TW201703291A - Substrate and method for manufacturing same, light-emitting element and method for manufacturing same, and device having said substrate or said light-emitting element - Google Patents

Abstract

To provide a substrate having a desired pattern on a surface thereof and a method for manufacturing the substrate, as well as a light-emitting element and a method for manufacturing said element, in which photosensitivity is imparted to a dielectric film composition and a pattern of protrusions can be formed without the use of a photoresist film, which makes it possible to reduce the number of steps and lower the costs associated with the reduction in the number of steps. A flat substrate is readied, a dielectric containing a photosensitive agent is formed on the surface of the substrate, and the dielectric is patterned to form the dielectric in a desired pattern on the surface of the substrate, yielding a flat substrate having a pattern comprising island-shaped protrusions formed on the surface thereof, the protrusions being configured from the dielectric.

Description

Substrate and manufacturing method thereof, light emitting element and manufacturing method thereof, and device having the same

The present invention relates to a substrate and a method of manufacturing the same, a light-emitting element and a method of manufacturing the same, and an apparatus having the substrate or the light-emitting element.

A light-emitting diode (LED) is one of EL (Electro Luminescence) elements that converts electric energy into light energy by using a compound semiconductor characteristic, and a light-emitting diode is practically used by a Group 3-5 compound semiconductor. Such a Group 3-5 compound semiconductor is a direct transition type semiconductor, and is stable at a high temperature compared to an element using other semiconductors. Furthermore, the Group 3-5 compound semiconductors are widely used in various lighting devices, lighting, electronic equipment, and the like because of their excellent energy conversion efficiency or long service life.

A light-emitting element of such an LED (hereinafter referred to as a "light-emitting element") is formed on a surface of a sapphire (Al ₂ O ₃ ) substrate, and a schematic diagram of the structure is shown in FIG. 17 (for example, refer to Patent Document 1 and FIG. 3). ). As shown in Fig. 17, the conventional light-emitting element 100 forms an n-type GaN contact layer (n-GaN layer) on a surface of the sapphire substrate 101 via a low-temperature growth buffer layer (not shown) made of a GaN-based semiconductor material. 102. An n-type electrode is formed on the n-GaN layer 102. An n-type AlGaN coating layer (not shown. omitting), an InGaN light-emitting layer (active layer) 103, and a p-type AlGaN cladding layer 104 are formed on the n-GaN layer 102, and a p-type GaN contact layer 105 is formed thereon. Further, an ITO (Indium Tin Oxide) transparent electrode 106 as a p-type electrode and a metal electrode are formed on the p-type GaN contact layer 105. The InGaN light-emitting layer 103 employs a multiple quantum well layer structure (MQW: Multiple Quantum Well) composed of an InGaN well layer and an InGaN (GaN) barrier layer. Further, a position where the InGaN light-emitting layer 103 is not formed on the n-GaN layer 102 forms an n-type electrode layer 107.

The light emitted from the InGaN light-emitting layer 103 of the light-emitting element 100 is taken out from the p-type electrode and/or the sapphire substrate 101, and the light-emitting efficiency is improved to reduce the misalignment. However, the GaN layer grown on the sapphire substrate 101 has a difference in lattice constant between the lattice constant of sapphire and the lattice constant of GaN, and due to the difference in lattice constant, it is a high-density non-light-emitting recombination in GaN crystal. The operation of the center creates a contradiction. This through-dislocation is responsible for the simultaneous reduction of light output (internal quantum efficiency) and endurance life, resulting in an increase in leakage current.

Furthermore, in the wavelength of the blue region, the refractive index of GaN is about 2.4, the refractive index of sapphire is about 1.8, the refractive index of air is 1.0, about 0.6 between GaN and sapphire, and about 1.4 between GaN and air. The difference in refractive index. Due to this refractive index difference, the light emitted from the InGaN light-emitting layer 103 is totally totally reflected between the p-type electrode, the interface between GaN and air, and the sapphire substrate 101. Due to this total reflection, the light is self-absorbed when it is propagated in the InGaN light-emitting layer 103 and propagates in the InGaN light-emitting layer 103, or is absorbed by an electrode or the like, and finally converted into heat. That is, the light extraction efficiency of the light-emitting element is greatly reduced due to the limitation of total reflection due to the difference in refractive index.

In order to enhance the light extraction efficiency, for example, a concave-convex pattern is formed on a surface of a sapphire substrate, and the above-described GaN layers 102 to 105 or light-emitting elements are formed on the uneven pattern. The formation of the concavo-convex pattern is a method of etching the surface of the sapphire substrate. Further, a light-emitting element which further improves the manufacturing efficiency of the uneven pattern is disclosed, and a concave-convex pattern composed of a dielectric material such as SiO ₂ , ZrO ₂ or TiO _{2 having a} refractive index smaller than that of GaN is formed on the surface of the flat sapphire substrate. Element (for example, refer to FIG. 1 of Patent Document 1).

The light-emitting element 108 disclosed in Patent Document 1 shown in Fig. 18 is formed on the surface of the sapphire substrate 101, and forms a pattern of the convex portion 109 made of a dielectric. By forming the pattern of the convex portion 109 on the surface of the sapphire substrate 101, a concave-convex refractive index interface can be formed under the InGaN light-emitting layer 103. Therefore, a portion of the light that has propagated in the lateral direction of the InGaN light-emitting layer 103 and is absorbed by the inside of the light-emitting element 108 can be taken out to the outside of the sapphire substrate 101 and the InGaN light-emitting layer 103 via the light scattering effect of the convex portion 109. In turn, the light extraction efficiency can be improved. Further, it is not necessary to etch the surface of the sapphire substrate 101, and the luminous efficiency of the light-emitting element 108 can be improved. At the same time, a growth mode of FACELO (Facet-Controlled Epitaxial Lateral Overgrowth) can be realized, and a GaN-based light-emitting element with reduced dislocation density can be obtained. .

[Previous Technical Literature]

[Patent Literature]

Patent Document 1: Japanese Laid-Open Patent Publication No. 2009-54898

However, in Patent Document 1 and the like, for the pattern formation of the convex portion 109, a general photo etching technique is used. In other words, when the convex portion 109 is formed, the SiO ₂ film which is the base of the convex portion 109 must be formed of a photoresist film formed of a phenol resin or the like on the SiO ₂ film, and patterned by the photomask. The resist film is formed by patterning a photoresist film as a new mask and etching the SiO ₂ film by etching. Therefore, since the film forming step of the photoresist film or the exposure step, the development step, and the etching step of the SiO ₂ film are necessary, the number of processes is increased, and the cost increases as the number of processes increases.

Further, when the convex portion 109 is formed by photolithography and etching, it is necessary to pass through the step of exposing and developing the photoresist film. In this case, since the cross-sectional shape of the convex portion 109 which can be formed is limited to the shape of the mesa, the degree of freedom of the shape of the convex portion which can be formed becomes low. Therefore, when the light extraction efficiency is improved and the convex portion having a cross-sectional shape capable of shortening the growth time of the GaN layer covering the convex portion is formed, the photoetching technique of the photoresist film formed on the dielectric film and as the light thereof The etching process of the cover becomes difficult

In addition, the patterned SiO ₂ film is formed as a new mask by etching on the surface of the sapphire substrate for patterning. In the end, the SiO ₂ film pattern manufacturing step in the process must have photoetching technology and etching of the photoresist film. machining. Therefore, the number of processes is increased and the cost is increased as the number of processes increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a photosensitive film composition having such a photosensitive property, and a convex pattern can be formed even without a photoresist film, so that the number of processes can be reduced, and the number of processes can be reduced to reduce the cost. A substrate having a predetermined pattern thereon, a method of manufacturing the same, and a light-emitting element and a method of manufacturing the same.

The above problems can be achieved by the following invention. that is,

(1) A method of manufacturing a substrate according to the present invention, wherein a flat substrate is prepared, a dielectric containing a photosensitive agent is formed on the surface of the substrate, and the dielectric is patterned to form a dielectric having a predetermined pattern on the surface of the substrate.

(2) In one embodiment of the method for producing a substrate of the present invention, after the dielectric pattern is formed, the dielectric is annealed, whereby the dielectric having the predetermined pattern is formed on the substrate surface. Further, in another embodiment of the method of manufacturing a substrate, it is preferable to post-baize the dielectric before the annealing after forming the pattern of the dielectric.

(3) Further, in another embodiment of the method for producing a substrate of the present invention, it is preferred that the post-baking is performed in a temperature range of from 100 ° C to 400 ° C.

(4) Further, in another embodiment of the method for producing a substrate of the present invention, it is preferred that the annealing be performed in a temperature range of from 700 ° C to 1700 ° C.

(5) In another embodiment of the method for producing a substrate of the present invention, the dielectric material is a siloxane oxide resin composition, a cerium oxide-containing cerium oxide resin composition, a zirconia-containing cerium oxide resin composition, and a composition. Any of the aluminoxane resin compositions of alumina is preferred.

(6) In another embodiment of the method for producing a substrate of the present invention, the dielectric is applied to the surface of the substrate, whereby the dielectric is formed on the surface of the substrate, and then the substrate is formed on the surface of the substrate. The substrate of the dielectric is pre-baking, and then the dielectric is exposed to a desired pattern using a photomask, and then the exposed dielectric is developed, and the dielectric is annealed to form the pattern. Preferably, the dielectric is formed on the surface of the substrate.

(7) Further, in another embodiment of the method for producing a substrate of the present invention, the dielectric is directly patterned by using the desired pattern in the above-described pattern. On the substrate surface, the substrate on which the dielectric is formed on the substrate surface is prebaked, and then the dielectric is exposed, and the dielectric is annealed to form the dielectric having the predetermined pattern on the substrate surface. It is better.

(8) In another embodiment of the method for producing a substrate of the present invention, the dielectric is applied to the surface of the substrate, whereby the dielectric is formed on the surface of the substrate, and then the mold is pressed onto the dielectric to cause the The dielectric is cured, and the dielectric is annealed so that the dielectric having the predetermined pattern is formed on the surface of the substrate.

(9) In the method of manufacturing a substrate of the present invention, the substrate is prepared, and the surface of the substrate is etched by using the pattern as a mask, and a desired pattern is formed on the surface of the substrate.

(10) In the method of producing a light-emitting device of the present invention, the substrate is prepared, and at least one GaN layer, an AlN layer, and an InN layer are formed on the convex portion and the substrate to produce a light-emitting element.

(11) Further, the substrate of the present invention has a pattern composed of island-like convex portions on the surface of the flat substrate, and the convex portion is made of a dielectric. Also, the substrate can be applied to a light source or display or a solar cell.

(12) In an embodiment of the substrate of the present invention, it is preferable that at least a portion of the convex portion has a curved surface (having a curved surface).

(13) In another embodiment of the substrate of the present invention, it is preferable that the dielectric constituting the convex portion has SiO ₂ , TiO ₂ , ZrO ₂ , and Al ₂ O ₃ as a main component.

(14) In another embodiment of the substrate of the present invention, the convex portion is a curved surface as a whole, and the top portion and the side portion are indistinguishable, and a curved surface shape having no flat surface is preferable.

(15) In another embodiment of the substrate of the present invention, it is preferable that the convex portion has a hemispherical shape.

(16) Further, in another embodiment of the substrate of the present invention, it is preferable that the planar shape of the convex portion is circular or elliptical.

(17) Further, in the substrate of the present invention, it is preferred that the surface of the substrate has a desired pattern as described above.

(18) Further, in the substrate of the present invention, the pattern has a uniform pitch on the surface of the substrate, and the pattern defect portion of the pattern is not formed in the surface of the pitch, and in the case where the pitch is formed, It is preferable that all of the above-mentioned patterns in the surface are 0% or more and 50% or less.

(19) The light-emitting element of the present invention includes the convex portion and the light-emitting element of the GaN layer, the AlN layer, and the InN layer formed on at least one of the substrates.

Also, the light-emitting element is preferably applied to a light source or a display.

According to the invention of any one of the above (1), (9), (11), and (17), since the dielectric containing the sensitizer is formed by patterning, it is not necessary to form a photoresist film, and a convex portion can be formed on the substrate surface. Scheduled pattern. Therefore, it is possible to reduce the number of processes, simplify the steps, and reduce the cost of the substrate as the number of processes is reduced. and Further, the substrate obtained thereby is suitable for use in a light source, a display, a substrate, or the like.

Further, according to the invention of the above (2), since the dielectric after the formation of the desired convex portion pattern is annealed, a desired pattern on the surface of the substrate can be formed into an arbitrary side shape. Further, the components of the photosensitive agent are removed by annealing, and the organic component can be prevented from being mixed into the light-emitting element such as the GaN layer.

Further, according to the invention of the above (3), since the post-baking is performed in a temperature range of 100 ° C or more and 400 ° C or less, the fluidity of the dielectric can be improved, and all or a part of the top/side portion of the dielectric pattern can be curled. Since it is formed into a curved shape, the light extraction efficiency of the light-emitting element can be improved. In addition, when the convex portion having a trapezoidal shape or a rectangular shape is compared, the convex portion is formed into a curved shape, and when the GaN layer or the like is formed, the growth time of the GaN layer in the lateral direction is shortened, so that the growth of the GaN layer can be shortened. time.

In addition, according to the invention of the above (4), annealing is performed in a temperature range of 700 ° C or more and 1700 ° C or less, and the photosensitive material component of the convex portion is removed by annealing, and the organic component is prevented from being mixed into the light-emitting element such as a GaN layer. . Further, it is possible to prevent the growth of the GaN layer from occurring on the convex portion or to make it difficult to grow. By suppressing the growth of the GaN layer on the convex portion, the growth mode of FACELO can be realized, and thus a GaN layer having a reduced dislocation density can be formed. Further, the convex portion after annealing can have heat resistance, and the shape and physical properties of the convex portion can be maintained even at the film formation temperature (about 1000 ° C) at the time of film formation of the n-GaN layer.

Further, according to the invention of the above (5), the composition of the decane resin, the cerium oxide resin composition containing titanium oxide, the cerium oxide resin composition containing zirconia, and the cerium oxide resin containing alumina The coating property is good, so that the surface of the substrate formed without the photoresist film can be formed into a uniform thickness or height. Chaotic dielectric. Further, compared with other resins, titanium oxide-containing resins, zirconia-containing resins, and alumina-containing resins, the hardening shrinkage is small, and therefore, the convex portions can be easily formed on the substrate surface at a desired height, size, and pitch. Further, a decane resin composition, a cerium oxide-containing cerium oxide resin composition, a zirconia-containing cerium oxide resin composition, and an alumina-containing cerium oxide resin composition are compared with other resins and titanium oxide-containing compounds. The resin, the zirconia-containing resin, and the alumina-containing resin are less likely to cause cracks after curing. Therefore, voids are less likely to occur in the dielectric of the convex portion, and when the GaN layer is grown, the interface between the convex portion and the GaN layer is less likely to cause a gap (hole). . Therefore, deterioration of electrical characteristics in the light-emitting element can be prevented.

Further, according to the invention of the above (6), a desired pattern formation by a photo-etching method using a dielectric containing a photosensitive agent can be performed, and a pattern can be formed on the surface of the substrate on which the photoresist film is not formed. Therefore, the number of processes is reduced, the steps are simplified, and the number of processes is reduced to reduce the cost of the substrate. Further, since the time of the step is short, the substrate having the desired pattern on the surface can be produced in a short time.

Further, according to the invention of the above (7), the inkjet method is used for the desired pattern formation, and the pattern formation can be directly performed, so that the degree of freedom of the type of the convex portion pattern is improved.

Further, according to the invention of the above (8), it is possible to form a pattern of convex portions having a desired size, pitch, and height on the substrate surface with a simple apparatus and at a low cost by using a nanoimprint method in a desired pattern formation.

Further, according to the invention of the above (10) or (19), the convex portion is formed on the surface of the substrate, and therefore, each convex portion has a light scattering effect. Therefore, a part of the light absorbed by the inside of the light-emitting element can be taken out to the outside of the substrate and the InGaN light-emitting layer, and the light extraction efficiency of the light-emitting element can be improved. And the luminescent element thus obtained The piece can be applied to a light source or a display.

Further, since the dielectric containing the photosensitive agent is formed by patterning, a desired pattern composed of the convex portions can be formed on the substrate surface, so that a pattern can be formed on the surface of the substrate on which the photoresist film is not formed. Therefore, it is possible to manufacture the light-emitting element in which the light extraction efficiency is improved while realizing the reduction in the number of processes and the simplification of the steps, and the reduction in the cost of the light-emitting element as the number of processes is reduced.

Further, according to the invention of the above (12), since one portion of the convex portion is formed in a curved shape, the light extraction efficiency of the light-emitting element can be further improved. In addition, the convex portion having a trapezoidal shape or a rectangular shape is formed into a curved convex portion, and the growth time in the lateral direction of the GaN layer is shortened when a GaN layer or the like is formed, so that the growth of the GaN layer can be shortened. time.

According to the invention of the above (13), the material constituting the convex portion is a dielectric material containing SiO ₂ , TiO ₂ , ZrO ₂ or Al ₂ O ₃ as a main component, and the growth of the GaN layer on the convex portion can be prevented. Or it is difficult to grow. By suppressing the growth of the GaN layer on the bump, the FACELO growth mode can be realized, so that a GaN layer having a reduced dislocation density can be formed.

Further, according to the invention of the above (14) or (15), since the convex portions are all formed by the curved surface, there is no difference between the top portion and the side portion, and there is no curved surface shape in which the flat surface exists, and therefore, the light extraction of the light-emitting element can be improved. effectiveness. Furthermore, the convex portion is formed into a hemispherical shape to further enhance the above-described light extraction efficiency. As described above, the convex portion having a trapezoidal shape or a rectangular shape is formed into a curved convex portion, and the growth time in the lateral direction of the GaN layer is shortened when a GaN layer or the like is formed, so that the GaN layer can be shortened. Growth time.

Furthermore, according to the invention of (16) above, the planar shape of the convex portion is The shape is set to a circular or elliptical shape, which simplifies the patterning step of the dielectric layer. In particular, by setting the planar shape to a circular shape, the above effect can be multiplied, and even if interaction (for example, interference) of reflection, refraction, attenuation, and the like of light caused by a plurality of convex portions occurs, the interaction does not occur. Since the light is emitted uniformly in all directions, it is possible to produce a light-emitting element having high light extraction efficiency.

According to the invention of the above (18), all of the pattern defects are set to 0% or more and 50% or less with respect to the ratio of all the patterns on the surface of the substrate, so that the light-emitting elements fabricated on the same substrate can be reduced. Inconsistent light output between components.

1‧‧‧Substrate with a predetermined pattern on the surface

1a‧‧‧Substrate

2b‧‧‧ convex

2‧‧‧n-type GaN contact layer (n-GaN layer)

3‧‧‧InGaN luminescent layer (active layer)

4‧‧‧p-type AlGaN coating

5‧‧‧p-type GaN contact layer

6‧‧‧p-type electrode

7‧‧‧n type electrode layer

8‧‧‧LED light-emitting components

9‧‧‧Metal electrode

10‧‧‧Photomask

11‧‧‧ model

12‧‧‧ nozzle

13‧‧‧-shaped convex

14‧‧‧Rectangular convex

100‧‧‧Lighting device

101‧‧‧Light source (light-emitting element)

200‧‧‧ display device

201‧‧‧Light source (lighting element)

300‧‧‧Solar battery

301‧‧‧Substrate

Fig. 1 is a schematic view showing the configuration of a light-emitting element related to the present invention.

Fig. 2 is a schematic view showing a substrate having a predetermined pattern on a surface according to the present invention.

Fig. 3(a) is an enlarged side view showing the substrate shown in Fig. 2.

Fig. 3(b) is an enlarged plan view showing a portion of the substrate shown in Fig. 2, showing only the convex portion.

Fig. 4(a) is an enlarged side view showing a substrate of a pattern having a convex portion having a planar elliptical shape on the surface according to the present invention.

Fig. 4(b) is a partial plan view showing only the convex portion of the substrate shown in Fig. 4(a).

Fig. 4(c) is an enlarged side view showing the substrate shown in Fig. 4(a) from a 90-degree different direction.

Fig. 4(d) is a partial plan view showing only the convex portion of the substrate shown in Fig. 4(c).

Fig. 5(a) shows only the convex portion of the present invention in which the plane shape is triangular Part of the floor plan.

Fig. 5(b) is a partial plan view showing only the convex portion in which the planar shape of the present invention is hexagonal.

Fig. 6 is a perspective view showing a substrate having a pattern having a convex portion having a planar polygonal shape on the surface according to the present invention.

Fig. 6A is an enlarged side view of the substrate of a variation of the substrate.

Fig. 6A(a) is an enlarged side view showing a substrate of a variation of the substrate shown in Fig. 3(a).

Fig. 6A(b) is an enlarged side view showing a substrate of a variation of the substrate shown in Fig. 4(c).

Fig. 6A(c) is an enlarged side view showing a substrate of a variation of the substrate shown in Fig. 6.

Fig. 7(a) is a view showing an enlarged stage of a convex portion of a GaN layer in a convex portion having a mesa shape.

Fig. 7(b) is a view showing an enlarged stage of a convex portion of a GaN layer in a convex portion having a rectangular shape.

Fig. 7(c) is a plan view showing a growth stage of the GaN layer in the convex portion in which all the patterns are formed into a curved shape, and is an enlarged view of the convex portion.

Fig. 7(d) shows a stage in which the GaN layer is formed in a convex portion formed in a curved shape at the top portion, and is an enlarged view of the convex portion.

Fig. 8 is a view showing a manufacturing process of the photolithography method according to an embodiment of the manufacturing method of the embodiment.

Fig. 9 is a view showing another embodiment of the manufacturing method of the embodiment, and a manufacturing procedure of the imprint method.

Fig. 10 is a view showing another aspect related to the manufacturing method of the embodiment. Schematic diagram of the manufacturing steps of the ink jet method.

Figure 11 is a cross-sectional view showing the manufacturing process of the light-emitting element of the present invention.

Fig. 12 is a view showing an AFM image of a cross-sectional shape of a convex portion of an embodiment of the present invention.

Fig. 13 is a view showing the AFM side view of the convex shape of the embodiment of the present invention.

Fig. 14 is a lighting device including a light source having the light-emitting element of the present invention.

Fig. 15 is a view showing a display device including a light source of the light-emitting element of the present invention.

Fig. 16 is a solar cell including the substrate of the present invention.

Fig. 17 is a schematic view showing the configuration of a conventional light-emitting element.

Fig. 18 is a schematic view showing the configuration of a conventional light-emitting element.

Hereinafter, a substrate which can be used for formation of a GaN layer for a light-emitting element, a substrate having a desired pattern on the surface, and a light-emitting device using the substrate will be described with reference to FIGS. 1 to 7. In the first embodiment, the substrate 1 having a desired pattern on the surface (hereinafter referred to as "substrate 1") is a base substrate of the LED light-emitting element 8 (hereinafter referred to as "light-emitting element 8"). Further, as shown in Fig. 2, the substrate 1 has a pattern composed of island-like convex portions 1b on the surface of the flat substrate 1a. Further, the convex portion 1b is made of a dielectric.

The island shape refers to the height from the top of the convex portion 1b to the surface of the substrate 1a in the thickness direction of the substrate 1a, and each convex portion 1b has an independent convex shape. Therefore, from the top of the convex portion 1b to the height of the surface of the substrate 1a, as long as each convex portion 1b has an independent convex shape, that is, an island-like pattern is satisfied, the substrate 1a is oriented from the substrate plane (Fig. 1 or 2) When viewed from the upper direction, the convex portions 1b are separated from each other, or the bottom surface of the convex portion 1b, that is, the side portions of the convex portions 1b on the surface of the substrate 1a are connected to each other.

The convex portion 1b is formed on the surface of the substrate 1a, and therefore, each convex portion 1b has a light scattering effect. Therefore, a part of the light absorbed inside the light-emitting element 8 can be taken out to the outside of the substrate 1a and the InGaN light-emitting layer 3, and the light extraction efficiency of the light-emitting element 8 can be improved.

The growth of the n-type GaN contact layer (n-GaN layer) 2 starts from the surface of the substrate 1a between the convex portions 1b, that is, the flat portion having no convex portion 1b, and becomes thicker as the thickness of the n-GaN layer 2 becomes thicker. The side and the top of the part 1b. Therefore, the surface of the cover substrate 1a and the pattern of the convex portion 1b form a GaN layer.

The substrate 1a is made of sapphire (Al ₂ O ₃ ), Si, SiC, GaAs, InP, spinel, etc., and a group 3-5 compound semiconductor can grow as a possible material, particularly sapphire, from a group 3-5 compound. The viewpoint of semiconductor formation is optimal. Hereinafter, the sapphire substrate is used as the substrate 1a as an example, and the description will be continued.

When the sapphire substrate is used as the substrate 1a, the surface of the substrate 1a may be appropriately selected from the C surface, the A surface, the R surface, or the like, or the surfaces may be inclined.

In addition, from the viewpoint of preventing the occurrence of defects in the growth of the crystals in the n-GaN layer 2, the surface of the substrate 1a at the start of growth of the n-GaN layer 2 has a mirror surface roughness of about 1 nm or less. good. In order to make the surface of the substrate 1a mirror-finished, for example, mirror polishing is preferably performed.

The material of the convex portion 1b is a dielectric containing a sensitizer. By forming the convex portion 1b by the dielectric containing the photosensitive agent, the pattern of the convex portion 1b can be formed on the surface of the substrate 1a even if there is no photoresist film (that is, the etching mask for forming the film by the convex portion 1b) as will be described later. . Further, as the dielectric material forming the convex portion 1b, a composition containing a binder resin or a sensitizer in a dielectric containing SiO ₂ , TiO ₂ , ZrO ₂ or Al ₂ O ₃ as a main component is preferable, and oxygen is used. An alkane resin is preferred as the resin. Examples of the dielectric composition include a photosensitive decane resin composition, a photosensitive titanium oxide-containing decane resin composition, a photosensitive zirconia-containing decane resin composition, and a photosensitive content. A hafnium oxide resin composition of alumina.

The decane resin composition contains a polymer having a main skeleton bonded with a decane. The polymer having a main skeleton bonded by a siloxane is not particularly limited, and preferably has a weight average molecular weight (Mw) of from 1,000 to 100,000 in terms of polystyrene measured by a gel permeation chromatography (GPC). More preferably, it is 2000~50000. When the Mw is less than 1,000, the coating property is deteriorated, and when it is more than 100,000, the solubility in the developer at the time of pattern formation is deteriorated.

Since the decane resin composition, the cerium oxide-containing cerium oxide resin composition, the zirconia-containing cerium oxide resin composition, and the alumina-containing cerium oxide resin composition have good coating properties, they can be used in the absence of light. The surface of the substrate 1a on which the resist film is formed forms a disorder-free dielectric with a uniform thickness or height. Further, compared with other resins, titanium oxide-containing resins, zirconia-containing resins, and alumina-containing resins, the hardening shrinkage is small, and therefore, the convex portions 1b can be easily formed on the surface of the substrate 1a at a desired height, size, and pitch. . Further, the decane resin composition, the cerium oxide-containing cerium oxide resin composition, the zirconia-containing cerium oxide resin composition, and the alumina-containing cerium oxide resin composition are compared with other resins and titanium oxide-containing resins. The zirconia-containing resin or the alumina-containing resin is less likely to cause cracks after curing, so that voids are less likely to occur in the dielectric of the convex portion, and the interface between the convex portion 1b and the GaN layer is less likely to occur when the GaN layer (2 to 5) is grown. Clearance (hole). Therefore, deterioration of electrical characteristics in the light-emitting element 8 can be prevented. Further, the above-described pitch means the minimum distance between the centers of the adjacent convex portions 1b.

In addition, since the material constituting the convex portion 1b is a dielectric material containing either SiO ₂ , TiO ₂ , ZrO ₂ or Al ₂ O ₃ as a main component, growth of the GaN layer on the convex portion 1b can be prevented or growth is less likely to occur. By suppressing the growth of the GaN layer on the convex portion 1b, the growth mode of FACELO can be realized, so that a GaN layer having a reduced dislocation density can be formed.

Further, the size of the convex portion 1b and the pitch between the convex portions 1b are set to at least λ/(when the light-emitting wavelength in the GaN layer of the light-emitting element 8 is set to λ from the viewpoint of sufficiently scattering or refracting light. 4n) Above is better. In addition, the size of the convex portion 1b is variously set depending on the planar shape of the convex portion 1b. However, when the planar shape is a circular shape to be described later, when the length of the radius is elliptical, The length of the radius indicated by the short axis direction is a length of one of the sides of the convex portion 1b when it is a polygonal shape. Further, n is a refractive index of the GaN layer, one of which is about 2.4. Further, when the substrate 1a is used in the light-emitting element 8, the refractive index of the dielectric is preferably at least different from the refractive index of gallium nitride (GaN). Further, from the viewpoint of preventing light penetration on the substrate side and improving the luminance of the light-emitting element, the refractive index of the dielectric is preferably smaller than the refractive index of gallium nitride (GaN).

When the total thickness of all the GaN layers 2 to 5 is 30 μm or less, the pitch between the convex portions 1b is preferably 50 μm or less from the viewpoint of reducing the total number of times of scattering or refracting light. Further, from the viewpoint of improving the crystallinity of the GaN layer (that is, preventing the occurrence of pits), the pitch between the convex portions 1b is preferably 20 μm or less. More preferably, the pitch between the convex portions is set to 10 μm or less, and by setting the pitch to 10 μm or less, the light scattering surface is increased to increase the incidence of light scattering or refraction, and the light extraction efficiency of the light-emitting element 8 can be further improved.

The side surface shape of the convex portion 1b is formed in a curved shape by at least a part of the convex portion 1b as shown in Fig. 3(a), Fig. 4(a) and Fig. 4(c), or Fig. 6; It is better. That is, at least a portion of the convex portion 1b has a curved surface. The light extraction efficiency of the light-emitting element 8 can be improved by forming a portion of the convex portion 1b into a curved shape. Further, the convex portion 1b formed into a curved shape as compared with the convex portion having a trapezoidal shape or a rectangular cross section on a surface perpendicular to the substrate, and a GaN layer formed when a GaN layer (2 to 5) or the like is formed. Since the growth time in the lateral direction is shortened, the growth time of the GaN layer can be shortened. In detail, as shown in Fig. 7(a), the convex portion 13 having a side shape in the shape of a table or the convex portion 14 having a rectangular shape on the side surface of Fig. 7(b) causes the GaN layer to grow in the lateral direction, and the GaN layer is as an arrow. It is shown that the first growth side portions 13a, 14a, and then the growth of the top portions 13b, 14b, must undergo two stages of growth. On the other hand, since the convex portion 1b which is formed into a curved surface as in the pattern of Fig. 7(c) can be formed on the convex portion 1b by continuing the lateral growth as indicated by the arrow, the growth time of the GaN layer can be shortened. . Further, as a part of the top portion of Fig. 7(d) is formed into a curved convex portion 1b, since the growth of the GaN layer at the side portion 1c can be quickly moved to the top portion 1d, the growth time of the GaN layer can be shortened. Even if only one of the side portions is formed into a curved convex portion, the growth of the GaN layer on the side portion is promoted, and the growth of the GaN layer can be shifted to the top, so that the growth time of the GaN layer can be shortened.

One of the shapes of the shape of the specific convex portion 1b is a polygonal shape as shown in Fig. 5(a) or Fig. 5(b), and the side surface shape is the side portion 1c shown in Fig. 6 . It is inclined, and the convex top portion 1d is formed into a curved shape.

When the wedge angle θ is 90°, the cross-sectional shape of the convex portion 1b becomes a rectangle, and when it is 180°, the convex portion 1b is completely flat. Since the convex portion 1b is to be buried with the GaN layer, the wedge angle θ must be at least 90° or more.

A slightly polygonal shape refers to a triangle or a hexagon. It does not have to be a geometrically complete polygon, including a lot of angles at the corners or side points due to processing. The angle is inside. Since the planar shape of the convex portion 1b is formed into a triangular shape or a hexagonal shape, a vertex having a vertex that is almost parallel to the growth and stability surface of the GaN layer can be formed, and a straight line intersecting with a surface almost parallel to the growth and stability surface of the GaN layer can be a constituent side.

Further, as another form of the planar shape of the convex portion 1b, from the viewpoint of enhancing the light extraction efficiency and shortening the growth time in the lateral direction of the GaN layers (2 to 5), the convex portions 1b are all formed into a curved surface, and have a top portion and The side portion is indistinguishable, and the curved surface shape in which no flat surface exists is preferable, and the convex portion 1b is preferably a hemispherical shape as shown in Fig. 3(a). Therefore, in each portion of the convex portion 1b, the curvature is larger than 0, and no corner portion exists except for the position where the convex portion 1b is connected to the substrate 1a. Further, the substrate 1a and the convex portion 1b shown in each of Figs. 3(a), 4(c), and 6th, respectively, may have variations as shown in Fig. 6A. In the variation shown in FIGS. 6A(a) and 6A(b), when the convex portions 1b are all formed by curved surfaces, the curved surface has an inflection point in the middle, and the front and back of the inflection point have the top and the top. The curvature of the surface has a curved surface 1f of opposite sign curvature. Further, the modification shown in (c) of Fig. 6A has a portion 1c which is a front surface 1c, and has a curved surface 1f having an opposite sign curvature from the curvature of the top curved surface. In these variations, since the convex portion 1b is smoothly continuous from the substrate 1a, the growth of the GaN layer is promoted, and the growth time can be shortened. Further, the convex portion 1b of Fig. 4(a) may also have the same curved surface 1f.

Further, the planar shape of the convex portion 1b is preferably a circular shape as shown in Fig. 3(b) or an elliptical shape as shown in Figs. 4(b) and 4(d). However, since it is formed in a circular shape, light reflection, refraction, attenuation, and the like caused by the plurality of convex portions 1b, 1b interact with each other (for example, interference), and the light is omnidirectional due to the non-directionality of the interactions. Uniform emission, so it can produce high light extraction efficiency Light-emitting element 8. Therefore, the convex portion 1b having a circular planar shape is more preferable. Further, when the planar shape is set to a circular shape or an elliptical shape, the dielectric layer can be simplified as described later in the patterning step.

It is desirable that all the convex portions 1b formed on the surface of the substrate 1a have the same size and shape. However, the size, shape, or curvature of each convex portion 1b may be somewhat different. Further, the arrangement of the convex portions 1b is not particularly limited, and may be arranged in a regular pitch as in a lattice-like arrangement, and may be arranged in an irregular pitch. Alternatively, as the planar shape of the convex portion 1b, a circular or elliptical shape and a slightly polygonal shape may be used in combination on the surface of one substrate 1a.

However, it is desirable that the pattern of the convex portion 1b is formed uniformly and periodically on the surface of the substrate 1a in terms of its size, height, shape, and pitch. If the periodic structure is derailed by a portion of the convex portion 1b, the light output between the elements fabricated in the light-emitting element of the substrate 1a may be inconsistent. Therefore, in the surface of the substrate 1a where the convex portion 1b should be formed at a uniform pitch, all of the positions where the pattern of the convex portion 1b is not formed (the defect of the pattern of the convex portion 1b) are formed with a uniform pitch. In the case of the portion 1b pattern, it is desirable to be in the range of 0% or more and 50% or less with respect to all of the patterns on the surface of the substrate 1a. According to this configuration, the inconsistency in light output between the elements of the light-emitting element 8 fabricated on the same substrate 1a can be reduced. The ratio of all the pattern defects (all of the pattern defects or all of the patterns on the surface of the substrate 1a) to all the patterns on the surface of the substrate 1a is described below as "pattern defect". When the ratio of the pattern defect exceeds 50%, the number of the convex portions 1b on the surface of the substrate 1a is insufficient due to the growth of the GaN layer in the lateral direction, and it becomes easy to introduce crystal defects into the GaN layer.

Furthermore, by making the ratio of pattern defects 0% to 30% The production in the lower range makes it easier to grow the GaN layer in the lateral direction, and it is less likely to introduce crystal defects. Therefore, the yield of electrostatic discharge of the light-emitting element can be improved, which is preferable. In addition, by making the ratio of the pattern defect in the range of 0% or more and 15% or less, the surface roughness at the time of film formation of the n-GaN layer can be reduced, and the amount of In introduced at the time of forming the InGaN light-emitting layer can be made on the substrate. It is preferable that the surface of 1a becomes uniform, and the wavelength of the light-emitting element is further reduced.

As described above, the light-emitting element 8 is manufactured by forming the two or more GaN layers 2 to 5 and the p-type electrode 6 and the n-type electrode layer 7 on the convex portion 1b formed on the surface of the substrate 1 and on the substrate 1a. The p-type electrode 6 is formed on the p-type GaN contact layer 5 together with the metal electrode, and the n-type electrode layer 7 is formed on the n-GaN layer 2 where the InGaN light-emitting layer 3 is not formed. Examples of the GaN layer having two or more layers include an n-type GaN contact layer (n-GaN layer) 2, an InGaN light-emitting layer (active layer) 3, a p-type AlGaN cladding layer 4, and p-type GaN as shown in Fig. 1 . The contact layer 5 is, but not limited to, such a configuration. It is preferable that it is composed of a layer of a group 3-5 nitride compound semiconductor having at least a layer having n-type conductivity, a layer having p-type conductivity, and a light-emitting layer sandwiched therebetween. As the active layer 3, a group 3-5 nitride compound semiconductor represented by Inx Gay Alz N (only, 0≦x≦1, 0≦y≦1, 0≦z≦1, x+y+z=1) The layer formed is preferred.

The group 3-5 nitride compound semiconductor formed on the substrate 1 is not limited to the GaN layer, and may be modified so as to include at least one layer of the AlN layer or the InN layer. Specifically, the n-GaN layer 2 is formed on a buffer layer formed of AlN or the like formed on the substrate 1. Further, a layer made of GaN may be used as the buffer layer.

Next, the manufacturing side of the substrate 1 will be described with reference to FIGS. 8 to 11 law. Fig. 8 is a schematic view showing a manufacturing process of a convex portion composed of a dielectric containing a photosensitive agent by photolithography according to an aspect of the above-described production method of the embodiment. Fig. 9 is a view showing another embodiment of the above-described manufacturing method of the embodiment, showing a manufacturing procedure of the imprint method. Fig. 10 is a view showing another embodiment of the above-described production method of the embodiment, showing a manufacturing procedure of the ink jet method.

As shown in Fig. 8 (a), Fig. 9 (a), and Fig. 10 (a), first, a flat substrate 1a is prepared, and then, as shown in Fig. 8 (b), Fig. 9 (b), and Fig. 10 (b), the photosensitive medium 1e containing a photosensitive agent and photosensitive is formed on the surface of the substrate 1a, the dielectric 1e is patterned, and the convex portion 1b composed of a dielectric of a desired pattern is formed on the surface of the substrate 1a. In the manufacturing method shown in Figs. 8 and 9, the dielectric 1e is formed into a film having a specific thickness, and in the manufacturing method of Fig. 10, a plurality of convex shapes are formed. Further, the substrate 1a is flat, and the surface of the substrate 1a on which the dielectric 1e is patterned is mirror-finished, and the surface roughness Ra is about 1 nm or less. Further, the desired pattern refers to a pattern composed of island-like convex portions 1b.

Since a dielectric material containing a photosensitive agent is formed by patterning, a desired pattern formed by the convex portion 1b is formed on the surface of the substrate 1a, so that a film can be formed without a photoresist film (the etching mask for forming the film by the convex portion 1b). A pattern is formed on the surface of the substrate 1a. Therefore, it is possible to reduce the number of processes and simplify the steps, and to reduce the cost of the substrate 1 as the number of processes is reduced.

Further, as the dielectric 1e, each step of the above-described decane resin composition will be described in detail. Hereinafter, a case where the substrate 1a is made of sapphire (hereinafter referred to as "sapphire substrate 1a") will be described as an example.

As a pre-step of the above-mentioned Fig. 8 (a), Fig. 9 (a), and Fig. 10 (a), the sapphire substrate 1a is washed with UV/O ³ , and then washed with water and dehydrated and dried. Further, the sapphire substrate 1a is subjected to a hexamethyldioxane (HMDS) step and dried, as shown in Fig. 8 (a), Fig. 9 (a), and Fig. 10 (a), prepared as A sapphire substrate 1a of a flat substrate.

Next, in Fig. 8(b) or Fig. 9(b), a decane resin composition is uniformly applied to the surface of the sapphire substrate 1a by a rotator.

Since the rhodium oxide resin composition is used for the material for forming the convex portion 1b, the coating property is good, so that a disorder-free dielectric can be formed on the surface of the substrate 1a with a uniform thickness or height. Further, since the hardening shrinkage is small compared to other resins, titanium oxide-containing resins, zirconia-containing resins, and alumina-containing resins, the convex portions 1b can be easily formed on the substrate 1a at a desired height, size, and pitch. on. In addition, the rhodium oxide resin composition is less prone to cracking after hardening than other resins, titanium oxide-containing resins, zirconia-containing resins, and alumina-containing resins, so that voids are less likely to occur in the dielectric of the convex portion, and the GaN layer (2) When the growth is 5), a gap (hole) is less likely to occur at the interface between the convex portion 1b and the GaN layer. Therefore, deterioration of the electrical characteristics of the light-emitting element 8 can be prevented.

After the rhodium oxide resin composition is formed on the surface of the substrate 1a, the desired pattern obtained by using the composition of the decane resin is formed on the surface of the substrate 1a. For example, photolithography described above may be mentioned. Method, imprint method, and inkjet method.

The steps of the photolithography method are as follows. As described above, the dielectric 1e is applied onto the surface of the substrate 1a, and the film of the dielectric 1e is formed on the surface of the substrate 1a (see Fig. 8(b)). Thereafter, the substrate 1a on which the film of the dielectric 1e is formed on the surface of the substrate 1a is pre-baked, and then, as shown in Fig. 8(c), the dielectric is used using the photomask 10. The film of 1e is exposed to the desired pattern. Further, the exposed dielectric 1e is developed (see Fig. 8(d)), and the developed dielectric 1e is post-baked. Further, as shown in Fig. 8(e), the dielectric 1e after the post-baking is annealed to form a dielectric 1e of a desired pattern (at the time point of Fig. 8(e), the dielectric 1e becomes the convex portion 1b). On the surface of the substrate 1a. Further, although the dielectric 1e is annealed after the post-baking of the developed dielectric 1e in the above example, the dielectric 1e is not limited thereto, and the dielectric 1e which is only developed may be directly annealed without post-baking.

The steps of the imprint method are as follows. As described above, the dielectric 1e is applied onto the surface of the substrate 1a, and the film of the dielectric 1e is formed on the surface of the substrate 1a (see FIG. 9(b)). Thereafter, the mold 11 is pressed against the film of the dielectric 1e, and is cured by irradiation with the dielectric light (see Fig. 9(c)). Next, the dielectric 1e is post-baked (see FIG. 9(d)), and as shown in FIG. 9(e), the dielectric 1e after the post-baking is annealed to form a dielectric 1e of a desired pattern (in At the time point of Fig. 9(e), the dielectric 1e is formed on the surface of the substrate 1a as the convex portion 1b).

The steps of the ink jet method are as follows. Instead of the above-described rotator coating of the siloxane resin composition, the dielectric 1e is directly formed on the surface of the substrate 1a by the nozzle 12, and patterned into a desired pattern (see FIG. 10(b)). Next, the substrate 1a on which the dielectric 1e is formed is prebaked, and then the dielectric 1e is exposed, followed by post-baking (see FIG. 10(c)). Next, as shown in FIG. 10(d), the post-baking dielectric 1e is annealed to form a dielectric 1e of a desired pattern (at the time point of FIG. 10(d), the dielectric 1e is a convex portion 1b). On the surface of the substrate 1a. Further, regardless of the imprint method or the inkjet method, post-baking may not be performed, and the dielectric 1e may be directly annealed.

In the photoetching method, as a light source for exposure, a fine pattern is formed From the point of view, the g-line (wavelength 436 nm), h-line (wavelength 405 nm), i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), etc. of a high-pressure mercury lamp, etc. It is better. In addition, as the film of the dielectric 1e, there are a positive type and a negative type, and from the viewpoint of miniaturization of the pattern, that is, a high resolution, and further, it is easy to reflow from the post-baking and annealing, and the shape of the pattern is easy to be smooth. Look, it is better to be positive. In the case of a positive type, after exposure, there is no need to dry and development is required. After the exposure, when drying at 60 ° C or higher, the oxime of the exposed portion has a condensation reaction, and the solubility in the developer is not good, and a pattern cannot be formed, which is not preferable.

For the positive photosensitive siloxane, a naphthoquinone diazide-5-sulfonic acid ester is preferably used as the sensitizer. From the viewpoint of pattern refinement, the exposure apparatus is preferably a device capable of reducing the projection exposure method.

Further, in the developing solution of the photolithography method, a chemical which can dissolve the composition of the decane resin is used, and when it is an organic solvent, there may be an organic base or an inorganic base. However, from the viewpoint of avoiding the incorporation of an inorganic base such as potassium hydroxide (KOH) in the subsequent step, an organic base of Tetra-methyl-ammonium-hydroxyde (TMAH) is preferred.

As described above, in the photolithography method, the imprint method, and the inkjet method, after the patterning of the dielectric 1e is formed, the dielectric 1e is further post-baked. After the post-baking, the rinse liquid adhering to the substrate 1a and the dielectric 1e can be removed by heating. Next, after the post-baking, the dielectric 1e is annealed, and a dielectric 1e of a desired pattern is formed on the surface of the substrate 1a.

By performing post-baking in a temperature range of 100 ° C or more and 400 ° C or less, the fluidity of the dielectric 1e can be improved, so that the pattern of the dielectric 1e is all Or a portion of the top/side portion may be formed into a curved curved shape to improve the light extraction efficiency of the light-emitting element 8. Further, compared with the convex portion (for example, the convex portion 109) having a trapezoidal shape or a rectangular cross-sectional shape, the convex portion 1b is formed into a curved shape, and when the GaN layer (2 to 5) or the like is formed, the transverse direction of the GaN layer is formed. Since the growth time in the direction is shortened, the growth time of the GaN layer can be shortened. Further, when the temperature is less than 100 ° C, the fluidity of the dielectric 1e is insufficient, and all of the pattern of the dielectric 1e or a part of the top portion or the side portion cannot be formed into a curved shape. Further, when it exceeds 400 ° C, the fluidity of the dielectric 1e becomes large, and a desired resolution pattern cannot be obtained.

The dielectric 1e after the formation of the desired pattern is annealed, and a desired pattern of any side shape can be formed on the surface of the substrate 1a formed without the photoresist film (the etching mask for forming the film by the convex portion 1b). Further, since the components of the photosensitive agent are removed by annealing, it is possible to prevent the organic component from being mixed into the light-emitting elements 8 such as the GaN layers (2 to 5). Further, the removal of the sensitizer component means that the sensitizer is liquefied and evaporated by annealing.

Further, by using a photolithography method at the time of formation of a desired pattern, a pattern can be formed on the surface of the substrate 1a on which the photoresist film (that is, the etching mask for forming the film of the convex portion 1b) is formed. Therefore, it is possible to reduce the number of processes, simplify the steps, and reduce the cost of the substrate 1 as the number of processes decreases. Further, since the time of the photolithography step is short, the substrate 1 having a desired pattern on the surface can be produced in a short time.

The imprint method will be described in more detail. As the material of the model 11, for example, a material having a good transmittance of ultraviolet rays such as quartz or the like is preferable. In the method of preparing the quartz model, quartz is first prepared, and then a photoresist is coated on the quartz substrate, and the island-shaped pattern is exposed and developed by a general photolithography method or electron beam lithography. Next, Al is deposited to a thickness of about 100 nm, and then peeled off. Then, using Al as a mask, the quartz is etched to a predetermined depth by a RIE (Reactive Ion Etching) apparatus using trifluoromethane (CHF ₃ ). until. The predetermined depth is the same as the height of the convex portion 1b. The Al remaining after the etching process is removed with phosphoric acid, and finally washed with pure water and dried to complete the quartz model.

This mold 11 is pressed against the dielectric 1e, and the dielectric 11e is cured by irradiating ultraviolet rays by the mold 11. At this time, the direction in which the ultraviolet rays are irradiated can be on the side of the mold 11, and since the sapphire substrate 1a itself is a transparent body, ultraviolet rays can be irradiated from the side of the sapphire substrate 1a. Further, when the ultraviolet ray is irradiated from the side of the substrate 1a, the material of the mold 11 does not necessarily have to be a transparent body. Therefore, a material other than quartz may be used. For example, an opaque body such as ruthenium may be used. Further, as a transparent material, sapphire can be used for the model 11.

Further, when the mold 11 is pressed against the dielectric 1e, it may be carried out in a vacuum environment so that bubbles do not enter the respective dielectrics 1e. Further, although the photon imprint method is exemplified here as an example of the imprint method, other thermal imprint methods in which the dielectric 1e is hardened by heat may be used.

After the island-shaped dielectric 1e is cured, it is separated from the mold 11, and a portion corresponding to the convex portion of the mold 11 (portion other than the island-shaped dielectric 1e) is left, and the excess dielectric is removed by the oxygen RIE device.

As described above, by using the nanoimprint method at the time of formation of a desired pattern, it is possible to form a pattern of the convex portion 1b having a desired size, pitch, and height on the surface of the substrate 1a with a simple apparatus and at a low cost. This dielectric pattern is not completely removed in the subsequent steps, retaining the protrusions formed by the dielectric and forming the device, so that the protrusions can be permanently retained to the final article.

Further, since the ink jet method is used in the formation of a desired pattern, the pattern can be formed directly, so that the degree of freedom of the pattern type of the convex portion 1b is improved. This electric The dielectric pattern is not completely removed in the subsequent steps, the protrusions formed by the dielectric are retained and the device is formed, so that the protrusions can be permanently retained to the final article.

Further, among the photoetching method, the imprint method, and the inkjet method, photolithography is preferred from the viewpoint of high generality. The dielectric pattern is not completely removed in the subsequent steps, the protrusions formed by the dielectric are retained and the device is formed, so that the protrusions can be permanently retained to the final article.

Then, by annealing at a temperature of 700 ° C or more and 1700 ° C or less, the photosensitive agent component of the convex portion 1b can be removed, so that the organic component can be prevented from being mixed into the light-emitting element 8 such as the GaN layer (2 to 5). Further, it is possible to prevent the growth of the GaN layer from occurring on the convex portion 1b or to make growth difficult. By suppressing the growth of the GaN layer on the convex portion 1b, the growth mode of FACELO can be realized, so that a GaN layer having a reduced dislocation density can be formed. Further, the convex portion 1b after annealing has heat resistance, and the shape and physical properties of the convex portion 1b can be maintained even in the film formation temperature (about 1000 ° C) at the time of film formation of the n-GaN layer. Further, when it is less than 700 ° C, either SiO ₂ , TiO ₂ , ZrO ₂ or Al ₂ O ₃ cannot be used as a main component. In addition, when it exceeds the melting point of any of SiO ₂ , TiO ₂ , ZrO ₂ , and Al ₂ O _{3 which} are main components of the convex portion 1b, the shape of the convex portion 1b is distorted or the like, which is not preferable.

Further, by setting the annealing temperature range to a temperature range of more than 1000 ° C to 1700 ° C or less, it is preferable to reduce the impurities contained in the pattern to reduce the influence on the device characteristics. Further, by setting the annealing temperature range to a temperature range of 1100 ° C or more to 1700 ° C or less, the adhesion between the substrate 1a and the pattern can be improved, which is preferable. By improving the adhesion between the substrate 1a and the pattern, it is possible to prevent the pattern from falling off, and it is possible to reduce the adverse effect on the yield such as the wavelength difference of the produced light-emitting elements and the inconsistency in brightness.

Next, a method of manufacturing the light-emitting element 8 will be described. First, the substrate 1 having a desired pattern on the surface manufactured by the manufacturing method described so far is prepared, and at least one GaN layer, AlN layer, and InN layer are formed on the convex portion 1b and the substrate 1a to fabricate the light-emitting element 8.

The GaN layers 2 to 5 shown in FIG. 1 may be grown by a conventional method such as an epitaxial growth method, or the GaN layers 2 to 5 may be formed by using different film formation methods and/or film formation conditions. Epitaxial growth includes homogenous epitaxial growth and heterogeneous epitaxial growth. As the film formation method, a liquid phase film formation method such as another plating method may be used. However, a vapor phase film formation method such as a sputtering method or a CVD method (Chemical Vapor Deposition) is preferably used. In the case of forming a semiconductor layer such as a Group 3-5 nitride compound semiconductor layer for the purpose of producing the light-emitting element 8, the MOCVD method (Metal Organic Chemical Vapor Deposition) and the MOVPE method (Metal Organic Vapor Phase Epitaxy) are used. A vapor phase film formation method such as HVPE method (Hydride vapor phase epitaxy) or MBE method (Molecular Beam Epitaxy) is more preferable. When the material used for the substrate 1b is an inorganic material such as sapphire, the material constituting each semiconductor layer is preferably an inorganic material such as a metal material, a metal oxide material or an inorganic semiconductor material, and it is desirable that all the layers be composed of such inorganic materials. . However, when the MOCVD method is used as the film formation method, the inorganic material of the semiconductor layer may contain an organic substance derived from an organic metal.

First, a buffer layer made of GaN or AlN is formed on the surface of the sapphire substrate 1 on the convex portion 1b side, and the n-GaN layer 2, the InGaN light-emitting layer (active layer) 3, and the p-type AlGaN coating layer are formed. 4. The p-type GaN contact layer 5 is formed in a film formation order. Thereafter, predetermined post-processing is performed to obtain the light-emitting element 8.

Since the convex portion 1b is composed of a dielectric, the surface of the convex portion 1b is The crystal surface of the specific surface orientation is not exposed, and it is difficult to form a core which is the starting point of the growth of the n-GaN layer 2. In other words, since the crystal surface of the specific surface orientation is not exposed at the side portion of the convex portion 1b, the crystal growth of the GaN layer from the side portion of the convex portion 1b is suppressed. Further, at least a portion (for example, the top portion) of the convex portion 1b is formed into a curved surface, and the almost flat portion is extremely narrow, so that the GaN layer cannot grow. However, since the crystal surface of the specific surface orientation (for example, the C surface of sapphire or the like) is entirely exposed on the surface of the substrate 1, the nucleus of GaN is easily formed, and the n-GaN layer 2 can grow.

Therefore, as shown in Fig. 11(a), the growth of the n-GaN layer 2 starts from the surface of the substrate 1a between the convex portions 1b, that is, from the flat portion of the non-convex portion 1b, with the thickness of the n-GaN layer 2 The n-GaN layer 2 is thickened in the lateral direction (horizontal direction), and covers the side and the top of the convex portion 1b as shown in Fig. 11(b). When the thickness of the n-GaN layer 2 is higher than the height of the convex portion 1b, the pattern of the surface of the substrate 1a and the convex portion 1b is covered by the n-GaN layer 2 as shown in FIG. 11(c), when viewed from the plane direction. Only the surface of the flat n-GaN layer 2 is seen.

Therefore, since the side portion of the convex portion 1b becomes the lateral growth region of the n-GaN layer 2, the occurrence of the displacement from the side portion of the convex portion 1b can be prevented. Further, at least a portion (for example, the top portion) of the convex portion 1b is formed into a curved shape, and the almost flat portion can be extremely narrow. Therefore, since the growth of the n-GaN layer 2 from the convex portion 1b is suppressed or prevented, occurrence of misalignment in the n-GaN layer 2 of the attachment of the convex portion 1b can be prevented. In the above manner, there is less penetration misalignment than the GaN layer grown on a flat substrate.

Further, by forming a buffer layer made of GaN or AlN, unevenness of the film quality or film thickness in the film thickness direction of the n-GaN layer 2 can be prevented.

Furthermore, after the GaN layers 3 to 5 are formed by a conventional method, by electricity The p-type electrode 6 is formed by a beam evaporation method. Next, the InGaN light-emitting layer 3 is not formed on the n-GaN layer 2, and the n-GaN layer 2 is exposed by etching using ICP-RIE. Then, an n-type electrode layer 7 made of a Ti/Al laminated layer is formed on the exposed n-GaN layer 2 by electron beam evaporation, and a p-type formed of Ti/Al is formed on the p-type electrode 6. The metal electrode 9 is used to fabricate the light-emitting element 8. Further, as the p-type electrode 6 and the n-type electrode layer 7, a metal such as Ni, Au, Pt, Pd, or Rh can be used.

Since the convex portion 1b is formed on the surface of the substrate 1a, each convex portion 1b can obtain a light scattering effect. Therefore, a part of the light absorbed by the inside of the light-emitting element 8 can be taken out to the outside of the substrate 1a and the InGaN light-emitting layer 3, and the light extraction efficiency of the light-emitting element 8 can be improved.

Further, since the dielectric material containing the photosensitive agent is patterned, the desired pattern composed of the convex portion 1b can be formed on the surface of the substrate 1a, so that the photoresist can be formed without the photoresist film (the mask for etching the convex portion 1b). A pattern is formed on the surface of the film-formed substrate 1a. Therefore, it is possible to reduce the number of processes, simplify the steps, and reduce the cost of the light-emitting elements 8 as the number of processes is reduced, and at the same time, the light-emitting elements 8 having improved light extraction efficiency can be manufactured.

Further, the pattern of the convex portion 1b made of a dielectric material is used as a photomask, and dry etching or wet etching treatment is performed on the surface of the substrate 1a, and an island-like pattern may be directly formed on the surface of the substrate 1a.

Hereinafter, the present invention will be described by way of Example 1, but the present invention is not limited to the following Example 1.

(Example 1)

[Production method]

First, a flat sapphire substrate having a mirror surface of a C surface and a surface roughness Ra of 1 nm was prepared. This sapphire substrate was subjected to UV/O ₃ washing for 5 minutes, then washed with water, and dehydrated and dried at 130 ° C for 3 minutes with a hot plate. Next, HMDS (hexamethyldisilazane) was applied to the surface of the sapphire substrate after dehydration and drying, and the coating was applied by a rotator at 300 rpm for 10 seconds followed by a two-step procedure at 700 rpm for 10 seconds. Thereafter, the sapphire substrate was dried by a hot plate at 120 ° C for 50 seconds.

Next, a film containing a composition of a naphthylquinone-5-sulfonate having a refractive index lower than that of GaN and having a refractive index of 2.4 as a sensitizer is used as a sensitizer. The sapphire substrate surface was formed at 700 rpm for 10 seconds followed by a two-stage step of 1500 rpm for 30 seconds. As a result, a film of a rhodium oxide resin composition having a thickness of 1.55 μm was formed. Further, the rhodium oxide resin composition was a positive photosensitive decane ER-S2000 manufactured by Toray Co., Ltd. (refractive index 1.52 (632.8 nm) prism coupling method of prebaked film).

In the present embodiment, a photolithography method is employed as a method of forming a desired pattern of a film of the above-described naphthene resin film on a surface of a sapphire substrate. The sapphire substrate on which the film of the decane resin composition was formed was prebaked at 110 ° C for 3 minutes by a hot plate, and then the film of the siloxane oxide resin composition was patterned and exposed. In the present embodiment, a positive-type photomask is produced in such a manner that a planar shape in which the convex portion is formed is a circular shape, a circular diameter is 4.9 μm, and a pitch between the convex portions is 6.0 μm, and a siloxane resin is used. The composition film is exposed. The light source to be exposed was converted into light of 65 mJ/cm ² by i-line, and wide light (g line = 436 nm, h line = 405 nm, i line = 365 nm) using g, h, and i lines was used. Further, a positive type is used as a film of a decane resin composition, and an exposure apparatus uses a contact exposure apparatus.

Next, the exposed siloxane oxide resin composition film was developed. Display The film solution was immersed in the developing solution for 60 seconds using 2.38 wt%-TMAH. Thereafter, the sapphire substrate and the developed decane resin composition were post-baked at 230 ° C for 3 minutes with a hot plate.

Next, the developed decane resin composition on the sapphire substrate after post-baking was annealed at 1000 ° C for 1 hour in an atmospheric environment to form a desired pattern and a side-shaped convex portion on the surface of the sapphire substrate.

[protrusion]

The convex portion produced by the above procedure was confirmed, and the following pattern and the convex portion containing SiO ₂ were confirmed.

Plane shape: round

Diameter of the circle: 4.9μm

Height: 0.47μm

Spacing: 6.0μm

Side shape: All are curved shapes formed by curved surfaces (refer to Figures 12 and 13)

Proportion of pattern defects in the convex part: 10%

(Example 2)

[Production method]

The rhodium oxide resin composition was changed to a positive photosensitive methoxy olefin ER-S2000 manufactured by Toray Co., Ltd., and changed into a positive-type photosensitive oxytane ER-S3000 containing a titanium oxide manufactured by Toray Co., Ltd. Similarly, a convex portion having a desired pattern and a side surface shape is formed on the surface of the sapphire substrate. The pre-baked film has a refractive index of 1.78 (632.8 nm) using a prism coupling method.

[protrusion]

The convex portion produced by the above procedure was confirmed, and the following pattern and the convex portion containing TiO ₂ were confirmed.

Plane shape: round

Diameter of the circle: 4.9μm

Height: 1.00μm

Spacing: 6.0μm

Side shape: All are curved shapes formed by curved surfaces (refer to Figures 12 and 13)

Proportion of pattern defects in the convex part: 12%

(Example 3)

[Production method]

The oxime resin composition was changed to a positive photosensitive methoxy olefin ER-S2000 manufactured by Toray Co., Ltd., and changed into a positive photosensitive zirconia-containing oxirane ER-S3100 manufactured by Toray Co., Ltd., and the remaining Example 1 Similarly, a convex portion having a desired pattern and a side surface shape is formed on the surface of the sapphire substrate. The refractive index of the prebaked film of 1.64 (632.8 nm) was measured by a prism coupling method.

[protrusion]

The convex portion produced by the above procedure was confirmed, and the following pattern and the convex portion containing ZrO ₂ were confirmed.

Plane shape: round

Diameter of the circle: 4.9μm

Height: 1.50μm

Spacing: 6.0μm

Side shape: all are curved shapes formed by curved surfaces (refer to Figure 12) And Figure 13)

Proportion of pattern defects in the convex part: 14%

(Comparative example)

The comparative example will be described below. In the comparative example, a SiO ₂ film was formed by a plasma CVD method, and then a photoresist film was formed on the SiO ₂ film. The photoresist film was exposed and developed in the same manner as in Example 1, and patterned in the same manner as in the pattern described in Example 1. The above photoresist film. The patterned photoresist film is used as a photomask to perform dry etching of the SiO ₂ film.

The pattern of the obtained convex portion and the content of SiO _{2 were} confirmed, and the same results as those of the convex portion of Example 1 were obtained.

<evaluation>

With respect to Example 1 and Comparative Example, the number of processes required for forming the convex portion and the delivery time were evaluated. As a result, the evaluation results of the required number of processes of 8 and the delivery time of 70 minutes were obtained in Example 1. On the other hand, the number of processes required for the comparative example was 9, and the delivery time was 110 points. From the above evaluation results, it was confirmed that the present embodiment can achieve a reduction in the number of processes and a shortened delivery time. Or the case where mass production of large-diameter substrate, the number of Comparative Example limited by the size of the wafer processing step of forming a SiO ₂ film or the step of dry etching of SiO ₂ film, addition of more significant difference in delivery time.

The substrate and the light-emitting element can be applied to the following devices, apparatuses, and the like. For example, the light-emitting element is included as a combined light source suitable for the light source 101 or the machine of the illumination 100 as shown in FIG. When the light-emitting element is composed of nitrogen (N) in the group V element, particularly from blue visible light to ultraviolet light, it can be used in a device that must emit blue visible light or ultraviolet light. . For example, blue light (short wavelength) illumination, signal, light projector, A light source such as an endoscope, a light source 201 of three primary colors of the camera display 200 (see FIG. 15), a light source for light detection, and a light source that can be used as a sterilization library or a refrigerator for emitting ultraviolet light. . In addition, it is combined with a coated surface of a fluorescent paint to produce white or electric light, as an illumination device such as a fluorescent lamp (for example, illumination for plant growth), a backlight for a display, a light for a vehicle, a projector, a flash for a camera, etc. The use of light sources. Needless to say, the light-emitting element of the present application is not limited to the nitride-based compound semiconductor, and the scope of application is not limited to the above.

Further, as shown in Fig. 16, the substrate of the present application can be used not only as a light-emitting element but also as a light-receiving element that receives light from each direction, and can be used as a substrate of a photodiode or a substrate 301 of a solar cell or solar photovoltaic panel 300. .

Further, the present invention is not limited to the embodiments or the applicable examples, and can be implemented in accordance with the scope of the content described in the claims. In other words, the present invention has been described with reference to the specific embodiments, and the present invention is described in detail with reference to the embodiments of the present invention. Those skilled in the art can make various changes.

1‧‧‧Substrate with a predetermined pattern on the surface

1a‧‧‧Substrate

2b‧‧‧ convex

Claims (23)

A method for producing a substrate, comprising preparing a flat substrate, forming a dielectric containing a photosensitive agent on the surface of the substrate, patterning the dielectric, and forming the dielectric in a predetermined pattern on the surface of the substrate. The method of manufacturing a substrate according to claim 1, wherein after the patterning of the dielectric is performed, the dielectric is annealed, and the dielectric having the predetermined pattern is formed on the surface of the substrate. The method for producing a substrate according to the second aspect of the invention, wherein after the patterning of the dielectric, the dielectric is post-baked before the annealing. The method for producing a substrate according to the third aspect of the invention, wherein the post-baking is carried out in a temperature range of from 100 ° C to 400 ° C. The method for producing a substrate according to any one of claims 2 to 4, wherein the annealing is performed in a temperature range of from 700 ° C to 1700 ° C. The method for producing a substrate according to any one of claims 1 to 5, wherein the dielectric material is a decane resin composition, a cerium oxide resin composition containing titanium oxide, and a cerium oxide resin containing zirconia. Any of the composition and the siloxane oxide resin composition containing alumina. The method for producing a substrate according to any one of claims 2 to 6, wherein the dielectric is formed on the surface of the substrate, and then the substrate on which the dielectric is formed on the substrate surface is prebaked. Next, the dielectric is exposed to a desired pattern by using a photomask, and then the exposed dielectric is developed, and the dielectric is annealed to form the dielectric of the predetermined pattern on the substrate surface. The method for producing a substrate according to any one of claims 2 to 6, wherein the dielectric is directly patterned on the substrate surface in a desired pattern, and then the substrate is formed on the substrate surface. The substrate of the dielectric is pre-baked, and then the dielectric is exposed, and the dielectric is annealed to form a desired dielectric of the pattern on the substrate surface. The method for producing a substrate according to any one of claims 2 to 6, wherein the dielectric is applied to the surface of the substrate, whereby the dielectric is formed on the surface of the substrate, and then the mold is attached thereto. The dielectric cures the dielectric, and the dielectric is annealed to form a desired dielectric of the pattern on the substrate surface. A substrate manufacturing method according to any one of claims 1 to 9, wherein the pattern is used as a mask, and a surface of the substrate is etched to form a desired pattern on a surface of the substrate. . A method of manufacturing a light-emitting element, the substrate of any one of claims 1 to 10, At least one GaN layer, AlN layer, and InN layer are formed on the convex portion and the substrate to fabricate a light-emitting element. A substrate having a pattern formed by an island-shaped convex portion on a flat surface of the substrate, wherein the convex portion is made of a dielectric. The substrate according to claim 12, wherein at least a portion of the convex portion is curved. The substrate according to claim 12 or 13, wherein the dielectric constituting the convex portion is made of any one of SiO ₂ , TiO ₂ , ZrO ₂ and Al ₂ O ₃ as a main component. The substrate according to any one of claims 12 to 14, wherein the convex portion is a curved surface as a whole, and the top portion and the side portion are indistinguishable, and has a curved surface shape without a flat surface. The substrate according to claim 15, wherein the convex portion is hemispherical. The substrate according to any one of claims 12 to 16, wherein the convex portion has a circular or elliptical shape. A substrate according to any one of claims 12 to 17, wherein the substrate has a desired pattern on a surface thereof. A substrate, which is a substrate according to any one of claims 12 to 17, which is characterized in that: The pattern having a uniform pitch on the surface of the substrate, and the pattern defect portion of the pattern is not formed on the surface of the pitch, and in the case where the pitch is formed, with respect to all of the patterns in the surface, It is 0% or more and 50% or less. A light-emitting device comprising: the substrate according to any one of claims 12 to 19, the convex portion, and a GaN layer, an AlN layer, and an InN layer formed on at least one of the substrates. A light source comprising the light-emitting element of claim 20 of the patent application. A display comprising the light-emitting element of claim 20 of the patent application. A solar cell comprising the substrate of any one of claims 12 to 19.