CN217468469U - Patterned substrate and light-emitting diode - Google Patents
Patterned substrate and light-emitting diode Download PDFInfo
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- CN217468469U CN217468469U CN202220798681.0U CN202220798681U CN217468469U CN 217468469 U CN217468469 U CN 217468469U CN 202220798681 U CN202220798681 U CN 202220798681U CN 217468469 U CN217468469 U CN 217468469U
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Abstract
The utility model discloses a graphical substrate and a light-emitting diode, wherein the graphical substrate comprises a substrate and a plurality of graphical structures which are arranged on the surface of the substrate and distributed at intervals, and the graphical structures comprise a first part formed on the surface of the substrate and a second part formed above the first part; the first part extends from the surface of the substrate to form a boss higher than the surface of the substrate, and a concave structure is formed on the surface of the first part; the second portion is located above the first portion and fills the recessed features of the first portion. The utility model discloses can reduce and grow in the intraformational line defect of epitaxy on graphical substrate top, improve LED's light extraction efficiency.
Description
Technical Field
The utility model relates to a semiconductor device technical field, concretely relates to graphical substrate and emitting diode.
Background
A Light Emitting Diode (LED) is a semiconductor solid Light Emitting device that directly converts electricity into Light using a semiconductor PN junction as a Light Emitting material. The group III nitride represented by gallium nitride is a wide bandgap semiconductor material with direct band gap, and has the advantages of high saturation velocity of electron drift, good thermal conductivity, strong chemical bond, high temperature resistance, corrosion resistance and the like. The band gap of the ternary alloy indium gallium nitride (InGaN) is continuously adjustable from 0.7eV indium nitride (InN) to 3.4eV gallium nitride (GaN), and the light-emitting wavelength covers the whole area of visible light and near ultraviolet light. The light emitting diode taking InGaN/GaN multi-quantum well as the active layer has the remarkable characteristics of high efficiency, environmental protection, energy conservation, long service life and the like, and is considered to be a novel solid-state cold light source which has the greatest potential to enter the field of common illumination.
However, because GaN single crystal materials are very difficult to prepare and it is difficult to find a substrate material which is lattice matched with GaN, at present, more than 99% of GaN-based LED devices are obtained by heteroepitaxial growth. Sapphire is generally adopted as a substrate material for preparing a GaN-based LED device, the difference between the lattice constants of the sapphire and the GaN material is about 15%, and meanwhile, the serious problem of thermal mismatch exists, so that the crystal quality of a nitride material grown on the sapphire substrate is poor, and the dislocation density reaches 108-1010 cm -2 Thereby affecting the lifetime and luminous efficiency of the device. The difference between the refractive indexes of the nitride and the sapphire material easily limits the total reflection of light, so that about 75% of light in the LED is limited in the device and cannot be emitted, and finally, heat is dissipated, so that how to improve the luminous efficiency of the GaN-based LED device with the sapphire as the substrate becomes a key problem for restricting the development of the LED.
In the prior art, a patterned substrate is used for preparing a GaN-based LED device. In order to improve the light extraction efficiency, a low refractive index material layer is generally disposed on top of the pattern of the patterned substrate to improve the light extraction efficiency. For example, the material on the top of the pattern of the patterned substrate is silicon dioxide, the material on the bottom is sapphire, and when light encounters SiO on the top of the pattern 2 Total reflection is easily generated, and the light extraction efficiency can be improved. However, since the surface of silicon dioxide cannot grow epitaxial material, serious line defects are easily generated in the epitaxial layer grown on the top of the pattern, and the light extraction efficiency of the LED is restricted to a certain extent.
SUMMERY OF THE UTILITY MODEL
In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a patterned substrate and a light emitting diode, so as to eliminate the line defect in the epitaxial layer grown on the top of the patterned substrate and improve the light extraction efficiency of the LED.
In order to achieve the above and other related objects, the present invention provides a patterned substrate, including a substrate and a plurality of pattern structures spaced apart from each other on a surface of the substrate, the pattern structures including:
the first part extends from the surface of the substrate to form a boss higher than the surface of the substrate, and a concave structure is formed on the surface of the first part;
and a second portion located above the first portion and filling the recessed structure of the first portion.
Optionally, the recessed structure includes a recessed edge and a recessed center, and a height of the first portion in a direction perpendicular to the surface of the substrate gradually decreases from the recessed edge to the recessed center.
Optionally, the recessed feature is a hemispherical recess or a semi-elliptical recess.
Optionally, the vertical distance of the recessed edge from the surface of the substrate is between 0.3 μm and 1.4 μm.
Optionally, the perpendicular distance of the center of the depression from the surface of the substrate is between 0.01 μm and 0.3 μm.
Optionally, the pattern structure is at a vertical distance of 1.4 μm to 2.4 μm from the surface of the substrate.
Optionally, the graphic structure further comprises:
and a reflective layer disposed between the first portion and the second portion.
Alternatively, the pattern structure is formed as a frustum structure or a tapered structure having a diameter gradually decreasing from the bottom to the top of the pattern structure.
Optionally, the material of the first portion of the pattern structure is the same as the material of the substrate.
Optionally, the substrate comprises one of a sapphire substrate, a SiC substrate, a Si substrate, a ZnO substrate, and a SiN substrate.
Optionally, the second portion is formed to comprise SiO 2 、Si 3 N 4 、ZnO 2 、Si、SiC、GaAs、Ti 3 O 5 、TiO 2 Of one or more of (a).
The utility model also provides a light emitting diode, include:
the patterned substrate of any of the above aspects;
and the epitaxial layer is formed on one side of the patterned substrate with the patterned structure and comprises a first semiconductor layer, an active layer and a second semiconductor layer which are sequentially stacked from the surface of the patterned substrate.
Compared with the prior art, graphical substrate and emitting diode possess following beneficial effect at least:
the utility model discloses a patterned substrate includes the substrate and is located the surface of substrate a plurality of interval distribution's figure structure, the figure structure including form the first part on the substrate surface and form the second part above the first part; the first part extends from the surface of the substrate to form a boss higher than the surface of the substrate, and a concave structure is formed on the surface of the first part; the second portion is located above the first portion and fills the recessed features of the first portion. Because the first part forms a concave structure with high edge and low middle in the direction vertical to the surface of the substrate, and the transverse socket defects in the epitaxial layer outside the concave edge are combined with the defects in the epitaxial layer on the surface of the substrate, the defect density in the epitaxial layer can be reduced, especially the linear defect density in the epitaxial layer at the top of the graph is reduced or eliminated, the lattice quality of epitaxial materials is improved, and the light extraction efficiency of the LED and the yield of devices are improved.
Further, a reflecting layer is arranged between the first part and the second part of the patterned substrate, and the reflecting layer can reflect light emitted to the surface of the reflecting layer through the epitaxial layer so as to further improve the light emitting efficiency.
Light emitting diode include above-mentioned patterned substrate, can realize above-mentioned effect equally.
Drawings
FIG. 1 is a Transmission Electron Microscope (TEM) photograph of a prior art epitaxial material grown on the surface of a patterned substrate;
FIG. 2 is a Transmission Electron Microscope (TEM) photograph of a prior art epitaxial material grown on the surface of a patterned substrate;
fig. 3 is a schematic top view of the patterned substrate according to embodiment 1 of the present invention;
FIG. 4 is a schematic cross-sectional view taken along A-A' of the patterned substrate of FIG. 3;
fig. 5a is a schematic structural view of a substrate in embodiment 1 of the present invention;
fig. 5b is a schematic structural diagram of etching the substrate to form the periodic array of protrusions on the surface of the substrate according to embodiment 1 of the present invention;
fig. 5c is a schematic structural diagram of the embodiment 1 of the present invention after a dielectric layer is formed on the surface of the etched substrate;
fig. 6 is a schematic structural view of the patterned substrate according to embodiment 2 of the present invention;
fig. 7 is a schematic structural diagram of a light emitting diode according to embodiment 3 of the present invention.
List of reference numerals:
1 patterning a substrate
2 silicon dioxide
3 line defect
100 patterned substrate
110 substrate
120 pattern structure
121 first part
122 recessed structure
1221 concave edge
1222 concave center
123 second part
200 reflective layer
300 epitaxial layer
301 first semiconductor layer
302 active layer
303 second semiconductor layer
401 first electrode
402 second electrode
500 protruding structure
600 dielectric layer
Detailed Description
The following description is provided for illustrative purposes, and other advantages and features of the present invention will become apparent to those skilled in the art from the following detailed description. The present invention may be embodied or carried out in other specific forms, and various modifications and changes may be made in the details within the description without departing from the spirit of the invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be understood that the drawings provided in the embodiments of the present invention are only for schematically illustrating the basic concept of the present invention, and although only the components related to the present invention are shown in the drawings, not drawn according to the number, shape and size of the components in actual implementation, the form, quantity and proportion of each component may be changed at will in actual implementation, and the layout of the components may be more complicated. The structure, ratio, size and the like shown in the drawings are only used for matching with the content disclosed in the specification, so that those skilled in the art can understand and read the content, and do not limit the limit conditions that the present application can be implemented, so that the essence of the technology is not existed, and any structural modification, ratio relationship change or size adjustment should still fall within the scope that the technical content disclosed in the present application can cover without affecting the efficacy and the achievable purpose of the present invention.
FIG. 1 provides a patterned substrate, the substrate and the bottom of the pattern are made of sapphire 1, and the top of the pattern is made of low refractive index materialAnd (3) silicon dioxide 2. When the patterned substrate shown in FIG. 1 is used for external extension crystallization, the crystal is formed due to SiO 2 Epitaxial material is not easy to grow, and internal defects of the epitaxial material can be combined at the top of the graph to generate thicker threading dislocation, as shown in figure 1. The threading dislocation is used as a leakage channel and is not beneficial to the antistatic performance of a subsequently grown semiconductor device. Fig. 2 provides a patterned substrate, and the substrate of the patterned substrate and the pattern material formed on the surface of the substrate are sapphire 1. Since the surface of the patterned substrate can be epitaxially grown, when the epitaxial growth is performed, the threading dislocation generated in the epitaxial layer grown on the top of the pattern is short as shown in fig. 2.
In order to eliminate the line defect formed in the epitaxial layer on top of the patterned substrate shown in fig. 1 and improve the light extraction efficiency of the LED, the present embodiment provides a patterned substrate and a light emitting diode.
Example 1
The embodiment provides a patterned substrate, which comprises a substrate and a plurality of pattern structures which are positioned on the surface of the substrate and distributed at intervals, wherein each pattern structure comprises a first part formed on the surface of the substrate and a second part formed above the first part; the first part extends from the surface of the substrate to form a boss higher than the surface of the substrate, and a concave structure is formed on the surface of the first part; the second portion is located above the first portion and fills the recessed features of the first portion.
Specifically, referring to fig. 4, the patterned substrate 100 includes a substrate 110 and a plurality of pattern structures 120 disposed on a surface of the substrate 110 and distributed at intervals, wherein a material of the substrate 110 may be one of sapphire, SiC, Si, ZnO, and SiN, and this embodiment takes a sapphire substrate as an example for description.
Referring to fig. 4, the pattern structure 120 is formed as a frustum structure or a cone structure having a diameter gradually decreasing from the bottom to the top of the pattern structure 120, and may be, for example, a polygonal pyramid, a polygonal frustum, a circular truncated cone, or a cone. In this embodiment, the pattern structure 120 has a conical shape.
The pattern structure 120 includes a first portion 121 formed on a surface of the substrate 110 and a second portion 123 formed on a surface of the first portion 121. The first portion 121 extends from the surface of the substrate 110 to form a boss higher than the surface of the substrate 110, and the surface of the first portion 121 is formed with a recess structure 122. Referring to fig. 3 and 4, the recessed feature 122 includes a recessed rim 1221 and a recessed center 1222. The height of the first portion 121 in a direction perpendicular to the surface of the substrate 110 is gradually decreased from the recessed edge 1221 to the recessed center 1222. For example, the concave structure 122 is a semi-sphere or a semi-ellipse, and in the present embodiment, the concave structure 122 is a semi-ellipse. Alternatively, the material of the first portion 121 may be the same as or different from the material of the substrate 110. In the present embodiment, the material of the first portion 121 is the same as that of the substrate 110, and is sapphire material.
In an alternative embodiment, the pattern structures are at a vertical distance H1 of between 1.4 μm and 2.4 μm from the surface of the substrate. The vertical distance H2 of the recessed edge 1221 from the surface of the substrate is between 0.3 μm and 1.4 μm. The vertical distance H3 of the recess center 1222 from the surface of the substrate is between 0.01 μm and 0.3 μm.
Referring to fig. 3, the second portion 123 is formed above the first portion 121 and fills the recess 122 on the surface of the first portion 121, and in order to improve the light extraction efficiency, the material of the second portion 123 is a low refractive index material, for example, the material of the second portion 123 may include SiO 2 、Si 3 N 4 、ZnO 2 、Si、SiC、GaAs、Ti 3 O 5 、TiO 2 One or more of (a). In the present embodiment, the material of the second portion 123 is SiO 2 。
Because the edge of the recessed structure 122 in this embodiment is high and low in the middle, the lateral socket defect in the epitaxial layer outside the recessed edge 1221 and the defect in the epitaxial layer on the substrate surface can be merged, so that the defect density in the epitaxial layer, especially the density of the linear defect in the epitaxial layer at the top of the pattern, can be reduced, and the lattice quality of the epitaxial material can be improved.
The patterned substrate can be formed by adopting the following preparation method:
s101: providing a substrate;
referring to fig. 5a, a sapphire substrate is provided.
S102: forming a pattern structure on the surface of a substrate;
first, referring to fig. 5b, a layer of photoresist (not shown) is coated on the substrate 110, the first region to be etched is exposed through a photolithography process, and the first region to be etched is etched to form a first pattern, which is a protrusion structure 500 in an alternative embodiment, on the surface of the substrate 110.
Then, referring to fig. 5c, a dielectric layer 600 is formed on the surface of the substrate 110 shown in fig. 5b, preferably, the dielectric layer 600 is SiO with a low refractive index 2 The layer, of course, may also be of other low refractive index materials, e.g. Si 3 N 4 、ZnO 2 、Si、SiC、GaAs、Ti 3 O 5 、TiO 2 One or more of (a). Specifically, a growth dielectric layer 600 is spin-coated on the surface of the substrate 110 between the first patterns by using a Molecular Beam Epitaxy (MBE), a vapor phase epitaxy (HVPE), or a Chemical Vapor Deposition (CVD) method to form a level surface above the surface of the substrate 110, a layer of photoresist is coated on the level surface, and the photoresist is patterned to expose the second region to be etched.
The dielectric layer 600 and the protrusion structure 500 in the second region to be etched are etched to form a frustum structure or a cone structure with a diameter gradually decreasing from the bottom to the top of the pattern structure 120, so as to obtain the patterned substrate 100 shown in fig. 4.
Example 2
This embodiment provides a patterned substrate, which is the same as embodiment 1, and is not repeated herein, except that:
in this embodiment, referring to fig. 6, the surface of the first portion 121 is further covered with a reflective layer 300, and the second portion 123 is formed above the reflective layer 300. The reflective layer 300 can reflect light emitted to the surface thereof by the epitaxial layer to further improve the light emission efficiency. Alternatively, the material of the reflective layer 300 may be a metallic reflective material, for example, rhodium, aluminum, or silver, etc. Alternatively, the reflective layer 300 may be a DBR reflective layer formed by repeatedly overlapping dielectric layers having different refractive indices, that is, a Bragg reflective layerAs an example, the dielectric layer may comprise TiO 2 、SiO 2 、HfO 2 、ZrO 2 、Nb 2 O 5 、MgF 2 And the like. In this embodiment, the reflective layer 300 may be a metal aluminum layer coated on the surface of the first portion 121.
Example 3
This embodiment provides a light emitting diode, which includes the patterned substrate of any of embodiments 1 or 2 and an epitaxial layer formed on a side of the patterned substrate having the patterned structure.
Specifically, referring to fig. 7, the epitaxial layer 200 includes a first semiconductor layer 201, an active layer 202, and a second semiconductor layer 203 in this order on the surface of the patterned substrate 100. Alternatively, a first electrode 401 is formed over the second semiconductor layer 203, and a second electrode 402 is formed over the first semiconductor layer 201. Alternatively, an electrode contact layer (not shown) and a transparent conductive layer (not shown) are further sequentially formed on the surfaces of the first semiconductor layer 201 and the second semiconductor layer 203, and the first electrode 401 and the second electrode 402 are formed on the transparent conductive layer. Optionally, the first semiconductor layer 201 is an N-type gallium nitride layer, and the second semiconductor layer 203 is a P-type gallium nitride layer.
The above embodiments are merely illustrative of the principles and effects of the present invention, and are not to be construed as limiting the invention. Modifications and variations can be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which may be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (12)
1. A patterned substrate, comprising a substrate and a plurality of spaced apart pattern structures on a surface of the substrate, wherein the pattern structures comprise:
the first part extends from the surface of the substrate to form a boss higher than the surface of the substrate, and a concave structure is formed on the surface of the first part;
a second portion located over the first portion and filling the recessed features of the first portion.
2. The patterned substrate of claim 1, wherein the recessed structure comprises a recessed edge and a recessed center, and the height of the first portion in a direction perpendicular to the surface of the substrate gradually decreases from the recessed edge to the recessed center.
3. The patterned substrate of claim 1, wherein the recessed features are hemispherical recesses or semi-elliptical recesses.
4. The patterned substrate of claim 1, wherein the recessed edge is spaced from the surface of the substrate by a vertical distance of 0.3 μm to 1.4 μm.
5. The patterned substrate of claim 1, wherein the vertical distance of the center of the depression from the surface of the substrate is in the range of 0.01 μm to 0.3 μm.
6. The patterned substrate of claim 1, wherein the pattern structures are at a vertical distance of 1.4 μm to 2.4 μm from the surface of the substrate.
7. The patterned substrate of claim 1, wherein the patterned structure further comprises:
a reflective layer disposed between the first portion and the second portion.
8. The patterned substrate of claim 1, wherein the pattern structure is formed as a frustum structure or a tapered structure having a diameter gradually decreasing from a bottom to a top of the pattern structure.
9. The patterned substrate of claim 1, wherein the material of the first portion of the patterned structure is the same as the material of the substrate.
10. The patterned substrate of claim 9, wherein the substrate comprises one of a sapphire substrate, a SiC substrate, a Si substrate, a ZnO substrate, a SiN substrate.
11. The patterned substrate of claim 1, wherein the second portion is formed to comprise SiO 2 、Si 3 N 4 、ZnO 2 、Si、SiC、GaAs、Ti 3 O 5 、TiO 2 Of one or more of (a).
12. A light emitting diode, comprising:
the patterned substrate of any one of claims 1-11;
the epitaxial layer is formed on one side of the patterned substrate with the patterned structure and comprises a first semiconductor layer, an active layer and a second semiconductor layer which are sequentially stacked from the surface of the patterned substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220798681.0U CN217468469U (en) | 2022-04-08 | 2022-04-08 | Patterned substrate and light-emitting diode |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202220798681.0U CN217468469U (en) | 2022-04-08 | 2022-04-08 | Patterned substrate and light-emitting diode |
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| CN217468469U true CN217468469U (en) | 2022-09-20 |
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| CN202220798681.0U Active CN217468469U (en) | 2022-04-08 | 2022-04-08 | Patterned substrate and light-emitting diode |
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