Composite patterned substrate, light emitting diode and method of making the same

Abstract

The application provides a composite pattern substrate, a light emitting diode and a manufacturing method thereof. The composite pattern substrate comprises a substrate and a plurality of periodically arranged pattern structures formed on the surface of the substrate. The pattern structure is formed as a convex structure, the convex structure comprises a first material layer and a second material layer which are alternately and sequentially stacked along the thickness direction of the substrate, the first material layer is inwardly recessed from the edge of the convex structure to the center of the convex structure to form a hollow area between adjacent second material layers, and the hollow area is formed as an annular structure around the convex structure. When the light passes through the composite pattern substrate, the light is reflected multiple times between the multiple layers of material and the hollow area, which greatly improves the axial light reflection capability of the middle region of the pattern structure. Since the hollow area has a lower refractive index than the multiple layers of material, the incident light above and on the side of the pattern structure is easily totally reflected in the hollow area, and the light is difficult to penetrate the pattern structure, thereby improving the light extraction efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, and in particular to a composite patterned substrate, a light emitting diode and a manufacturing method thereof. BACKGROUND

[0002] A light emitting diode (LED) is a kind of semiconductor device, and its basic structure includes a PN junction between a P-type semiconductor and an N-type semiconductor. When a forward voltage is applied to the LED, electrons and holes recombine at the junction of the PN junction, releasing energy, which is emitted in the form of photons, forming light radiation.

[0003] The light emitting efficiency of the LED mainly depends on the internal quantum efficiency and the light extraction efficiency. The difference between the refractive index of the epitaxial structure and the substrate easily limits the total reflection of light, resulting in a large amount of light being confined in the device and not being able to be emitted, and finally being dissipated in the form of heat. In the face of the increasingly high light efficiency requirements of the LED, how to improve the light emitting efficiency of the LED device has become a key problem restricting the development of the LED.

[0004] Therefore, it is necessary to provide an improved technical solution for the above-mentioned deficiencies in the prior art. SUMMARY

[0005] In view of the defects and deficiencies of the LED chip in the prior art described above, the purpose of the present application is to provide a composite patterned substrate, a light emitting diode and a manufacturing method thereof, by forming a special pattern structure with high reflection function on the surface of the substrate to improve the light extraction effect of the LED chip.

[0006] In a first aspect, the present application provides a composite patterned substrate, comprising a substrate and a plurality of periodically arranged pattern structures formed on the surface of the substrate; wherein,

[0007] The pattern structure is formed as a protruding structure, the protruding structure comprises a first material layer and a second material layer alternately stacked in the thickness direction of the substrate, the first material layer is inwardly recessed from the edge of the protruding structure to the center of the protruding structure to form a hollow area between adjacent second material layers, and the hollow area is formed as an annular structure around the protruding structure.

[0008] In a second aspect, the present application provides a manufacturing method of a composite patterned substrate, comprising:

[0009] providing a substrate;

[0010] depositing a first material layer and a second material layer on the surface of the substrate in sequence;

[0011] etching the first material layer and the second material layer to form initial pattern structures arranged periodically;

[0012] performing heat treatment on the initial pattern structures, so that the first material layer is inwardly retracted from edges of the initial pattern structures to the center of the initial pattern structures to form hollowed-out areas between adjacent second material layers, and pattern structures arranged periodically on the surface of the substrate are formed.

[0013] In a third aspect, the present application provides a light-emitting diode, comprising a substrate and an epitaxial layer formed on the surface of the substrate, wherein the substrate is the composite pattern substrate provided in the above technical solutions, and the epitaxial layer is formed on the side of the composite pattern substrate having the pattern structures.

[0014] Compared with the prior art, the technical solutions provided in the present application have the following beneficial effects:

[0015] The technical solutions of the present application form a plurality of pattern structures arranged periodically on the surface of the substrate, the pattern structure is a convex structure formed by the first material layer and the second material layer being alternately and sequentially stacked in the thickness direction of the substrate, and the first material layer arranged at intervals is inwardly retracted to the center of the convex structure, so that the size of the first material layer is smaller than the size of the adjacent second material layers above and below, to form an annular hollowed-out area around the convex structure between the adjacent second material layers. When the light emitted by the LED passes through the composite pattern substrate, the light is reflected multiple times between the first material layer and the second material layer and the hollowed-out area, greatly improving the axial light reflection capability of the middle region of the pattern structure. Since the hollowed-out area has a lower refractive index than the first material layer and the second material layer, the incident light above and on the side of the pattern structure is easily totally reflected in this area, and the light is difficult to penetrate the composite pattern substrate, thereby improving the light extraction efficiency.

[0016] In addition, the manufacturing method of the composite pattern substrate provided in the present application first sequentially deposits the first material layer and the second material layer on the surface of the substrate, then etches the first material layer and the second material layer to form initial pattern structures arranged periodically, and finally performs heat treatment to make the first material layer with thermal shrinkage property deform and shrink under high temperature conditions, while the second material layer has high temperature stability and remains stable without deformation, so that the hollowed-out area formed by the inward retraction of the first material layer is formed between the adjacent second material layers, and finally the above-mentioned composite pattern substrate is obtained. The manufacturing method of the composite pattern substrate can form a high-reflectivity pattern structure with a hollowed-out area through a one-step heat treatment process, and the process flow is simple and the parameters are controllable, so that a pattern structure with precise topography and a high-quality composite pattern substrate can be obtained.

[0017] In addition, the light emitting diode provided by the application comprises the composite pattern substrate obtained by the above manufacturing method, thus having good light emitting effect, and the brightness of the light emitting diode is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 Structure schematic diagram of the composite pattern substrate provided for example 1;

[0019] Figure 2 Structure schematic diagram of the composite pattern substrate provided for example 1 from the top;

[0020] Figure 3 Structure schematic diagram of the composite pattern substrate provided for example 1 from the top; Figure 2 Structure schematic diagram of the cross section of the composite pattern substrate in A-A direction;

[0021] Figure 4 Structure schematic diagram of the composite pattern substrate provided for example 1 from the top;

[0022] Figure 5 Structure schematic diagram of the composite pattern substrate provided for example 1 from the top; Figure 2 Structure schematic diagram of the cross section of the composite pattern substrate in B-B direction;

[0023] Figure 6 Flow chart of the manufacturing method of the composite pattern substrate in example 2;

[0024] Figures 7a-7d Structure schematic diagram of the manufacturing process of the composite pattern substrate in example 2;

[0025] Figure 8 Structure schematic diagram of the light emitting diode provided for example 3;

[0026] Figure 9 Structure schematic diagram of the light emitting device provided for example 4.

[0027] Explanation of the reference signs:

[0028] 100 Composite graphic substrate 110 Substrate 111 Bump 120 Graphic structure 121 First material layer 122 Second material layer 123 Hollowed-out region 131 First semiconductor layer 132 Active layer 133 Second semiconductor layer 140 First electrode 150 Second electrode 10 Circuit substrate 20 Light-emitting element DETAILED DESCRIPTION

[0029] The advantages and effects of the application can be easily understood by the skilled in the art from the above description. The application can also be implemented or applied by different specific embodiments, and the details in the description can be modified or changed based on different views and applications without departing from the spirit of the application.

[0030] The conventional sapphire substrate has a highly flat surface, and the difference between the refractive index of the epitaxial structure and the sapphire material easily limits the reflection of light, causing part of the light inside the LED to be confined inside the device and not to be emitted, and finally to be dissipated in the form of heat, or part of the light to be absorbed by the substrate and not to be completely emitted, resulting in a low light extraction efficiency. In the prior art, in order to improve the light extraction efficiency of the light emitting diode, the light extraction efficiency can be improved by patterning the substrate. PSS (Patterned Sapphire Substrate), i.e. patterned sapphire substrate, forms a micron-level periodic pattern structure, such as a circular or conical concave-convex, on the surface of the sapphire substrate to change the refraction and reflection characteristics of light, thereby improving the light extraction efficiency. These micron-level structures can scatter and refract light, so that more light can escape from the LED chip, achieving higher light extraction efficiency and improving the light emitting performance of the LED.

[0031] For the increasingly high LED light efficiency requirement, the light extraction effect needs to be further improved. Therefore, how to improve the light emitting efficiency of the LED chip with sapphire as the substrate has become a key problem restricting the development of LED.

[0032] In view of the above defects, the application provides a composite patterned substrate, which comprises a substrate and a plurality of periodically arranged pattern structures formed on the surface of the substrate; wherein,

[0033] The pattern structure is formed as a convex structure, the convex structure comprises first material layers and second material layers which are alternately and sequentially stacked along the thickness direction of the substrate, the first material layers are inwardly recessed from the edges of the convex structure to the center of the convex structure to form hollow areas between adjacent second material layers, and the hollow areas are formed as annular structures around the convex structure.

[0034] By adopting the above technical scheme, a plurality of periodically arranged pattern structures are formed on the surface of the substrate, the pattern structure is a convex structure formed by alternately and sequentially stacking first material layers and second material layers along the thickness direction of the substrate, and the spaced first material layers are inwardly recessed to the center of the convex structure, so that the size of the first material layer is smaller than the size of the adjacent second material layers above and below, to form an annular hollow area around the convex structure between adjacent second material layers. When the light emitted by the LED passes through the composite patterned substrate, the light is reflected multiple times between the first material layers, the second material layers and the hollow areas thereof, greatly improving the axial light reflection capability of the middle region of the pattern structure. Since the hollow area has a lower refractive index than the first material layer and the second material layer, the incident light above and on the side of the pattern structure is easily totally reflected in this region, and the light is difficult to penetrate the composite patterned substrate, thereby improving the light extraction efficiency.

[0035] In one embodiment, the patterned structure is formed as a cylindrical structure or a polygonal prism structure with equal radial dimension. The cylindrical and prism-shaped patterned structure has the same height and radial dimension, and the prism or cylinder surface is at a right angle with the substrate surface, which can provide a larger surface area, expand the contact range between light and each material layer, and enhance the light extraction efficiency by increasing the optical path length of the material layer.

[0036] In one embodiment, the patterned structure is formed as a frustum structure or a conical structure with a gradually decreasing radial dimension from the bottom to the top of the protrusion. Unlike the prism-shaped patterned structure, the frustum structure or the conical structure with a certain taper angle not only increases the interaction between light and materials, causing multiple reflections and refractions of light, but also improves the uniformity of light emission, and more effectively improves the light emission intensity of the LED.

[0037] In the above embodiment, in the orthographic projection of the substrate surface, the width of the annular structure formed by the hollowed-out area gradually decreases from the bottom to the top of the protrusion. That is, the inclination of the first material layer after the inward shrinkage is smaller than the taper of the protrusion, so that the patterned structure has a strong and area support structure foundation at the bottom, and the second material layer near the top of the patterned structure also has a suitable contact area, ensuring that the patterned structure after the inward shrinkage of the first material layer maintains a certain structural strength, and maintains the structural quality and stability of the protrusion structure.

[0038] In one embodiment, the patterned structure is formed as a right circular cone. To further improve the uniformity of light emission and the amount of light extraction, and improve the overall light emission performance of the LED.

[0039] In the above embodiment, the taper of the patterned structure is between 1:0.5 and 1:4. To achieve a more optimal reflection path of light and take into account the deposition process difficulty of each material layer of the patterned structure and the stability and interlayer adhesion performance of the patterned structure.

[0040] In one embodiment, the substrate includes a raised portion between the substrate and the patterned structure. The raised portion is the formation position of each patterned structure, and the raised portion provides a good process platform for the formation of the first material layer, avoiding adverse effects on the non-patterned area of the substrate.

[0041] In one embodiment, the refractive index of the first material layer is less than the refractive index of the second material layer. By stacking a plurality of pairs of first material layers and second material layers in turn, a distributed Bragg reflector (DBR) is obtained, which greatly improves the axial light reflection capability of the middle region of the patterned structure.

[0042] In one embodiment, the material of the first material layer is a silicon-oxygen polymer. It includes one or more combinations of polymethylsiloxane, polydimethylsiloxane, and other methylsiloxane polymers.

[0043] In one embodiment, the material of the second material layer is silicon dioxide. The transparent silicon dioxide (SiO2) with low refractive index as the second material layer reduces the absorption of the material layer to the light, and the significant refractive index difference between the above-mentioned silicon-oxygen polymer (refractive index of 1.2-1.3) and SiO2 (refractive index of 1.4-1.5) with lower refractive index can improve the reflection ability of the axial light, and increase the light emission efficiency of the LED chip.

[0044] In some embodiments, the thickness of the first material layer is 10 nm-1000 nm; and the thickness of the second material layer is 10 nm-1000 nm.

[0045] In some embodiments, the number of the stacked layers of the first material layer and the second material layer is 2-50.

[0046] In one embodiment, the minimum distance between adjacent pattern structures is 0.05 μm-0.5 μm. The exposed substrate area between the pattern structures is reduced to a certain range, and the total reflection of the light is achieved.

[0047] The application also provides a manufacturing method of the composite pattern substrate, comprising:

[0048] providing a substrate;

[0049] sequentially depositing a first material layer and a second material layer on the surface of the substrate;

[0050] etching the first material layer and the second material layer to form initial pattern structures arranged periodically;

[0051] performing heat treatment on the initial pattern structures, so that the first material layer is inwardly retracted along the edges of the initial pattern structures to the center of the initial pattern structures to form hollow areas between adjacent second material layers, and form pattern structures arranged periodically on the surface of the substrate.

[0052] By using the above technical solution, first, a first material layer and a second material layer are sequentially deposited on the surface of a substrate, then the first material layer and the second material layer are etched to form initial pattern structures arranged periodically, and finally, the first material layer with heat shrinkage performance is deformed and shrunk under high temperature conditions, and the second material layer has high temperature stability and remains stable without deformation, so that hollow areas are formed between adjacent second material layers due to the inward retraction of the first material layer, and finally the above-mentioned composite pattern substrate is obtained. The manufacturing method of the composite pattern substrate can form high-reflection pattern structures with hollow areas through one-step heat treatment process, and the process flow is simple and the parameters are controllable, and the pattern structures with accurate topography and the composite pattern substrate with high quality can be obtained.

[0053] In one embodiment, the patterned structure is formed as a cylindrical structure or a multi-prism structure with equal radial dimensions, or a frustum structure or a conical structure with radial dimensions gradually decreasing from the bottom to the top of the patterned structure. The frustum structure or the conical structure with a certain taper angle can not only increase the interaction between light and material, but also improve the uniformity of light emission and the luminous intensity of the LED.

[0054] In the above embodiment, the first material layer and the second material layer are etched to form the initial patterned structure, and the method further comprises:

[0055] The substrate is etched to form a protrusion between the substrate and the patterned structure. The protrusion is formed by a pretreatment of the substrate by etching process, and the position of the protrusion is the forming position of each patterned structure. The protrusion provides a good process platform for the formation of the first material layer, and avoids adverse effects on the non-patterned area of the substrate.

[0056] In one embodiment, the refractive index of the first material layer is less than the refractive index of the second material layer. By stacking multiple pairs of first material layers and second material layers, a distributed Bragg reflector (DBR) structure is obtained, which greatly improves the axial light reflection capability of the middle region of the patterned structure.

[0057] In one embodiment, the thickness of the first material layer is 10 nm to 1000 nm; and the thickness of the second material layer is 10 nm to 1000 nm.

[0058] In one embodiment, the number of pairs of the first material layer and the second material layer is 2 to 50.

[0059] The application also provides a light-emitting diode, comprising a substrate and an epitaxial layer formed on the surface of the substrate, wherein the substrate is the composite patterned substrate according to any one of the above technical solutions, and the epitaxial layer is formed on the side of the composite patterned substrate having the patterned structure. The light-emitting diode comprises the composite patterned substrate obtained by the above manufacturing method, and thus has good light emission effect and greatly improved brightness.

[0060] In one embodiment, the epitaxial layer comprises a first semiconductor layer, an active layer, and a second semiconductor layer opposite to the first semiconductor layer, which are sequentially formed on the side of the composite patterned substrate having the patterned structure.

[0061] The technical solutions of the application are described in detail below through Examples 1 to 4.

[0062] Example 1:

[0063] This embodiment provides a composite patterned substrate 100, such as Figure 1 As shown, the composite patterned substrate 100 includes a substrate 110 and a plurality of periodically arranged patterned structures 120 formed on the surface of the substrate 110; wherein,

[0064] The patterned structure 120 is formed as a raised structure, which includes a first material layer 121 and a second material layer 122 alternately stacked along the thickness direction of the substrate 110. The first material layer 121 is recessed from the edge of the raised structure towards the center of the raised structure to form a hollow area 123 between adjacent second material layers 122. The hollow area 123 is formed as a ring structure surrounding the raised structure. By adopting the above technical solution, a plurality of periodically arranged patterned structures 120 are formed on the surface of the substrate 110. The patterned structure 120 is a raised structure formed by the alternating stacking of the first material layer 121 and the second material layer 122 along the thickness direction of the substrate 110. The spaced first material layers 121 are recessed towards the center of the raised structure, so that the size of the first material layer 121 is smaller than the size of its adjacent second material layers 122, so as to form a ring hollow area 123 surrounding the raised structure between adjacent second material layers. The hollow area 123 is an empty sandwich structure that does not contain any material. The light emitted by the LED is transmitted downward to the composite patterned substrate 100. The light from above and to the side of the patterned structure 120 will undergo multiple reflections between the first material layer 121, the second material layer 122, and their hollow area 123, which greatly improves the axial light reflection capability of the middle area of ​​the patterned structure 120. Since the hollow area 123 has an extremely low refractive index that is lower than that of the first material layer 121 and the second material layer 122, the incident light from above and to the side of the patterned structure 120 is easy to form total internal reflection in this area, and the light is difficult to penetrate the composite patterned substrate 100, thereby improving the light extraction efficiency.

[0065] Specifically, the substrate 110 can be any one of Al2O3, Si, SiC, PET, MgAl2O4, LiAlO2, LiGaO2, GaN, AlN, GaAs, Ga2O3, ZrB2, and ZnO. As an example, in this embodiment, the substrate 110 is an Al2O3 substrate, that is, a sapphire substrate.

[0066] See Figures 2-3 In one embodiment, the pattern structure 121 is formed as a cylindrical structure or a polygonal prism structure with equal radial dimensions. The cylindrical and prism-shaped pattern structures have the same height and radial dimensions, and the facets or prisms are perpendicular to the substrate surface, providing a larger surface area, i.e., a larger light contact area. This expands the contact range between light and each material layer, thereby enhancing light extraction efficiency by increasing the optical path length of the material layers. Figure 2 andFigure 3 The top view and the cross-sectional view along the vertical plane of the pattern structure 121 are shown respectively. It can be understood that, according to the distribution position and interval size of the pattern structure 120 on the substrate 110, the pattern structure 121 can also be formed into a triangular prism, a quadrangular prism or a pentagonal prism, etc. to achieve the best light output efficiency.

[0067] Referring to Figures 4-5 In an embodiment, the pattern structure 121 is formed into a frustum structure or a conical structure with the radial size gradually decreasing from the bottom to the top of the protruding structure. Different from the pattern structure 120 with the multi-prism or cylindrical structure in the above embodiment, the frustum structure or the conical structure with a certain taper angle can not only increase the interaction between the light and the material, making the light multiple reflection and refraction, but also improve the light emission uniformity, and more effectively improve the light emission intensity of the LED. Figure 4 and Figure 5 The top view and the cross-sectional view along the vertical plane of the pattern structure 121 are shown respectively. It can be understood that, according to the distribution position and interval size of the pattern structure 120 on the substrate 110, the pattern structure 121 can also be formed into a frustum structure or a conical structure with a certain taper angle to further adjust the light output angle.

[0068] Referring to Figure 1 and Figure 5 In an embodiment, in the orthographic projection of the substrate 100 surface, the width w of the annular structure formed by the hollowed-out area 123 gradually decreases from the bottom to the top of the protruding structure. That is, the inclination of the first material layer 121 after the inward shrinkage is smaller than the taper of the protruding structure, so that the pattern structure 120 has a sufficient strength and area of support structure basis at the bottom, and also makes the second material layer 122 close to the top of the pattern structure 120 have a suitable contact area, so that the second material layer 122 can be effectively connected to the first material layer 121. Figure 1 It can be clearly understood that the width of the first material layer 121 close to the top of the pattern structure 120 is close to the width of the second material layer 122 adjacent above and below, so as to ensure that the pattern structure 120 after the inward shrinkage of the first material layer 121 maintains a certain structural strength, and maintains the structural quality and stability of the protruding structure.

[0069] Continuing to refer to Figure 1 and Figure 5In one embodiment, the pattern structure 120 is formed as a regular conical structure with a taper ranging from 1:0.5 to 1:4. Since the pattern structure 120 is formed as a convex structure with a certain taper, the surface area of the material layer gradually decreases as the first material layer 121 and the second material layer 122 are deposited in sequence, and the adhesion force and adhesion area between the layers are also reduced accordingly. Meanwhile, the precision requirement of the etching process is higher. In order to form a Bragg mirror structure with a better reflection period, the number of material layer stacks should be at least 4 or even 8. In order to balance the structure quality of the top material layer and the process difficulty, the taper of the pattern structure 120 should be avoided to be too small. As an example, the taper of the regular conical structure can be 1:1, that is, the central cross section of the pattern structure 120 is an equilateral triangle, and the angle between the side surface and the bottom surface of the pattern structure 120 is 60 degrees.

[0070] Referring to Figure 1 , Figure 3 and Figure 5 In some embodiments, the substrate 110 includes a convex portion 111 between the substrate 110 and the pattern structure 120, and the convex portion 111 is located at the forming position of each pattern structure 120. The convex portion 111 can form part of the convex structure together with the pattern structure 120. The convex portion 111 can provide a good process platform for the formation of the first material layer 121, and avoid adverse effects on the non-patterned area of the exposed surface of the substrate 110 during the formation of the pattern structure 120.

[0071] Referring to Figures 2-4 In one embodiment, the minimum distance d between adjacent pattern structures 120 is 0.05 μm to 0.5 μm, so that the exposed substrate area between the pattern structures 120 and the total surface area of the substrate are reduced to a certain range, for example, within 10%, so as to achieve full reflection of light.

[0072] In one embodiment, the first material layer 121 has a refractive index less than that of the second material layer 122. With the superposition of multiple pairs of first material layer 121 and second material layer 122, a distributed Bragg reflector (DBR) is obtained, which greatly improves the axial light reflection capability of the middle region of the pattern structure, and the reflectivity can be more than 99%. As an example, the material of the first material layer 121 is a silicon-oxygen polymer, including one or more combinations of polymethylsiloxane, polydimethylsiloxane and other methylsiloxane polymers. As an example, the material of the second material layer 122 is one or more of SiO2, SiN, Si2N, Si2N3, MgF2, CaF2, Al2O3, SiO, TiO2, Ti2O3, TiO, MgO, ZnO. As a preferred embodiment, the first material layer 121 is polymethylsiloxane, and the second material layer 122 is SiO2. The transparent SiO2 with low refractive index is used as the second material layer 122, which reduces the absorption of the material to the light. The significant refractive index difference between polymethylsiloxane (refractive index 1.2~1.3) and SiO2 (refractive index 1.4~1.5) can further improve the reflection capability of the axial light, and increase the light efficiency of the LED.

[0073] Referring to Figure 1 In some embodiments, the thickness of the first material layer 121 is 10nm~1000nm; the thickness of the second material layer 122 is 10nm~1000nm. As an example, the thickness of the first material layer 121 can be 60nm~90nm, and the thickness of the second material layer can be 40nm~70nm, so as to achieve effective reflection of light at the target working wavelength.

[0074] Continuing to refer to Figure 1 In some embodiments, one first material layer 121 and the adjacent second material layer 122 located above it form one stack, and the number of stacks of the first material layer 121 and the second material layer 122 is 2~50, that is, the Bragg reflector has 2~50 reflection periods. As an example, the stack is set to 4, 8 or 16. The Bragg reflector with the above reflection periods can provide higher light reflection efficiency and wavelength selectivity, and achieve efficient reflection of light in a wider wavelength range, which has a certain tolerance for wavelength changes in applications or instability of light sources. In addition, the preparation process of the Bragg reflector with this stack parameter is relatively convenient and controllable, and the manufacturing cost is relatively low compared to Bragg reflectors with more reflection periods, which is easy to industrialize.

[0075] Embodiment 2:

[0076] The present embodiment provides a method for manufacturing a composite pattern substrate, as shown in Figure 6 The manufacturing method comprises the following steps:

[0077] a substrate 110 is provided;

[0078] A first material layer 121 and a second material layer 122 are sequentially deposited on the surface of the substrate 110;

[0079] The first material layer 121 and the second material layer 122 are etched to form an initial pattern structure arranged periodically;

[0080] The initial pattern structure is subjected to a heat treatment, so that the first material layer 121 is inwardly retracted from the edge of the initial pattern structure to the center of the initial pattern structure to form a hollow area 123 between adjacent second material layers 122, thereby forming a pattern structure 120 arranged periodically on the surface of the substrate 110. By adopting the technical scheme, the first material layer 121 and the second material layer 122 are sequentially deposited on the surface of the substrate 110 first, then the first material layer 121 and the second material layer 122 are etched to form an initial pattern structure arranged periodically, and finally the first material layer 121 with heat shrinkage performance is deformed and shrunk under high temperature conditions, while the second material layer 122 with high temperature stability keeps the structure stable and does not deform, so that the hollow area 123 formed by the inward retraction of the first material layer 121 is formed between adjacent second material layers 122, and finally the above-mentioned composite pattern substrate 100 is obtained. The manufacturing method of the composite pattern substrate 100 can form a high-reflection pattern structure 120 with a hollow area 123 through one-step heat treatment process, and the process flow is simple and the parameters are controllable, and at the same time, the pattern structure 120 with accurate topography and the composite pattern substrate 100 with high quality can be obtained.

[0081] In the embodiment, referring to Figures 7a-7d The manufacturing method of the composite pattern substrate 100 includes:

[0082] S100: referring to Figure 7a , a substrate 110 is provided first, which can be any one of Al2O3, Si, SiC, PET, MgAl2O4, LiAlO2, LiGaO2, GaN, AlN, GaAs, Ga2O3, ZrB2, ZnO, as an example, the substrate 110 in the embodiment is an Al2O3 substrate, i.e. a sapphire substrate, and the sapphire substrate is soaked in deionized water for surface cleaning to remove impurities and particles on the surface of the substrate 110, thereby providing a clean and defect-free base material for the growth of the pattern structure 120.

[0083] Continuing to refer to Figure 7aThe protruding part 111 is formed between the substrate 110 and the pattern structure 120 by pre-treating part of the substrate 100 through an etching process, and the position of the protruding part 111 is the forming position of each pattern structure 120. Specifically, the minimum distance d between adjacent pattern structures 120 is 0.05 μm to 0.5 μm, and preferably, the minimum distance d is less than or equal to 0.1 μm, so that the exposed substrate area between the finally formed pattern structures 120 and the total surface area of the substrate are reduced to a certain range to achieve full reflection of light. The protruding part 111 provides a good process platform for the formation of the first material layer 121, avoiding adverse effects on the exposed non-patterned area of the substrate 110.

[0084] S100: see Figure 7b The first material layer 121 and the second material layer 122 are sequentially deposited on the surface of the substrate 110

[0085] Due to the advantages of low cost, high replicability and good uniformity of the thin film coating process of spin coating (Spin Coating Process), as an example, the process of spin coating methylsiloxane polymer solution on the substrate 110 is used to form the first material layer 121.

[0086] First, the first material layer 121 is dropped at the center position of the surface of the substrate 110, and then the solution is uniformly distributed on the entire surface by rapidly rotating the substrate 110. The high-speed rotation process generates a centrifugal force, which forms a uniform polymer material layer film on the surface of the substrate 110. It can be understood that the methylsiloxane polymer solution as the first material layer 121 should also include solvents and other chemical components necessary for spin coating film formation, such as 2- (methoxymethyl) tetrahydrofuran, isopropyl alcohol, n-butanol and ultrapure water, etc.

[0087] Subsequently, a low-temperature evaporation / solidification process is performed. At an evaporation temperature of 120 degrees, various solvents in the solution gradually evaporate and are removed, so that the spin coating material substrate is solidified, leaving the desired thin film layer on the substrate 110 to form the bottom layer of the Bragg reflector. In addition, the polymer material will generate a pore structure formed after the solvent evaporates. The pores in the layer further reduce the refractive index of the first material layer 121.

[0088] As an example, the second material layer 122 is deposited on the first material layer 121 at the bottom by a chemical vapor deposition process (CVD: Chemical Vapor Deposition) to obtain a material combination of the first material layer 121 and the second material layer 122; and the chemical vapor deposition can be a plasma-enhanced chemical vapor deposition (PECVD: Plasma-Enhanced Chemical Vapor Deposition) to deposit materials.

[0089] The above two material layers are sequentially repeated to obtain a material combination of one or more pairs of the first material layer 121 and the second material layer 122 to form a Bragg reflector with effective reflectivity. As an example, one pair of the first material layer 121 and the second material layer 122 is one layer, and the number of the first material layer 121 and the second material layer 122 is 2-50, that is, the Bragg reflector has 2-50 reflection periods. As an example, the number of the layers is 4, 8, or 16, and the Bragg reflector with the above reflection periods can provide higher light reflection efficiency and wavelength selectivity, and efficiently reflect light in a wider wavelength range, which has a certain tolerance for wavelength changes in applications or instability of light sources; in addition, the preparation process of the Bragg reflector with the above layer parameters is relatively convenient and controllable, and the manufacturing cost is relatively low compared to the Bragg reflector with more reflection periods, which is easy to industrialize.

[0090] In some embodiments, the refractive index of the first material layer 121 is less than the refractive index of the second material layer 122. By stacking multiple pairs of the first material layer 121 and the second material layer 122, a distributed Bragg reflector structure with a significant difference in refractive index is obtained, which greatly improves the axial light reflection capability of the middle region of the pattern structure. The reflectivity of the pattern structure 120 formed in the present embodiment can reach more than 99%. As an example, the material of the first material layer 121 is a siloxane polymer, such as a methylsiloxane polymer; and the material of the second material layer 122 is one or more of SiO2, SiN, Si2N, Si2N3, MgF2, CaF2, Al2O3, SiO, TiO2, Ti2O3, TiO, MgO, ZnO. Using transparent SiO2 with low refractive index as the second material layer 122 reduces the absorption of light by the material, and the significant difference in refractive index between the siloxane polymer (refractive index 1.2-1.3) with a hole structure and SiO2 (refractive index 1.4-1.5) with a lower refractive index can improve the axial light reflection capability and increase the light output efficiency of the LED.

[0091] In some embodiments, the thickness of the first material layer 121 and the second material layer 122 is 10 nm to 1000 nm; the thickness of the second material layer 122 is 10 nm to 1000 nm, and the thickness of the first material layer 121 can be 60 nm to 90 nm and the thickness of the second material layer can be 40 nm to 70 nm as an example, so as to achieve effective reflection of light at the target working wavelength.

[0092] S300: Referring to Figure 7c , etching the first material layer 121 and the second material layer 122 to form an initial pattern structure arranged periodically.

[0093] Referring to Figures 3-4 In some embodiments, the pattern structure 120 can be formed into a cylindrical structure or a multi-prism structure with equal radial dimensions, or a frustum structure or a conical structure with the radial dimension gradually decreasing from the bottom to the top of the pattern structure 120. The cylindrical and prismatic pattern structure has the same height and radial dimension, and the prism or cylinder surface is at a right angle with the substrate surface, which can provide a larger surface area and light contact area, expand the contact range between light and each material layer, increase the optical path length of the material layer, and thus enhance the light extraction efficiency. In the present embodiment, the pattern structure 121 is formed into a frustum structure or a conical structure with the radial dimension gradually decreasing from the bottom to the top of the protruding structure, which can be a right circular cone structure with a taper range of 1:0.5 to 1:4. As an example, the taper of the right circular cone structure is 1:1, that is, the central cross section of the pattern structure 120 is an equilateral triangle, and the angle between the side surface of the pattern structure 120 and the bottom surface is 60 degrees. Since the pattern structure 120 is formed into a protruding structure with a certain taper, as the first material layer 121 and the second material layer 122 are deposited in sequence, the surface area of the material layer also gradually decreases, the adhesion force and adhesion area between the layers also decrease accordingly, and the precision requirement of the etching process is higher. In order to form a Bragg reflector structure with a better reflection period, the number of material layer stacks should be at least 4 groups, such as 4 groups, 8 groups or 16 groups, etc. In order to balance the structure quality of the top material layer and the process difficulty, the taper of the pattern structure 120 should not continue to decrease. Unlike the multi-prism or cylindrical pattern structure 120 in the above embodiments, the frustum structure or conical structure with a certain taper angle not only can increase the interaction between light and material, make the light reflect and refract multiple times, but also can improve the uniformity of light emission, and more effectively improve the light emission intensity of the LED.

[0094] S400: Referring to Figure 7dThe initial pattern structure is subjected to high-temperature heat treatment, so that the first material layer 121 is inwardly retracted from the edge of the initial pattern structure to the center of the initial pattern structure to form the hollowed-out area 123 between the adjacent second material layers 122, thereby forming the pattern structure 120 periodically arranged on the surface of the substrate 110. As an example, the materials of the first material layer 121 and the second material layer 122 are selected to be methylsilicone polymer and SiO2, respectively, and the heat treatment process preferably has a temperature parameter of 800 degrees or higher. After the inward thermal retraction of the first material layer 121, i.e., the silicone polymer, the first material layer 121 forms a plurality of air layers, i.e., the hollowed-out areas 123. Since air has a very low refractive index, the light incident from above and from the side of the pattern structure 120 is easily subjected to total reflection in the interlayer region, and the light is difficult to penetrate the composite pattern substrate 100. This structure greatly improves the axial reflectivity and extraction efficiency of light.

[0095] In one embodiment, the step of forming the hollowed-out area 123 can be performed simultaneously with the deposition of the epitaxial layer. As an example, a high-temperature MOCVD process can be used to form the hollowed-out area 123 due to the design of the stacked structure during the deposition of the epitaxial layer. The epitaxial layer has a higher deposition rate, and the pattern structure 120 has better material quality and lower surface defect density. The process can achieve precise control over the fabrication process of the thin film material. The high temperature in the process causes the first material layer 121 to inwardly retract to form a plurality of interlayer structures inside the epitaxial layer, thereby further optimizing the LED chip manufacturing process.

[0096] Embodiment 3:

[0097] The application also provides a light-emitting diode, which includes a substrate 110 and an epitaxial layer formed on the surface of the substrate 110. The substrate 110 is the composite pattern substrate 100 provided in Embodiment 1, and the epitaxial layer is formed on the side of the composite pattern substrate 100 having the pattern structure 120. As an example, the material of the substrate 110 of the composite pattern substrate 100 is sapphire, and the pattern structure 120 is a right pyramidal protruding structure formed by the first material layer 121 and the second material layer 122 having different refractive indices. The first material layer 121 is inwardly retracted from the edge of the protruding structure to the center of the protruding structure to form the hollowed-out area 123 between the adjacent second material layers 122. The hollowed-out area 123 is formed as an annular structure surrounding the protruding structure.

[0098] The epitaxial layer includes a first semiconductor layer 131, an active layer 132, and a second semiconductor layer 133 of the opposite type to the first semiconductor layer 131, sequentially formed on one side of the composite patterned substrate 100 having a patterned structure 120. As an example, the first semiconductor layer 131 may be an N-type gallium nitride layer, and the second semiconductor layer 133 may be a P-type gallium nitride layer. A first electrode 140 is formed on the first semiconductor layer 131, and a second electrode 150 is formed on the second semiconductor layer 133. The materials of the formed first electrode 140 and second electrode 150 may be at least one of the following: gold, silver, copper, aluminum, chromium, nickel, titanium, and platinum, or at least one alloy or stack of the above materials.

[0099] The light-emitting diode includes a composite patterned substrate 100 obtained by the fabrication method provided in Example 2, thus having a good light emission effect and significantly improving the luminous brightness of the light-emitting diode.

[0100] Example 4:

[0101] This application also provides a light-emitting device, such as... Figure 9 As shown, the light-emitting device includes a circuit board 10 and a light-emitting element 20 disposed above the circuit board 10. The light-emitting element 20 can be a light-emitting diode (LED) provided in the above embodiments of this application. The LED has a composite patterned substrate 100. Incident light above and to the side of the composite patterned substrate 100 is easily internally reflected in this area, making it difficult for light to penetrate the composite patterned substrate 100. This significantly improves the light extraction efficiency of the LED, thus the light-emitting device with this LED also has good light extraction performance.

[0102] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A composite graphic substrate, characterized by, The substrate and a plurality of periodically arranged pattern structures formed on the surface of the substrate, wherein The pattern structure is formed as a convex structure, the convex structure comprises first material layers and second material layers which are alternately stacked in sequence along the thickness direction of the substrate, the refractive index of the first material layer is less than the refractive index of the second material layer, so as to form a distributed Bragg reflector; The material of the first material layer is a silicon-oxygen polymer, after a heat treatment process, the first material layer is inwardly retracted from the edge of the convex structure to the center of the convex structure, so as to form a hollow area between adjacent second material layers, the hollow area is formed as an annular structure around the convex structure.

2. The composite graphic substrate of claim 1, wherein, The pattern structure is formed as a cylindrical structure or a multi-prism structure with equal radial dimensions.

3. The composite graphic substrate of claim 1, wherein, The pattern structure is formed as a frustum structure or a conical structure with gradually decreasing radial dimensions from the bottom to the top of the convex structure.

4. The composite graphic substrate of claim 3, wherein, In the orthographic projection of the surface of the substrate, the width of the annular structure formed by the hollow area decreases from the bottom to the top of the convex structure.

5. The composite graphic substrate of claim 1, wherein, The pattern structure is formed as a right circular cone.

6. The composite graphic substrate of claim 5, wherein, The taper of the pattern structure is between 1:0.5 and 1:

4.

7. The composite graphic substrate of claim 1, wherein, The substrate comprises a convex part between the substrate and the pattern structure.

8. The composite graphic substrate of claim 1, wherein, The material of the second material layer is silicon dioxide.

9. The composite graphic substrate of any one of claims 1-8, wherein, The thickness of the first material layer is 10nm-1000nm; the thickness of the second material layer is 10nm-1000nm.

10. The composite graphic substrate of any one of claims 1-8, wherein, The number of layers of the first material layer and the second material layer is 2-50.

11. The composite graphic substrate of claim 1, wherein, The minimum distance between adjacent pattern structures is 0.05μm-0.5μm.

12. A method of fabricating a composite graphic substrate, comprising: The substrate and a plurality of periodically arranged pattern structures formed on the surface of the substrate, wherein A substrate is provided; First material layers and second material layers are alternately deposited in sequence along the thickness direction of the substrate, wherein the material of the first material layer is a silicon-oxygen polymer, the refractive index of the first material layer is less than the refractive index of the second material layer, so as to form a distributed Bragg reflector; The first material layers and the second material layers are etched to form periodically arranged initial pattern structures; The initial pattern structures are subjected to a heat treatment, so that the first material layers are inwardly retracted from the edge of the initial pattern structure to the center of the initial pattern structure, so as to form a hollow area between adjacent second material layers, and form pattern structures periodically arranged on the surface of the substrate.

13. The method of claim 12, wherein: The pattern structure is formed as a cylindrical structure or a multi-prism structure with equal radial dimensions, or a frustum structure or a conical structure with gradually decreasing radial dimensions from the bottom to the top of the pattern structure.

14. The method of claim 13, wherein The first material layers and the second material layers are etched to form periodically arranged initial pattern structures, and the method further comprises: Part of the substrate is etched to form a convex part between the substrate and the pattern structure.

15. The method of claim 12, wherein The thickness of the first material layer is 10nm-1000nm; the thickness of the second material layer is 10nm-1000nm.

16. The method of claim 12, wherein The number of layers of the first material layer and the second material layer is 2-50.

17. A light emitting diode, comprising: A semiconductor device comprising a substrate and an epitaxial layer formed on a surface of the substrate, the substrate being a composite graphic substrate according to any one of claims 1 to 11, the epitaxial layer being formed on a side of the composite graphic substrate having the graphic structure.

18. The light emitting diode of claim 17, wherein, The epitaxial layer comprises a first semiconductor layer, an active layer and a second semiconductor layer of a type opposite to that of the first semiconductor layer, formed in this order on the side of the composite graphic substrate having the graphic structure.

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