JP6201846B2 - LIGHT EMITTING ELEMENT AND MANUFACTURING METHOD THEREOF - Google Patents

Description

  The present invention relates to a light emitting device made of a group III nitride semiconductor and a method for manufacturing the same. In particular, the back surface of the sapphire substrate (the surface opposite to the side where the semiconductor layer is laminated) is a reflection film made of a dielectric that reflects light by light interference, or an antireflection made of a dielectric that prevents light reflection. The present invention relates to a light-emitting element provided with a film and a method for manufacturing the same.

  2. Description of the Related Art Conventionally, a reflection film made of a dielectric that increases reflectance by utilizing light interference and an antireflection film made of a dielectric that similarly prevents light reflection by utilizing light interference are known. In particular, DBR (distributed Bragg reflector) is widely known as a reflection film, and a single-layer AR film is widely known as an antireflection film. The DBR has a structure in which two kinds of dielectric films having different refractive indexes are alternately laminated with an optical film thickness of λ / 4. For example, Patent Document 1 describes a semiconductor laser having a dielectric multilayer film having a DBR structure. In the single-layer AR film, a dielectric film having a refractive index intermediate between the two members and an optical film thickness of λ / 4 is provided at the interface between the two members to prevent reflection.

  Even in a face-up type light-emitting device made of a group III nitride semiconductor, a DBR structure dielectric multilayer film is provided on the rear surface of the sapphire substrate (the surface opposite to the semiconductor layer stacking side) to improve the light extraction rate. Is being considered.

  On the other hand, in Patent Documents 2 and 3, when bonding a semiconductor substrate and a sapphire substrate, surface activation treatment is performed on the surface on the bonding side of the sapphire substrate to improve the adhesion between the semiconductor substrate and the sapphire substrate. Is described. As the surface activation treatment, ion beam treatment is cited. It is described that the adhesion can be improved because dangling bonds (unbonded hands) are exposed on the surface by irradiation with an ion beam. It is not described that a dielectric film is formed on an ion beam-treated sapphire substrate.

JP 2013-138176 A JP 2010-161355 A JP 2010-161359 A

  However, when the inventors examined the provision of a dielectric multilayer film having a DBR structure on the back surface of the sapphire substrate, the following problems became apparent. That is, when the flatness of the back surface of the sapphire substrate is poor, the reflection efficiency by the dielectric multilayer film is poor. The reflective function of the dielectric multilayer film is not sufficiently exhibited, and the light extraction rate of the light emitting element is lowered.

  Accordingly, an object of the present invention is to improve the flatness of the back surface of the sapphire substrate in a light emitting device made of a group III nitride semiconductor.

According to another aspect of the present invention , there is provided a method for manufacturing a face-up type light emitting device in which an n-type layer made of a group III nitride semiconductor, a light emitting layer, and a p type layer are sequentially laminated on one surface of a sapphire substrate. Irradiating rare gas or oxygen ions to the other surface of the substrate to cause surface reconstruction and flatten the surface. After the first step, use light interference on the other surface of the sapphire substrate. And a second step of forming a reflective film made of a dielectric material that reflects light toward the light extraction side.

The present invention also provides a method for manufacturing a flip-chip type light emitting device in which an n-type layer made of a group III nitride semiconductor, a light emitting layer, and a p type layer are sequentially laminated on one surface of a sapphire substrate. A first step of irradiating the other surface with ions of a rare gas or oxygen to cause surface reconstruction and flattening, and after the first step, the other surface of the sapphire substrate is utilized for interference of light. And a second step of forming an antireflection film made of a dielectric material that prevents reflection of light in the direction opposite to the light extraction side.

As a reflective film of the invention different from the present invention, for example, a DBR structure in which silicon oxide and titanium oxide are alternately and repeatedly stacked can be used. A single-layer AR film can be used as the antireflection film of the present invention.

  In the first step of the present invention, it is desirable to perform ion irradiation at an acceleration energy of 0.08 to 0.15 keV for 5 to 10 minutes. This is because the other surface of the sapphire substrate is further planarized, and the reflection efficiency by the reflection film or the transmittance by the antireflection film is further improved.

  Further, it is preferable that the arithmetic average roughness of the other surface of the sapphire substrate is 0.2 nm or less, the root mean square roughness is 0.2 nm or less, and the ten-point average roughness is 5 nm or less by ion irradiation. Similarly, the flatness of the other surface of the sapphire substrate can be further improved.

  Moreover, it is good to provide the process of grind | polishing the other surface of a sapphire substrate and thinning a sapphire substrate before a 1st process. By reducing the thickness, the light extraction rate can be improved and the flatness of the other surface of the sapphire substrate can be further improved.

Another aspect of the present invention is a face-up type light emitting device in which an n-type layer, a light emitting layer, and a p type layer made of a group III nitride semiconductor are sequentially laminated on one surface of a sapphire substrate. The other surface of the sapphire is provided with a reflective film made of a dielectric material that reflects light toward the light extraction side by utilizing light interference, and the other surface of the sapphire substrate has an arithmetic average roughness of 0.2 nm or less and a square. An average square root roughness is 0.2 nm or less, and a ten-point average roughness is 5 nm or less.

  According to another aspect of the present invention, there is provided a flip chip type light emitting device in which an n-type layer made of a group III nitride semiconductor, a light emitting layer, and a p type layer are sequentially laminated on one surface of a sapphire substrate. The other surface of the substrate is provided with an antireflection film made of a dielectric material that prevents light reflection in the direction opposite to the light extraction side by utilizing light interference, and the other surface of the sapphire substrate has an arithmetic average. The light-emitting element has a roughness of 0.2 nm or less, a root mean square roughness of 0.2 nm or less, and a ten-point average roughness of 5 nm or less.

According to the present invention, dangling bonds are exposed on the surface layer of the sapphire substrate by ion irradiation on the surface of the sapphire substrate. And surface reconfiguration occurs to reduce the dangling bonds, and the surface flatness is increased. Therefore, the reflection efficiency by the reflection film or the transmittance by the antireflection film is improved, and the light extraction rate can be improved.

FIG. 6 shows a structure of a light-emitting element of Example 1. FIG. 6 shows a manufacturing process of the light-emitting element of Example 1. FIG. 6 shows a manufacturing process of the light-emitting element of Example 1. The graph which showed the result of having measured the roughness of the back surface 10a of the sapphire substrate 10. FIG. Graph comparing radiation intensity. Graph comparing radiation intensity. FIG. 6 shows a structure of a light-emitting element of Example 2.

  Hereinafter, specific examples of the present invention will be described with reference to the drawings. However, the present invention is not limited to the examples.

  FIG. 1 is a diagram showing the configuration of the light emitting device of Example 1. FIG. The light emitting device of Example 1 has a sapphire substrate 10 as shown in FIG. The layer 13 has a structure in which the layers 13 are sequentially stacked. A transparent electrode 14 is located on the p-type layer 13, a p-electrode 15 is located on the transparent electrode 14, and an n-electrode 16 is provided on the bottom surface of the groove opened from the p-type layer 13 side. A dielectric multilayer film 17 (corresponding to the reflective film of the present invention) is provided on the back surface 10a of the sapphire substrate 10 (the surface opposite to the n-type layer 11 formation side). The light emitting device of Example 1 is a face-up type device in which the p-electrode 15 and the n-electrode 16 are located on the same surface side, and light is extracted from the p-electrode 15 side.

  The sapphire substrate 10 is a growth substrate for crystal growth of a group III nitride semiconductor on its main surface. The main surface is, for example, a-plane or c-plane. The thickness of the sapphire substrate 10 is 100 to 600 μm. The surface of the sapphire substrate 10 on the n-type layer 11 side may be subjected to uneven processing such as a dot shape or a stripe shape in order to improve the light extraction rate.

  The roughness of the back surface 10a of the sapphire substrate 10 is as follows: Ra (arithmetic mean roughness) is 0.2 nm or less, RMS (root mean square roughness) is 0.2 nm or less, and Rz (ten-point mean roughness) is 5 nm or less. Good. By making the back surface 10a of the sapphire substrate 10 a surface having such high flatness, the reflectance of the dielectric multilayer film 17 can be increased.

The n-type layer 11 is located on the surface of the sapphire substrate 10 via a buffer layer (not shown) made of AlN. The n-type layer 11 has a structure in which an n-contact layer, an ESD layer, and an n-clad layer are stacked in this order from the sapphire substrate 10 side. The n contact layer is made of, for example, n-GaN having a Si concentration of 1 × 10 ¹⁸ / cm ³ or more. The n contact layer may be composed of a plurality of layers having different Si concentrations. The ESD layer is, for example, a layer in which non-doped GaN and n-GaN are stacked, and is a layer for increasing electrostatic withstand voltage. The n-clad layer is a layer having a superlattice structure in which, for example, InGaN and n-GaN are alternately and repeatedly stacked.

  The light-emitting layer 12 has an MQW structure in which a unit structure is repeatedly stacked with a structure in which a well layer, a protective layer, and a barrier layer are stacked in this order as a unit. The number of repetitions is 3 to 10 times. The well layer is made of InGaN and has a thickness of 1 to 5 nm. The protective layer is GaN or AlGaN, and the band gap is less than or equal to the band gap of the barrier layer. A stack of GaN and AlGaN may be sequentially formed from the well layer side. This protective layer is a layer grown at the same temperature as the well layer. The thickness is 2 to 20 mm. The barrier layer is made of AlGaN. The Al composition ratio is 3 to 10%, and the thickness is 1 to 10 nm. The barrier layer is not limited to an AlGaN single layer and may be composed of a plurality of layers. For example, a plurality of layers having different Al composition ratios can be formed.

The p-type layer 13 has a structure in which a p-clad layer and a p-contact layer are laminated in order from the light emitting layer 12 side. The p-clad layer has a superlattice structure in which p-InGaN and p-AlGaN are alternately and repeatedly stacked. The In composition ratio of p-InGaN is 5 to 12%, and the thickness is 2 nm. The Al composition ratio of p-AlGaN is 25 to 40% and the thickness is 2.5 nm. The p contact layer is p-GaN having an Mg concentration of 1 × 10 ¹⁹ / cm ³ or more and a thickness of 80 nm. The p contact layer may be composed of a plurality of layers having different Mg concentrations.

  The transparent electrode 14 is made of ITO and is formed on almost the entire surface of the p-type layer 13. In addition to ITO, IZO (zinc-doped indium oxide), ICO (cerium-doped indium oxide), or the like can be used as the material of the transparent electrode 14.

  The p electrode 15 is located on the transparent electrode 14. The n electrode 16 is located on the n contact layer of the n-type layer 11 exposed at the bottom surface of the groove. The groove is provided in a part of the semiconductor layer (n-type layer 11, light emitting layer 12, p-type layer 13), and has a depth reaching the n-contact layer of the n-type layer 11 from the surface of the p-type layer 13. is there. The p-electrode 15 and the n-electrode 16 have a pad portion connected to the wire and a wiring-like portion extending linearly continuously from the pad portion.

The dielectric multilayer film 17 is a DBR (distributed Bragg reflector) in which SiO ₂ films (not shown) and TiO ₂ films (not shown) are alternately and repeatedly stacked. The film in contact with the back surface 10a of the sapphire substrate 10 is a SiO ₂ film. The number of repetitions is 3 to 50 times. The thicknesses of the SiO ₂ film and the TiO ₂ film are such that the optical film thickness is λ / 4. Here, λ is the emission wavelength of the light emitting device of Example 1. For example, when λ is 450 nm, the refractive index of SiO ₂ is approximately 1.47, and the refractive index of TiO ₂ is approximately 2.67. Therefore, the physical thickness of the SiO ₂ film is 76.5 nm, and the physical thickness of TiO ₂ is The typical thickness is 42.1 nm.

  The dielectric multilayer film 17 which is the DBR strongly reflects light having a wavelength near λ due to the light interference effect. The number of repetitions of the dielectric multilayer film 17 may be designed so that the reflectance at the wavelength λ is 90% or more, preferably 95% or more.

  Since the dielectric multilayer film 17 is provided on the back surface 10 a of the sapphire substrate 10, the light traveling from the light emitting layer 12 toward the sapphire substrate 10 can be reflected by the dielectric multilayer film 17 toward the p electrode 15 and the n electrode 16. it can. Since the light emitting element of Example 1 is a face-up type, the p-electrode 15 and the n-electrode 16 side is the light extraction side. Therefore, the light extraction rate can be improved by providing the dielectric multilayer film 17. Further, as described above, since the light emitting device of Example 1 has high flatness on the back surface 10a of the sapphire substrate 10, the reflection efficiency by the dielectric multilayer film 17 is high. Therefore, the dielectric multilayer film 17 sufficiently exhibits the reflection function by the DBR structure, and the light extraction rate is improved.

  Note that the two materials of the dielectric multilayer film 17 are not limited to the above. Two kinds of dielectric materials that transmit light with respect to the emission wavelength λ and have different refractive indexes can be used. Since the reflectance of the dielectric multilayer film 17 can be improved as the refractive index difference is larger, two kinds of materials having a refractive index difference at the wavelength λ of 1 or more, preferably 1.5 or more may be used.

As specific materials for the dielectric multilayer film 17 other than the above, as the metal oxide, Al ₂ O ₃ , ZrO ₂ , Ta ₂ O ₅ , Nb ₂ O ₅ , ZrO, ZrO ₂ , metal nitride, AlN, SiN, TiN, metal oxynitride, SiON, metal fluoride, MgF ₂ , CaF ₂ , etc.

The thicknesses of the SiO ₂ film and the TiO ₂ film are not limited to the thickness at which the optical film thickness is λ / 4, but may be a thickness that is an odd multiple of λ / 4. However, since the entire dielectric multilayer film 17 is thick, it is desirable that the optical film thickness be λ / 4. Further, it is not necessarily strictly an odd multiple of λ / 4, and an error is allowed in the range of 0.9 to 1.1 times the odd multiple of λ / 4.

Next, the manufacturing process of the light emitting element of Example 1 will be described with reference to FIGS. The MOCVD method is used for crystal growth of the group III nitride semiconductor. Raw material gas used in the MOCVD method, as the nitrogen source, ammonia (NH _3), as a Ga source, trimethyl gallium _{(Ga (CH 3) 3)} , as an In source, trimethylindium _{(In (CH 3) 3)} , Al source As trimethylaluminum (Al (CH ₃ ) ₃ ), n-type doping gas as silane (SiH ₄ ), p-type doping gas as cyclopentadienylmagnesium (Mg (C ₂ H ₅ ) ₂ ), and carrier gas as H ₂ and N ₂ . Of course, it is also possible to use organometallic gases other than these as source gas.

  First, a sapphire substrate 10 having a thickness of 500 to 1000 μm is prepared, and the surface is cleaned by heating in a hydrogen atmosphere. Next, a buffer layer (not shown) made of AlN is formed on the sapphire substrate 10 by MOCVD, and an n-type layer 11 made of a group III nitride semiconductor, a light emitting layer 12, and a p-type layer 13 are formed on the buffer layer. Are sequentially stacked (see FIG. 2A).

  Next, the transparent electrode 14 is formed in a predetermined region on the surface of the p-type layer 13 by vapor deposition or sputtering. Then, a predetermined region of the p-type layer 13 is dry-etched to form a groove 19 having a depth reaching the n-contact layer of the n-type layer 11 from the surface of the p-type layer 13. Next, the p electrode 15 is formed on the transparent electrode 14, and the n electrode 16 is formed on the surface of the n contact layer of the n-type layer 11 exposed at the bottom of the groove (see FIG. 2B).

  Next, the back surface 10a of the sapphire substrate 10 is polished to reduce the thickness of the sapphire substrate 10 to 100 to 600 μm (see FIG. 3A). The light extraction rate is improved by thinning the sapphire substrate 10.

  Note that polishing may be performed simply to planarize the back surface 10a of the sapphire substrate 10. Further, the next step may be performed without polishing the back surface 10a of the sapphire substrate 10. However, since the flatness of the back surface 10a of the sapphire substrate 10 is further improved by performing ion irradiation in the next step after polishing, it is desirable to perform polishing before ion irradiation. As a polishing method, CMP polishing or the like can be used in addition to mechanical polishing.

  Next, Ar ion irradiation is performed on the back surface 10a of the sapphire substrate 10 at an acceleration energy of 0.08 keV for 10 minutes (see FIG. 3B). As a result, dangling bonds (unbonded hands) are exposed on the back surface 10a of the sapphire substrate 10 and surface reconstruction occurs in a direction to reduce the dangling bonds, so that the back surface 10a of the sapphire substrate 10 is flattened. Accordingly, the roughness of the back surface 10a of the sapphire substrate 10 is preferably set such that Ra is 0.2 nm or less, RMS is 0.2 nm or less, and Rz is 5 nm or less.

  As the ion species to be irradiated, a rare gas other than Ar (He, Ne, Kr, Xe) or oxygen can be used, or a mixture thereof may be used. Each ionization potential is 13.6 eV for oxygen and 24. for He. Ne is 21.6 eV, Ar is 15.8 eV, Kr is 14.0 eV, and Xe is 12.1 eV.

  Note that the acceleration energy of ion irradiation is not limited to the above value, and may be 0.08 to 0.15 keV. If it is less than 0.08 keV, the energy is too small and dangling bonds are not exposed on the back surface 10 a of the sapphire substrate 10. This is not desirable. Undesirable.

  Also, the ion irradiation time is not limited to the above value, and may be 5 to 10 minutes. If irradiation time is this range, the back surface 10a of the sapphire substrate 10 can be efficiently planarized.

  Various methods such as a DC method and an RF method can be used as an ion generation method, but the RF method is preferable. This is because it is easy to give large energy to ions.

  Moreover, the temperature of the sapphire substrate 10 can be set to room temperature during ion irradiation. It is considered that the flatness of the back surface 10a is further increased by raising the temperature of the sapphire substrate 10. However, the energy given to the atoms of the surface layer of the sapphire substrate 10 by heating is very small compared to the energy of ions. Therefore, even if ion irradiation is performed while heating the sapphire substrate 10, there is not much influence on the improvement in flatness, and it is better to carry out at room temperature in consideration of the heating effort.

Next, the dielectric multilayer film 17 is formed by alternately and repeatedly laminating an SiO ₂ film having an optical film thickness of λ / 4 and a TiO ₂ film having an optical film thickness of λ / 4 on the back surface 10a of the sapphire substrate 10 by vapor deposition or sputtering. (See FIG. 3C).

  Here, the back surface 10a of the sapphire substrate 10 has a very high flatness with Ra of 0.2 nm or less, RMS of 0.2 nm or less, and Rz of 5 nm or less. Therefore, the reflection efficiency by the dielectric multilayer film 17 is increased, and the light extraction rate can be improved.

  Next, a laser is irradiated along the element division planned line to form a modified portion and a continuous crack in the modified portion in the sapphire substrate 10, and each element is started from the modified portion and the crack by braking. Divide every. In this way, the light emitting device of Example 1 is manufactured.

  According to the manufacturing method of the light emitting element of Example 1 described above, the surface reconstruction is caused on the back surface 10a of the sapphire substrate 10 by Ar ion irradiation and the flatness becomes very high, so that the light extraction rate is improved. Can do.

  Next, various experimental results relating to the light-emitting element of Example 1 will be described.

  FIG. 4 is a graph showing the results of measuring the roughness of the back surface 10a of the sapphire substrate 10 before and after Ar ion irradiation. Ion irradiation was performed at 0.08 keV for 10 minutes. The roughness was evaluated by three methods of Ra, RMS, and Rz. The roughness curve of the back surface 10a was measured by AFM, and a 50 μm section selected at random was used.

  As shown in FIG. 4, Ra was decreased from 0.124 nm to 0.1 nm and RMS was decreased from 0.164 nm to 0.131 nm by ion irradiation, and both Ra and RMS were slightly improved. On the other hand, Rz was greatly reduced from 15.061 nm to 2.153 nm. Thus, it was found that surface reconstruction occurred by ion irradiation, and the flatness of the back surface 10a of the sapphire substrate 10 was improved.

  5 and 6 are graphs comparing the radiation intensities of the light emitting device of Example 1 and the light emitting devices of Comparative Examples 1 to 3. FIG. The light emitting device of Comparative Example 1 is the light emitting device of Example 1 in which the dielectric multilayer film 17 is not provided. The light-emitting element of Comparative Example 2 is obtained by providing the dielectric multilayer film 17 in the light-emitting element of Example 1 without performing ion irradiation. The light emitting element of Comparative Example 3 is the same as the light emitting element of Example 1, except that ion irradiation is not performed and a low refractive index material having a refractive index of 1.2 at the emission wavelength is provided instead of the dielectric multilayer film 17. . The radiation intensity is in a direction perpendicular to the main surface of the sapphire substrate 10 and is a relative value based on the radiation intensity of Comparative Example 1.

  As shown in FIG. 6, the emission intensity of the light emitting element of Comparative Example 2 was lower than that of the light emitting element of Comparative Example 1. That is, it was found that the dielectric multilayer film 17 having the DBR structure does not function as a reflective film that improves the light extraction rate. Further, as shown in FIG. 6, the light emitting element of Comparative Example 3 provided with the low refractive index material had lower radiation intensity than the light emitting elements of Comparative Examples 1 and 2. From this, in the light emitting element of the comparative example 2, since Rz is 15 nm or more, it is thought that the radiation intensity is reduced.

  Further, as shown in FIG. 5, the light emitting element of Example 1 was improved in radiation intensity by 1.2% compared to the light emitting element of Comparative Example 1. From the comparison with Comparative Example 2, since the Rz of the light emitting element of Example 1 is 5 nm or less, it is considered that the function as the reflective film of the dielectric multilayer film 17 is exhibited and the radiation intensity is improved.

  FIG. 7 is a diagram showing the configuration of the light emitting device of Example 2. In addition, the same code | symbol is attached | subjected to the component similar to Example 1. FIG.

  The light emitting element of Example 2 has a sapphire substrate 10 as shown in FIG. 7, and an n-type layer 11 made of a group III nitride semiconductor, a light emitting layer 12, and a p-type on one surface of the sapphire substrate 10. The layer 13 has a structure in which the layers 13 are sequentially stacked. A transparent electrode 14 is disposed on the p-type layer 13, and a plurality of dot-shaped p-contact electrodes 25 are disposed on the transparent electrode 14. An n-contact electrode 26 is provided on the bottom surface of the groove opened from the p-type layer 13 side. It has been. A single-layer AR film 27 (corresponding to the antireflection film of the present invention) is provided on the back surface 10a of the sapphire substrate 10 (surface opposite to the n-type layer 11 formation side).

  The p-contact electrode 25 and the n-contact electrode 26 are covered with the insulating film 20 except for the upper surfaces thereof. A reflective film (not shown) made of Al is provided in the insulating film 20. A p-junction electrode 28 is provided on each p-contact electrode 25 so as to connect the p-contact electrodes 25 to each other, and an n-junction electrode 29 is provided on the n-contact electrode 26. In the light emitting device of Example 2, the p contact electrode 25 and the n contact electrode 26 are located on the same surface side, and light is emitted from the side opposite to the p contact electrode 25 and the n contact electrode 26 side, that is, from the back surface 10a side of the sapphire substrate 10. This is a flip-chip type element that takes out the.

The single-layer AR film 27 is made of a dielectric having an optical film thickness of λ / 4 and a refractive index between the sapphire substrate 10 and the sealing member (not shown) of the light emitting element of Example 2. For example, a SiO ₂ film. By providing this single-layer AR film 27 between the sapphire substrate 10 and the sealing member, light directed toward the light extraction side is prevented from being reflected at the interface between the sapphire substrate 10 and the sealing member, and the transmittance And the light extraction rate can be improved.

  In the manufacturing process of the light emitting device of Example 2, after the device structure is formed on the sapphire substrate 10, before the single-layer AR film 27 is formed, the back surface 10a of the sapphire substrate 10 is polished, and Ar is formed on the back surface 10a of the sapphire substrate 10. The surface reconstruction is caused by ion irradiation. Polishing and ion irradiation are the same as in Example 1. Thereby, the flatness of the back surface 10a of the sapphire substrate 10 is very high. Thereafter, the single-layer AR film 27 is formed. Therefore, as in Example 1, the flatness of the interface between the back surface 10a of the sapphire substrate 10 and the single-layer AR film 27 becomes very high, so that the light extraction rate is improved.

  The present invention is not limited to the element structures shown in the first and second embodiments, and can be applied to any conventionally known face-up type element or flip chip type element. In the case of a face-up type element, the film provided on the back surface 10a of the sapphire substrate 10 is not limited to the dielectric multilayer film 17 having the DBR structure as in the first embodiment, and light is transmitted to the light extraction side using light interference. Any known structure can be used as long as it is a reflective film made of a dielectric material to be reflected, regardless of whether it is a single layer or multiple layers. In the case of a flip-chip type device, the film provided on the back surface 10a of the sapphire substrate 10 is not limited to the single-layer AR film 27 as in the second embodiment, but is directed in the direction opposite to the light extraction side using light interference. Any known structure can be used as long as it is an antireflection film made of a dielectric material that prevents reflection of light, regardless of whether it is a single layer or multiple layers.

  The light-emitting element manufactured by the present invention can be used as a light source for a lighting device or a display device.

10: Sapphire substrate 11: n-type layer 12: light-emitting layer 13: p-type layer 14: transparent electrode 15: p-electrode 16: n-electrode 17: dielectric multilayer film 27: single-layer AR film

Claims (5)

In a method of manufacturing a flip chip type light emitting device in which an n-type layer made of a group III nitride semiconductor, a light emitting layer, and a p type layer are sequentially laminated on one surface of a sapphire substrate,
A first step of planarizing the other surface of the sapphire substrate by ion irradiation with a rare gas or oxygen to cause surface reconstruction;
After the first step, a second step of forming on the other surface of the sapphire substrate an antireflection film made of a dielectric material that prevents light reflection in the direction opposite to the light extraction side using light interference. When,
A method for manufacturing a light-emitting element, comprising: 2. The method of manufacturing a light emitting element according to claim 1 , wherein in the first step, ion irradiation is performed at an acceleration energy of 0.08 to 0.15 keV for 5 to 10 minutes. By the ion irradiation, Ra (arithmetic mean roughness) of the other surface of the sapphire substrate is 0.2 nm or less, RMS (root mean square roughness) is 0.2 nm or less, and Rz (ten-point mean roughness) is 5 nm. The method for producing a light-emitting element according to claim 1 , wherein: Before the first step, the by polishing the other surface of the sapphire substrate, of the comprising a step of thinning the sapphire substrate, it claimed in any one of claims 1 to 3, characterized in Manufacturing method of light emitting element. In a flip chip type light emitting device in which an n-type layer made of a group III nitride semiconductor, a light emitting layer, and a p type layer are sequentially laminated on one surface of a sapphire substrate,
On the other surface of the sapphire substrate, an antireflection film made of a dielectric material that prevents light reflection in the direction opposite to the light extraction side using light interference is provided,
The other surface of the sapphire substrate has an arithmetic average roughness of 0.2 nm or less, a root mean square roughness of 0.2 nm or less, and a ten-point average roughness of 5 nm or less.
A light emitting element characterized by the above.

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