Reverse polarity LED structure
By combining an ITO contact layer and a P-type patterned surface layer in the LED structure, and optimizing the refractive and adhesive layers, the reliability and light absorption issues of the P-surface ohmic contact structure were solved, the external quantum efficiency was improved, and the fabrication difficulty was reduced.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- YANGZHOU CHANGELIGHT
- Filing Date
- 2025-06-16
- Publication Date
- 2026-06-25
Smart Images
Figure CN2025101115_25062026_PF_FP_ABST
Abstract
Description
A reverse polarity LED structure
[0001] This application claims priority to Chinese Patent Application No. 202411882383.X, filed on December 19, 2024, entitled "An Inverse Polarity LED Structure", and also claims priority to Chinese Patent Application No. 202423146589.4, filed on December 19, 2024, entitled "An Inverse Polarity LED Structure", the entire contents of which are incorporated herein by reference. Technical Field
[0002] This application relates to the field of semiconductor device technology, and more specifically, to a reverse polarity light-emitting diode (LED) structure. Background Technology
[0003] As a new lighting source for the 21st century, LED structures offer advantages such as consuming only 1 / 10 the power of ordinary incandescent lamps while extending lifespan by 100 times, all while maintaining the same brightness. LEDs are cold light sources with high luminous efficacy, low operating voltage, low power consumption, small size, and planar packaging, facilitating the development of thin and lightweight products. They are also robust, have a long lifespan, and contain no harmful substances like mercury or lead, producing no infrared or ultraviolet pollution during production or use. Therefore, semiconductor lamps made with LED structures are energy-saving, environmentally friendly, and have long lifespans. Just as transistors replaced vacuum tubes, semiconductor lamps replacing traditional incandescent and fluorescent lamps is an inevitable trend. Whether from the perspective of saving energy, reducing greenhouse gas emissions, or reducing environmental pollution, LED structures have great potential to replace traditional lighting sources. While LED structures have many advantages, there is still room for improvement. Summary of the Invention
[0004] In view of this, this application provides a reverse polarity LED structure that effectively solves the existing technical problems. By combining an ITO contact layer and a P-type patterned surface layer as the P-plane ohmic contact structure of the LED, it not only improves the reliability of the P-plane ohmic contact structure but also effectively reduces its light absorption, thereby increasing the external quantum efficiency of the LED structure. Furthermore, the alloying time and temperature required for forming the P-plane ohmic contact structure with the ITO contact layer and the P-type patterned surface layer are both low, reducing the fabrication difficulty of the reverse polarity LED structure.
[0005] To achieve the above objectives, the technical solution provided in this application is as follows:
[0006] A reverse polarity LED structure, the reverse polarity LED structure comprising:
[0007] An epitaxial structure comprising an N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer stacked sequentially along the growth direction, wherein the P-type GaP window layer comprises a P-type base layer located on the P-type confinement layer and a P-type patterned surface layer located on the side of the P-type base layer away from the P-type confinement layer, wherein the P-type patterned surface layer comprises a hollowed-out pattern exposing the P-type base layer;
[0008] An ITO contact layer located on the side of the surface of the P-shaped pattern away from the P-shaped limiting layer, wherein the ITO contact layer is hollowed out at the location of the hollowed-out pattern;
[0009] A dielectric film layer located in the hollow pattern and on the side of the P-type base layer away from the P-type limiting layer, the dielectric film layer exposing the ITO contact layer;
[0010] A mirror layer located on the side of the ITO contact layer opposite to the P-type confinement layer;
[0011] The target substrate located on the side of the mirror layer opposite to the P-type confinement layer;
[0012] In addition, a P-type electrode located on the side of the target substrate opposite to the P-type confinement layer, and an N-type electrode located on the side of the N-type confinement layer opposite to the P-type confinement layer.
[0013] Optionally, the doping concentration of the P-type patterned surface layer is greater than the doping concentration of the P-type base layer.
[0014] Optionally, the reverse polarity LED structure further includes:
[0015] The perforated pattern is located at the refractive layer between the P-type base layer and the dielectric film layer.
[0016] Optionally, the refractive layer includes at least two sub-refractive layers that are sequentially stacked along the growth direction;
[0017] Along the growth direction, the refractive index of the at least two sub-refractive layers varies in a gradient.
[0018] Optionally, along the growth direction, the refractive indices of the P-type substrate, the at least two sub-refractive layers, and the dielectric film layer exhibit a gradient change.
[0019] Optionally, the at least two sub-refractive layers include:
[0020] An IZO sub-refractive layer and an Al2O3 sub-refractive layer are sequentially stacked along the growth direction, wherein the IZO sub-refractive layer is located on the side closer to the P-type base layer.
[0021] Optionally, the reverse polarity LED structure further includes:
[0022] An adhesion layer located between the dielectric film layer and the mirror layer.
[0023] Optionally, the adhesion layer includes at least two oxide sub-adhesion layers that are sequentially stacked along the growth direction.
[0024] Optionally, the at least two oxide sub-adhesion layers include:
[0025] An IZO sub-adhesion layer, an Al2O3 sub-adhesion layer, and an ITO sub-adhesion layer are sequentially stacked along the growth direction, wherein the IZO sub-adhesion layer is located on the side closer to the dielectric film layer.
[0026] Optionally, the epitaxial structure further includes:
[0027] An N-type roughening layer is located between the N-type confinement layer and the N-type electrode, wherein the surface of the N-type roughening layer facing away from the P-type confinement layer includes an electrode region and a roughening region, the N-type electrode is located in the electrode region, and the roughening region includes the roughened surface of the N-type roughening layer;
[0028] And / or, an ohmic contact layer located between the N-type confinement layer and the N-type electrode, wherein the N-type electrode covers the ohmic contact layer, wherein when the epitaxial structure includes the N-type roughening layer, the ohmic contact layer is located between the N-type roughening layer and the N-type electrode.
[0029] Compared with existing technologies, the technical solution provided in this application has at least the following advantages:
[0030] This application provides a reverse polarity LED structure, comprising: an epitaxial structure, the epitaxial structure including an N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer sequentially stacked along the growth direction; the P-type GaP window layer including a P-type base layer located on the P-type confinement layer, and a P-type patterned surface layer located on the side of the P-type base layer facing away from the P-type confinement layer; wherein the P-type patterned surface layer includes a hollowed-out pattern exposing the P-type base layer; and a P-type patterned surface layer located on the side of the P-type patterned surface layer facing away from the P-type confinement layer. An ITO contact layer, wherein the ITO contact layer is hollowed out at the location corresponding to the hollowed-out pattern; a dielectric film layer located on the hollowed-out pattern and on the side of the P-type substrate away from the P-type confinement layer, the dielectric film layer exposing the ITO contact layer; a mirror layer located on the side of the ITO contact layer away from the P-type confinement layer; a target substrate located on the side of the mirror layer away from the P-type confinement layer; and a P-type electrode located on the side of the target substrate away from the P-type confinement layer, and an N-type electrode located on the side of the N-type confinement layer away from the P-type confinement layer.
[0031] As can be seen from the above, the technical solution provided in this application combines an ITO contact layer and a P-type patterned surface layer as the P-side ohmic contact structure of the LED structure. This not only improves the reliability of the P-side ohmic contact structure but also effectively reduces its light absorption, thereby increasing the external quantum efficiency of the LED structure. Furthermore, the alloying time and temperature required for the ITO contact layer and the P-type patterned surface layer to form the P-side ohmic contact structure are both relatively low, thus reducing the difficulty of fabricating the reverse polarity LED structure. Attached Figure Description
[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0033] Figure 1 is a schematic diagram of a reverse polarity LED structure provided in an embodiment of this application;
[0034] Figure 2 is a schematic diagram of a hollowed-out pattern provided in an embodiment of this application;
[0035] Figure 3 is a schematic diagram of another reverse polarity LED structure provided in an embodiment of this application;
[0036] Figure 4 is a schematic diagram of another reverse polarity LED structure provided in an embodiment of this application;
[0037] Figure 5 is a schematic diagram of another reverse polarity LED structure provided in an embodiment of this application;
[0038] Figures 6a to 6d are schematic diagrams of the corresponding structures in each step of a method for preparing an anti-polarity LED structure according to an embodiment of this application.
[0039] Figure 7 is a schematic diagram of another reverse polarity LED structure provided in the embodiments of this application. Detailed Implementation
[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0041] As described in the background section, LED structures, as a new lighting source for the 21st century, consume only 1 / 10 the power of ordinary incandescent lamps while extending their lifespan by 100 times, achieving the same brightness. LEDs are cold light sources with high luminous efficacy, low operating voltage, low power consumption, small size, and planar packaging, facilitating the development of thin and lightweight products. They are also robust and have a long lifespan. Furthermore, the light source itself does not contain harmful substances such as mercury or lead, and produces no infrared or ultraviolet pollution, thus avoiding pollution during production and use. Therefore, semiconductor lamps made with LED structures are energy-saving, environmentally friendly, and have a long lifespan. Just as transistors replaced vacuum tubes, semiconductor lamps replacing traditional incandescent and fluorescent lamps is an inevitable trend. Whether from the perspective of saving energy, reducing greenhouse gas emissions, or reducing environmental pollution, LED structures have great potential to replace traditional lighting sources. Although LED structures have many advantages, there is still room for improvement.
[0042] Based on this, the embodiments of this application provide a reverse polarity LED structure, which effectively solves the existing technical problems. By combining an ITO contact layer and a P-type patterned surface layer as the P-plane ohmic contact structure of the LED structure, not only can the reliability of the P-plane ohmic contact structure be improved, but the light absorption of the P-plane ohmic contact structure can also be effectively reduced, thereby improving the external quantum efficiency of the LED structure. Furthermore, the alloying time and temperature required for the ITO contact layer and the P-type patterned surface layer to form the P-plane ohmic contact structure are both low, reducing the difficulty of fabricating the reverse polarity LED structure.
[0043] To achieve the above objectives, the technical solutions provided by the embodiments of this application are as follows, and the technical solutions provided by the embodiments of this application will be described in detail with reference to Figures 1 to 7.
[0044] Referring to Figures 1 and 2, Figure 1 is a structural schematic diagram of a reverse polarity LED structure provided in an embodiment of this application, and Figure 2 is a schematic diagram of a hollow pattern provided in an embodiment of this application. The reverse polarity LED structure provided in this embodiment includes an epitaxial structure comprising an N-type confinement layer 110, an active layer 120, a P-type confinement layer 130, and a P-type GaP window layer sequentially stacked along the growth direction Y. The P-type GaP window layer includes a P-type base layer 141 located on the P-type confinement layer 130, and a P-type patterned surface layer 142 located on the side of the P-type base layer 141 facing away from the P-type confinement layer 130. The P-type patterned surface layer 142 includes a hollow pattern 142a exposing the P-type base layer 141, as shown in Figure 2.
[0045] The reverse polarity LED structure further includes: an ITO contact layer 200 located on the side of the P-type pattern surface layer 142 facing away from the P-type confinement layer 130, wherein the ITO contact layer 200 is hollowed out at the location corresponding to the hollowed-out pattern 142a; a dielectric film layer 300 located on the hollowed-out pattern 142a and on the side of the P-type base layer 141 facing away from the P-type confinement layer 130, wherein the dielectric film layer 300 exposes the ITO contact layer 200; a mirror layer 400 located on the side of the ITO contact layer 200 facing away from the P-type confinement layer 130; similarly, the mirror layer 400 is also located on the side of the dielectric film layer 300 facing away from the P-type confinement layer 130; and a target substrate 500 located on the side of the mirror layer 400 facing away from the P-type confinement layer 130. In addition, a P-type electrode 610 located on the side of the target substrate 500 opposite to the P-type confinement layer 130, and an N-type electrode 620 located on the side of the N-type confinement layer 110 opposite to the P-type confinement layer 130.
[0046] It should be noted that the patterns of the P-type patterned surface layer 142 (i.e., the pattern corresponding to the gray shading in Figure 2) and the hollowed-out pattern 142a (i.e., the pattern related to the black shading in Figure 2) provided in this application embodiment are not limited to the shapes shown in Figure 2. In some other embodiments, the P-type patterned surface layer 142 and the hollowed-out pattern 142a can also be other pattern shapes, and this application does not impose specific limitations on them. Similarly, the ITO contact layer 200 is located on the side of the P-type patterned surface layer 142 opposite to the P-type limiting layer 130, and the pattern of the ITO contact layer 200 is the same as that of the P-type patterned surface layer 142.
[0047] As can be seen from the above, compared with the existing technology that uses AuBe / AuZn as the P-side contact structure, the technical solution provided in this application combines the ITO contact layer 200 and the P-type patterned surface layer 142 as the P-side ohmic contact structure of the LED structure. This not only improves the reliability of the P-side ohmic contact structure but also effectively reduces the light absorption of the P-side ohmic contact structure, thereby improving the external quantum efficiency of the LED structure. Furthermore, the alloying time and alloying temperature required for the ITO contact layer 200 and the P-type patterned surface layer 142 to form the P-side ohmic contact structure are both lower, thus reducing the difficulty of fabricating the reverse polarity LED structure.
[0048] In some embodiments, the P-type GaP window layer provided in this application is configured as a non-full-surface GaP layer, which can reduce the light absorption capacity of the P-type GaP window layer to a certain extent, while also improving the current spreading capacity and voltage reduction performance of the P-type GaP window layer. Furthermore, the doping concentration of the P-type patterned surface layer 142 provided in this application is greater than the doping concentration of the P-type base layer 141, to further reduce the light absorption capacity of the P-type GaP window layer, thereby improving the light output brightness of the reverse polarity LED structure.
[0049] Furthermore, embodiments of this application can further optimize the structure of the reverse polarity LED structure shown in Figure 1 by adding more optimization layers to improve device performance. Specifically, referring to Figure 3, which is a schematic diagram of another reverse polarity LED structure provided by an embodiment of this application, the reverse polarity LED structure further includes a refractive layer 700 located between the P-type base layer 141 and the dielectric film layer 300 at the hollowed-out pattern 142a, thereby improving the light extraction efficiency of the reverse polarity LED structure. In some embodiments, the refractive layer 700 provided by this application can be flush with the surface layer 142 of the P-type pattern, thereby improving the flatness of the dielectric film layer 300 during subsequent fabrication.
[0050] In some embodiments, the refractive layer 700 provided in this application includes at least two sub-refractive layers sequentially stacked along the growth direction Y; the refractive indices of the at least two sub-refractive layers exhibit a gradient change along the growth direction Y, thereby improving the light extraction efficiency of the anti-polarity LED structure. Optionally, the refractive indices of all sub-refractive layers provided in this application exhibit a decreasing gradient change along the growth direction Y. Further, the refractive indices of the P-type substrate 141, the at least two sub-refractive layers, and the dielectric film layer 300 exhibit a gradient change along the growth direction Y, thereby improving the light extraction efficiency of the anti-polarity LED structure. Similarly, the refractive indices of the P-type substrate 141, the at least two sub-refractive layers, and the dielectric film layer 300 provided in this application can exhibit a decreasing gradient change along the growth direction Y. Continuing as shown in FIG3, the at least two sub-refractive layers provided in this application include: an IZO sub-refractive layer 710 and an Al2O3 sub-refractive layer 720 sequentially stacked along the growth direction Y, wherein the IZO sub-refractive layer 710 is located on the side closer to the P-type substrate 141. Among them, the GaP refractive index of the P-type substrate 141 is 2.6, the refractive index of the IZO sub-refractive layer 710 is 2, the refractive index of the Al2O3 sub-refractive layer 720 is 1.7, and the dielectric film layer 300 can be a SiO2 dielectric film layer with a refractive index of 1.5. It can be seen that along the growth direction Y, the refractive indices of the P-type substrate 141, the IZO sub-refractive layer 710, the Al2O3 sub-refractive layer 720 and the dielectric film layer 300 show a decreasing gradient, thereby improving the light extraction efficiency of the reverse polarity LED structure.
[0051] Referring to Figure 4, which is a schematic diagram of another reverse polarity LED structure provided in this application embodiment, the reverse polarity LED structure provided in this application embodiment further includes an adhesion layer 800 located between the dielectric film layer 300 and the mirror layer 400, thereby improving the adhesion strength between the dielectric film layer 300 and the mirror layer 400. In some embodiments, the adhesion layer 800 provided in this application embodiment may include at least two oxide sub-adhesion layers sequentially stacked along the growth direction Y. Specifically, the at least two oxide sub-adhesion layers provided in this application embodiment include an IZO sub-adhesion layer 810, an Al2O3 sub-adhesion layer 820, and an ITO sub-adhesion layer 830 sequentially stacked along the growth direction Y, wherein the IZO sub-adhesion layer 810 is located on the side closer to the dielectric film layer 300.
[0052] Referring to Figure 5, which is a schematic diagram of another reverse polarity LED structure provided in this application embodiment, the epitaxial structure provided in this application embodiment further includes: an N-type roughening layer 910 located between the N-type confinement layer 110 and the N-type electrode 620, wherein the surface of the N-type roughening layer 910 facing away from the P-type confinement layer 130 includes an electrode region and a roughened region, the N-type electrode 620 is located in the electrode region, and the roughened region includes the roughened surface of the N-type roughening layer 910, thereby improving the light emission effect of the reverse polarity LED structure. Also, an ohmic contact layer 920 is located between the N-type confinement layer 110 and the N-type electrode 620, the N-type electrode 620 covering the ohmic contact layer 920, thereby improving the ohmic contact performance between the N-type electrode 620 and the epitaxial structure, and improving the performance of the reverse polarity LED structure. When the epitaxial structure includes the N-type roughening layer 910, the ohmic contact layer 920 is located between the N-type roughening layer 910 and the N-type electrode 620.
[0053] It should be noted that the reverse polarity LED structure provided in this application embodiment may include an N-type roughening layer 910 alone, or an ohmic contact layer 920 alone, or both an N-type roughening layer 910 and an ohmic contact layer 920. The specific design needs to be made according to the actual application.
[0054] The technical solution provided in this application will be described in more detail below with reference to the structural schematic diagrams corresponding to the preparation method and related steps. Referring to Figures 5 and 6a to 6d, Figures 6a to 6d are structural schematic diagrams corresponding to each step in the preparation method of an anti-polarity LED structure provided in this application embodiment.
[0055] As shown in Figure 6a, corresponding to step S1, along the growth direction Y, a set deposition process is used to sequentially deposit a buffer layer 20 and an etch stop layer 30 on the temporary substrate 10, and then deposit an epitaxial structure on the etch stop layer. The epitaxial structure includes an initial ohmic contact layer 920', an initial N-type roughening layer 910', an N-type confinement layer 110, an active layer 120, a P-type confinement layer 130, and a P-type GaP window layer, which are deposited sequentially. The P-type GaP window layer includes a P-type base layer 141 located on the P-type confinement layer 130, and an initial P-type surface layer 142' located on the side of the P-type base layer 141 away from the P-type confinement layer 130. The doping concentration of the initial P-type surface layer 142' is greater than the doping concentration of the P-type base layer 141.
[0056] In some embodiments, the deposition process provided in this application can be Metal-Organic Chemical Vapor Deposition (MOCVD). The temporary substrate 10 can be made of GaAs. The buffer layer 20 can be made of GaAs. The initial ohmic contact layer 920' can be made of GaAs. The active layer 120 can be a multi-quantum-well active layer. The doping concentration of the P-type base layer 141 can be 1 × 10¹⁸ cm⁻³, and the doping concentration of the initial P-type surface layer 142' can be 2 × 10¹⁸ cm⁻³.
[0057] Optionally, the thickness of the P-type GaP window layer provided in this application embodiment can be 5000 angstroms, and the thickness of the initial P-type surface layer 142' can be 1000 angstroms.
[0058] As shown in Figure 6b, corresponding to step S2, an initial ITO contact layer is deposited on the side of the initial P-type surface layer 142' away from the P-type confinement layer 130. Then, photolithography is used to etch the initial ITO contact layer and the initial P-type surface layer 142' to form the P-type patterned surface layer 142, the ITO contact layer 200, and the hollow pattern 142a. A refractive layer 700 is formed at the hollow pattern 142a.
[0059] In some embodiments, the initial ITO contact layer and initial P-type surface layer 142' provided in this application can be cleaned with acetone, isopropanol, deionized water, etc., before etching. Then, photolithography can be combined with dry or wet etching processes. The pattern of the etched P-type patterned surface layer 142 and ITO contact 200 can be a regular or irregular shape such as a circle, rhombus, or rectangle; this application does not impose specific limitations on this. Furthermore, in this application, a sputtering machine can be used to sequentially deposit an IZO sub-refractive layer 710 and an Al2O3 sub-refractive layer 720 (the sub-refractive layer can be peeled off after depositing all sub-refractive layers on the entire surface to form individual sub-refractive layers), and the refractive layer 700 can fill the hollow pattern 142a of the P-type patterned surface layer 142.
[0060] Optionally, the thickness of the ITO contact 200 provided in this embodiment can be 100 angstroms. And the thickness of the refractive layer 700 provided in this embodiment can be 1000 angstroms.
[0061] As shown in Figure 6c, corresponding to step S3, an initial dielectric film and an initial adhesion layer are deposited on the entire surface of the epitaxial structure. Then, photolithography is used to etch the initial dielectric film and the initial adhesion layer to form the dielectric film 300 and the adhesion layer 800. The dielectric film 300 can be made of SiO2. It can be seen that along the growth direction Y, the refractive indices of the P-type substrate 141, the IZO sub-refractive layer 710, the Al2O3 sub-refractive layer 720, and the dielectric film 300 exhibit a decreasing gradient, thereby improving the light extraction efficiency of the reverse polarity LED structure. Furthermore, the preparation of the adhesion layer 800 enhances the adhesion strength between the dielectric film 300 and the subsequently prepared mirror layer 400.
[0062] Optionally, the adhesion layer 800 provided in this application embodiment may include an IZO sub-adhesion layer 810, an Al2O3 sub-adhesion layer 820, and an ITO sub-adhesion layer 830 sequentially stacked along the growth direction Y. The thickness of the adhesion layer 800 may be 100 angstroms to 200 angstroms.
[0063] As shown in Figure 6d, corresponding to step S4, the mirror layer 400 is sputtered and bonded to the target substrate 500, followed by the removal of the temporary substrate 10, buffer layer 20, and etching stop layer 30. The initial ohmic contact layer 920' is etched to form the ohmic contact layer 920, and the initial N-type roughening layer 910' is roughened to form a roughened surface. Then, a P-type electrode 610 is formed on the side of the target substrate 500 opposite to the P-type confinement layer 130, and an N-type electrode 620 is formed on the side of the N-type roughening layer 910 opposite to the P-type confinement layer 130, with the N-type electrode 620 covering the ohmic contact layer 920. Finally, the structure is diced to form a single reverse polarity LED structure. The preparation of the roughened surface of the N-type roughening layer 910 improves the light extraction performance of the reverse polarity LED structure. Furthermore, the design of the N-type electrode 620 covering the ohmic contact layer 920 improves the ohmic contact performance between the N-type electrode 620 and the epitaxial structure, thereby enhancing the performance of the reverse polarity LED structure.
[0064] Optionally, the mirror layer 400 provided in this embodiment can be an Ag-TiW-Ti-Pt-Au layer sequentially stacked along the growth direction Y. Furthermore, the target substrate 500 provided in this embodiment can be made of Si, and this application does not impose specific limitations on this.
[0065] Referring further to Figure 7, which is a schematic diagram of another reverse polarity LED structure provided in this application embodiment, the reverse polarity LED structure provided in this application embodiment further includes a protective layer 930 located on the side of the reverse polarity LED structure having the N-type electrode 620, wherein the protective layer 930 exposes the N-type electrode 620. Optionally, the material of the protective layer 930 can be SiN, and this application does not impose specific limitations on it.
[0066] This application provides a reverse polarity LED structure, comprising: an epitaxial structure, the epitaxial structure including an N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer sequentially stacked along the growth direction; the P-type GaP window layer including a P-type base layer on the P-type confinement layer, and a P-type patterned surface layer located on the side of the P-type base layer away from the P-type confinement layer; wherein the P-type patterned surface layer includes a hollowed-out pattern exposing the P-type base layer; the side of the P-type patterned surface layer away from the P-type confinement layer... The ITO contact layer is hollowed out at the location corresponding to the hollowed-out pattern; a dielectric film layer is located on the hollowed-out pattern and on the side of the P-type substrate away from the P-type confinement layer, the dielectric film layer exposing the ITO contact layer; a mirror layer is located on the side of the ITO contact layer away from the P-type confinement layer; a target substrate is located on the side of the mirror layer away from the P-type confinement layer; and a P-type electrode is located on the side of the target substrate away from the P-type confinement layer, and an N-type electrode is located on the side of the N-type confinement layer away from the P-type confinement layer.
[0067] As can be seen from the above, the technical solution provided in this application combines the ITO contact layer and the P-type patterned surface layer as the P-side ohmic contact structure of the LED structure. This not only improves the reliability of the P-side ohmic contact structure but also effectively reduces the light absorption of the P-side ohmic contact structure, thereby improving the external quantum efficiency of the LED structure. Furthermore, the alloying time and temperature required for the ITO contact layer and the P-type patterned surface layer to form the P-side ohmic contact structure are both low, thus reducing the difficulty of fabricating the reverse polarity LED structure.
[0068] In the description of the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and other terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0070] In the embodiments of this application, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0071] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0072] In the embodiments of this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0073] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.
Claims
1. A reverse polarity LED structure, characterized by, The reverse polarity LED structure includes: An epitaxial structure comprising an N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer stacked sequentially along the growth direction, wherein the P-type GaP window layer comprises a P-type base layer located on the P-type confinement layer and a P-type patterned surface layer located on the side of the P-type base layer away from the P-type confinement layer, wherein the P-type patterned surface layer comprises a hollowed-out pattern exposing the P-type base layer; An ITO contact layer is located on the side of the surface of the P-shaped pattern that is away from the P-shaped limiting layer, and the ITO contact layer is hollowed out at the location of the hollowed-out pattern. A dielectric film layer located in the hollow pattern and on the side of the P-type base layer away from the P-type limiting layer, the dielectric film layer exposing the ITO contact layer; A mirror layer located on the side of the ITO contact layer opposite to the P-type confinement layer; The target substrate located on the side of the mirror layer opposite to the P-type confinement layer; In addition, a P-type electrode located on the side of the target substrate opposite to the P-type confinement layer, and an N-type electrode located on the side of the N-type confinement layer opposite to the P-type confinement layer.
2. The reverse polarity LED structure of claim 1, wherein, The doping concentration of the P-type patterned surface layer is greater than the doping concentration of the P-type base layer.
3. The reverse polarity LED structure of claim 1, wherein, The reverse polarity LED structure also includes: The perforated pattern is located at the refractive layer between the P-type base layer and the dielectric film layer.
4. The reverse polarity LED structure of claim 3, wherein, The refractive layer includes at least two sub-refractive layers stacked sequentially along the growth direction; Along the growth direction, the refractive index of the at least two sub-refractive layers varies in a gradient.
5. The reverse polarity LED structure according to claim 4, characterized in that, Along the growth direction, the refractive index of the P-type substrate, the at least two sub-refractive layers, and the dielectric film layer varies in a gradient.
6. The reverse polarity LED structure of claim 4, wherein, The at least two sub-refractive layers include: An IZO sub-refractive layer and an Al2O3 sub-refractive layer are sequentially stacked along the growth direction, wherein the IZO sub-refractive layer is located on the side closer to the P-type base layer.
7. The reverse polarity LED structure of claim 1, wherein, The reverse polarity LED structure also includes: An adhesion layer located between the dielectric film layer and the mirror layer.
8. The reverse polarity LED structure of claim 7, wherein, The adhesion layer comprises at least two oxide sub-adhesion layers that are sequentially stacked along the growth direction.
9. The reverse polarity LED structure of claim 8, wherein, The at least two oxide sub-adhesive layers include: An IZO sub-adhesion layer, an Al2O3 sub-adhesion layer, and an ITO sub-adhesion layer are sequentially stacked along the growth direction, wherein the IZO sub-adhesion layer is located on the side closer to the dielectric film layer.
10. The reverse polarity LED structure of claim 1, wherein, The epitaxial structure further includes: An N-type roughening layer is located between the N-type confinement layer and the N-type electrode, wherein the surface of the N-type roughening layer facing away from the P-type confinement layer includes an electrode region and a roughening region, the N-type electrode is located in the electrode region, and the roughening region includes the roughened surface of the N-type roughening layer; And / or, an ohmic contact layer located between the N-type confinement layer and the N-type electrode, wherein the N-type electrode covers the ohmic contact layer, wherein when the epitaxial structure includes the N-type roughening layer, the ohmic contact layer is located between the N-type roughening layer and the N-type electrode.