CN216488118U

CN216488118U - Graphical composite substrate, LED epitaxial structure comprising same and chip

Info

Publication number: CN216488118U
Application number: CN202123359880.6U
Authority: CN
Inventors: 付星星; 芦玲
Original assignee: Huaian Aucksun Optoelectronics Technology Co Ltd
Current assignee: Huaian Aucksun Optoelectronics Technology Co Ltd
Priority date: 2021-12-29
Filing date: 2021-12-29
Publication date: 2022-05-10
Anticipated expiration: 2031-12-29

Abstract

The utility model relates to the field of semiconductor technology, a graphical composite substrate and contain LED epitaxial structure and chip of this substrate is disclosed, the substrate includes: the substrate comprises a substrate body (110) and a periodic raised structure (120) arranged on the substrate body (110), wherein the raised structure (120) comprises a bottom pattern layer (123), a top pattern layer (121) and at least one metal thin film reflecting layer (122) embedded inside the top pattern layer (121). Through the dual function of top layer pattern layer and metal film reflecting layer in this application, improve the reflectivity of substrate jointly, and then improve LED chip's luminous efficacy.

Description

Graphical composite substrate, LED epitaxial structure comprising same and chip

Technical Field

The utility model relates to a semiconductor field, in particular to graphical composite substrate and contain LED epitaxial structure and chip of this substrate.

Background

At present, a GaN-based LED device mainly uses sapphire as a substrate, and due to the difference between the sapphire substrate and the GaN-based LED material in terms of lattice constant and thermal expansion coefficient, the GaN-based LED epitaxial layer has quite high threading dislocation density (10)⁸～10¹⁰cm^-2) And very large internal stress, which seriously affects the further improvement of the optical characteristics of the GaN-based LED. The existence of material defects and internal stress is a further step of the GaN-based LED technologyThe main bottleneck to improve internal quantum efficiency. In order to reduce the defect density and internal stress in GaN epitaxial materials, plasma etching (korean patent 1020080087406) and wet chemical etching (chinese patent CN1700449A) are currently used to fabricate a patterned substrate (i.e., a PSS pattern layer) on sapphire, which can reduce the dislocation density in the epitaxial layer and improve the internal quantum efficiency of the LED to some extent. However, the reflectivity of the interface between GaN and sapphire to incident light is not high, which causes most of the light entering the sapphire substrate to be not extracted effectively, resulting in low external quantum efficiency of the LED device.

With the rapid development of the LED display industry, the requirements of the consumer market on the product quality and brightness are higher and higher, and the current LED chip brightness technology of the traditional micro-nano patterned sapphire substrate is bottleneck, and is difficult to meet the requirements of the market on the high-brightness LED, so that a new sapphire substrate preparation method must be adopted to meet the requirements of people starting from the aspects of materials and structures.

SUMMERY OF THE UTILITY MODEL

Utility model purpose: to the problem that exists among the prior art, the utility model provides a graphical composite substrate and contain LED epitaxial structure and chip of this substrate, through the dual function of top layer pattern layer and metallic film reflection stratum in this application, improve the reflectivity of substrate jointly, and then improve the luminous efficacy of LED chip.

The technical scheme is as follows: the utility model provides a graphical composite substrate, including the substrate body to and set up the periodic protruding structure on this substrate body, protruding structure includes bottom pattern layer, top pattern layer and inlays top pattern layer inside at least one deck metal film reflection stratum.

Preferably, the metal thin film reflective layer is a planar layer parallel to the substrate body. The metal thin film reflecting layer is designed to be parallel to the substrate body, so that the light reflecting effect of the metal thin film reflecting layer can be exerted to a greater extent.

Preferably, the diameter d1 of the metal thin film reflective layer is smaller than the bottom surface diameter d2 of the top pattern layer. The design is so as to ensure that the metal film reflecting layer can be completely wrapped in the top pattern layer, and the metal film reflecting layer is prevented from being exposed to the outside to generate a leakage phenomenon.

Preferably, the diameter d1 of the metal thin film reflection layer is 50-95% of the diameter d2 of the bottom surface of the top pattern layer. The diameter of the metal film reflecting layer is too large to ensure that the metal film reflecting layer is completely wrapped by the top pattern layer, and the reflecting effect is poor if the diameter of the metal film reflecting layer is too small.

Preferably, the thickness of the metal thin film reflecting layer is 10 nm-500 nm. For example, 10nm, 20nm, 30nm, 50nm, 100nm, 200nm, 300nm, 400nm, 500nm, etc., but are not limited to the recited values, and other values not recited in the above range are also applicable; in a certain range, the thicker the thickness of the metal thin film reflecting layer is, the better the reflection effect on light is, but after the thickness is further increased, the reflection effect cannot be infinitely increased, but other problems can be caused due to the increase of the thickness, and finally the thickness range is determined to be more appropriate between 10nm and 500 nm.

Preferably, the distance L between the metal thin film reflecting layer and the top surface of the bottom pattern layer is 0-500 nm. For example, 0nm, 10nm, 20nm, 30nm, 50nm, 100nm, 200nm, 300nm, 400nm, 500nm, etc., but are not limited to the recited values, and other values not recited within the range of the values are also applicable; in order to ensure the length maximization of the metal thin film reflecting layer, the length L is preferably 0nm, and the length of the metal thin film reflecting layer is reduced if the distance L is too large, which is not beneficial to improving the light reflection effect.

Preferably, the metal thin film reflective layer is a cone, a triangular pyramid or a rectangular pyramid coaxially disposed with the top pattern layer. When the metal film reflecting layer is of the structure, the area of the metal film reflecting layer can be further increased, and the reflection effect of the metal film reflecting layer is more favorably improved.

Preferably, the distance between the upper surface of the metal thin film reflection layer and the upper surface of the top pattern layer is 50 nm-1000 nm. Because the metal film reflecting layer must be wrapped by the top pattern layer to avoid the electric leakage condition after the metal film reflecting layer is exposed, the interval range can ensure that the metal film reflecting layer is completely wrapped, and can ensure that the area of the metal film reflecting layer is as large as possible, thereby improving the reflecting effect of the metal film reflecting layer as much as possible.

Preferably, the metal film reflecting layer is an upper layer and a lower layer, and the materials of the upper layer and the lower layer are the same or different. The upper and lower metal film reflecting layers can play a better reflecting effect.

Preferably, the metal film reflecting layer is two layers, the upper layer is an Ag layer, and the lower layer is an Al layer. Preferably, the metal thin film reflective layer is an Ag thin film and/or an Al thin film.

Preferably, the top pattern layer is made of SiO2 or TiO 2.

Preferably, the bottom pattern layer and the substrate body are made of the same material, and preferably, the substrate body is made of sapphire.

Preferably, the convex structure is cone-like, triangular pyramid-like or quadrangular pyramid-like.

Preferably, the top pattern layer is cone-like, triangular pyramid-like, or quadrangular pyramid-like.

Preferably, the bottom pattern layer is a truncated cone or a truncated cone.

Preferably, the period P of the periodic convex structure is 0.5 um-5 um. For example, 0.5. mu.m, 1. mu.m, 2. mu.m, 3. mu.m, 4. mu.m, 5 μm, etc., but the numerical values are not limited to the above-mentioned values, and other numerical values not shown in the above-mentioned numerical ranges are also applicable.

Preferably, the diameter D of the lower bottom surface of the protruding structure is 0.45 um-4.9 um. For example, 0.45. mu.m, 1. mu.m, 2. mu.m, 3. mu.m, 4. mu.m, 4.9 μm, etc., but the numerical values are not limited to the above-mentioned values, and other numerical values not shown in the above-mentioned numerical ranges are also applicable.

Preferably, the height H of the protruding structure is 0.3 um-2.5 um. For example, 0.3 μm, 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, etc., but the numerical values are not limited to the enumerated values, and other numerical values not enumerated within the numerical range are also applicable; longer epitaxy time is not beneficial to reducing the cost of the LED when the height H is too high, and lateral epitaxy effect is not beneficial to reducing the dislocation density of epitaxy when the height H is too low.

Preferably, the top pattern layer has a height H1 of 50% to 95% of the height H of the raised structures. For example, the height H1 is 50%, 60%, 70%, 80%, 90%, 95% of the height H, but not limited to the values listed, and other values not listed in the range are also suitable, and the height of the top pattern layer in the range of the height of the bump structure has an effect on the LED brightness, and a too high ratio may result in a virtual high and rapid fluctuation of the chip brightness, and a too low ratio may not effectively improve the chip light extraction efficiency.

The utility model also provides a LED epitaxial structure, include graphical composite substrate.

The utility model also provides a LED chip, include graphical composite substrate.

Has the advantages that: in the protruding pattern structure on the graphical composite substrate in this application, inlay into the metallic film reflection stratum in top layer pattern layer, compare with graininess metallic particle figure (especially nanometer metallic particle, hardly absorb nor reflect to light), thereby the metallic film reflection stratum can greatly increased to reflect to light the luminance of the LED chip of being prepared by this sapphire plain film greatly improved. The metal film reflecting layer is wrapped up in by top layer pattern layer, and top layer pattern layer can prevent effectively that direct exposure from being oxidized in the air, guarantees the performance of whole sapphire plain film. And the top pattern layer is usually made of a material with a refractive index smaller than that of sapphire, so that the light scattering effect of the substrate can be effectively improved.

Through the dual function of top layer pattern layer and metal film reflecting layer in this application, improve the reflectivity of substrate jointly, and then improve LED chip's luminous efficacy. The composite substrate has the advantages of simple process flow, high processing efficiency, stable structural performance, low cost and good reliability.

Drawings

Fig. 1 is a schematic structural view of a patterned composite substrate in embodiment 1;

FIG. 2 is a schematic top view of a patterned composite substrate;

FIG. 3 is a schematic illustration of a composite patterned substrate in accordance with embodiment 1;

FIG. 4 is a schematic structural view of a patterned composite substrate in embodiment 2;

FIG. 5 is an enlarged schematic view of a portion of one of the projection structures in the patterned composite substrate according to embodiment 2;

FIG. 6 is an enlarged schematic view of a portion of one of the projection structures in the patterned composite substrate according to embodiment 3;

FIG. 7 is an enlarged schematic view of a portion of one of the raised structures in the patterned composite substrate of embodiment 4;

fig. 8 is a schematic structural view of an epitaxial structure of an LED in embodiment 5;

fig. 9 is a schematic structural view of an LED chip in embodiment 6.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1:

the present embodiment provides a patterned composite substrate 100, as shown in fig. 1 to 3, including a substrate body 110 made of sapphire, and a periodic bump structure 120 disposed on the substrate body 110, wherein a period P of the bump structure 120 is 3 μm ± 0.05 μm, a diameter D of a bottom surface is 2.90 μm ± 0.05 μm, and a total height H of the bump structure is 2 μm ± 0.05 μm. The bump structure 120 includes a bottom pattern layer 123, a top pattern layer 121, and a metal thin film reflective layer 122 embedded inside the top pattern layer 121. The bottom pattern layer 123 is made of the same material as the substrate body 110, the top pattern layer 121 is made of SiO2, and the height h1 of the top pattern layer 121 is 1.8 μm +/-0.05 μm; the metal thin film reflecting layer 122 is an Ag thin film layer uniformly distributed in the top pattern layer 121; and the metal thin film reflective layer 122 is a planar layer structure parallel to the substrate body 110. The diameter d1 of the metal thin film reflective layer 122 is smaller than the bottom surface diameter d2 of the top pattern layer 121, and preferably the diameter d1 of the metal thin film reflective layer 122 is 95% of the bottom surface diameter d2 of the top pattern layer. The thickness h3 of the metal thin film reflective layer 122 is 200 nm. The distance L from the top surface of the bottom pattern layer 123 is 0nm, i.e., the metal thin film reflective layer 122 is directly disposed on the top surface of the bottom pattern layer 123. The bump structure 120 is a cone-like structure, wherein the top pattern layer 121 is cone-like and the bottom pattern layer 123 is truncated cone-like.

Embodiment 2:

this embodiment is substantially the same as embodiment 1, except that in the patterned composite substrate 100 in this embodiment, the distance L between the metal thin-film reflective layer 122 and the top surface of the bottom pattern layer 123 is 200 nm. As shown in fig. 4 and 5.

Otherwise, this embodiment is identical to embodiment 1, and will not be described herein.

Embodiment 3:

this embodiment is substantially the same as embodiment 1, and differs only in that, as shown in fig. 6, the patterned composite substrate 100 in this embodiment has upper and lower metal thin film reflective layers 122 in the top pattern layer 121, and the pitch h2 between the upper and lower metal thin film reflective layers 122 is 300 nm. The upper layer is an Ag thin film layer with the thickness of 150 nm, the lower layer is an Al thin film layer with the thickness of 200nm, and the distance L from the lower metal thin film reflecting layer 122 to the top surface of the bottom pattern layer 123 is 100 nm.

Embodiment 4:

this embodiment is substantially the same as embodiment 1, and is different only in that the metal thin film reflective layer 122 in this embodiment is a conical-like shape provided coaxially with the top pattern layer 121. As shown in fig. 7, the distance h4 between the upper surface of the metal thin film reflective layer 122 and the upper surface of the top pattern layer 121 is 150 nm.

Embodiment 5:

the present embodiment provides an LED epitaxial structure, as shown in fig. 8, including the patterned composite substrate 100 of any one of embodiments 1 to 4, and further including an N-type semiconductor layer 200, a multi-quantum well layer 300, and a P-type semiconductor layer 400 disposed over the patterned composite substrate 100.

Embodiment 6:

this embodiment provides an LED chip, as shown in fig. 9, including the LED epitaxial structure of embodiment 5, and a current blocking layer 600 located above the P-type semiconductor layer 400, a current spreading layer 500 located above the current blocking layer 600, and an N-electrode 700 electrically connected to the N-type semiconductor layer 200 and a P-electrode electrically connected to the P-type semiconductor layer 400.

The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose of the embodiments is to enable those skilled in the art to understand the contents of the present invention and to implement the present invention, which cannot limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered by the protection scope of the present invention.

Claims

1. The patterned composite substrate is characterized by comprising a substrate body (110) and a periodic raised structure (120) arranged on the substrate body (110), wherein the raised structure (120) comprises a bottom pattern layer (123), a top pattern layer (121) and at least one metal thin film reflecting layer (122) embedded inside the top pattern layer (121).

2. The patterned composite substrate of claim 1, wherein the metallic thin film reflective layer (122) is a planar layer parallel to the substrate body (110).

3. The patterned composite substrate of claim 2, wherein the diameter d1 of the metallic thin film reflective layer (122) is less than the bottom surface diameter d2 of the top pattern layer (121);

and/or the thickness h3 of the metal film reflecting layer (122) is 10 nm-500 nm;

and/or the distance L between the metal film reflecting layer (122) and the top surface of the bottom pattern layer (123) is 0-500 nm.

4. The patterned composite substrate of claim 1, wherein the metallic thin-film reflective layer (122) is cone-like, triangular pyramid-like, or quadrangular pyramid-like disposed coaxially with the top pattern layer (121).

5. The patterned composite substrate of claim 4, wherein the spacing h4 between the upper surface of the metal thin film reflective layer (122) and the upper surface of the top pattern layer (121) is 50nm to 1000 nm.

6. The patterned composite substrate of claim 1, wherein the metal thin film reflective layer (122) comprises an upper layer and a lower layer, and the upper layer and the lower layer are made of the same or different materials.

7. The patterned composite substrate according to claim 1, wherein the metallic thin film reflective layer (122) is an Ag thin film and/or an Al thin film.

8. The patterned composite substrate according to any of claims 1 to 7, wherein the periodic raised structures (120) have a period P of 0.5 um to 5 um;

and/or the diameter D of the lower bottom surface of the convex structure (120) is 0.45 um-4.9 um;

and/or the total height H of the protruding structure (120) is 0.3 um-2.5 um;

and/or the height H1 of the top pattern layer (121) is 50% -95% of the total height H of the raised structure (120).

9. LED epitaxial structure, characterized in that it comprises a patterned composite substrate (100) according to any one of claims 1 to 8.

10. An LED chip, characterized in that it comprises a patterned composite substrate (100) according to any one of claims 1 to 8.