Reversed polarity LED structure

Abstract

The invention provides a reversed-polarity LED structure, and relates to the technical field of semiconductor devices. The reversed-polarity LED structure comprises an epitaxial structure, the epitaxial structure comprises an N-type limiting layer, an active layer, a P-type limiting layer and a P-type GaP window layer which are sequentially stacked in the growth direction, and the P-type GaP window layer comprises a P-type base layer located on the P-type limiting layer and a P-type pattern surface layer located on the side, away from the P-type limiting layer, of the P-type base layer; and the ITO contact layer is positioned on one side, deviating from the P-type limiting layer, of the P-type pattern surface layer. The ITO contact layer and the P-type pattern surface layer are combined to serve as the P-face ohmic contact structure of the LED structure, the reliability of the P-face ohmic contact structure can be improved, and the light absorption condition of the P-face ohmic contact structure can be effectively reduced. And moreover, the alloying time and the alloying temperature required when the ITO contact layer and the P-type pattern surface layer form the P-surface ohmic contact structure are relatively low, so that the difficulty of the preparation process of the reversed-polarity LED structure is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor devices, and more specifically, to a reverse polarity light-emitting diode (LED) structure. Background Art

[0002] LED structure is a new lighting source in the 21st century. Under the same brightness, the power consumption of semiconductor lamps prepared by LED structure is only 1 / 10 of that of ordinary incandescent lamps, while the life span can be extended by 100 times. LED is a cold light source with high light efficiency, low operating voltage, low power consumption, small size, flat packaging, easy development of thin and light products, strong structure and long life. In addition, the light source itself does not contain harmful substances such as mercury and lead, no infrared and ultraviolet pollution, and will not cause pollution to the outside world during production and use. Therefore, semiconductor lamps prepared by LED structure have the characteristics of energy saving, environmental protection, and long life. Just like transistors replace electron tubes, semiconductor lamps will replace traditional incandescent lamps and fluorescent lamps, which will also be the general trend. Whether from the perspective of saving electricity, reducing greenhouse gas emissions, or reducing environmental pollution, LED structure as a new lighting source has great potential to replace traditional lighting sources. Although LED structure has many advantages, it still has room for improvement. Summary of the invention

[0003] In view of this, the present application provides a reverse polarity LED structure, which effectively solves the existing technical problems. The combination of the ITO contact layer and the P-type pattern surface layer as the P-side ohmic contact structure of the LED structure can not only improve the reliability of the P-side ohmic contact structure, but also effectively reduce the light absorption of the P-side ohmic contact structure, thereby improving the external quantum efficiency of the LED structure. In addition, the alloying time and alloying temperature required when the ITO contact layer and the P-type pattern surface layer form the P-side ohmic contact structure are both low, thereby reducing the difficulty of the preparation process of the reverse polarity LED structure.

[0004] To achieve the above objectives, the technical solutions provided by this application are as follows:

[0005] A reverse polarity LED structure, comprising:

[0006] An epitaxial structure, the epitaxial structure comprising an N-type confinement layer, an active layer, a P-type confinement layer and a P-type GaP window layer sequentially stacked along a growth direction, the P-type GaP window layer comprising a P-type base layer located on the P-type confinement layer, and a P-type pattern surface layer located on a side of the P-type base layer away from the P-type confinement layer, wherein the P-type pattern surface layer comprises a hollow pattern exposing the P-type base layer;

[0007] An ITO contact layer located on a side of the surface of the P-type pattern away from the P-type restriction layer, wherein the ITO contact layer is hollowed out at a position corresponding to the hollowed-out pattern;

[0008] A dielectric film layer located in the hollow pattern and on a side of the P-type base layer away from the P-type restriction layer, wherein the dielectric film layer exposes the ITO contact layer;

[0009] A mirror layer located on a side of the ITO contact layer away from the P-type restriction layer;

[0010] A target substrate located on a side of the mirror layer away from the P-type confinement layer;

[0011] And, a P-type electrode located on a side of the target substrate away from the P-type confinement layer, and an N-type electrode located on a side of the N-type confinement layer away from the P-type confinement layer.

[0012] Optionally, the doping concentration of the P-type pattern surface layer is greater than the doping concentration of the P-type base layer.

[0013] Optionally, the reverse polarity LED structure further includes:

[0014] At the hollow pattern, a refractive layer is located between the P-type base layer and the dielectric film layer.

[0015] Optionally, the refractive layer comprises at least two sub-refractive layers sequentially stacked along the growth direction;

[0016] Along the growth direction, the refractive index of the at least two sub-refractive layers changes in a gradient.

[0017] Optionally, along the growth direction, the refractive indices of the P-type base layer, the at least two sub-refractive layers and the dielectric film layer vary in a gradient.

[0018] Optionally, the at least two sub-refractive layers include:

[0019] 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 close to the P-type base layer.

[0020] Optionally, the reverse polarity LED structure further includes:

[0021] An adhesion layer is located between the dielectric film layer and the mirror layer.

[0022] Optionally, the adhesion layer includes at least two oxide sub-adhesion layers sequentially stacked along the growth direction.

[0023] Optionally, the at least two oxide sub-adhesion layers include:

[0024] 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 close to the dielectric film layer.

[0025] Optionally, the epitaxial structure further includes:

[0026] An N-type roughening layer located between the N-type restriction layer and the N-type electrode, wherein a surface of the N-type roughening layer on a side facing away from the P-type restriction layer comprises an electrode region and a roughening region, the N-type electrode is located in the electrode region, and the roughening region comprises a roughened surface of the N-type roughening layer;

[0027] and / or, an ohmic contact layer between the N-type restriction layer and the N-type electrode, the N-type electrode covering 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.

[0028] Compared with the prior art, the technical solution provided by this application has at least the following advantages:

[0029] The present application provides a reverse polarity LED structure, the reverse polarity LED structure comprising: an epitaxial structure, the epitaxial structure comprising an N-type confinement layer, an active layer, a P-type confinement layer and a P-type GaP window layer sequentially stacked along a growth direction, the P-type GaP window layer comprising a P-type base layer located on the P-type confinement layer, and a P-type pattern surface layer located on a side of the P-type base layer away from the P-type confinement layer, wherein the P-type pattern surface layer comprises a hollow pattern exposing the P-type base layer; a P-type pattern surface layer located on a side of the P-type pattern surface layer away from the P-type confinement layer; An ITO contact layer, wherein the ITO contact layer is hollowed out at a position corresponding to the hollow pattern; a dielectric film layer located in the hollow pattern and on a side of the P-type base layer away from the P-type restriction layer, wherein the dielectric film layer exposes the ITO contact layer; a mirror layer located on a side of the ITO contact layer away from the P-type restriction layer; a target substrate located on a side of the mirror layer away from the P-type restriction layer; and a P-type electrode located on a side of the target substrate away from the P-type restriction layer, and an N-type electrode located on a side of the N-type restriction layer away from the P-type restriction layer.

[0030] From the above content, it can be seen that the technical solution provided by this application combines the ITO contact layer and the P-type pattern surface layer as the P-side ohmic contact structure of the LED structure, which can not only improve the reliability of the P-side ohmic contact structure, but also effectively reduce the light absorption of the P-side ohmic contact structure, thereby improving the external quantum efficiency of the LED structure. In addition, the alloying time and alloying temperature required when the ITO contact layer and the P-type pattern surface layer form the P-side ohmic contact structure are both relatively low, thereby reducing the difficulty of the preparation process of the reverse polarity LED structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0032] Figure 1 A schematic diagram of a reverse polarity LED structure provided in an embodiment of the present application;

[0033] Figure 2 A schematic diagram of a hollow pattern provided in an embodiment of the present application;

[0034] Figure 3 A schematic structural diagram of another reverse polarity LED structure provided in an embodiment of the present application;

[0035] Figure 4 A structural schematic diagram of another reverse polarity LED structure provided in an embodiment of the present application;

[0036] Figure 5 A structural schematic diagram of another reverse polarity LED structure provided in an embodiment of the present application;

[0037] Figures 6a to 6d A schematic diagram of the corresponding structures of each step in a method for preparing a reverse polarity LED structure provided in an embodiment of the present application;

[0038] Figure 7 A schematic structural diagram of another reverse polarity LED structure provided in an embodiment of the present application. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] As described in the background technology, LED structure is a new light source for lighting in the 21st century. Under the same brightness, the power consumption of semiconductor lamps prepared by using LED structure is only 1 / 10 of that of ordinary incandescent lamps, while the life span can be extended by 100 times. LED is a cold light source with high luminous efficiency, low operating voltage, low power consumption, small size, flat packaging, easy development of thin and light products, strong structure and long life span, and the light source itself does not contain harmful substances such as mercury and lead, no infrared and ultraviolet pollution, and will not cause pollution to the outside world during production and use. Therefore, the semiconductor lamp prepared by using LED structure has the characteristics of energy saving, environmental protection, and long life span. Just like transistors replacing electron tubes, semiconductor lamps replacing traditional incandescent lamps and fluorescent lamps will also be the general trend. Whether from the perspective of saving electric energy, reducing greenhouse gas emissions, or from the perspective of reducing environmental pollution, LED structure as a new type of lighting source has great potential to replace traditional lighting sources. Although LED structure has many advantages, it still has room for improvement.

[0041] Based on this, the embodiment of the present application provides a reverse polarity LED structure, which effectively solves the existing technical problems. The combination of the ITO contact layer and the P-type pattern surface layer as the P-side ohmic contact structure of the LED structure can not only improve the reliability of the P-side ohmic contact structure, but also effectively reduce the light absorption of the P-side ohmic contact structure, thereby improving the external quantum efficiency of the LED structure. In addition, the alloying time and alloying temperature required when the ITO contact layer and the P-type pattern surface layer form the P-side ohmic contact structure are both low, which reduces the difficulty of the preparation process of the reverse polarity LED structure.

[0042] To achieve the above purpose, the technical solution provided in the embodiment of the present application is as follows, specifically combined with Figures 1 to 7 The technical solution provided in the embodiments of the present application is described in detail.

[0043] Combination Figure 1 and Figure 2 As shown, Figure 1 A schematic diagram of a reverse polarity LED structure provided in an embodiment of the present application is shown in FIG. Figure 2 A schematic diagram of a hollow pattern provided in an embodiment of the present application. The reverse polarity LED structure provided in an embodiment of the present application includes: an epitaxial structure, the epitaxial structure includes 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 a 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 pattern surface layer 142 located on a side of the P-type base layer 141 away from the P-type confinement layer 130, wherein the P-type pattern surface layer 142 includes a hollow pattern 142a exposing the P-type base layer 141, as shown in FIG. Figure 2 The hollow pattern 142a is shown.

[0044] The reverse polarity LED structure further includes: an ITO contact layer 200 located on the side of the P-type pattern surface layer 142 away from the P-type restriction layer 130, wherein the ITO contact layer 200 is hollowed out at the hollow pattern 142a. A dielectric film layer 300 located on the hollow pattern 142a and on the side of the P-type base layer 141 away from the P-type restriction 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 away from the P-type restriction layer 130; similarly, the mirror layer 400 is also located on the side of the dielectric film layer 300 away from the P-type restriction layer 130. A target substrate 500 located on the side of the mirror layer 400 away from the P-type restriction layer 130. Also, a P-type electrode 610 located on a side of the target substrate 500 away from the P-type confinement layer 130 , and an N-type electrode 620 located on a side of the N-type confinement layer 110 away from the P-type confinement layer 130 .

[0045] It should be noted that the P-type pattern surface layer 142 (i.e. Figure 2 The corresponding pattern in medium gray shade) and the hollow pattern 142a (i.e. Figure 2 The shape of the pattern is not limited to the black shadow related pattern Figure 2 In some other embodiments, the P-type pattern surface layer 142 and the hollow pattern 142a can also be other pattern shapes, which is not specifically limited in this application. Similarly, the ITO contact layer 200 is located on the side of the P-type pattern surface layer 142 away from the P-type restriction layer 130, and the pattern of the ITO contact layer 200 is the same as that of the P-type pattern surface layer 142.

[0046] It can be seen from the above content that, compared with the prior art structure of using AuBe / AuZn as a P-side contact structure, the technical solution provided by the embodiment of the present application combines the ITO contact layer 200 and the P-type pattern surface layer 142 as the P-side ohmic contact structure of the LED structure, which can not only improve the reliability of the P-side ohmic contact structure, but also effectively reduce the light absorption of the P-side ohmic contact structure, thereby improving the external quantum efficiency of the LED structure. In addition, the alloying time and alloying temperature required when the ITO contact layer 200 and the P-type pattern surface layer 142 form the P-side ohmic contact structure are both relatively low, thereby reducing the difficulty of the preparation process of the reverse polarity LED structure.

[0047] In some embodiments, the P-type GaP window layer provided in the embodiment of the present application is set as a non-entire GaP layer, which can reduce the light absorption capacity of the P-type GaP window layer to a certain extent, and at the same time can improve the current expansion capacity and voltage drop performance of the P-type GaP window layer. In addition, the doping concentration of the P-type pattern surface layer 142 provided in the embodiment of the present application is greater than the doping concentration of the P-type base layer 141, so as 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.

[0048] Furthermore, the embodiments of the present application can also be Figure 1 The structure of the reverse polarity LED is optimized based on the structure shown in the figure, and the performance of the device is improved by setting more optimization layers. Figure 3 , which is a schematic diagram of another reverse polarity LED structure provided in an embodiment of the present application, wherein the reverse polarity LED structure provided in an embodiment of the present application further includes: a refractive layer 700 located between the P-type base layer 141 and the dielectric film layer 300 at the hollow pattern 142a, thereby improving the light extraction efficiency of the reverse polarity LED structure. In some embodiments, the refractive layer 700 provided in the embodiment of the present application can be flush with the P-type pattern surface layer 142, thereby improving its flatness when the dielectric film layer 300 is subsequently prepared.

[0049] In some embodiments, the refractive layer 700 provided in the embodiment of the present application includes at least two sub-refractive layers sequentially stacked along the growth direction Y; along the growth direction Y, the refractive index of the at least two sub-refractive layers changes in a gradient, thereby improving the light extraction efficiency of the reverse polarity LED structure. Optionally, along the growth direction Y, the refractive index of all the sub-refractive layers provided in the embodiment of the present application changes in a decreasing gradient. Further, along the growth direction Y, the refractive index of the P-type base layer 141, the at least two sub-refractive layers and the dielectric film layer 300 changes in a gradient, thereby improving the light extraction efficiency of the reverse polarity LED structure. Similarly, the refractive index of the P-type base layer 141, the at least two sub-refractive layers and the dielectric film layer 300 provided in the embodiment of the present application can change in a decreasing gradient along the growth direction Y. Continue as Figure 3As shown, the at least two sub-refractive layers provided in the embodiment of the present 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 a side close to the P-type base layer 141. The GaP refractive index of the P-type base layer 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 indexes of the P-type base layer 141, the IZO sub-refractive layer 710, the Al2O3 sub-refractive layer 720 and the dielectric film layer 300 change in a decreasing gradient, thereby improving the light extraction efficiency of the reverse polarity LED structure.

[0050] refer to Figure 4 As shown, it is a structural schematic diagram of another reverse polarity LED structure provided in an embodiment of the present application, wherein the reverse polarity LED structure provided in an embodiment of the present application further includes: an adhesion layer 800 located between the dielectric film layer 300 and the mirror layer 400, so as to improve the adhesion strength between the dielectric film layer 300 and the mirror layer 400. In some embodiments, the adhesion layer 800 provided in an embodiment of the present application may include at least two oxide sub-adhesion layers sequentially stacked along the growth direction Y. The at least two oxide sub-adhesion layers provided in an embodiment of the present application 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 close to the dielectric film layer 300.

[0051] refer to Figure 5 As shown, it is a structural schematic diagram of another reverse polarity LED structure provided by the embodiment of the present application, wherein the epitaxial structure provided by the embodiment of the present application also includes: an N-type roughening layer 910 located between the N-type restriction layer 110 and the N-type electrode 620, wherein the surface of the N-type roughening layer 910 on the side away from the P-type restriction layer 130 includes an electrode region and a roughening region, the N-type electrode 620 is located in the electrode region, and the roughening region includes the roughening surface of the N-type roughening layer 910, thereby improving the light emitting effect of the reverse polarity LED structure. And, an ohmic contact layer 920 located between the N-type restriction layer 110 and the N-type electrode 620, the N-type electrode 620 covers 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 .

[0052] It should be noted that the reverse polarity LED structure provided in the embodiment of the present application may include an N-type roughening layer 910 alone, or may include an ohmic contact layer 920 alone, or may include both an N-type roughening layer 910 and an ohmic contact layer 920 at the same time, which needs to be specifically designed according to the actual application.

[0053] The following is a more detailed description of the technical solution provided by the embodiment of the present application in conjunction with the structural schematic diagram corresponding to the preparation method and related steps. Figure 5 and Figures 6a to 6d As shown, Figures 6a to 6d This is a schematic structural diagram corresponding to each step in a method for preparing a reverse polarity LED structure provided in an embodiment of the present application.

[0054] like Figure 6a As shown, corresponding to step S1, along the growth direction Y, a buffer layer 20 and an etching stop layer 30 are sequentially deposited on the temporary substrate 10 by using a set deposition process, and then an epitaxial structure is deposited on the etching 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 deposited in sequence, and 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, wherein the doping concentration of the initial P-type surface layer 142' is greater than the doping concentration of the P-type base layer 141.

[0055] In some embodiments, the set deposition process provided in the embodiments of the present application may be a metal organic chemical vapor deposition process (MOCVD). The temporary substrate 10 may be made of GaAs. The buffer layer 20 may be made of GaAs. The initial ohmic contact layer 920' may be made of GaAs. The active layer 120 may be a multi-quantum well active layer. The doping concentration of the P-type base layer 141 may be 1×10 18 cm -3 , and the doping concentration of the initial P-type surface layer 142' can be 2×10 18 cm -3 .

[0056] Optionally, the thickness of the P-type GaP window layer provided in the embodiment of the present application may be 5000 angstroms, and the thickness of the initial P-type surface layer 142 ′ may be 1000 angstroms.

[0057] like Figure 6bAs shown, corresponding to step S2, an initial ITO contact layer is plated on the side of the initial P-type surface layer 142' away from the P-type limiting layer 130, and then the initial ITO contact layer and the initial P-type surface layer 142' are etched by photolithography to form a P-type pattern surface layer 142, an ITO contact layer 200 and a hollow pattern 142a. A refractive layer 700 is formed at the hollow pattern 142a.

[0058] In some embodiments, before etching the initial ITO contact layer and the initial P-type surface layer 142' provided in the embodiment of the present application, the surface of the structure can be cleaned by acetone, isopropyl alcohol, deionized water, etc., and then the etching can be combined with a photolithography process and a dry or wet etching process can be used for etching. Among them, the pattern of the P-type pattern surface layer 142 and the ITO contact 200 formed by etching can be a regular pattern or an irregular pattern such as a circle, a diamond, a rectangle, etc., and the present application does not make specific restrictions on this. In addition, the embodiment of the present application can use a Sputter sputtering machine 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 the sub-refractive layers on the entire surface to form each sub-refractive layer), and the refractive layer 700 can fill the hollow pattern 142a of the P-type pattern surface layer 142.

[0059] Optionally, the thickness of the ITO contact 200 provided in the embodiment of the present application may be 100 angstroms. Also, the thickness of the refractive layer 700 provided in the embodiment of the present application may be 1000 angstroms.

[0060] like Figure 6c As shown, corresponding to step S3, an initial dielectric film layer and an initial adhesion layer are plated on the entire surface of the epitaxial structure, and then the initial dielectric film layer and the initial adhesion layer are etched by a photolithography process to form a dielectric film layer 300 and an adhesion layer 800. The material of the dielectric film layer 300 can be SiO2. It can be seen that along the growth direction Y, the refractive index of the P-type base layer 141, the IZO sub-refractive layer 710, the Al2O3 sub-refractive layer 720 and the dielectric film layer 300 changes in a decreasing gradient, thereby improving the light extraction efficiency of the reverse polarity LED structure. And, through the preparation of the adhesion layer 800, the adhesion strength between the dielectric film layer 300 and the subsequently prepared mirror layer 400 can be improved.

[0061] Optionally, the adhesion layer 800 provided in the embodiment of the present application 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.

[0062] like Figure 6dAs shown, corresponding to step S4, the mirror layer 400 is sputtered and the target substrate 500 is bonded, and then the temporary substrate 10, the buffer layer 20 and the corrosion stop layer 30 are removed. 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 away from the P-type restriction layer 130, and an N-type electrode 620 is formed on the side of the N-type roughening layer 910 away from the P-type restriction layer 130, and the N-type electrode 620 covers the ohmic contact layer 920. Finally, the cutting and splitting are performed to form a single reverse polarity LED structure. Among them, the preparation of the roughened surface of the N-type roughening layer 910 can improve the light emitting effect of the reverse polarity LED structure. And the design of the N-type electrode 620 covering the ohmic contact layer 920 can improve the ohmic contact performance between the N-type electrode 620 and the epitaxial structure, and improve the performance of the reverse polarity LED structure.

[0063] Optionally, the mirror layer 400 provided in the embodiment of the present application may be Ag-TiW-Ti-Pt-Au layers stacked in sequence along the growth direction Y. Also, the material of the target substrate 500 provided in the embodiment of the present application may be Si, which is not specifically limited in the present application.

[0064] Further references Figure 7 , which is a schematic diagram of another reverse polarity LED structure provided in an embodiment of the present application, wherein the reverse polarity LED structure provided in an embodiment of the present application 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 may be SiN, which is not specifically limited in the present application.

[0065] The embodiment of the present application provides a reverse polarity LED structure, the reverse polarity LED structure comprising: an epitaxial structure, the epitaxial structure comprising an N-type confinement layer, an active layer, a P-type confinement layer and a P-type GaP window layer sequentially stacked along a growth direction, the P-type GaP window layer comprising a P-type base layer located on the P-type confinement layer, and a P-type pattern surface layer located on a side of the P-type base layer away from the P-type confinement layer, wherein the P-type pattern surface layer comprises a hollow pattern exposing the P-type base layer; a P-type pattern surface layer located on a side of the P-type pattern surface layer away from the P-type confinement layer An ITO contact layer, wherein the ITO contact layer is hollowed out at a position corresponding to the hollow pattern; a dielectric film layer located in the hollow pattern and on a side of the P-type base layer away from the P-type restriction layer, wherein the dielectric film layer exposes the ITO contact layer; a mirror layer located on a side of the ITO contact layer away from the P-type restriction layer; a target substrate located on a side of the mirror layer away from the P-type restriction layer; and a P-type electrode located on a side of the target substrate away from the P-type restriction layer, and an N-type electrode located on a side of the N-type restriction layer away from the P-type restriction layer.

[0066] From the above content, it can be seen that the technical solution provided by the embodiment of the present application combines the ITO contact layer and the P-type pattern surface layer as the P-side ohmic contact structure of the LED structure, which can not only improve the reliability of the P-side ohmic contact structure, but also effectively reduce the light absorption of the P-side ohmic contact structure, thereby improving the external quantum efficiency of the LED structure. In addition, the alloying time and alloying temperature required when the ITO contact layer and the P-type pattern surface layer form the P-side ohmic contact structure are both relatively low, thereby reducing the difficulty of the preparation process of the reverse polarity LED structure.

[0067] In the description of the embodiments of the present application, it needs to be understood that the orientation or position relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0068] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the embodiments of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0069] In the embodiments of the present application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0070] In the embodiments of the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0071] In the embodiments of the present application, if the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" appear, it means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples without contradiction.

[0072] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A reverse polarity LED structure, characterized in that: The reverse polarity LED structure comprises: An epitaxial structure, the epitaxial structure comprising an N-type confinement layer, an active layer, a P-type confinement layer and a P-type GaP window layer sequentially stacked along a growth direction, the P-type GaP window layer comprising a P-type base layer located on the P-type confinement layer, and a P-type pattern surface layer located on a side of the P-type base layer away from the P-type confinement layer, wherein the P-type pattern surface layer comprises a hollow pattern exposing the P-type base layer; An ITO contact layer located on a side of the surface of the P-type pattern away from the P-type restriction layer, wherein the ITO contact layer is hollowed out at a position corresponding to the hollowed-out pattern; A dielectric film layer located in the hollow pattern and on a side of the P-type base layer away from the P-type restriction layer, wherein the dielectric film layer exposes the ITO contact layer; A mirror layer located on a side of the ITO contact layer away from the P-type restriction layer; A target substrate located on a side of the mirror layer away from the P-type confinement layer; And, a P-type electrode located on a side of the target substrate away from the P-type confinement layer, and an N-type electrode located on a side of the N-type confinement layer away from the P-type confinement layer.

2. The reverse polarity LED structure according to claim 1, characterized in that: The doping concentration of the P-type pattern surface layer is greater than the doping concentration of the P-type base layer.

3. The reverse polarity LED structure according to claim 1, characterized in that: The reverse polarity LED structure further comprises: At the hollow pattern, a refractive layer is located between the P-type base layer and the dielectric film layer.

4. The reverse polarity LED structure according to claim 3, characterized in that: The refractive layer comprises at least two sub-refractive layers sequentially stacked along the growth direction; Along the growth direction, the refractive index of the at least two sub-refractive layers changes in a gradient.

5. The reverse polarity LED structure according to claim 4, characterized in that: Along the growth direction, the refractive indices of the P-type base layer, the at least two sub-refractive layers and the dielectric film layer vary in a gradient.

6. The reverse polarity LED structure according to claim 4, characterized in that: 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 close to the P-type base layer.

7. The reverse polarity LED structure according to claim 1, characterized in that: The reverse polarity LED structure further comprises: An adhesion layer is located between the dielectric film layer and the mirror layer.

8. The reverse polarity LED structure according to claim 7, characterized in that: The adhesion layer includes at least two oxide sub-adhesion layers sequentially stacked along the growth direction.

9. The reverse polarity LED structure according to claim 8, characterized in that: The at least two oxide sub-adhesion 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 close to the dielectric film layer.

10. The reverse polarity LED structure according to claim 1, characterized in that: The epitaxial structure further comprises: An N-type roughening layer located between the N-type restriction layer and the N-type electrode, wherein a surface of the N-type roughening layer on a side facing away from the P-type restriction layer comprises an electrode region and a roughening region, the N-type electrode is located in the electrode region, and the roughening region comprises a roughened surface of the N-type roughening layer; and / or, an ohmic contact layer between the N-type restriction layer and the N-type electrode, the N-type electrode covering 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.

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