 nm, which is the formation position of 2D-PhC, is 60 nm, this depth is fixed, and R / a = 0.3 (order m = 2) and R / a in Table 9 are set. = 0.35 (order m = 2), R / a = 0.3 (order m = 3), R / a = 0.35 (order m = 3) Analyzed. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (27.3%) of the NC-RC reflector 17 and the angle of 75 degrees obtained by the ray tracing method. The results are shown in FIG. 8C and Table 36.

(Ninth embodiment)
As the deep ultraviolet LED device according to the ninth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

The deep ultraviolet LED element structure of the present embodiment has the same structure as that of the sixth embodiment. However, as shown in FIG. 9A (a-1), a sapphire hemispherical lens 20a is joined to the back surface of the sapphire substrate 2. The hemispherical lens covers at least the inner side wall of the upper surface of the AlN package 15, the transparent resin film 21a is adhered to the surface of the hemispherical lens, and the upper outer peripheral portion of the AlN package 15 is sealed. Stopped. The reason for sealing with the transparent resin film 21a is to prevent aging of the deep ultraviolet LED element. The radius of the sapphire hemispherical lens 20a is equal to or larger than the radius of a circumcircle of the inner side wall of the AlN package 15.

Note that the structure of the deep ultraviolet LED from the sapphire substrate 2 to the Rh reflective electrode layer 16 is the same as that of the second embodiment. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as those in the second embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Table 37 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 38 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. Table 9 is referred to for the parameters of the calculation model of the reflection type two-dimensional photonic crystal by the FDTD method. The calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 7B and 7C in the seventh embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
Similarly to the sixth embodiment, the inner side wall angle θ of the AlN package is varied to 45 degrees, 60 degrees, 75 degrees, and 90 degrees as variables, and the inner bottom surface and the inner side walls are formed as NC-RC reflectors 17 for deep ultraviolet. The LEE of the LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), the LEE without the Al coat film, the Au reflection film, and without the reflection film was analyzed, and the results are shown in FIG. 9B and Table 39.

(Calculation of LEE by FDTD method)
As in the sixth embodiment, in the position where 2D-PhC is formed, the LEE increase factor becomes maximum when G = 69 nm. Since the depth when G = 69 nm, which is the formation position of 2D-PhC, is 60 nm, this depth is fixed, and R / a = 0.3 (order m = 2) and R / a in Table 9 are set. = 0.35 (order m = 2), R / a = 0.3 (order m = 3), R / a = 0.35 (order m = 3) Analyzed. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (28.9%) of the NC-RC reflector 17 and the angle of 75 degrees obtained by the ray tracing method. The results are shown in FIG. 9C and Table 40.

(Tenth embodiment)
As the deep ultraviolet LED device according to the tenth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

As shown in FIG. 10A (a-1), the present embodiment has the same structure as the fourth embodiment except for the quartz hemispherical lens 22a. Further, the reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as in the fourth embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Therefore, Table 41 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 42 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. The parameters of the FDTD calculation model of the reflection type two-dimensional photonic crystal are the same as in Table 3. Further, the calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 4B and 4C in the fourth embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
Similarly to the fourth embodiment, the inner side wall angle θ of the AlN package is varied to 45 degrees, 60 degrees, 75 degrees, and 90 degrees by using the inner bottom surface and the inner side walls as NC-RC reflectors 17 in the deep ultraviolet. The LEE of the LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), LEE in the case of an Al coat film, an Au reflection film, and no reflection film was analyzed, and the results are shown in FIG. 10B and Table 43.

(Calculation of LEE by FDTD method)
In the calculation model of FIG. 4C, the angle of the NC-RC reflector 17 is set to 60 degrees as in the first embodiment. Further, the depth of 150 nm when G = 61 nm, which is the formation position of 2D-PhC, was fixed. Then, R / a = 0.3 (order m = 3), R / a = 0.3 (order m = 4), R / a = 0.4 (order m = 3), R selected from Table 3. The LEE increase factor was analyzed using a calculation model of 2DPhC where /a=0.4 (order m = 4). Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (9.0%) of the NC-RC reflector 17 and the angle of 60 degrees obtained by the ray tracing method. The results are shown in FIG. 10C and Table 44.

(Eleventh embodiment)
As the deep ultraviolet LED device according to the eleventh embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. 11A (a-1) and 11 (a). -2).

As shown in FIG. 11A (a-1), this embodiment has the same structure as the fifth embodiment except for the quartz hemispherical lens 22a. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as in the fifth embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Table 45 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 46 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. Table 9 is referred to for the parameters of the calculation model of the reflection type two-dimensional photonic crystal by the FDTD method. The calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 4B and 4C in the fourth embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
Similarly to the fifth embodiment, the inner side wall angle θ of the AlN package is changed to 45 °, 60 °, 75 °, and 90 ° as variables, and the inner bottom surface and the inner side wall are formed as NC-RC reflectors 17 for deep ultraviolet. The LEE of the LED device was calculated. As a comparison of the NC-RC reflector 17, the LEE in the case of the Al coating film, the Au reflection film, and the case without the reflection film was analyzed, and the results are shown in FIG. 11B and Table 47.

(Calculation of LEE by FDTD method)
As in the fifth embodiment, in the formation position of 2D-PhC, when G = 69 nm, the LEE increase factor becomes the maximum. Since the depth when G = 69 nm, which is the position where 2D-PhC is formed, is 150 nm, this depth is fixed and R / a = 0.3 (order m = 2) and R / a in Table 9. = 0.35 (order m = 2), R / a = 0.3 (order m = 3), R / a = 0.35 (order m = 3) Analyzed. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (22.8%) of the NC-RC reflector 17 and the angle of 60 degrees obtained by the ray tracing method. The results are shown in FIG. 11C and Table 48.

(Twelfth embodiment)
As a deep ultraviolet LED device according to a twelfth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

As shown in FIG. 12A (a-1), the present embodiment has the same structure as the sixth embodiment except for the quartz hemispherical lens 22a. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as in the sixth embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Table 49 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 50 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. Table 9 is referred to for the parameters of the calculation model of the reflection type two-dimensional photonic crystal by the FDTD method. The calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 4B and 4C in the fourth embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
Similarly to the sixth embodiment, the inner side wall angle θ of the AlN package is varied to 45 degrees, 60 degrees, 75 degrees, and 90 degrees as variables, and the inner bottom surface and the inner side walls are formed as NC-RC reflectors 17 for deep ultraviolet. The LEE of the LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), the LEE in the case of the Al reflective film, Au reflective film, and no reflective film was analyzed, and the results are shown in FIG. 12B and Table 51.

(Calculation of LEE by FDTD method)
As in the sixth embodiment, in the position where 2D-PhC is formed, the LEE increase factor becomes maximum when G = 69 nm. Since the depth when G = 69 nm, which is the formation position of 2D-PhC, is 60 nm, this depth is fixed, and R / a = 0.3 (order m = 2) and R / a in Table 9 are set. = 0.3 (order m = 3), R / a = 0.35 (order m = 2), R / a = 0.35 (order m = 3) 2D-PhC Calculation Model Analyzed. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (24.3%) of the NC-RC reflector 17 and the angle of 60 degrees obtained by the ray tracing method. The results are shown in FIG. 12C and Table 52.

(Thirteenth embodiment)
As the deep ultraviolet LED device according to the thirteenth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

As shown in FIG. 13A (a-1), this embodiment has the same structure as that of the seventh embodiment except for the quartz hemispherical lens 22a. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as in the seventh embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Therefore, Table 53 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 54 shows each parameter of the calculation model of the FDTD method of the deep ultraviolet LED device. The parameters of the FDTD calculation model of the reflection type two-dimensional photonic crystal are the same as in Table 3. The calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 7B and 7C in the seventh embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
In the calculation model of the ray tracing method of FIG. 7B, the inner side wall angle θ of the AlN package is changed to 45 degrees, 60 degrees, 75 degrees, and 90 degrees as variables, and the inner bottom surface and the inner side walls are used as the NC-RC reflector 17. The LEE of the deep ultraviolet LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), LEE in the case of an Al coat film, an Au reflection film, and no reflection film was analyzed, and the results are shown in FIG.

(Calculation of LEE by FDTD method)
In the calculation model of FIG. 7C, the angle of the NC-RC reflector 17 was set to 75 degrees based on the result of the ray tracing method. Further, the depth of 150 nm when G = 61 nm, which is the formation position of 2D-PhC, was fixed. Then, R / a = 0.3 and order m = 3, R / a = 0.3 and order m = 4, R / a = 0.4 and order m = 3, R / a = The LEE increase factor was analyzed with a 2DPhC calculation model of 0.4 and order m = 4. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (9.7%) of the NC-RC reflector 17 and the angle of 75 degrees obtained by the above ray tracing method. The results are shown in FIG. 13C and Table 56.

(14th embodiment)
As a deep ultraviolet LED device according to a fourteenth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

As shown in FIG. 14A (a-1), the present embodiment has the same structure as the eighth embodiment except for the quartz hemispherical lens 22a. The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as in the eighth embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Therefore, Table 57 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 58 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. Table 9 is referred to for the parameters of the calculation model of the reflection type two-dimensional photonic crystal by the FDTD method. The calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 7B and 7C in the seventh embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
Similarly to the eighth embodiment, the inner side wall angle θ of the AlN package is changed to 45 °, 60 °, 75 °, and 90 ° as a variable, and the inner bottom surface and the inner side wall are formed as NC-RC reflectors 17 for deep ultraviolet. The LEE of the LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), LEE in the case of an Al coat film, an Au reflection film, and no reflection film was analyzed, and the results are shown in FIG.

より From the above results, the LEE of the deep ultraviolet LED device having the NC-RC reflector 17 is higher than the other cases. In addition, the angle of the inner side wall does not depend much on the angle, but shows a high LEE in the range of 45 to 75 degrees.

(Calculation of LEE by FDTD method)
As in the eighth embodiment, in the position where 2D-PhC is formed, the LEE increase factor is maximized when G = 69 nm. Since the depth when G = 69 nm, which is the formation position of 2D-PhC, is 60 nm, this depth is fixed, and R / a = 0.3 (order m = 2) and R / a in Table 9 are set. = 0.35 (order m = 2), R / a = 0.3 (order m = 3), R / a = 0.35 (order m = 3) Analyzed. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (24.6%) of the NC-RC reflector 17 and the angle of 75 degrees obtained by the ray tracing method. The results are shown in FIG.

(Fifteenth embodiment)
As the deep ultraviolet LED device according to the fifteenth embodiment of the present invention, the structure (cross-sectional view and plan view) of an AlGaN-based deep ultraviolet LED device having a design wavelength λ of 280 nm is shown in FIGS. -2).

This embodiment has the same structure as the ninth embodiment except for the quartz hemispherical lens 22a, as shown in FIG. 15A (a-1). The reflection effect of the two-dimensional photonic crystal and the method of optimization are the same as in the ninth embodiment. Therefore, a cross simulation of the FDTD method and the ray tracing method is performed to obtain the LEE due to the reflection effect and the hemispheric lens effect of the photonic crystal.

Therefore, Table 61 shows the calculation model of the ray tracing method of the deep ultraviolet LED device, and Table 62 shows the parameters of the calculation model of the FDTD method of the deep ultraviolet LED device. Table 9 is referred to for the parameters of the calculation model of the reflection type two-dimensional photonic crystal by the FDTD method. The calculation model of the ray tracing method and the calculation model of the FDTD method are substantially the same as those in FIGS. 7B and 7C in the seventh embodiment, and are not particularly illustrated.

(Calculation of LEE by ray tracing method)
Similarly to the ninth embodiment, the inner side wall angle θ of the AlN package is varied to 45 degrees, 60 degrees, 75 degrees, and 90 degrees as variables, and the inner bottom surface and the inner side walls are formed as NC-RC reflectors 17 for deep ultraviolet. The LEE of the LED device was calculated. As a comparison of the NC-RC reflector 17 (inorganic paint coating), LEE in the case of an Al coat film, an Au reflection film, and no reflection film was analyzed, and the results are shown in FIG. 15B and Table 63.

(Calculation of LEE by FDTD method)
As in the ninth embodiment, the position at which 2D-PhC is formed has a maximum LEE increase factor when G = 69 nm. Since the depth when G = 69 nm, which is the formation position of 2D-PhC, is 60 nm, this depth is fixed, and R / a = 0.3 (order m = 2) and R / a in Table 9 are set. = 0.35 (order m = 2), R / a = 0.3 (order m = 3), R / a = 0.35 (order m = 3) Analyzed. Then, the LEE of each 2D-PhC calculation model is calculated by multiplying each LEE increase factor obtained above by the LEE (26.2%) of the NC-RC reflector 17 and the angle of 75 degrees obtained by the above ray tracing method. The results are shown in FIG. 15C and Table 64.

As a comparative example of the first to fifteenth embodiments, the thickness of the sapphire substrate 2 was changed to 130 μm, 280 μm, and 430 μm, and analysis was performed by the ray tracing method, and the thickness of the sapphire substrate 2 and no PhC The LEE relationship of the LED was determined. Since the thickness of the sapphire substrate 2 is not different from that of the above embodiment, it is not shown. The results are shown in FIGS. 16A to 16C and Tables 65 to 69.

Here, FIG. 16A is a diagram in which the thickness of the sapphire substrate shown as a comparative example was changed to 130 μm, 280 μm, and 430 μm, analysis was performed by the ray tracing method, and the relationship between the sapphire substrate thickness and the LEE of the LED without PhC was obtained. It is. FIG. 16B is an LEE analysis result when a sapphire lens with a quartz window and a quartz lens are used as comparative examples. FIG. 16C is an analysis result of light extraction efficiency when a sapphire lens with a transparent resin film and a quartz lens shown as a comparative example are used.

Also, the LEE increase factor and LEE maximum value in the first to fifteenth embodiments (the thickness of the sapphire substrate 2 is all 430 μm with PhC) and the LEE maximum value of the PhC-less LED and the PhC-containing LED of the above comparative example. Are summarized in Table 70. The maximum value of LEE of the LED with PhC of the comparative example = the maximum value of LEE of the LED without PhC of the comparative example × the maximum value of the LEE increase factor.

比較 Comparing the results in Table 70, the LEE of the p-type GaN contact LED was increased by about 2.8 times in the increase factor due to the reflection effect of the reflection type PhC. In addition, the sapphire hemispherical lens junction further increased the LEE by a factor of 2.7, and it was confirmed that the integrated photonic effect of the reflective PhC and the hemispherical lens junction was 7 times or more at the maximum.

In the p-type AlGaN contact LED, the LEE increased by a factor of 1.28 to 1.45 due to the reflection effect of the reflection type PhC. Further, the sapphire hemispherical lens junction further increased the LEE increasing factor by 2.0 times, and it was confirmed that the integrated photonic effect by the reflective PhC and the hemispherical lens junction was less than 3 times at the maximum. LEE at this time was 51.4% at the maximum.
In the case of partial sapphire hemispherical lens bonding, LEE was increased by a factor of 1.2 by reducing the thickness of the sapphire substrate 2, but this was not enough to compensate for the increase in the cost of grinding and polishing the back surface of the sapphire substrate 2. .

(Sixteenth embodiment)
As shown in FIG. 1A, a method of manufacturing a deep ultraviolet LED has a design wavelength of λ (200 nm to 355 nm) and a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate, and includes a reflective electrode layer (Au). 10, a metal layer (Ni) 9, a p-type GaN contact layer 8, a p-type AlGaN layer 7, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, and an n-type AlGaN layer This is a step of forming a laminated structure containing the AlN buffer layer 4, the AlN buffer layer 3, and the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.

In this process,
1) A plurality of vacancies provided in a range in the thickness direction of the metal layer 9 and the p-type GaN contact layer 8 and not exceeding the interface between the p-type GaN contact layer 8 and the p-type AlGaN layer 7 Forming a reflective two-dimensional photonic crystal periodic structure 100 having 101 (h);
2) a step of preparing a mold for forming the reflection type two-dimensional photonic crystal periodic structure 100;
3) a step of forming a resist layer on the p-type GaN contact layer 8 and transferring a mold structure by a nanoimprint method;
4) forming a two-dimensional photonic crystal periodic structure by etching the p-type GaN contact layer 8 using the resist layer onto which the structure has been transferred as a mask;
5) a step of forming a metal layer 9 and a reflective electrode layer 10 in this order by an oblique vapor deposition method after forming the reflective type two-dimensional photonic crystal 100;
6) dicing the sapphire substrate 2 to produce a deep ultraviolet LED element;
7) a step of preparing a surface-mounted aluminum nitride ceramic package having an inner side wall angle of not less than 45 degrees and not more than 60 degrees;
8) coating the inner bottom surface and the inner side wall of the package 15 with an NC-RC reflector 17 having a reflectance of 91% or more with respect to a design wavelength λ;
9) mounting a deep ultraviolet LED element on the package 15;
10) sealing the outermost surface of the package 15 with a quartz window.

Nanoimprint is a technology that transfers the photonic crystal pattern of a mold onto a large-area processed surface at once. Further, by using a resin mold, transfer can be performed even if the surface to be processed is warped by several hundred microns. Furthermore, if a two-layer resist is used, fluidity and an etching selectivity with respect to a workpiece can be obtained, so that a highly accurate photonic crystal can be processed.

(Seventeenth embodiment)
As shown in FIG. 2A, regarding the method of manufacturing a deep ultraviolet LED, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Au). 10, a metal layer (Ni) 9, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, and an AlN buffer layer 3. And a step of forming a laminated structure containing the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.

In this step, the difference from the sixteenth embodiment is that the p-type GaN contact layer is replaced with a p-type AlGaN contact layer. Only the differences from the sixteenth embodiment are specifically described below. .
1) In the step of forming the two-dimensional photonic crystal periodic structure 100, in the thickness direction of the metal layer 9 and the p-type AlGaN contact layer 8a, and the p-type AlGaN contact layer 8a and the multiple quantum barrier layer (or A plurality of holes 101 (h) are provided at positions not exceeding the interface with the electron block layer) 6.
The steps 2) to 10) described in the sixteenth embodiment are the same as the sixteenth embodiment except that the p-type GaN contact layer is replaced with a p-type AlGaN contact layer.

(Eighteenth Embodiment)
As shown in FIG. 3A, regarding the method of manufacturing a deep ultraviolet LED, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Rh). 16, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron blocking layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, an AlN buffer layer 3, and a sapphire substrate 2. This is a step of forming a laminated structure to be contained in this order from the side opposite to the substrate 2.

This step is different from the seventeenth embodiment only in that the present structure has no metal layer (Ni) 9 and the reflective electrode layer is replaced with a reflective electrode layer (Rh) 16 instead of (Au) 10. is there.
Therefore, it can be explained by replacing the reflective electrode (Au) and the metal layer (Ni) 9 with the reflective electrode (Rh) 16 in the steps 1) to 10) described in the seventeenth embodiment.

(Nineteenth Embodiment)
As shown in FIG. 4A, regarding the method of manufacturing the deep ultraviolet LED, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Au). 10, a metal layer (Ni) 9, a p-type GaN contact layer 8, a p-type AlGaN layer 7, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, and an n-type AlGaN layer This is a step of forming a laminated structure containing the AlN buffer layer 4, the AlN buffer layer 3, and the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.
Further, a step of bonding a sapphire hemispherical lens 20a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the steps of forming the laminated structure and the LED element are the same as the steps described in 1) to 6) of the sixteenth embodiment. After forming the LED element in the step 6), the sapphire hemispherical lens 20a described below is joined, and after the sapphire hemispherical lens 20a is joined, the sapphire hemispherical lens 20a is joined again according to 7) to 10) of the sixteenth embodiment. It has the same steps as the steps.
1) The same as the step 1) of the sixteenth embodiment,
2) The same as step 2) of the sixteenth embodiment,
3) The same as the step 3) of the sixteenth embodiment,
4) The same as step 4) of the sixteenth embodiment,
5) The same as step 5) of the sixteenth embodiment,
6) The same as the step 6) of the sixteenth embodiment,
7) preparing a sapphire hemispherical lens 20a having a radius equal to or larger than the circumcircle of the LED element substrate;
8) flattening the back surface of the LED element substrate and the back surface of the sapphire hemispherical lens 20a;
9) activating the back surface of the sapphire hemispherical lens 20a and the back surface of the LED element substrate with an ion beam or atmospheric pressure plasma;
10) joining the back surface of the sapphire hemispherical lens 20a subjected to the surface activation treatment to the back surface of the LED element substrate;
11) Same as step 7) of the sixteenth embodiment,
12) Same as step 8) of the sixteenth embodiment,
13) The same as the step 9) of the sixteenth embodiment,
14) Same as step 10) of the sixteenth embodiment.
Further, the effects of the nanoimprint, the resin mold, and the two-layer resist are the same as in the sixteenth embodiment.

(Twentieth embodiment)
As shown in FIG. 5A for the method of manufacturing a deep ultraviolet LED, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Au). 10, a metal layer (Ni) 9, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, and an AlN buffer layer 3. And a step of forming a laminated structure containing the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.
Further, a step of bonding a sapphire hemispherical lens 20a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the steps of producing the laminated structure and the LED element are the same as the steps described in 1) to 6) of the seventeenth embodiment. After the LED element is formed in the step 6), the sapphire hemispherical lens 20a is bonded to the sapphire hemispherical lens 20a according to the steps 7) to 10) described in the nineteenth embodiment. It has the same steps as the steps 7) to 10) described in the embodiment.
1) The same as the step 1) of the seventeenth embodiment,
2) The same as the step 2) of the seventeenth embodiment,
3) The same as the step 3) of the seventeenth embodiment,
4) The same as step 4) of the seventeenth embodiment,
5) The same as the step 5) of the seventeenth embodiment,
6) The same as the step 6) of the seventeenth embodiment,
7) Same as step 7) of the nineteenth embodiment,
8) The same as the step 8) of the nineteenth embodiment,
9) The same as step 9) in the nineteenth embodiment,
10) The same as the step 10) of the nineteenth embodiment,
11) Same as step 7) of the seventeenth embodiment,
12) Same as step 8) of the seventeenth embodiment,
13) Same as step 9) of the seventeenth embodiment,
14) Same as step 10) of the seventeenth embodiment.
Further, the effects of the nanoimprint, the resin mold, and the two-layer resist are the same as in the sixteenth embodiment.

(Twenty-first embodiment)
As shown in FIG. 6A, regarding the method of manufacturing a deep ultraviolet LED, as shown in FIG. 6A, a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm) is performed. 16, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron blocking layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, an AlN buffer layer 3, and a sapphire substrate 2. This is a step of forming a laminated structure to be contained in this order from the side opposite to the substrate 2.
Further, a step of bonding a sapphire hemispherical lens 20a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the only difference from the twentieth embodiment is that the present structure does not include the metal layer (Ni) 9 and the reflective electrode layer (Au) 10 is replaced with the reflective electrode layer (Rh) 16. .
Therefore, the description can be made by replacing the reflective electrode (Au) and the metal layer (Ni) 9 with the reflective electrode (Rh) 16 in the steps 1) to 14) described in the twentieth embodiment. Omitted.

(Twenty-second embodiment)
As shown in FIG. 7A for the method of manufacturing a deep ultraviolet LED, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Au). 10, a metal layer (Ni) 9, a p-type GaN contact layer 8, a p-type AlGaN layer 7, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, and an n-type AlGaN layer This is a step of forming a laminated structure containing the AlN buffer layer 4, the AlN buffer layer 3, and the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.
Further, a step of bonding a sapphire hemispherical lens 20a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the steps of producing the laminated structure and the LED element and coating the surface mount type ceramic package 15 with the NR-RC reflector 17 are the steps described in 1) to 8) of the sixteenth embodiment. Is the same. After the coating step in the step 8), as described below, a step of bonding the sapphire hemispherical lens 20a and covering the surface of the sapphire hemispherical lens 20a with the transparent resin film 21a is provided.
1) The same as the step 1) of the sixteenth embodiment,
2) The same as step 2) of the sixteenth embodiment,
3) The same as the step 3) of the sixteenth embodiment,
4) The same as step 4) of the sixteenth embodiment,
5) The same as step 5) of the sixteenth embodiment,
6) The same as the step 6) of the sixteenth embodiment,
7) Same as step 7) of the sixteenth embodiment,
8) The same as step 8) of the sixteenth embodiment,
9) preparing a sapphire hemispherical lens 20a having a radius greater than or equal to the circumcircle of the package inner wall;
10) flattening the back surface of the LED element substrate and the back surface of the sapphire hemispherical lens 20a;
11) a step of activating the back surface of the sapphire hemispherical lens 20a and the back surface of the LED element substrate with an ion beam or atmospheric pressure plasma;
12) joining the back surface of the sapphire hemispherical lens 20a subjected to the surface activation treatment to the back surface of the LED element substrate;
13) mounting a sapphire hemispherical lens 20a bonded LED element to the package 15;
14) simultaneously covering and sealing the surface of the sapphire hemispherical lens 20a and the upper surface of the package with a resin film 21a transparent to the wavelength λ.
The effects of the nanoimprint, the resin mold, and the two-layer resist are the same as in the sixteenth embodiment.

(Twenty-third embodiment)
As shown in FIG. 8A, regarding the method of manufacturing a deep ultraviolet LED, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Au). 10, a metal layer (Ni) 9, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, and an AlN buffer layer 3. And a step of forming a laminated structure containing the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.
Further, a step of bonding a sapphire hemispherical lens 20a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the steps of producing the laminated structure and the LED element and coating the surface mount type ceramic package 15 with the NR-RC reflector 17 are the steps described in 1) to 8) of the seventeenth embodiment. Is the same as After the coating step in the step 8) is completed, the step of bonding the sapphire hemispherical lens 20a and covering the surface of the sapphire hemispherical lens 20a with the transparent resin film 21a includes the steps of 9) to 14) of the twenty-second embodiment. The steps are the same as described. Therefore, the details are omitted.

(Twenty-fourth embodiment)
As shown in FIG. 9A for the method of manufacturing a deep ultraviolet LED, as shown in FIG. 9A, a design wavelength is set to λ (200 nm to 355 nm), and a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate is performed. 16, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron blocking layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, an AlN buffer layer 3, and a sapphire substrate 2. This is a step of forming a laminated structure to be contained in this order from the side opposite to the substrate 2.
Further, a step of bonding a sapphire hemispherical lens 20a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the only difference from the twenty-third embodiment is that the present structure does not include the metal layer (Ni) 9 and the reflective electrode layer (Au) 10 is replaced with the reflective electrode layer (Rh) 16. .
Accordingly, the description can be made by replacing the reflective electrode (Au) and the metal layer (Ni) 9 with the reflective electrode (Rh) 16 in the process described in the twenty-third embodiment, and a detailed description thereof will be omitted.

(Twenty-fifth embodiment)
As shown in FIG. 10A, a method of manufacturing a deep ultraviolet LED is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Au). 10, a metal layer (Ni) 9, a p-type GaN contact layer 8, a p-type AlGaN layer 7, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, and an n-type AlGaN layer This is a step of forming a laminated structure containing the AlN buffer layer 4, the AlN buffer layer 3, and the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.
Further, a step of bonding a quartz hemispherical lens 22a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the only difference from the nineteenth embodiment is that the sapphire hemispherical lens 20a is replaced by a quartz hemispherical lens 22a in the present structure. Therefore, since the description can be made by replacing the sapphire hemispherical lens 20a in the process described in the nineteenth embodiment with a quartz hemispherical lens 22a, the details are omitted.

(Twenty-sixth embodiment)
As shown in FIG. 11A, regarding the method of manufacturing a deep ultraviolet LED, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Au). 10, a metal layer (Ni) 9, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, and an AlN buffer layer 3. And a step of forming a laminated structure containing the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.
Further, a step of bonding a quartz hemispherical lens 22a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the only difference from the twentieth embodiment is that the sapphire hemispherical lens 20a is replaced by a quartz hemispherical lens 22a in this structure. Accordingly, the process can be described by replacing the sapphire hemispherical lens 20a in the process described in the twentieth embodiment with a quartz hemispherical lens 22a, and a detailed description thereof will be omitted.

(Twenty-seventh embodiment)
As shown in FIG. 12A, regarding the method of manufacturing a deep ultraviolet LED, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Rh). 16, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron blocking layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, an AlN buffer layer 3, and a sapphire substrate 2. This is a step of forming a laminated structure to be contained in this order from the side opposite to the substrate 2.
Further, a step of bonding a quartz hemispherical lens 22a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the only difference from the twenty-first embodiment is that the sapphire hemispherical lens 20a is replaced with the quartz hemispherical lens 22a in the present structure. Therefore, since the description can be made by replacing the sapphire hemispherical lens 20a in the process described in the twenty-first embodiment with the quartz hemispherical lens 22a, the details are omitted.

(Twenty-eighth embodiment)
As shown in FIG. 13A for the method of manufacturing a deep ultraviolet LED, as shown in FIG. 13A, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm). 10, a metal layer (Ni) 9, a p-type GaN contact layer 8, a p-type AlGaN layer 7, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, and an n-type AlGaN layer This is a step of forming a laminated structure containing the AlN buffer layer 4, the AlN buffer layer 3, and the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.
Further, a step of bonding a quartz hemispherical lens 22a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the only difference from the twenty-second embodiment is that the sapphire hemispherical lens 20a is replaced with the quartz hemispherical lens 22a in the present structure. Accordingly, since the description can be made by replacing the sapphire hemispherical lens 20a in the process described in the twenty-second embodiment with the quartz hemispherical lens 22a, the details are omitted.

(Twenty-ninth embodiment)
As shown in FIG. 14A, a method for manufacturing a deep ultraviolet LED is to form a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Au). 10, a metal layer (Ni) 9, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron block layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, and an AlN buffer layer 3. And a step of forming a laminated structure containing the sapphire substrate 2 in this order from the side opposite to the sapphire substrate 2.
Further, a step of bonding a quartz hemispherical lens 22a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

In this step, the only difference from the twenty-third embodiment is that the sapphire hemispherical lens 20a is replaced by a quartz hemispherical lens 22a in this structure. Therefore, the description can be made by replacing the sapphire hemispherical lens 20a in the process described in the twenty-third embodiment with the quartz hemispherical lens 22a, and a detailed description thereof will be omitted.

(Thirtieth embodiment)
As shown in FIG. 14A, regarding the method of manufacturing a deep ultraviolet LED, this is a step of forming a laminated structure using a sapphire substrate 2 as a growth substrate with a design wavelength of λ (200 nm to 355 nm), and a reflective electrode layer (Rh). 16, a p-type AlGaN contact layer 8a, a multiple quantum barrier layer (or electron blocking layer) 6, a multiple quantum well layer 5, an n-type AlGaN layer 4, an AlN buffer layer 3, and a sapphire substrate 2. This is a step of forming a laminated structure to be contained in this order from the side opposite to the substrate 2.
Further, a step of bonding a quartz hemispherical lens 22a having a radius equal to or larger than the circumcircle of the LED element substrate to the back surface of the sapphire substrate 2 is included.

This step is different from the twenty-fourth embodiment only in that the sapphire hemispherical lens 20a is replaced by a quartz hemispherical lens 22a in this structure. Therefore, the process can be described by replacing the sapphire hemispherical lens 20a with the quartz hemispherical lens 22a in the process described in the twenty-fourth embodiment, and a detailed description thereof will be omitted.

(Thirty-first embodiment)
In the thirty-first embodiment, as a modification of the first embodiment and the tenth embodiment, an embodiment in which Au is deposited on the inner wall of an aluminum nitride ceramic package is shown.

The purpose of the present embodiment is to realize a low-cost, high-LEE, deep ultraviolet LED device. Therefore, although the reflectance is lower than that of the inorganic paint NC-RC, the effect of the Au coating film used at relatively low cost is also comparatively verified by simulation.

深 In the structure of the deep ultraviolet LED device of the present embodiment, the inorganic paint coating film 17 is changed to the Au coating film 18 in the structures of the first embodiment and the tenth embodiment. For reference, FIG. 17 shows a structure which is a modification of the tenth embodiment. Since the modification of the first embodiment has a structure in which the quartz hemispherical lens 22a is removed from FIG. 17, the drawing is omitted.

The parameters of the Au coating film 18 are 200 nm in film thickness, 1.678 in refractive index, 1.873 in extinction coefficient, 1.0 in relative magnetic permeability, and 1.0 in relative dielectric constant.

In the reflection type two-dimensional photonic crystal 100, the distance G between the well of the multi-well layer 5 and the shortest end face of the reflection type two-dimensional photonic crystal 100 is 61 nm, the order m = 3, and R / a is R / a. = 0.30, 0.35, and 0.40. The reflective secondary photonic crystal 100 was provided so as not to exceed the interface between the p-type GaN contact layer 8 and the p-type AlGaN layer 7 and to be embedded in the p-type GaN contact layer 8. This is because, after the formation of the reflection type two-dimensional photonic crystal and before the formation of the electrodes (Ni electrode 9 and Au reflection electrode 10), the crystal growth of GaN in the lateral direction is performed, so that the holes of the two-dimensional photonic crystal are formed. The electrode formation process is performed by covering the upper part of the holes 101 (h) and flattening the interface between the p-type GaN contact layer 8 and the Ni electrode 9 while leaving 101 (h) in the p-type GaN contact layer 8. This is to make it easier to do.

The results are shown in Tables 71 and 72.

Table 71 shows the results of Table 4 using an LEE calculation result by the ray tracing method of the structure in which the quartz hemispherical lens was not joined, which was shown in (First Embodiment), and an Au coating film was provided on the results of Table 4. It is the result calculated by multiplying the LEE increase factor by the FDTD of the structure.

In Table 72, an Au coating film was provided on the results of Table 43, using the LEE calculation result table 43 by the ray tracing method of the structure in which the quartz hemispherical lenses were joined, shown in (Tenth Embodiment). It is the result calculated by multiplying the LEE increase factor by the FDTD of the structure.

The above result is compared with the results of (first embodiment) and (tenth embodiment).

First, in Table 4 of the first embodiment, the LEE of the Au reflective film is 4.0% in the case of the package side wall angle of 60 °, whereas the LEE of the side wall angle of 60 ° in Table 71 is, for example, two-dimensional photo. When the nick crystal has R / a = 0.40, LEE is 10.6%, which is an improvement of 2.66 times after the formation of the two-dimensional photonic crystal. In comparison with the inorganic paint coating film, in Table 6, LEE was 8.9% when R / a = 0.3, whereas in Table 71, LEE was 7.3%, and R / a in [Table 6] was also used. In Table 71, LEE was 12.1%, whereas LEE was 12.6%. In Table 71, LEE was lower than that of the inorganic coating film, but was relatively close to that of the inorganic coating film.

In Table 43 of the tenth embodiment, the LEE of the Au reflection film is 7.2% for the package side wall angle of 60 degrees, whereas the LEE of the side wall angle of 60 degrees in Table 72 is, for example, R / a. At 0.40, it is 20.9%, which is 2.9 times improved after the formation of the two-dimensional photonic crystal. In comparison with the inorganic coating film, in Table 44, LEE was 19% at R / a = 0.3, whereas LEE was 14.6% in Table 72, and LEE25 at R / a = 0.4 in Table 44. In Table 72, LEE was 20.9%, whereas LEE was lower than that of the inorganic coating film, but LEE close to that of the inorganic coating film was obtained.

These results show that, in the present invention, in addition to the inorganic coating film, a structure using Au vapor deposition on the inner wall material of the aluminum nitride ceramic package is also effective as an option.

In the above embodiment, the illustrated configuration and the like are not limited to these, and can be appropriately changed within a range in which the effects of the present invention are exhibited. In addition, the present invention can be appropriately modified and implemented without departing from the scope of the object of the present invention.
In addition, each component of the present invention can be arbitrarily selected, and the present invention includes an invention having the selected configuration.

The present invention is applicable to deep ultraviolet LEDs.

DESCRIPTION OF SYMBOLS 1 ... Quartz window 2 ... Sapphire substrate 3 ... AlN buffer layer 4 ... N-type AlGaN layer 5 ... Multi quantum well layer 6 ... Multi quantum barrier layer (or electron block layer)
7 p-type AlGaN layer 8 p-type GaN contact layer 8 a p-type AlGaN contact layer 9 metal layer (Ni, Ni layer)
10. Reflective electrode layer (Au, Au reflective electrode layer)
15: Surface mount type aluminum nitride ceramic package, AlN package 15a: AlN package inner side wall angle θ
16 Rh reflection electrode layer 17 Inorganic paint coating film (NC-RC reflector)
18 Au coating film 20a Sapphire hemispherical lens 21a Transparent resin film 22a Quartz hemispherical lens 100 Reflective two-dimensional photonic crystal 101 (h) Void (columnar structure, hole)
All publications, patents and patent applications cited herein are hereby incorporated by reference in their entirety.

Claims

A surface-mount type aluminum nitride ceramic package in which an inorganic coating film having a reflectance of 91% or more at a design wavelength λ (200 nm to 355 nm) of a deep ultraviolet LED element is coated on an inner bottom surface and an inner side wall; A package having an inner side wall angle of not less than 45 degrees and not more than 60 degrees, and a package whose outermost surface is sealed with a quartz window, and a deep ultraviolet LED element mounted in the package, (Au), metal layer (Ni), p-type GaN contact layer, p-type AlGaN layer, multiple quantum barrier layer (or electron block layer), multiple quantum well layer, n-type AlGaN layer, and AlN Having a buffer layer and a sapphire substrate in this order from the side opposite to the sapphire substrate,
A plurality of holes are provided within a range in a thickness direction of the metal layer and the p-type GaN contact layer and at a position not exceeding an interface between the p-type GaN contact layer and the p-type AlGaN layer. A reflection type two-dimensional photonic crystal, wherein the reflection type two-dimensional photonic crystal periodic structure has a photonic band gap opened to a TE polarized light component, and reflects the light of the design wavelength λ. The period a of the periodic type two-dimensional photonic crystal structure satisfies the Bragg condition, and the Bragg conditional expression mλ / n eff = 2a (where m: order, λ: design wavelength, n eff : two-dimensional photonic crystal) The effective index of refraction, a: the period m of the two-dimensional photonic crystal) satisfies 3 ≦ m ≦ 4, and when the radius of the hole is R, the R / a ratio is 0.30 ≦ R / satisfies a ≦ 0.40 A deep ultraviolet LED device.
Further, the sapphire substrate has a sapphire or quartz hemispherical lens that is transparent to a wavelength λ that is bonded to the back surface of the sapphire substrate, and a radius of the hemispherical lens is equal to or larger than a radius of a circumcircle of the sapphire substrate. The deep ultraviolet LED device according to claim 1.
A method of manufacturing a deep ultraviolet LED device having a design wavelength of λ (200 nm to 355 nm), wherein a step of forming a laminated structure using a sapphire substrate as a growth substrate includes a reflective electrode layer (Au) and a metal layer. (Ni), a p-type GaN contact layer, a p-type AlGaN layer, a multiple quantum barrier layer (or an electron block layer), a multiple quantum well layer, an n-type AlGaN layer, an AlN buffer layer, and a sapphire substrate. In the step of forming a laminated structure containing the sapphire substrate in this order from the opposite side,
A plurality of holes are provided within a range in a thickness direction of the metal layer and the p-type GaN contact layer and at a position not exceeding an interface between the p-type GaN contact layer and the p-type AlGaN layer. Forming a reflective two-dimensional photonic crystal periodic structure;
Preparing a mold for forming the reflective two-dimensional photonic crystal periodic structure;
Forming a resist layer on the p-type GaN contact layer, and transferring the structure of the mold by nanoimprinting;
Etching the p-type GaN contact layer using the resist layer to which the structure has been transferred as a mask to form a two-dimensional photonic crystal periodic structure;
Forming the reflective two-dimensional photonic crystal and then forming the metal layer and the reflective electrode layer in this order by oblique deposition;
Dicing the sapphire substrate to create a deep ultraviolet LED element,
A step of preparing a surface-mounted aluminum nitride ceramic package having an inner side wall angle of not less than 45 degrees and not more than 60 degrees;
Coating the inorganic coating film on the inner bottom surface and the inner side wall of the package;
A step of mounting the deep ultraviolet LED element on the package, and a step of sealing the outermost surface of the package with a quartz window,
A method for manufacturing a deep ultraviolet LED device having:
Further, a step of preparing a sapphire or quartz hemispherical lens having a radius equal to or larger than the circumcircle of the LED element substrate,
Flattening the LED element substrate back surface and the hemispheric lens back surface,
A step of surface-activating the hemispheric lens back surface and the LED element substrate back surface with an ion beam or atmospheric pressure plasma,
Bonding the hemispherical lens back surface and the LED element substrate back surface that have been subjected to the surface activation processing,
A step of preparing a surface-mounted aluminum nitride ceramic package having an inner side wall angle of not less than 45 degrees and not more than 60 degrees;
Coating the inorganic coating film on the inner bottom surface and the inner side wall of the package;
Mounting the hemispherical lens junction LED element on the package;
4. The method of manufacturing a deep ultraviolet LED device according to claim 3, further comprising: sealing the outermost surface of the package with a quartz window.
At the design wavelength λ (200 nm to 355 nm) of the deep ultraviolet LED element, the Au coating film is a surface mount type aluminum nitride ceramic package coated on the inner bottom surface and the inner side wall, and the inner side wall angle of the package is 60 mm. Not less than 90 degrees, and the outermost surface of the package is a package sealed with a quartz window, and a deep ultraviolet LED element mounted in the package,
Reflective electrode layer (Au), metal layer (Ni), p-type GaN contact layer, p-type AlGaN layer, multiple quantum barrier layer (or electron block layer), multiple quantum well layer, and n-type AlGaN layer And an AlN buffer layer and a sapphire substrate in this order from the side opposite to the sapphire substrate,
A plurality of holes are provided within a range in a thickness direction of the metal layer and the p-type GaN contact layer and at a position not exceeding an interface between the p-type GaN contact layer and the p-type AlGaN layer. A reflection type two-dimensional photonic crystal, wherein the reflection type two-dimensional photonic crystal periodic structure has a photonic band gap opened to a TE polarized light component, and reflects the light of the design wavelength λ. The period a of the periodic type two-dimensional photonic crystal structure satisfies the Bragg condition, and the Bragg conditional expression mλ / n eff = 2a (where m: order, λ: design wavelength, n eff : two-dimensional photonic crystal) The effective refractive index, a: the order m in the period of the two-dimensional photonic crystal) satisfies m = 3, and when the radius of the hole is R, the R / a ratio is 0.30 ≦ R / a ≦ Depth satisfying 0.40 A deep ultraviolet LED device, comprising: an ultraviolet LED element.
further,
6. The sapphire substrate according to claim 5, further comprising: a quartz hemispherical lens transparent to a wavelength λ, which is bonded to a back surface of the sapphire substrate, wherein a radius of the hemispherical lens is equal to or larger than a radius of a circumcircle of the sapphire substrate. Deep ultraviolet LED device.