Light emitting device and method for manufacturing the same

Abstract

The present application relates to the field of semiconductor technology, and specifically discloses a light-emitting device and a manufacturing method thereof, wherein the light-emitting device comprises a substrate and a plurality of epitaxial layers formed on the substrate in an epitaxial generation manner, wherein a plurality of artificial micro-pits are arranged in the light-emitting device, wherein the artificial micro-pits use the substrate and / or at least one epitaxial layer in the plurality of epitaxial layers as a stop layer, and extend to a subsequent epitaxial layer subsequently formed on the stop layer, wherein the artificial micro-pit has two side walls opposite to each other in a first cross-sectional shape on a first reference plane perpendicular to the substrate, and the intersection angle between at least one side wall and the substrate is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate. By the above method, the side wall angle of the artificial micro-pit is flexibly controllable, thereby achieving the optimization of the hole injection effect of the artificial micro-pit.

Description

Technical Field

[0001] The present application relates to the field of semiconductor technology, in particular to a light emitting device and a method for manufacturing the same. Background Art

[0002] Light-emitting diode (LED) is a photoelectric device that converts electrical energy into light energy and is widely used in lighting, backlighting and display. At present, the third-generation semiconductor nitride LED has a dislocation density of 10 9 / cm 2 At the level of , the wall-plug efficiency (WPE) can still reach more than 60%. The mainstream explanation for this phenomenon is that the multi-quantum well (MQW) of the V-pits (Pits) is thinner and has a lower In content than the MQW in the platform area, so it has a wider bandgap, which can form a potential barrier near the dislocation to prevent carriers from being captured. The principle of naturally formed V-pits is that the temperature of the superlattice growth layer is low, and the lateral epitaxial ability of nitrides (such as GaN) is poor. At this time, penetrating dislocations will form V-pits.

[0003] During the long-term research and development process, the inventors of the present application discovered that the side wall angle of the existing "artificial V-shaped pit" is limited to a fixed value or a very small range, resulting in a certain loss of light-emitting area, and it is impossible to optimize the hole injection effect of the V-shaped pit.

[0004] Therefore, it is necessary to design an artificial micro-pit with flexible and controllable side wall angle. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a light-emitting device and a manufacturing method thereof, so that the side wall angle of the artificial micro-pit is flexibly controllable, thereby optimizing the hole injection effect of the artificial micro-pit.

[0006] On the one hand, the present application provides a light-emitting device, which includes a substrate and a plurality of epitaxial layers stacked on the substrate in an epitaxial generation manner, wherein a plurality of artificial micro-pits are arranged in the light-emitting device, wherein the artificial micro-pits use the substrate and / or at least one epitaxial layer in the plurality of epitaxial layers as a termination layer, and extend into a subsequent epitaxial layer subsequently formed on the termination layer, wherein the artificial micro-pits have two side walls opposite to each other in a first cross-sectional shape on a first reference plane perpendicular to the substrate, and an intersection angle between at least one side wall and the substrate is different from an intersection angle between a natural growth crystal plane of the subsequent epitaxial layer and the substrate.

[0007] On the other hand, the present application provides a method for manufacturing a light-emitting device, the method comprising: providing a substrate; using the substrate and / or at least one epitaxial layer on the substrate as a stop layer, and forming a starting micro-pit in the stop layer; continuing to grow a subsequent epitaxial layer on the stop layer, so that an induced micro-pit is formed in the subsequent epitaxial layer as the subsequent epitaxial layer is epitaxially generated under the induction of the starting micro-pit, wherein the starting micro-pit and the induced micro-pit have two side walls opposite to each other in a first cross-sectional shape on a first reference plane perpendicular to the substrate, wherein an angle between the side wall of the starting micro-pit and the substrate is different from an angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate, and the pit depth of the starting micro-pit is set so that the extension direction of the side wall of the induced micro-pit is consistent with that of the side wall of the starting micro-pit.

[0008] On the other hand, the present application provides a method for manufacturing a light-emitting device, the method comprising: providing a substrate; forming a plurality of epitaxial layers by stacking them on the substrate in an epitaxial growth manner; using the substrate and / or at least one of the plurality of epitaxial layers as a stop layer; etching a subsequent epitaxial layer subsequently formed on the stop layer from a side of the subsequent epitaxial layer facing away from the substrate to form a plurality of artificial micro-pits, wherein the artificial micro-pits have two side walls opposite to each other in a first cross-sectional shape on a first reference plane perpendicular to the substrate, and an angle between at least one side wall and the substrate is different from an angle between a natural growth crystal plane of the subsequent epitaxial layer and the substrate.

[0009] Different from the prior art, the artificial micro-pit of the present application uses at least one epitaxial layer in the substrate and / or multiple epitaxial layers as a stop layer, and extends to the subsequent epitaxial layer subsequently formed on the stop layer, that is, the present application can break through the limiting factors of the existing "artificial V-shaped pit", and can select any substrate and / or epitaxial layer as the stop layer of the artificial micro-pit, and the intersection angle between at least one side wall and the substrate is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate, so that the side wall angle of the artificial micro-pit is flexible and controllable. By changing the intersection angle, the In content and crystal plane type of the quantum well active layer at the side wall can be regulated; further, since different types of crystal planes have different adsorption capacities for reactants, the film thickness obtained by deposition is different, and the thickness of the quantum well active layer at the side wall can be regulated, and finally the purpose of regulating the side wall band structure is achieved, further reducing the hole injection barrier height, increasing the efficiency and uniformity of lateral current injection on the side wall, and improving the luminescence efficiency. In addition, by increasing the intersection angle, an artificial micro-pit with a smaller duty cycle can be obtained, thereby reducing the loss of the epitaxial layer light-emitting area caused by the formation of artificial micro-pits and increasing the light output. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0011] Figure 1 It is a structural schematic diagram corresponding to the manufacturing process of the light-emitting device provided in the first embodiment of the present application;

[0012] Figure 2 is a structural schematic diagram corresponding to the manufacturing process of the light-emitting device provided in the second embodiment of the present application;

[0013] Figure 3 is a structural schematic diagram corresponding to the manufacturing process of the light-emitting device provided in the third embodiment of the present application;

[0014] Figure 4 is a structural schematic diagram corresponding to the manufacturing process of the light-emitting device provided in the fourth embodiment of the present application;

[0015] Figure 5 is a schematic structural diagram of a light-emitting device provided in a fifth embodiment of the present application;

[0016] Figure 6 is a schematic structural diagram of a light-emitting device provided in a sixth embodiment of the present application;

[0017] Figure 7 is a schematic flow chart of a method for manufacturing a light-emitting device provided in a seventh embodiment of the present application;

[0018] Figure 8 It is a schematic flow chart of a method for manufacturing a light-emitting device provided in the eighth embodiment of the present application. DETAILED DESCRIPTION

[0019] 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.

[0020] like Figures 1 to 5 As shown, the embodiment of the present application provides a light emitting device 100, which includes: a substrate 101 and multiple epitaxial layers. The multiple epitaxial layers are stacked on the substrate 101 by epitaxial growth.

[0021] A plurality of artificial micro-pits are arranged in the light emitting device 100 . The artificial micro-pits use the substrate 101 and / or at least one epitaxial layer in the multiple epitaxial layers as a stop layer and extend into a subsequent epitaxial layer subsequently formed on the stop layer.

[0022] Specifically, the material of the substrate 101 includes, but is not limited to, at least one of sapphire, Si, SiC, GaN, ZnO, InP, and GaAs.

[0023] The multilayer epitaxial layer may include a first conductive type semiconductor layer 103 (e.g., an N-type GaN layer 103), a quantum well active layer 105 (e.g., a multi-quantum well active (MQW) layer or a superlattice quantum well active layer 105), and a second conductive type semiconductor layer 107 (e.g., a P-type GaN layer 107) stacked in sequence on a substrate 101.

[0024] Furthermore, the material system of the quantum well active layer 105 includes: Al x1 In y1 Ga z1 N x2 P y2 As z2 , where 0≤x1 or y1 or z1 or x2 or y2 or z2≤1, optionally, x1+y1+z1=1, x2+y2+z2=1.

[0025] Furthermore, the multi-layer epitaxial layer may include a buffer layer 102102, a first conductive type semiconductor layer 103, a pre-well preparation layer 104, a quantum well active layer 105, an electron blocking layer 106, a second conductive type semiconductor layer 107 or a second conductive type heavily doped semiconductor layer stacked in sequence on the substrate 101.

[0026] The artificial micro-pits may use at least one of the first conductive type semiconductor layer 103, the quantum well active layer 105 and the second conductive type semiconductor layer 107 and / or the substrate 101 as a stop layer, and extend into a subsequent epitaxial layer subsequently formed on the stop layer.

[0027] For example, the artificial micro-pits use the first conductive type semiconductor layer 103 as a stop layer and extend into the quantum well active layer 105 and the second conductive type semiconductor layer 107 subsequently formed on the first conductive type semiconductor layer 103 .

[0028] For another example, the artificial micro-pits use the first conductive type semiconductor layer 103 as a stop layer and extend into the quantum well active layer 105 subsequently formed on the first conductive type semiconductor layer 103. At this time, the quantum well active layer 105 is used as a stop layer again and extends into the second conductive type semiconductor layer 107 subsequently formed on the quantum well active layer 105.

[0029] For another example, the artificial micro-pits use the substrate 101 as a stop layer and extend into the first conductive type semiconductor layer 103 , the quantum well active layer 105 , and the second conductive type semiconductor layer 107 that are subsequently formed on the substrate 101 .

[0030] For another example, the artificial micro-pits use the substrate 101 as a stop layer and extend into a first conductive type semiconductor layer 103 subsequently formed on the substrate 101, and then use the first conductive type semiconductor layer 103 as a stop layer and extend into a quantum well active layer 105 and a second conductive type semiconductor layer 107 subsequently formed on the first conductive type semiconductor layer 103.

[0031] For another example, the artificial micro-pits use the substrate 101 as a stop layer and extend into a first conductive type semiconductor layer 103 subsequently formed on the substrate 101, and then use the first conductive type semiconductor layer 103 as a stop layer and extend into a quantum well active layer 105 subsequently formed on the first conductive type semiconductor layer 103, and then use the quantum well active layer 105 as a stop layer and extend into a second conductive type semiconductor layer 107 subsequently formed on the quantum well active layer 105.

[0032] The artificial micro-pit has two side walls 12 and 13 opposite to each other on a first reference plane perpendicular to the substrate 101 , and the intersection angle between at least one side wall 12 and 13 and the substrate 101 is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101 .

[0033] The first cross-sectional shape of the artificial micro-pit in the embodiment of the present application on the first reference plane perpendicular to the substrate 101 has two side walls 12 and 13 opposite to each other, and the first cross-sectional shape can be a non-isosceles triangle. The intersection angle α between at least one side wall 12, 13 and the substrate 101 is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101.

[0034] Among them, the natural growth habit of the naturally grown crystal plane is different from the growth habit of the subsequent epitaxial layer artificially grown in the embodiment of the present application, and therefore, the intersection angle α between the sidewalls 12, 13 related to the subsequent epitaxial layer artificially grown and the substrate 101 is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101. The present application changes the natural growth habit of the crystal so that the intersection angle between the sidewalls 12, 13 of the second cross-sectional shape of the artificial micro-pit on the second reference plane perpendicular to the substrate 101 and the substrate 101 is flexible and controllable, thereby obtaining second cross-sectional shapes of different shapes.

[0035] The second cross-sectional shape of the artificial micro-pit in the embodiment of the present application on the second reference plane parallel to the substrate 101 is a closed ring, which can be a circle, an ellipse or a polygon, and the second cross-sectional shape is asymmetric or symmetric relative to the central axis. In other embodiments, the second cross-sectional shape of the artificial micro-pit on the second reference plane parallel to the substrate 101 can also be other custom patterns.

[0036] Different from the prior art, the artificial micro-pit of the present application uses the substrate 101 and / or at least one epitaxial layer in the multiple epitaxial layers as a stop layer, and extends to the subsequent epitaxial layer subsequently formed on the stop layer, that is, the present application can break through the limiting factors of the existing "artificial V-shaped pit", and any substrate 101 and / or epitaxial layer can be selected as the stop layer of the artificial micro-pit, and the intersection angle between at least one side wall 12, 13 and the substrate 101 is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101, so that the side walls 12, 13 of the artificial micro-pit are The angle is flexible and controllable. By changing the intersection angle, the In content and crystal plane type of the quantum well active layer 105 at the side walls 12 and 13 can be regulated; further, since different types of crystal planes have different adsorption capacities for reactants, the deposited film thickness is different, and the thickness of the quantum well active layer 105 at the side walls 12 and 13 can be regulated, and finally the purpose of regulating the band structure of the side walls 12 and 13 is achieved, further reducing the hole injection barrier height, increasing the efficiency and uniformity of the lateral current injection of the side walls 12 and 13, and improving the luminous efficiency. In addition, by increasing the intersection angle, an artificial micro-pit with a smaller duty cycle can be obtained, reducing the loss of the epitaxial layer luminous area caused by the formation of artificial micro-pits, and increasing the light output.

[0037] In one embodiment, the absolute difference between the intersection angle between at least one side wall 12, 13 and the substrate 101 and the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101 is not less than 5 degrees, for example 5 degrees, 15 degrees, 45 degrees, 50 degrees, 70 degrees or 90 degrees.

[0038] In one embodiment, an intersection angle α between at least one of the side walls 12 , 13 and the substrate 101 is 60 degrees to 90 degrees, such as 60 degrees, 70 degrees, 80 degrees or 90 degrees.

[0039] In one embodiment, the intersection angles between the two sidewalls 12 and 13 and the substrate 101 are different.

[0040] In one embodiment, the artificial micropits are further divided into starting micropits and induced micropits. The starting micropits are artificially formed in the stop layer, and the induced micropits are formed in the subsequent epitaxial layer as the subsequent epitaxial layer grows epitaxially under the induction of the starting micropits.

[0041] Among them, the intersection angle between the side walls 12, 13 of the starting micro-pit and the substrate 101 is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101, and the pit depth of the starting micro-pit is set so that the side walls 12, 13 of the induced micro-pits formed in the subsequent epitaxial layer during the epitaxial growth process are consistent with the extension direction of the side walls 12, 13 of the starting micro-pit.

[0042] In one embodiment, a starting micropit forms an opening on the surface of one side of the stop layer facing the subsequent epitaxial layer, and the cross-sectional shape of the opening of the starting micropit on the second reference plane parallel to the substrate 101 can be a non-regular hexagon or a regular hexagon, and the size of the opening of the starting micropit is set so that the cross-sectional shape of the induced micropit formed in the subsequent epitaxial layer during the epitaxial growth process on the second reference plane parallel to the substrate 101 is consistent with the cross-sectional shape of the opening on the second reference plane parallel to the substrate 101.

[0043] like Figure 1 As shown, the opening width w of the starting micropit is the maximum distance between any two points on the edge of the cross-sectional shape of the opening of the starting micropit. Wherein, the opening width w of the starting micropit is defined in the present application as 1nm to 10μm, and optionally, the opening width w of the starting micropit can be 1nm to 15nm, 15nm to 100nm, 100nm to 500nm, 500nm to 1000nm, 1μm to 5μm, 5μm to 10μm, for example, the opening width w of the starting micropit can be 1nm, 15nm, 20nm, 100nm, 500nm, 600nm, 750nm, 1000nm, 2μm, 5μm, 10μm.

[0044] like Figure 1 As shown, the pit depth d of the starting micropit is the vertical distance from a point on the starting micropit that is shortest from the main surface of the side of the substrate 101 away from the epitaxial layer to the main surface of the side of the stop layer away from the substrate 101. The pit depth d of the starting micropit is defined as 1nm to 10μm in the present application. Optionally, the pit depth d of the starting micropit can be 1nm to 15nm, 15nm to 100nm, 100nm to 500nm, 500nm to 1000nm, 1μm to 5μm, 5μm to 10μm. For example, the pit depth d of the starting micropit can be 1nm, 15nm, 20nm, 100nm, 500nm, 600nm, 750nm, 1000nm, 2μm, 5μm, 10μm.

[0045] Based on the growth principle of naturally formed V-shaped pits, the greater the pit depth of the naturally formed V-shaped pit, the greater the opening width is required, that is, the pit depth of the naturally formed V-shaped pit is positively correlated with the opening width of the naturally formed V-shaped pit. Therefore, the pit depth of the naturally formed V-shaped pit is limited by the size of the light-emitting device 100. Different from the prior art, the pit depth d of the starting micro-pit in the embodiment of the present application depends on the position of the stop layer and has no correlation with the opening width w of the starting micro-pit. Optionally, the ratio between the pit depth d of the starting micro-pit of the present application and the opening width w of the starting micro-pit is 1:10 to 100:1, for example, 1:10, 1:5, 1:1, 5:1, 10:1, 50:1, 100:1.

[0046] In one embodiment, the light emitting device 100 has a platform region at the periphery of the artificial micro-pit, and the subsequent epitaxial layer is at least located in the platform region, wherein the film composition of the sidewalls 12 and 13 on the side of the stop layer facing the subsequent epitaxial layer is different from the film composition of the subsequent epitaxial layer in the platform region. The light emitting device has a platform region at the periphery of the artificial micro-pit, and the subsequent epitaxial layer is at least formed in the platform region, wherein the film composition of the sidewalls 12 and 13 on the side of the stop layer facing the subsequent epitaxial layer is different from the film composition of the subsequent epitaxial layer in the platform region.

[0047] It should be noted that, in the embodiment of the present application, “the film layer composition of the sidewalls 12 and 13 located on the side of the stop layer facing the subsequent epitaxial layer” may include materials for realizing lateral hole transport.

[0048] The number of film layers of the sidewalls 12 and 13 on the side of the stop layer facing the subsequent epitaxial layer is less than or greater than the number of film layers of the subsequent epitaxial layer in the platform area.

[0049] The film composition of the sidewalls 12 and 13 on the side of the stop layer facing the subsequent epitaxial layer is different from the film composition of the subsequent epitaxial layer in the platform area.

[0050] The film layer of the sidewalls 12 and 13 on the side of the stop layer facing the subsequent epitaxial layer includes at least one custom epitaxial layer 108 different from the subsequent epitaxial layer in the platform area.

[0051] In one embodiment, the custom epitaxial layer 108 is a carrier injection layer.

[0052] The material of the carrier injection layer may include but is not limited to: indium gallium nitride, aluminum gallium nitride, aluminum indium gallium, zinc oxynitride, and the conductivity type of the carrier injection layer is: N-type, P-type or intrinsic.

[0053] It can be understood that the embodiments of the present application can make the light-emitting device emit two or more colors of light or white light by regulating the film layer composition of the side walls 12, 13 on the side of the stop layer facing the subsequent epitaxial layer and / or the film layer composition of the subsequent epitaxial layer in the platform area. For example, the film layer of the side walls 12, 13 on the side of the stop layer facing the subsequent epitaxial layer and the film layer of the subsequent epitaxial layer in the platform area can use different color luminescent materials.

[0054] Through the above-mentioned method, the present application can break through the limiting factors of the existing "artificial V-shaped pits", select any substrate 101 and / or epitaxial layer as the stop layer of the artificial micro-pit, and the film composition of the side walls 12 and 13 on the side of the stop layer facing the subsequent epitaxial layer is different from the film composition of the subsequent epitaxial layer in the platform area, thereby achieving the purpose of regulating the band structure of the side walls 12 and 13, optimizing the hole injection path, and further reducing the hole injection barrier height, increasing the efficiency and uniformity of the lateral current injection of the side walls 12 and 13, and improving the luminous efficiency.

[0055] In one embodiment, the artificial micro-pits are formed by etching the subsequent epitaxial layer from a side of the subsequent epitaxial layer facing away from the substrate 101 .

[0056] Specifically, the subsequent epitaxial layer formed on the stop layer is etched from the side of the subsequent epitaxial layer away from the substrate 101 to form the starting micro-pit, and an induced micro-pit surrounding the starting micro-pit is continuously epitaxially grown under the induction of the starting micro-pit, and the cross-sectional shape of the induced micro-pit is consistent with the cross-sectional shape of the opening of the starting micro-pit. It should be noted that the size of the opening of the starting micro-pit must be set so that the cross-sectional shape of the induced micro-pit formed by the subsequent epitaxial layer during the epitaxial growth process is consistent with the opening.

[0057] like Figure 7 As shown, the embodiment of the present application also provides a method for manufacturing the light emitting device 100 of the above embodiment, the method comprising:

[0058] S101: providing a substrate 101.

[0059] Specifically, the material of the substrate 101 includes, but is not limited to, at least one of sapphire, Si, SiC, GaN, ZnO, InP, and GaAs.

[0060] S102: using the substrate 101 and / or at least one epitaxial layer on the substrate 101 as a stop layer, and forming a starting micro-pit in the stop layer.

[0061] S103: Continue to grow a subsequent epitaxial layer on the stop layer, so that an induced micropit is formed in the subsequent epitaxial layer as the subsequent epitaxial layer is epitaxially generated under the induction of the starting micropit, wherein the starting micropit and the induced micropit have two side walls 12, 13 opposite to each other on a first reference plane perpendicular to the substrate 101, respectively, wherein an intersection angle between the side walls 12, 13 of the starting micropit and the substrate 101 is different from an intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101, and the pit depth of the starting micropit is set so that the side walls 12, 13 of the induced micropit are consistent with the extension direction of the side walls 12, 13 of the starting micropit.

[0062] Specifically, when the substrate 101 is used as a stop layer, a starting micro-pit is prepared by an etching process on the substrate 101 that has not undergone epitaxial growth, and subsequent epitaxial layers (such as the first conductive type semiconductor layer 103, the quantum well active layer 105, and the second conductive type semiconductor layer 107) continue to grow on the substrate 101. Under the induction of the starting micro-pit, an induced micro-pit is formed in the subsequent epitaxial layer as the subsequent epitaxial layer is epitaxially generated, wherein the starting micro-pit and the induced micro-pit cooperate to form an artificial micro-pit, and the starting micro-pit and the induced micro-pit respectively have two side walls 12 and 13 opposite to each other on a first reference plane perpendicular to the substrate 101, wherein the intersection angle of the side walls 12 and 13 of the starting micro-pit with the substrate 101 is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101, and the pit depth of the starting micro-pit is set so that the side walls 12 and 13 of the induced micro-pit are consistent with the extension direction of the side walls 12 and 13 of the starting micro-pit.

[0063] Different from the prior art, the artificial micro-pits prepared by the manufacturing method provided by the present application use the substrate 101 and / or at least one of the multiple epitaxial layers as a stop layer, and extend to the subsequent epitaxial layer subsequently formed on the stop layer, that is, the present application can break through the limiting factors of the existing "artificial V-shaped pits", and any substrate 101 and / or epitaxial layer can be selected as the stop layer of the artificial micro-pits, and the intersection angle between at least one side wall 12, 13 and the substrate 101 is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101, so that the artificial micro-pits The angles of the side walls 12 and 13 are flexible and controllable. By changing the intersection angle, the In content and crystal plane type of the quantum well active layer 105 at the side walls 12 and 13 can be regulated; further, since different crystal planes have different adsorption capacities for reactants, the deposited film thickness is different, and the thickness of the quantum well active layer 105 at the side walls 12 and 13 can be regulated, and finally the purpose of regulating the band structure of the side walls 12 and 13 is achieved, further reducing the hole injection barrier height, increasing the efficiency and uniformity of the lateral current injection of the side walls 12 and 13, and improving the luminous efficiency. In addition, by increasing the intersection angle, an artificial micro-pit with a smaller duty cycle can be obtained, reducing the loss of the epitaxial layer luminous area caused by the formation of artificial micro-pits, and increasing the light output.

[0064] like Figure 8 As shown, the embodiment of the present application also provides a method for manufacturing the light emitting device 100 of the above embodiment, the method comprising:

[0065] S201: providing a substrate 101.

[0066] Specifically, the material of the substrate 101 includes, but is not limited to, at least one of sapphire, Si, SiC, GaN, ZnO, InP, and GaAs.

[0067] S202: Form a plurality of epitaxial layers on the substrate 101 by epitaxial growth.

[0068] A first conductive type semiconductor layer 103 and a quantum well active layer 105 are formed on the substrate 101 by epitaxial growth, or a first conductive type semiconductor layer 103 , a quantum well active layer 105 and a second conductive type semiconductor layer 107 are formed on the substrate 101 by epitaxial growth.

[0069] More specifically, a buffer layer 102, a first conductive type semiconductor layer 103, a pre-well preparation layer, a quantum well active layer 105 and / or a superlattice quantum well active layer 105, an electron blocking layer, a second conductive type semiconductor layer 107 and / or a second conductive type heavily doped semiconductor layer are formed by epitaxial growth on the substrate 101. The stop layer may be at least two continuous stacks of the buffer layer 102, the first conductive type semiconductor layer 103, the pre-well preparation layer 104, the quantum well active layer 105, the superlattice quantum well active layer 105, the electron blocking layer 106, the second conductive type semiconductor layer 107, and the second conductive type heavily doped semiconductor layer.

[0070] S203: using the substrate 101 and / or at least one of the plurality of epitaxial layers as a stop layer.

[0071] S204: Etching a subsequent epitaxial layer subsequently formed on the stop layer from a side of the subsequent epitaxial layer facing away from the substrate 101 to form a plurality of artificial micro-pits, wherein the artificial micro-pits have two side walls 12, 13 opposite to each other on a first reference plane perpendicular to the substrate 101, and an intersection angle between at least one side wall 12, 13 and the substrate 101 is different from an intersection angle between a natural growth crystal plane of the subsequent epitaxial layer and the substrate 101.

[0072] Specifically, when the substrate 101 is used as a stop layer, the second conductive type semiconductor layer 107, the quantum well active layer 105 and the first conductive type semiconductor layer 103 are etched from the side of the second conductive type semiconductor layer 107 away from the substrate 101 to form a plurality of artificial micro-pits, wherein the artificial micro-pits have two side walls 12 and 13 opposite to each other on a first reference plane perpendicular to the substrate 101, and the intersection angle between at least one side wall 12, 13 and the substrate 101 is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101.

[0073] Furthermore, a mask layer can be deposited on the stop layer and patterned to obtain a mask pattern. The mask layer can be an organic photoresist, or a non-metallic compound such as SiO2, Si3N4, or a metal layer. The deposition method includes but is not limited to chemical vapor deposition, physical vapor deposition, and electrochemical deposition. The patterning method includes but is not limited to dry etching, wet etching, and stripping. The non-mask area is etched using the mask pattern to form a plurality of artificial micro-pits. The etching rate, angle, anisotropy, etc. can be adjusted by changing the process parameters, and the depth, cross-sectional shape, and angles of the sidewalls 12 and 13 of the artificial micro-pits can be controlled.

[0074] Different from the prior art, the artificial micro-pits prepared by the manufacturing method provided by the present application use the substrate 101 and / or at least one of the multiple epitaxial layers as a stop layer, and extend to the subsequent epitaxial layer subsequently formed on the stop layer, that is, the present application can break through the limiting factors of the existing "artificial V-shaped pits", and any substrate 101 and / or epitaxial layer can be selected as the stop layer of the artificial micro-pits, and the intersection angle between at least one side wall 12, 13 and the substrate 101 is different from the intersection angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate 101, so that the artificial micro-pits The angles of the side walls 12 and 13 are flexible and controllable. By changing the intersection angle, the In content and crystal plane type of the quantum well active layer 105 at the side walls 12 and 13 can be regulated; further, since different crystal planes have different adsorption capacities for reactants, the deposited film thickness is different, and the thickness of the quantum well active layer 105 at the side walls 12 and 13 can be regulated, and finally the purpose of regulating the band structure of the side walls 12 and 13 is achieved, further reducing the hole injection barrier height, increasing the efficiency and uniformity of the lateral current injection of the side walls 12 and 13, and improving the luminous efficiency. In addition, by increasing the intersection angle, an artificial micro-pit with a smaller duty cycle can be obtained, reducing the loss of the epitaxial layer luminous area caused by the formation of artificial micro-pits, and increasing the light output.

[0075] The specific embodiments of the present application are described in detail below in combination with the technical solutions and drawings.

[0076] Example 1

[0077] like Figure 1As shown, a substrate 101 is provided, and a buffer layer 102 and an N-type GaN layer 103 are sequentially stacked on the substrate 101 by epitaxial growth. The N-type GaN layer 103 is used as a stop layer, and an initial micro-pit is formed on the N-type GaN layer 103 by an etching process.

[0078] The pre-well preparation layer 104, the MQW active layer 105, the electron blocking layer 106 and the P-type GaN layer 107 are successively grown on the N-type GaN layer 103, wherein, under the induction effect of the starting micro-pits, induced micro-pits are formed in the pre-well preparation layer 104, the MQW active layer 105, the electron blocking layer 106 and the P-type GaN layer 107 in the area where the starting micro-pits are located.

[0079] The starting micropit has a first side wall 12, 13 and a second side wall 12, 13 on a first reference plane perpendicular to the substrate 101. The induced micropit has a third side wall 12, 13 and a fourth side wall 12, 13 on a first reference plane perpendicular to the substrate 101. The intersection angle between the first side wall 12, 13 or the second side wall 12, 13 and the substrate 101 is different from the intersection angle between the P-type GaN layer 107 and the substrate 101. The intersection angle α between at least one of the side walls 12, 13 and the substrate 101 is greater than 60°, and the ratio w / d between the opening width w of the starting micropit and the pit depth d of the starting micropit is less than

[0080] Example 2

[0081] like Figure 2 As shown, a substrate 101 is provided, and a buffer layer 102, an N-type GaN layer 103, a pre-well preparation layer 104, and an MQW active layer 105 are sequentially stacked on the substrate 101 by epitaxial growth. The MQW active layer 105 is used as a stop layer, and an initial micro-pit is formed on the MQW active layer 105 by an etching process, wherein the pit depth of the initial micro-pit is less than the thickness of the MQW active layer 105.

[0082] The electron blocking layer 106 and the P-type GaN layer 107 are successively grown on the MQW active layer 105 , wherein, under the induction of the starting micropits, induced micropits are formed in the electron blocking layer 106 and the P-type GaN layer 107 in the region where the starting micropits are located.

[0083] The starting micropit has a first side wall 12, 13 and a second side wall 12, 13 on a first reference plane perpendicular to the substrate 101, the induced micropit has a third side wall 12, 13 and a fourth side wall 12, 13 on the first reference plane perpendicular to the substrate 101, and the intersection angle between the first side wall 12, 13 or the second side wall 12, 13 and the substrate 101 is different from the intersection angle between the P-type GaN layer 107 and the substrate 101. The intersection angle α between at least one of the side walls 12, 13 and the substrate 101 is greater than 60°, and the ratio w / d between the opening width w of the starting micropit and the pit depth d of the starting micropit is less than

[0084] Example 3

[0085] like Figure 3 As shown, a substrate 101 is provided, and a buffer layer 102, an N-type GaN layer 103, a pre-well preparation layer 104, and an MQW active layer 105 are sequentially stacked on the substrate 101 by epitaxial growth. The MQW active layer 105 is used as a stop layer, and an initial micro-pit is formed on the MQW active layer 105 by an etching process, wherein the pit depth of the initial micro-pit is less than the thickness of the MQW active layer 105.

[0086] The custom epitaxial layer 108, the electron blocking layer 106 and the P-type GaN layer 107 are sequentially grown in the region where the starting micropit is located, and the electron blocking layer 106 and the P-type GaN layer 107 are sequentially grown in the peripheral region of the starting micropit. Under the induction of the starting micropit, the custom epitaxial layer 108, the electron blocking layer 106 and the P-type GaN layer 107 in the region where the starting micropit is located form an induced micropit, and the electron blocking layer 106 and the P-type GaN layer 107 in the peripheral region of the starting micropit form a platform region.

[0087] The starting micropit has a first side wall 12, 13 and a second side wall 12, 13 on a first reference plane perpendicular to the substrate 101, the induced micropit has a third side wall 12, 13 and a fourth side wall 12, 13 on the first reference plane perpendicular to the substrate 101, and the intersection angle between the first side wall 12, 13 or the second side wall 12, 13 and the substrate 101 is different from the intersection angle between the P-type GaN layer 107 and the substrate 101. The intersection angle α between at least one of the side walls 12, 13 and the substrate 101 is greater than 60°, and the ratio w / d between the opening width w of the starting micropit and the pit depth d of the starting micropit is less than

[0088] Example 4

[0089] like Figure 4As shown, a substrate 101 is provided, and a buffer layer 102, an N-type GaN layer 103, a pre-well preparation layer 104, an MQW active layer 105, and an electron blocking layer 106 are sequentially stacked on the substrate 101 by epitaxial growth, and the pit depth of the starting micro-pit is less than the thickness of the MQW active layer 105. With the electron blocking layer 106 as a stop layer, an initial micro-pit is formed on the electron blocking layer 106 by an etching process, and the pit depth of the starting micro-pit is less than the thickness of the electron blocking layer 106.

[0090] The P-type GaN layer 107 continues to grow on the electron blocking layer 106. Under the induction of the initial micro-pit, the P-type GaN layer 107 in the region where the initial micro-pit is located forms an induced micro-pit.

[0091] The starting micropit has a first side wall 12, 13 and a second side wall 12, 13 on a first reference plane perpendicular to the substrate 101, the induced micropit has a third side wall 12, 13 and a fourth side wall 12, 13 on the first reference plane perpendicular to the substrate 101, and the intersection angle between the first side wall 12, 13 or the second side wall 12, 13 and the substrate 101 is different from the intersection angle between the P-type GaN layer 107 and the substrate 101. The intersection angle α between at least one of the side walls 12, 13 and the substrate 101 is greater than 60°, and the ratio w / d between the opening width w of the starting micropit and the pit depth d of the starting micropit is less than

[0092] Example 5

[0093] like Figure 5 As shown, a substrate 101 is provided, and a buffer layer 102, an N-type GaN layer 103, a pre-well preparation layer 104, an MQW active layer 105, and an electron blocking layer 106 are sequentially stacked on the substrate 101 by epitaxial growth. With the electron blocking layer 106 as a stop layer, an initial micro-pit is formed on the electron blocking layer 106 by an etching process, and the pit depth of the initial micro-pit is less than the thickness of the electron blocking layer 106.

[0094] The custom epitaxial layer 108 and the P-type GaN layer 107 are sequentially grown in the region where the starting micropit is located, and the P-type GaN layer 107 is grown in the peripheral region of the starting micropit. Under the induction of the starting micropit, the custom epitaxial layer 108 and the P-type GaN layer 107 in the region where the starting micropit is located form an induced micropit, and the P-type GaN layer 107 in the peripheral region of the starting micropit forms a platform region.

[0095] The starting micropit has a first side wall 12, 13 and a second side wall 12, 13 on a first reference plane perpendicular to the substrate 101, the induced micropit has a third side wall 12, 13 and a fourth side wall 12, 13 on the first reference plane perpendicular to the substrate 101, and the intersection angle between the first side wall 12, 13 or the second side wall 12, 13 and the substrate 101 is different from the intersection angle between the P-type GaN layer 107 and the substrate 101. The intersection angle α between at least one of the side walls 12, 13 and the substrate 101 is greater than 60°, and the ratio w / d between the opening width w of the starting micropit and the pit depth d of the starting micropit is less than

[0096] Example 6

[0097] like Figure 6 As shown, a substrate 101 is provided, and a buffer layer 102, an N-type GaN layer 103, a pre-well preparation layer 104, and an MQW active layer 105 are sequentially stacked on the substrate 101 by epitaxial growth. The MQW active layer 105 is used as a stop layer, and an initial micro-pit is formed on the MQW active layer 105 by an etching process. The pit depth of the initial micro-pit is greater than the thickness of the MQW active layer 105, and an insulating layer 109 is deposited at the bottom of the initial micro-pit to insulate the subsequent epitaxial layer at the area where the initial micro-pit is located from the pre-well preparation layer 104.

[0098] The electron blocking layer 106 and the P-type GaN layer 107 are successively grown on the MQW active layer 105 , wherein, under the induction of the starting micropits, induced micropits are formed in the electron blocking layer 106 and the P-type GaN layer 107 in the region where the starting micropits are located.

[0099] The starting micropit has a first side wall 12, 13 and a second side wall 12, 13 on a first reference plane perpendicular to the substrate 101, the induced micropit has a third side wall 12, 13 and a fourth side wall 12, 13 on the first reference plane perpendicular to the substrate 101, and the intersection angle between the first side wall 12, 13 or the second side wall 12, 13 and the substrate 101 is different from the intersection angle between the P-type GaN layer 107 and the substrate 101. The intersection angle α between at least one of the side walls 12, 13 and the substrate 101 is greater than 60°, and the ratio w / d between the opening width w of the starting micropit and the pit depth d of the starting micropit is less than

[0100] Different from the prior art, the artificial micro-pit of the present application uses the substrate 101 and / or at least one of the multiple epitaxial layers as a stop layer, and extends to the subsequent epitaxial layer subsequently formed on the stop layer, that is, the present application can break through the limiting factors of the existing "artificial V-shaped pits", select any substrate 101 and / or epitaxial layer as the stop layer of the artificial micro-pit, and the film composition of the side walls 12 and 13 on the side of the stop layer facing the subsequent epitaxial layer is different from the film composition of the subsequent epitaxial layer in the platform area, thereby achieving the purpose of regulating the band structure of the side walls 12 and 13, optimizing the hole injection path, and further reducing the hole injection barrier height, increasing the efficiency and uniformity of lateral current injection of the side walls 12 and 13, and improving the luminescence efficiency.

[0101] The above are only implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A light emitting device, characterized in that: The light emitting device comprises a substrate and a plurality of epitaxial layers formed on the substrate in an epitaxial generation manner, wherein a plurality of artificial micro-pits are arranged in the light emitting device, wherein the artificial micro-pits use the substrate and / or at least one of the epitaxial layers as a stop layer and extend into a subsequent epitaxial layer subsequently formed on the stop layer, wherein the artificial micro-pits have two side walls opposite to each other in a first cross-sectional shape on a first reference plane perpendicular to the substrate, and an angle of intersection between at least one of the side walls and the substrate is different from an angle of intersection between a natural growth crystal plane of the subsequent epitaxial layer and the substrate; The artificial micro-pits are further divided into starting micro-pits artificially formed in the stop layer and induced micro-pits formed in the subsequent epitaxial layer as the subsequent epitaxial layer is epitaxially generated under the induction of the starting micro-pits, wherein the angle between the side wall of the starting micro-pit and the substrate is different from the angle between the natural growth crystal plane of the subsequent epitaxial layer and the substrate, and the pit depth of the starting micro-pit is set so that the side wall of the induced micro-pit formed in the epitaxial generation process of the subsequent epitaxial layer is consistent with the extension direction of the side wall of the starting micro-pit.

2. The light emitting device according to claim 1, characterized in that: An absolute difference between an intersection angle between at least one of the side walls and the substrate and an intersection angle between a natural growth crystal plane of the subsequent epitaxial layer and the substrate is not less than 5 degrees.

3. The light emitting device according to claim 1, characterized in that: An intersection angle between at least one of the side walls and the substrate is 60 degrees to 90 degrees.

4. The light emitting device according to claim 1, characterized in that: The intersection angles between the two side walls and the substrate are different from each other.

5. The light emitting device according to claim 1, characterized in that: The starting micropit forms an opening on the surface of one side of the stop layer facing the subsequent epitaxial layer, and the second cross-sectional shape of the opening on a second reference plane parallel to the substrate is a non-regular hexagon or a regular hexagon, and the size of the opening is set so that the cross-sectional shape of the induced micropit is consistent with the opening.

6. The light emitting device according to claim 5, characterized in that: The ratio of the width of the opening to the pit depth of the initial micro-pit is 1:10 to 100:

1.

7. The light emitting device according to claim 5, characterized in that: The width of the opening is 1 nm to 10 μm.

8. The light emitting device according to claim 1, characterized in that: The pit depth of the initial micropit is 1 nm to 10 μm.

9. The light emitting device according to claim 1, characterized in that: The density of the artificial micro-pits is 1×10 7 ~5×10 9 / cm 2 .

10. The light emitting device according to claim 1, characterized in that: The light-emitting device has a platform area around the artificial micro-pit, and the subsequent epitaxial layer is at least located in the platform area, wherein the film composition of the sidewall on the side of the stop layer facing the subsequent epitaxial layer is different from the film composition of the subsequent epitaxial layer in the platform area.

11. A method for manufacturing a light emitting device, characterized in that: The method comprises: providing a substrate; Using the substrate and / or at least one epitaxial layer on the substrate as a stop layer, and forming a starting micro-pit in the stop layer; A subsequent epitaxial layer continues to grow on the stop layer, so that an induced micropit is formed in the subsequent epitaxial layer as the subsequent epitaxial layer is epitaxially generated under the induction of the starting micropit, wherein the starting micropit and the induced micropit have two side walls opposite to each other in a first cross-sectional shape on a first reference plane perpendicular to the substrate, respectively, wherein an angle between the side wall of the starting micropit and the substrate is different from an angle between a natural growth crystal plane of the subsequent epitaxial layer and the substrate, and a pit depth of the starting micropit is set so that the side wall of the induced micropit is consistent with the extension direction of the side wall of the starting micropit.

Images