JP2009267263A - Light-emitting device and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting device capable of suppressing the generation of non-radiation level caused by defective crystal, by reducing the height of irregularities, when improving external quantum efficiency, using photonic crystalline structure. <P>SOLUTION: The system is configured by a plurality of semiconductor crystalline layers that are laminated and is provided with a light-emitting device 2, having a light-emitting layer 12; a support substrate 3 that is disposed on one principal plane 21 side of the light-emitting device 2 and supports the light-emitting device 2, and a metal film 4; a photonic crystalline structure 23, that reflects light from the light-emitting layer 12 to the side of the other principal plane 22 is formed on one principal plane section in the light-emitting layer 2, and one principal plane 21 in the light-emitting device 2 is covered with the metal film 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light emitting device and a method for manufacturing the same.

  In a conventional light emitting device, a light emitting element including a light emitting layer is formed on one main surface of a host substrate, a photonic crystal structure is formed on one main surface of the light emitting element, and a photonic crystal structure is formed. To extract light. The photonic crystal structure is realized by a periodic lattice of holes formed in the epitaxial layer, and is covered with a dielectric. In such a light emitting device, an epitaxial layer is grown on a crystal growth substrate, the epitaxial layer is bonded to one main surface of a host substrate via a bonding layer, the crystal growth substrate is removed, The photonic crystal structure is formed on one main surface portion of the epitaxial layer (see, for example, Patent Document 1).

Japanese Patent No. 2006-54473

  The photonic crystal structure in the conventional light emitting device has a minute uneven shape, and light is extracted in a predetermined direction by light interference according to the period of the unevenness and the optical path difference. When the height is increased, non-light emitting levels due to crystal defects are generated in the light emitting layer, which may reduce the external quantum efficiency. Further, in the conventional method for manufacturing a light emitting device, since the photonic crystal structure is formed in the portion where the substrate for crystal growth is removed, it is difficult to accurately form the photonic crystal structure.

  Accordingly, an object of the present invention is to improve the external quantum efficiency by using a photonic crystal structure, and to reduce the height of unevenness and to suppress the generation of non-light emitting levels due to crystal defects And a method of manufacturing a light emitting device capable of forming a photonic crystal structure with high precision in the light emitting device.

A light-emitting device of the present invention includes a light-emitting element in which a plurality of semiconductor crystal layers are stacked and includes a light-emitting region;
A support substrate that is disposed on one main surface side of the light emitting element and supports the light emitting element;
A reflective conductive film,
The one main surface portion of the light emitting element is formed with a photonic crystal structure that reflects light from the light emitting region to the other main surface side,
The photonic crystal structure is covered with the reflective conductive film.

The method for manufacturing a light emitting device of the present invention includes a step of stacking a plurality of semiconductor crystal layers on one main surface of a crystal growth substrate to form a light emitting element having a light emitting region,
Forming a photonic crystal structure that reflects light from the light emitting region on the other main surface side of the light emitting element on one main surface portion of the light emitting element;
Forming a reflective conductive film covering the one main surface of the light emitting element;
Bonding the support substrate supporting the light emitting element to the reflective conductive film;
And a step of removing the substrate for crystal growth.

  According to the present invention, the light traveling from the light emitting region toward one main surface of the light emitting element is reflected by the photonic crystal structure toward the other main surface of the light emitting element. The photonic crystal structure has a minute concavo-convex shape, and light is reflected in a predetermined direction when light interferes according to the period of the concavo-convex and the optical path difference, and light is emitted at a predetermined angle according to the structure. Since part of the light emitted from the light emitting region is converted into a diffracted light path and incident on the interface within the total reflection angle, the light extraction efficiency to the outside of the device is improved. , External quantum efficiency can be improved.

  According to the present invention, a plurality of semiconductor crystal layers are stacked on one main surface of a crystal growth substrate to form a light emitting device having a light emitting region, and a photonic crystal structure is formed on one main surface portion of the light emitting device. After forming the body, a metal film is formed so as to cover one main surface of the photonic crystal structure, a support substrate that supports the light emitting element is bonded to the metal film, and then the substrate for crystal growth is removed. Compared to the conventional technique of forming a photonic crystal structure in a portion where the substrate for crystal growth is removed, the photonic crystal structure can be formed with higher accuracy.

  FIG. 1 is a cross-sectional view showing a configuration of a light emitting device 1 according to an embodiment of the present invention. The light emitting device 1 is a flip chip type light emitting device. The light emitting device 1 basically includes a light emitting element 2, a support substrate 3, and a metal film 4 that is a reflective conductive film, and further includes a crystal growth substrate 5, first and second electrodes 6, 7, The first and second joint portions 8 and 9 are provided.

  The light emitting element 2 is an LED (Light Emitting Diode), and includes a plurality of semiconductor crystal layers stacked on one main surface 5a of the crystal growth substrate 5, and includes a light emitting region. The light emitting element 2 includes, from one main surface 5a of the crystal growth substrate 5, a semiconductor layer 11 of one of n-type and p-type conductivity, a contact layer 14, and one of n-type and p-type. The other conductive type semiconductor layer 13 and the contact layer 14 are laminated in the order described. In the present embodiment, one conductivity type semiconductor layer 11, the light emitting layer 12, and the other conductivity type semiconductor layer 13 are formed of a III-V group compound semiconductor. In this embodiment, one conductivity type is n-type and the other conductivity type is p-type. Hereinafter, one conductivity type semiconductor layer is referred to as a p-type semiconductor layer, and the other conductivity type semiconductor. The layer is referred to as an n-type semiconductor layer.

The n-type semiconductor layer 11 is made of gallium nitride (GaN) doped with n-type impurities. The thickness of the n-type semiconductor layer 11 is selected from 10 nm to 1000 nm. The n-type impurity is, for example, silicon (Si). The doping concentration of the n-type semiconductor layer 11 is selected from 1 × 10 ¹⁷ / cm ³ to 1 × 10 ¹⁸ / cm ³ .

  The light emitting layer 12 forms a light emitting region and is made of non-doped indium gallium nitride (InGaN). The thickness of the light emitting layer 12 is selected from 10 nm to 100 nm.

The p-type semiconductor layer 13 is made of GaN doped with p-type impurities. The thickness of the p-type semiconductor layer 13 is selected from 10 nm to 100 nm. The p-type impurity is, for example, magnesium (Mg). The doping concentration of the p-type semiconductor layer 13 is selected from 1 × 10 ¹⁷ / cm ³ to 1 × 10 ¹⁸ / cm ³ .

The contact layer 14 is made of GaN doped with p-type impurities. The thickness of the contact layer 14 is selected from 10 nm to 100 nm. The doping concentration of the contact layer 14 is selected from 1 × 10 ¹⁸ / cm ³ to 1 × 10 ¹⁹ / cm ³ .

  The n-type semiconductor layer 11 is laminated on the entire main surface 5a of the crystal growth substrate 5. The n-type semiconductor layer 11 is formed so that the thickness of one end 15 in a predetermined direction parallel to the main surface 5 a is smaller than the thickness of the portion 16 excluding the one end 15. The light emitting layer 12 is laminated on the entire surface of one main surface 16a of the portion 16 of the n-type semiconductor layer 11 excluding the one end 15. A p-type semiconductor layer 13 is stacked on the entire surface of one main surface 12 a of the light emitting layer 12. A contact layer 14 is laminated on the entire surface of one main surface 13 a of the p-type semiconductor layer 13.

  A photonic crystal structure 23 that reflects light from the light emitting layer 12 toward the other main surface 22 is formed on one main surface of the light emitting element 2. The photonic crystal structure 23 is formed in the contact layer 14. The photonic crystal structure 23 is formed in a region excluding the other end 24 in the predetermined direction on one main surface 14a of the contact layer 14. Details of the photonic crystal structure 23 will be described later.

The light emitting element 2 is formed on a crystal growth substrate 5 by MOCVD (metal organic chemical vapor deposition: Metal-
Organic Chemical Vapor Deposition (MBE) method or MBE (molecular beam epitaxial growth:
Each semiconductor layer is stacked by epitaxial growth using a molecular beam epitaxy method, and then a predetermined resist mask is formed by photolithography and etching is performed.

  The crystal growth substrate 5 is made of a material capable of crystal growth of each semiconductor layer of the light emitting element 2 and transmitting light from the light emitting layer 12 of the light emitting element 2. The crystal growth substrate 5 is made of a material having a refractive index lower than that of the light emitting element 2. In the present embodiment, the crystal growth substrate 5 is made of, for example, sapphire. In the present embodiment, since the light emitting element 2 is mainly made of GaN, its refractive index is about 2.3 at room temperature, and since the crystal growth substrate 5 is made of sapphire, its refractive index is about 1.8 at room temperature. It is.

  The metal film 4 is provided so as to cover one main surface 21 of the light emitting element 2. The metal film 4 is made of a metal having a high reflectance with respect to light from the light emitting layer 12 of the light emitting element 2. The reflectance is 80% or more. In the present embodiment, the light emitting layer 12 includes GaN, and the light emission wavelength is 450 nm to 365 nm. In the present embodiment, the metal film 4 is made of an alloy containing silver (Ag) and nickel (Ni), or silver or nickel, and has a high reflectance with respect to the wavelength range. The alloy containing silver and nickel may contain copper (Cu) or palladium (Pb). The metal film 4 is provided in close contact with one main surface of the photonic crystal structure 23. The metal film 4 is formed by depositing a metal, forming a predetermined resist mask by photolithography, and performing etching. Of the one main surface 14a of the contact layer 14, the other end in the predetermined direction is formed. It is formed by being laminated in a region excluding the portion 24. The metal film 4 and the contact layer 14 are in ohmic contact.

  The first electrode 6 is made of metal and connected to the n-type semiconductor layer 11. The first electrode 6 is formed by being laminated on one end 15 in the predetermined direction of the n-type semiconductor layer 11 and is separated from the light emitting layer 12, the p-type semiconductor layer 13, the contact layer 14, and the metal film 4. Provided. The first electrode 6 includes an ohmic junction 25 that is ohmic-bonded to the n-type semiconductor layer 11, and a pad portion 26 that covers the ohmic junction 25 and connects the ohmic junction 25 to the first junction 8. . The ohmic junction 25 is formed of an alloy made of titanium (Ti) and aluminum (Al). The pad portion 26 is made of gold (Au). The pad portion 26 is formed such that one main surface 26 a protrudes toward the support substrate 3 from the surface of the metal film 4 facing the support substrate 3.

  The second electrode 7 is an element side electrode, made of metal, and connected to the contact layer 14 and the metal film 4. The second electrode 7 is formed by laminating one end portion 24 of the contact layer 14 in the predetermined direction and one end portion 29 of the metal film 4 in the predetermined direction. The second electrode 7 is made of gold (Au). The second electrode 7 is formed such that one main surface 7 a protrudes toward the support substrate 3 from the surface of the metal film 4 facing the support substrate 3.

  The support substrate 3 includes a base material 31 and a wiring portion 32 that is a substrate-side wiring film formed on at least a surface portion of the base material 31 facing the light emitting element 2. The base material 31 has electrical insulation and is formed of, for example, ceramic. The wiring part 32 is made of, for example, Au or Al. The wiring part 32 is provided at a position facing the first and second electrodes 6 and 7.

  The first electrode 6 is electrically connected to the wiring portion 32 via the first joint portion 8, and the second electrode 7 is electrically connected to the wiring portion 32 via the second joint portion 9. The first and second joints 8 and 9 are formed by solder, for example. The first and second electrodes 6 and 7 are separated from the support substrate 3 by the thickness of the first and second joints 8 and 9. Therefore, the metal film 4 is also provided apart from the support substrate 3.

In the light emitting element 2, only a part of the light emitted from the light emitting layer 12 can be extracted and used outside the element. Light that cannot be extracted to the outside of the element is repeatedly reflected and scattered inside the element and gradually converted into heat energy or the like, so that it cannot be used effectively. One of the biggest reasons why this light cannot be extracted efficiently is the phenomenon of total reflection at the interface between the element and the outside. First, total reflection will be described. When a medium having a refractive index n1 is incident on a medium having a refractive index n2 at an incident angle θ ₁ and is emitted at an outgoing angle θ ₂ , the relationship of the following expression (1) is established between the incident light and the outgoing light.
n1 · sin θ ₁ = n2 · sin θ ₂ (1)

Here, in the case of n1> n2, that is, when light enters the interface from a medium having a high refractive index to a medium having a low refractive index, when entering at an incident angle greater than or equal to sin θ ₁ = n2 / n1, Equation (1) is obtained. A state where there is no satisfactory θ ₂ exists. In other words, the presence of a light wave that passes through the interface is not allowed, and is totally reflected at the interface. This phenomenon is called total reflection, and θ ₁ at this time is called a total reflection angle θ _T. In particular, since the optical semiconductor material has a large refractive index, this effect becomes significant.

For example, gallium nitride has a refractive index of about 2.5 in its emission region, so the total reflection angle with respect to the air interface (n = 1.0) is approximately 23 degrees, and between gallium nitride and sapphire The total reflection angle with respect to the interface is approximately 46 degrees, and approximately 34 degrees at the interface between sapphire and air. Here, assuming that the light intensity distribution emitted from the light emitting layer 12 is a Lambert distribution (I (φ) = I ₀ · cos (φ): I ₀ is the light emission intensity in the main line direction), the total reflection angle θ _T The light energy radiated in the inside is (1−cos 2θ _T ) / 2 × 100 (%) with respect to the total radiant energy. Here, Fresnel reflection is not considered. When the total reflection angle is substituted, light energy radiated within the total reflection angle θ _{T at} the interface between air and gallium nitride, the interface between sapphire and gallium nitride, and the interface between air and sapphire is about 15 respectively. %, 48% and 31%. Of course, since the reflection loss due to Fresnel reflection is further added, this value is actually further reduced. Therefore, in order to suppress or eliminate this problem, it is essential to reduce / suppress this total reflection.

  The photonic crystal structure 23 has an uneven fine structure. The principle of reducing and suppressing the total reflection by the photonic crystal structure 23 will be described. Here, in order to facilitate understanding, first, the one-dimensional diffraction phenomenon will be described. Consider a case where light is incident on a reflective diffraction grating in which a one-dimensional uneven microstructure is formed and a highly reflective metal film is deposited. When the concave-convex microstructure is sufficiently larger than the incident light wavelength, the light path can be obtained by performing ray tracing in detail according to the law of reflection. However, when the size of the concave-convex microstructure is on the order of the incident light wavelength, the light wave diffraction phenomenon becomes prominent. The simplest handling of the light incident on the diffraction grating is to obtain a Fraunhofer diffraction image for the periodic aperture. In this case, the light wave amplitude incident on the aperture is given in the form of a Fourier transform of the aperture function.

  A reflective diffraction grating in which an uneven microstructure is formed and a highly reflective metal film is deposited can be considered as a phase diffraction grating in principle. That is, in the concavo-convex pattern, the optical path length difference between the convex portion and the concave portion when viewed from the light emitting layer is 2nd, where n is the refractive index of the light propagation portion and d is the height of the concavo-convex portion. The reason why the numerical value “2” is added to the product (nd) of the refractive index of the light propagation part and the uneven part height is that the light propagated through the convex part is reflected by the reflecting mirror and propagates back and forth through the convex part again. It depends.

  Here, consider the simplest case where the aperture function u (x) of the diffraction grating having the period a and the phase difference φ = 4πnd / λ is expressed by the following trigonometric function equation (2).

  It is generated at a ratio of light wave electric field amplitude Jm (φ / 2) to basic light (0th order diffracted light) and mth order diffracted light.

That is, a part of the light incident on the reflecting mirror can be optically path-converted as diffracted light, and total reflection at the exit interface can be reduced. Here, J _m is an m-th order Bessel function, and by setting φ / 2 appropriately, it is possible to adjust the diffraction efficiency of a desired order although it is limited. In an actual light emitting device, since the emitted light is incident on the diffraction grating in a spherical wave manner, the effective diffraction angle and the diffraction efficiency of each order are calculated for all directions of the incident wave, and the period and depth of the uneven microstructure are calculated. There is a need to decide.

  Regarding the depth, since the optical interference effect is large and appropriate when the optical path difference between the concave and convex portions of the concave-convex microstructure has a half wavelength (reverse phase), the light emitting element 2 is made of a gallium nitride material. In this case, n = 2.5 and about 50 nm to 100 nm are appropriate. In particular, one of the greatest advantages of using a reflective diffraction grating is that this fine concavo-convex structure depth is the minimum necessary. For example, when a fine concavo-convex pattern is formed on a transparent electrode or the like and the diffraction phenomenon is used, the refractive index of the gallium nitride and ITO (indium tin oxide) transparent conductive film is about n = 2 to 2.5. Since the surrounding medium is air or the like, the uneven refractive index difference is relatively small at a maximum of about 1.5. In addition, since the optical path is unidirectional, in order to make the optical path length relatively long, it is necessary to make the depth of the fine uneven pattern relatively large. On the other hand, in the reflection type diffraction grating, the refractive index difference of the concavo-convex part can be the medium refractive index itself, and the optical path length difference is the reciprocal part of the convex part. A long optical path length can be secured.

If a relatively long optical path difference can be ensured with a relatively small uneven depth, a particularly significant effect can be obtained when microfabrication is performed on the surface portion of a semiconductor layer made of p-type gallium nitride. The resistance of p-type gallium nitride is relatively large. Compared to a semiconductor material such as GaAs, the bulk resistivity is relatively large, such as about 10 ³ to 10 ⁴ Ω · m. Therefore, the thickness of the semiconductor layer (contact layer 14) made of p-type gallium nitride needs to be relatively small. Specifically, it is necessary to form the semiconductor layer (contact layer 14) made of p-type gallium nitride to have a thickness of about 100 nm to 200 nm. In addition, in order to relatively increase the uneven height of the uneven microstructure, a relatively large defect may be generated in the light emitting layer 12 when a large-scale processing is performed such as forming a large etching groove in the contact layer. . In this case, the non-light emission order due to the defects in the light emitting layer 12 is increased, and there is a concern that the external quantum efficiency may be relatively lowered. Since the photonic crystal structure 23 has only a relatively small uneven depth, the defects in the light emitting layer 12 are small and the proportion of non-light emitting levels is also relatively small.

  The specific refractive index distribution of the concavo-convex microstructure is not represented by a simple periodic function such as the formula (2). However, as described above, the diffracted light electric field distribution is a Fourier transform of the aperture function. Basically, the same handling is possible. Here, in order to facilitate understanding, the description has been limited to a one-dimensional uneven microstructure, but the basic idea can be easily extended to a two-dimensional diffraction grating.

  In the case of a two-dimensional diffraction grating, the concave-convex microstructure can have various geometric structures with a period a, and for example, a square lattice, a triangular lattice, or the like can be considered. Furthermore, a structure in which a plurality of periods are superimposed is also possible.

  FIG. 2 is a partial plan view showing an example of the photonic crystal structure 23. In the present embodiment, the photonic crystal structure 23 is a two-dimensional photonic crystal, and is preliminarily formed in one main surface 14a of the contact layer 14 in two directions parallel to the main surface 14a and perpendicular to each other. The holes 41 are formed in a square lattice pattern with a predetermined interval T. The inner peripheral surface of the hole 41 is formed in a cylindrical shape. The predetermined interval T is a distance between the centers of adjacent holes 41 in two directions parallel to the main surface 14a and perpendicular to each other.

  The hole 41 is formed by forming a resist mask by photolithography and removing a portion of the contact layer 14 where the resist mask is not formed by reactive ion etching (RIE). Here, the shape of the hole 41 is formed so that the orthographic projection surface in the thickness direction of the contact layer 14 is circular, but the orthographic projection surface may be formed to be a regular polygon. The predetermined interval T is selected from, for example, 100 nm to 1000 nm, the depth d of the hole 41 is selected from 10 nm to 200 nm, and the maximum dimension of the orthographic projection plane in the thickness direction of the contact layer 14 of the hole 41 is 50 nm. It is preferable to be selected to ˜500 nm.

  Here, the hole 41 is formed in one main surface 14a of the contact layer 14, but the photonic crystal structure 23 is formed by forming a plurality of convex portions on one main surface 14a of the contact layer 14. It may be formed. The shape of the convex portion may be any of a columnar shape, a polygonal columnar shape, a cone, a polygonal thrust, a truncated cone and a polygonal thruster. In this case, the height of the convex portion is selected to be equal to the depth d of the hole 41, and the interval between the convex portions is selected to be equal to the interval T of the hole 41, and the orthographic projection in the thickness direction of the contact layer 14 of the convex portion. The maximum dimension of the surface diameter is selected to be equal to the maximum dimension of the orthographic projection plane in the thickness direction of the contact layer 14 of the hole 41.

  As described above, in the light emitting device 1, the light traveling from the light emitting layer 12 toward the one main surface 21 of the light emitting element 2 is reflected by the photonic crystal structure 23 toward the other main surface 22 of the light emitting element 2. . The photonic crystal structure 23 has a minute concavo-convex shape, and light is reflected in a predetermined direction by light interference according to the period of the concavo-convex and the optical path difference, and at a predetermined angle according to the structure. Since light can be reflected, a part of the light emitted from the light emitting layer 12 is optically converted as diffracted light and incident on the interface within the total reflection angle, thereby improving the light extraction efficiency outside the device. Thus, the external quantum efficiency can be improved.

  The photonic crystal structure 23 is covered with the metal film 4, and a reflective diffraction grating can be formed while ensuring electrical connection between the light emitting element 2 and the metal film 4. In the convex part of the photonic crystal structure 23 having the concavo-convex fine structure, the light traveling from the light emitting layer 12 toward the metal film 4 is reciprocally propagated. The height of the unevenness can be reduced to ½, and the height of the unevenness can be reduced. Since the concavo-convex portion is formed by processing the contact layer 14 of the light-emitting element, the height of the concavo-convex portion can be reduced, so that generation of non-light-emitting levels due to crystal defects can be suppressed. Formation becomes easy.

  Further, since the photonic crystal structure 23 has a minute uneven shape, the contact area with the metal film 4 can be made larger than when the metal film 4 is connected to a flat surface. Contact resistance can be reduced. Therefore, it is possible to improve the external quantum efficiency by suppressing the current supplied through the second electrode 7 from being consumed by heat.

  Furthermore, the light traveling from the light emitting layer 12 toward the one main surface 21 of the light emitting element 2 is reflected not only by the photonic crystal structure 23 but also by the metal film 4, so that light leaks to the support substrate 3 side. As a result, the formation accuracy required for the photonic crystal structure 23 can be relaxed, and the manufacturing cost can be reduced.

  FIG. 3 is a cross-sectional view showing a configuration of a light emitting device 51 according to another embodiment of the present invention. Since the light-emitting device 51 of the present embodiment and the light-emitting device 1 of the above-described embodiment are similar, the same components are denoted by the same reference numerals, the description thereof is omitted, and only different portions are described. To do. The light emitting device 51 basically includes the light emitting element 2, the support substrate 3, and the metal film 4, and further includes an electrode 52 and a connection layer 53.

  The light emitting element 2 is composed of a semiconductor layer similar to that of the above-described embodiment, and only the shape is different from that of the above-described embodiment. In the present embodiment, the light emitting element 2 is formed in a substantially rectangular parallelepiped shape. That is, the light emitting layer 12 is laminated on the entire surface of one main surface 11 a of the n-type semiconductor layer 11, and the photonic crystal structure 23 is formed over the entire surface of one main surface 14 a of the contact layer 14.

  In the present embodiment, support substrate 3 is made of a conductive metal material, for example, aluminum or an aluminum alloy, and functions as a conductive path and a heat sink.

  The metal film 4 of the light emitting element 2 is bonded to the support substrate 3 through a conductive connection layer 53. The connection layer 53 is formed by being laminated over the entire surface of one main surface 4 a of the metal film 4. The connection layer 53 is made of, for example, solder.

  An electrode 52 is provided on the peripheral edge 54 on the other main surface 22 of the light emitting element 2. The electrode 52 is made of the same material as the ohmic junction 25 of the first electrode 6 described above. The electrode 52 is formed in an annular shape at the peripheral edge 54.

  In the light emitting device 51 described above, the same effect as that of the light emitting device 1 described above can be achieved, and the distance between the light emitting element 2 and the support substrate 3 can be made closer to that of the light emitting device 1, and the crystal growth substrate can be obtained. 5 is not provided, it is possible to reduce the height by realizing a low profile. In addition, since the entire surface of one main surface 4a of the metal film 4 is supported by the support substrate 3 via the connection layer 53, the bonding strength can be improved and the heat dissipation can be improved. Therefore, the reliability of the light emitting device can be improved and the occurrence of thermal saturation can be suppressed.

  FIG. 4 is a flowchart showing a manufacturing process of the light emitting device 51. When the manufacturing process is started, the process proceeds from step s0 to step s1. In step s1, the crystal growth substrate 5 is prepared, and the light emitting element 2 including the photonic crystal structure 23 is formed on the crystal growth substrate 5. Then, the process proceeds to step s2. In step s1, first, the n-type semiconductor layer 11, the light emitting layer 12, the p-type semiconductor layer 13, and the contact layer 14 are formed on one main surface 5a of the crystal growth substrate 5 by using the MOCVD method or the MBE method. The semiconductor films are sequentially stacked. Then, a resist mask is formed on one main surface of the semiconductor film farthest from the crystal growth substrate 5 among the stacked semiconductor films using photolithography, and then the n-type semiconductor layer 11 and the light emitting layer 12 are etched. A plurality of stacked bodies each including the p-type semiconductor layer 13 and the contact layer 14 are formed. Then, after forming a resist mask on one main surface of each of the plurality of stacked bodies using photolithography, a plurality of holes 41 are formed in the contact layer 14 by RIE to form the light emitting element 2.

  In step s2, the metal film 4 is formed on one main surface 14a of the contact layer 14 by vapor deposition, and the process proceeds to step s3. In step s2, after vapor-depositing a metal so as to cover the plurality of light emitting elements 2, a resist mask is formed by stacking on the light emitting element 2 using photolithography, and then the metal between the light emitting elements 2 is removed by etching.

  In step s3, the support substrate 3 is prepared, solder is applied on one main surface 4a of the metal film 4 of each light emitting element 2, and this surface is made to face the support substrate 3, so that the substrate for crystal growth is obtained. While pressurizing 5 to the support substrate 3, the support substrate 3 is heated, each light emitting element 2 is joined to the support substrate 3, and it moves to step s4.

  In step s4, the crystal growth substrate 5 is removed, and the process proceeds to step s5. The crystal growth substrate 5 is removed by using a technique such as a laser lift-off method.

  In step s5, the electrode 52 is formed on the other main surface 22 of the light emitting element 2, and the process proceeds to step s6. In step s5, a metal is vapor-deposited on the other main surface 22 of the light emitting element 2, and a resist mask is formed by stacking on the light emitting element 2 using photolithography, and then the peripheral portion 54 of the light emitting element 2 is removed by etching. The metal between the portion and the light emitting element 2 is removed to form the electrode 52.

  In step s6, the support substrate 3 is diced into individual pieces to form a plurality of light emitting devices 51, and the process proceeds to step s7 to complete the process.

  By manufacturing the light emitting device 51 as described above, the photonic crystal structure 23 is formed with higher accuracy than the conventional technique of forming the photonic crystal structure in the portion where the substrate for crystal growth is removed. be able to. Further, instead of arranging each light emitting element 2 on the mounting substrate 3, a plurality of light emitting elements 2 on the crystal growth substrate 5 formed by patterning are collectively bonded to the support substrate 3. , Mounting accuracy can be improved.

  In each of the embodiments described above, the light-emitting element 2 includes the n-type semiconductor layer 11, the light-emitting layer 12, the p-type semiconductor layer 13, and the contact layer 14, but the n-type semiconductor layer 11, the light-emitting layer 12, and the p-type semiconductor layer. The light emitting layer 12 may be formed by a plurality of semiconductor layers instead of a single layer to form a multiple quantum well structure. For example, a buffer is provided between the crystal growth substrate 5 and the n-type semiconductor layer 11. A layer may be formed. In each embodiment, one conductivity type is n-type and the other conductivity type is p-type. However, one conductivity type may be p-type and the other conductivity type may be n-type. In each of the above-described embodiments, the light emitting element 2 is made of a GaN-based material, but may be made of, for example, a GaAs-based material. In this case, the photonic crystal structure 23 is appropriately set according to the oscillation wavelength. Just design.

It is sectional drawing which shows the structure of the light-emitting device 1 of one Embodiment of this invention. 4 is a partial plan view showing an example of a photonic crystal structure 23. FIG. It is sectional drawing which shows the structure of the light-emitting device 51 of other embodiment of this invention. 4 is a flowchart showing manufacturing steps of the light emitting device 51.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light-emitting device 2 Light emitting element 3 Support substrate 4 Metal film 5 Crystal growth substrate 6 1st electrode 7 2nd electrode 8 1st junction part 9 2nd junction part 12 Light emitting layer 23 Photonic crystal structure 51 Light-emitting device 52 Electrode 53 Connection layer 54

Claims (7)

A plurality of semiconductor crystal layers stacked, and a light emitting element including a light emitting region;
A support substrate that is disposed on one main surface side of the light emitting element and supports the light emitting element;
A reflective conductive film,
The one main surface portion of the light emitting element is formed with a photonic crystal structure that reflects light from the light emitting region to the other main surface side,
The light-emitting device, wherein the photonic crystal structure is covered with the reflective conductive film. An element side electrode electrically connected to the reflective conductive film is provided on the one main surface side of the light emitting element,
The support substrate is
The light-emitting device according to claim 1, wherein the element-side electrode is bonded to a substrate-side wiring film provided on a surface of the support substrate facing the light-emitting element to support the light-emitting element. . The support substrate is
2. The light emitting device according to claim 1, wherein the reflective conductive film is bonded to a substrate-side wiring film provided on a surface of the support substrate facing the light emitting device to support the light emitting device. apparatus.   The light emitting device according to claim 1, wherein the reflective conductive film and the semiconductor crystal layer of the light emitting element are in ohmic contact. The light emitting region of the light emitting element is configured to include gallium nitride,
The light-emitting device according to claim 1, wherein the reflective conductive film is made of an alloy containing silver and nickel, or silver or nickel. An electrode provided on a peripheral edge on the other main surface of the light emitting element;
The light-emitting device according to claim 1, wherein the reflective conductive film is bonded to a support substrate via a conductive connection layer. A step of stacking a plurality of semiconductor crystal layers on one main surface of the crystal growth substrate to form a light emitting element having a light emitting region;
Forming a photonic crystal structure that reflects light from the light emitting region on the other main surface side of the light emitting element on the one main surface portion of the light emitting element;
Forming a reflective conductive film so as to cover one main surface of the light emitting element;
Bonding the support substrate supporting the light emitting element to the reflective conductive film;
And a step of removing the crystal growth substrate.

Images