Preparation method of constant-current driving light-emitting device and constant-current driving light-emitting device

Abstract

The embodiment of the invention relates to a preparation method of a constant current driving light-emitting device and the constant current driving light-emitting device, and the preparation method comprises the steps: providing a semiconductor growth substrate which comprises a first surface and a second surface which are opposite to each other; a semiconductor epitaxial layer is epitaxially grown on the second surface side, the semiconductor epitaxial layer comprises a third surface connected with the semiconductor growth substrate, and the semiconductor epitaxial layer comprises a first semiconductor epitaxial layer, a light-emitting layer and a second semiconductor epitaxial layer which are sequentially stacked in the direction away from the semiconductor growth substrate, the first semiconductor epitaxial layer, the light-emitting layer and the second semiconductor epitaxial layer are used for forming a light-emitting unit; removing a part of the semiconductor growth substrate from the first surface side to expose a part of the third surface, the third surface being a light emitting surface of the light emitting unit; and carrying out ion doping in the residual semiconductor growth substrate to form a plurality of ion doped regions so as to form a constant current unit. Therefore, the stability of the light-emitting device is improved.

Description

Technical Field

[0001] The present application relates to the technical field of light-emitting devices, and in particular to a method for preparing a constant-current driven light-emitting device and a constant-current driven light-emitting device. Background Art

[0002] Among many light-emitting devices, light-emitting diodes (LEDs) have the characteristic of converting electrical energy into light energy. They are formed by combining group III and group V elements in the periodic table and can emit light of various colors by controlling the element composition ratio.

[0003] LED is a PN junction light-emitting device with the electrical characteristics of a junction device. In the forward working area of ​​the LED, the working current changes exponentially with the applied voltage. Therefore, when a constant voltage is used to drive the LED, the current is greatly affected by the voltage fluctuation, and the LED luminous power is prone to large fluctuations, and may even burn out due to the large current. In order to use LEDs stably and reliably, most of the currents in this field currently use constant current to drive LEDs, which is feasible for independent single LEDs and can better stabilize the luminous effect of a single LED; but for a light-emitting module formed by connecting multiple LEDs in series or in parallel, even if a constant current is used to drive the light-emitting module, there are still slight differences in the working voltage between the multiple LEDs, resulting in differences in the power of each device in the light-emitting module, causing uneven light emission of the light-emitting module, and even partial damage to the dead light. Especially in a light-emitting module composed of multiple LEDs in parallel, each individual LED will evenly divide the total driving current. Once an individual LED is damaged and disconnected, the remaining LEDs will bear a larger current, which may burn out one by one until the entire light-emitting module is completely disconnected and cannot work normally. It can be seen that even if a constant current drive is used, the stability of the light-emitting device in the circuit cannot be guaranteed.

[0004] Therefore, how to further improve the stability of light-emitting devices has become an urgent problem to be solved in this field. Summary of the invention

[0005] In view of this, the embodiments of the present application provide a method for preparing a constant current driven light emitting device and a constant current driven light emitting device to solve at least one problem existing in the background technology.

[0006] In a first aspect, an embodiment of the present application provides a method for preparing a constant current driven light emitting device, comprising:

[0007] providing a semiconductor growth substrate, the semiconductor growth substrate comprising a first surface and a second surface opposite to each other;

[0008] epitaxially growing a semiconductor epitaxial layer on the second surface side, the semiconductor epitaxial layer comprising a third surface connected to the semiconductor growth substrate, the semiconductor epitaxial layer comprising a first semiconductor epitaxial layer, a light emitting layer and a second semiconductor epitaxial layer sequentially stacked in a direction away from the semiconductor growth substrate, the first semiconductor epitaxial layer, the light emitting layer and the second semiconductor epitaxial layer being used to constitute a light emitting unit;

[0009] Removing a portion of the semiconductor growth substrate from the first surface side to expose a portion of the third surface, wherein the third surface is a light emitting surface of the light emitting unit;

[0010] Ion doping is performed in the remaining semiconductor growth substrate to form a plurality of ion doping regions to form a constant current unit.

[0011] In combination with the first aspect of the present application, in an optional implementation, the remaining semiconductor growth substrate is located in a boundary region of the light emitting unit.

[0012] In conjunction with the first aspect of the present application, in an optional implementation manner, ion doping is performed in the remaining semiconductor growth substrate to form a plurality of ion doped regions, including:

[0013] forming a second doping layer and a first doping layer sequentially stacked in a direction away from the semiconductor epitaxial layer in the remaining semiconductor growth substrate;

[0014] Forming a first doping region, a second doping region and a third doping region in sequence arranged along a direction perpendicular to the thickness of the semiconductor epitaxial substrate on a surface layer of the first doping layer away from the semiconductor epitaxial layer;

[0015] Among them, the first doping layer, the first doping region and the third doping region have a first conductivity type, the second doping layer and the second doping region have a second conductivity type different from the first conductivity type, the bottom surface of the second doping region is spaced apart from the bottom surface of the first doping layer, the bottom surface of the second doping region is the surface of the second doping region close to the second doping layer, and the bottom surface of the first doping layer is the surface of the first doping layer close to the second doping layer.

[0016] In conjunction with the first aspect of the present application, in an optional implementation manner, after forming the constant current unit, the preparation method further includes:

[0017] forming a first electrode, wherein the first electrode covers the first doped region to electrically lead out the first doped region;

[0018] forming a second electrode, wherein the second electrode covers the second doping region and the third doping region and extends along the side wall of the constant current unit toward the light emitting unit to conductively connect the second doping region, the third doping region and the second doping layer;

[0019] The first electrode is used for conductive connection with the light emitting unit, and the second electrode is used for conductive connection with the negative electrode of the power supply.

[0020] In conjunction with the first aspect of the present application, in an optional implementation manner, the performing ion doping in the remaining semiconductor growth substrate to form a plurality of ion doped regions further includes:

[0021] forming a third doping layer in the remaining semiconductor growth substrate, the third doping layer being located on a side of the second doping layer away from the first doping layer; wherein the third doping layer has a second conductivity type, and a doping concentration of the third doping layer is higher than a doping concentration of the second doping layer;

[0022] The second electrode extends along the side wall of the constant current unit toward the light emitting unit to conductively connect the second doping region, the third doping region and the second doping layer, including:

[0023] The second electrode extends along the side wall of the constant current unit toward the light emitting unit to connect with the third doping layer, so as to conductively connect the second doping region, the third doping region and the second doping layer.

[0024] In conjunction with the first aspect of the present application, in an optional implementation manner, before forming the first electrode, the preparation method further includes:

[0025] forming a first isolation layer, wherein one end of the first isolation layer extends to the first doped region to cover a portion of the first doped layer, and the other end of the first isolation layer extends to the second surface to cover at least a portion of the side wall of the constant current unit;

[0026] The first electrode includes a first portion and a second portion, the first portion covers the top surface of the first isolation layer and the second doping region, and the second portion covers the side surface of the first isolation layer;

[0027] After forming the first electrode, the preparation method further comprises:

[0028] A third electrode is formed, wherein the third electrode covers a portion of the third surface and is conductively connected to the second portion, and the light emitting unit and the constant current unit are conductively connected through the first electrode and the third electrode.

[0029] In combination with the first aspect of the present application, in an optional implementation manner, the line width of the second portion is less than or equal to the line width of the third electrode.

[0030] In conjunction with the first aspect of the present application, in an optional implementation manner, after forming the first electrode, the preparation method further includes:

[0031] forming a second isolation layer, wherein the second isolation layer covers a top surface and an inner side surface of the first electrode, wherein the inner side surface of the first electrode is a side surface of the first electrode close to the second doping region;

[0032] The second electrode covers the second isolation layer.

[0033] In conjunction with the first aspect of the present application, in an optional implementation manner, before forming the first isolation layer, the preparation method further includes:

[0034] forming a first groove, wherein a sidewall of the first groove is adjacent to the first doped region;

[0035] The first isolation layer fills the first groove, and a top surface of the first isolation layer is coplanar with a top surface of the semiconductor growth substrate. The top surface of the semiconductor growth substrate is a surface of the semiconductor growth substrate away from the semiconductor epitaxial layer.

[0036] In combination with the first aspect of the present application, in an optional implementation manner, the remaining semiconductor growth substrate is located in a boundary region of the light emitting unit;

[0037] The first isolation layer covers at least part of the side wall of the constant current unit, including: the first isolation layer covers at least part of the inner side wall of the constant current unit, and the inner side wall of the constant current unit is the side wall of the constant current unit close to the center of the third surface.

[0038] In a second aspect, an embodiment of the present application provides a constant current driven light emitting device, comprising:

[0039] A semiconductor growth substrate including a first surface and a second surface opposite to each other;

[0040] A semiconductor epitaxial layer, located on the second surface side, the semiconductor epitaxial layer includes a first semiconductor epitaxial layer, a light-emitting layer, and a second semiconductor epitaxial layer stacked in sequence in a direction away from the semiconductor growth substrate, the first semiconductor epitaxial layer, the light-emitting layer, and the second semiconductor epitaxial layer are used to constitute a light-emitting unit; wherein,

[0041] The semiconductor growth substrate covers a portion of the semiconductor epitaxial layer;

[0042] A surface of the semiconductor epitaxial layer that is not covered by the semiconductor growth substrate is a third surface, and the third surface is a light-emitting surface of the light-emitting unit;

[0043] The semiconductor growth substrate includes a plurality of ion doping regions, and the plurality of ion doping regions are used to form a constant current unit.

[0044] In conjunction with the second aspect of the present application, in an optional implementation, the semiconductor growth substrate is located in a boundary region of the light emitting unit.

[0045] In conjunction with the second aspect of the present application, in an optional implementation manner, the semiconductor growth substrate includes a plurality of ion doping regions, including:

[0046] A first doping layer and a second doping layer sequentially stacked from the first surface to the second surface;

[0047] The first doping layer is formed with a first doping region, a second doping region and a third doping region arranged in sequence along a direction perpendicular to the thickness of the constant current unit on a surface away from the semiconductor epitaxial layer;

[0048] Among them, the first doping layer, the first doping region and the third doping region have a first conductivity type, the second doping layer and the second doping region have a second conductivity type different from the first conductivity type, the bottom surface of the second doping region is spaced apart from the bottom surface of the first doping layer, the bottom surface of the second doping region is the surface of the second doping region close to the second doping layer, and the bottom surface of the first doping layer is the surface of the first doping layer close to the second doping layer.

[0049] In conjunction with the second aspect of the present application, in an optional implementation manner, the device further includes:

[0050] a first electrode, covering the first doped region to electrically lead the first doped region out;

[0051] a second electrode, covering the second doping region and the third doping region, and extending from the first surface to the second surface to conductively connect the second doping region, the third doping region and the second doping layer;

[0052] The first electrode is used for conductive connection with the light emitting unit, and the second electrode is used for conductive connection with the negative electrode of the power supply.

[0053] In conjunction with the second aspect of the present application, in an optional implementation, the semiconductor growth substrate includes a plurality of ion doping regions, and further includes: a third doping layer located on a side of the second doping layer away from the first doping layer; wherein the third doping layer has a second conductivity type, and a doping concentration of the third doping layer is higher than a doping concentration of the second doping layer;

[0054] The second electrode extends from the first surface to the second surface to conductively connect the second doping region, the third doping region and the second doping layer, including:

[0055] The second electrode extends from the first surface to the second surface to connect with the third doping layer, so as to conductively connect the second doping region, the third doping region and the second doping layer.

[0056] In conjunction with the second aspect of the present application, in an optional implementation manner, the device further includes:

[0057] a first isolation layer, wherein one end of the first isolation layer extends to the first doping region to cover a portion of the first doping layer, and the other end of the first isolation layer extends to the second surface to cover at least a portion of a side wall of the constant current unit;

[0058] The first electrode includes a first portion and a second portion, the first portion covers the top surface of the first isolation layer and the first doping region, and the second portion covers the side surface of the first isolation layer;

[0059] The device further comprises:

[0060] A third electrode covers a portion of the third surface and is conductively connected to the second portion. The light-emitting unit and the constant current unit are conductively connected through the first electrode and the third electrode.

[0061] In conjunction with the second aspect of the present application, in an optional implementation, the line width of the second portion is less than or equal to the line width of the third electrode.

[0062] In conjunction with the second aspect of the present application, in an optional implementation manner, the device further includes:

[0063] The second isolation layer covers the top surface and the inner side surface of the first electrode, wherein the inner side surface of the first electrode is the side surface of the first electrode close to the second doping region.

[0064] In conjunction with the second aspect of the present application, in an optional implementation, the top surface of the first isolation layer is coplanar with the first surface.

[0065] In conjunction with the second aspect of the present application, in an optional implementation manner, the semiconductor growth substrate is located in a boundary region of the light emitting unit;

[0066] The first isolation layer covers at least part of the side wall of the constant current unit, including: the first isolation layer covers at least part of the inner side wall of the constant current unit, and the inner side wall of the constant current unit is the side wall of the constant current unit close to the center of the third surface.

[0067] The preparation method of the constant current driven light emitting device and the constant current driven light emitting device provided in the embodiment of the present application integrate the constant current unit on the light emitting unit so that the light emitting unit can work under constant current drive, thereby improving stability; the constant current unit is prepared by using a semiconductor growth substrate, and the light emitting unit is prepared by using a semiconductor epitaxial layer epitaxially grown on the semiconductor growth substrate, so that a single light emitting device itself has constant current drive, and there is no need to add additional constant current components in the circuit, thereby reducing costs, reducing light absorption caused by adding components in the circuit, and improving light extraction efficiency; integration is achieved in the preparation process of a single light emitting device, thereby avoiding the integration of the light emitting device and the constant current device in the packaging stage, which is conducive to device miniaturization; and the light emitting device itself has constant current drive, even if some light emitting devices in a light emitting module composed of multiple light emitting devices connected in parallel are short-circuited, the current on the light emitting units in other light emitting devices is still controlled by the constant current unit integrated therewith, that is, it will not cause the current on the light emitting units in other light emitting devices to increase, thereby ensuring that the entire light emitting module can still work normally, thereby improving device stability.

[0068] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0070] Figure 1 A schematic diagram of a process for preparing a constant current driven light emitting device provided in an embodiment of the present application;

[0071] Figures 2 to 10 A schematic diagram of the cross-sectional structure of a constant current driven light emitting device during the preparation process provided in an embodiment of the present application;

[0072] Figure 11 to Figure 12 for Fig.10 The cross-sectional structure diagram of the constant current unit in the circle during the preparation process;

[0073] Fig.13A top view of a constant current driven light emitting device provided in an embodiment of the present application;

[0074] Fig.14 The constant current driving light emitting device provided in the embodiment of the present application is Fig.13 Schematic diagram of the cross-sectional structure along line AA';

[0075] Fig.15 for Fig.14 Schematic diagram of the cross-section of the structure in the circle;

[0076] Fig.16 The constant current driving light emitting device provided in the embodiment of the present application is Fig.13 Schematic diagram of the cross-sectional structure along line BB';

[0077] Fig.17 for Fig.16 Schematic diagram of the cross-section of the structure in the circle;

[0078] Fig.18 It is the IV curve diagram of the constant current unit;

[0079] Fig.19 It is a circuit diagram of the light-emitting module. DETAILED DESCRIPTION

[0080] The exemplary embodiments disclosed in the present application will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the specific embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope disclosed in the present application to those skilled in the art.

[0081] In the following description, a large number of specific details are given to provide a more thorough understanding of the present application. However, it is obvious to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features known in the art are not described; that is, all features of the actual embodiments are not described here, and well-known functions and structures are not described in detail.

[0082] In the drawings, the sizes of layers, regions, elements and their relative sizes may be exaggerated for clarity. Like reference numerals denote like elements throughout.

[0083] It should be understood that when an element or layer is referred to as "on ...", "adjacent to ...", "connected to" or "coupled to" other elements or layers, it can be directly on, adjacent to, connected to or coupled to other elements or layers, or there can be intervening elements or layers. On the contrary, when an element is referred to as "directly on ...", "directly adjacent to ...", "directly connected to" or "directly coupled to" other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as the second element, component, region, layer or part. And when the second element, component, region, layer or part is discussed, it does not indicate that the present application necessarily has the first element, component, region, layer or part.

[0084] Spatially relative terms such as "under", "beneath", "below", "under", "above", "above", etc., may be used here for convenience of description to describe the relationship between an element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientation shown in the figure, the spatial relationship terms are intended to also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is turned over, then the elements or features described as "under other elements" or "under it" or "under it" will be oriented as "on" other elements or features. Therefore, the exemplary terms "under" and "under" may include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0085] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0086] In order to thoroughly understand the present application, detailed steps and detailed structures will be presented in the following description to illustrate the technical solution of the present application. The preferred embodiments of the present application are described in detail below, but in addition to these detailed descriptions, the present application may also have other implementation methods.

[0087] Figure 1 A schematic diagram of a process flow of a method for preparing a constant current driven light emitting device provided in an embodiment of the present application. As shown in the figure, the method for preparing a constant current driven light emitting device provided in an embodiment of the present application comprises:

[0088] Step S101: providing a semiconductor growth substrate, wherein the semiconductor growth substrate comprises a first surface and a second surface opposite to each other;

[0089] Step S102: epitaxially growing a semiconductor epitaxial layer on the second surface side, the semiconductor epitaxial layer including a third surface connected to the semiconductor growth substrate, the semiconductor epitaxial layer including a first semiconductor epitaxial layer, a light-emitting layer, and a second semiconductor epitaxial layer stacked in sequence in a direction away from the semiconductor growth substrate, the first semiconductor epitaxial layer, the light-emitting layer, and the second semiconductor epitaxial layer are used to constitute a light-emitting unit;

[0090] Step S103: removing a portion of the semiconductor growth substrate from the first surface side to expose a portion of the third surface, where the third surface is a light-emitting surface of the light-emitting unit;

[0091] Step S104: performing ion doping in the remaining semiconductor growth substrate to form a plurality of ion doping regions to form a constant current unit.

[0092] Therefore, a constant current unit is integrated on the light-emitting unit, so that the light-emitting unit can work under constant current drive, thereby improving stability; the constant current unit is prepared using a semiconductor growth substrate, and the light-emitting unit is prepared using a semiconductor epitaxial layer epitaxially grown on the semiconductor growth substrate, so that the prepared single light-emitting device itself has a constant current drive, and there is no need to add an additional constant current device to the circuit during actual use, thereby reducing costs, reducing light absorption caused by adding components to the circuit, and improving light extraction efficiency; integration is achieved during the preparation process of a single light-emitting device, thereby avoiding integrating the light-emitting device and the constant current device at the packaging stage, which is conducive to device miniaturization; and the light-emitting device itself has a constant current drive, even if some light-emitting devices in a light-emitting module composed of multiple light-emitting devices connected in parallel are short-circuited, the current on the light-emitting units in other light-emitting devices is still controlled by the constant current unit integrated therewith, that is, it will not cause the current on the light-emitting units in other light-emitting devices to increase, thereby ensuring the normal operation of the entire light-emitting module and improving device stability.

[0093] It can be understood that the light-emitting unit may include any electronic component known to those skilled in the art that can convert electrical energy into light energy, such as a light-emitting diode, a laser diode, an organic light-emitting diode, etc.; the constant current unit may include any electronic component known to those skilled in the art that can output a constant current value within a certain voltage range, such as a CRD (CurrentRegulative Diode), a BJT (Bipolar Junction Transistor), and a MOSFET (Metal Oxide Semiconductor Field Effect Transistor). This embodiment is specifically described by taking the light-emitting unit as a light-emitting diode and the constant current unit as a constant current diode as an example.

[0094] Please refer to Figure 2 , performing step S101: providing a semiconductor growth substrate 100, the semiconductor growth substrate 100 includes a first surface 101 and a second surface 102 opposite to each other.

[0095] The material of the semiconductor growth substrate 100 may include any suitable semiconductor material, such as one or more of aluminum oxide (Al2O3), gallium nitride (GaN), silicon carbide (SiC), zinc oxide (ZnO), silicon (Si), germanium (Ge), gallium phosphide (GaP), indium phosphide (InP), silicon germanium (SiGe), gallium arsenide (GaAs) and gallium oxide (Ga2O3). It can be understood that sapphire material is currently generally used in the art as a substrate to provide a process basis for preparing light-emitting units, but sapphire material has high hardness and high wear resistance, making it difficult to be cut during processing, and sapphire material has good chemical stability and is not prone to chemical reactions. Therefore, it is difficult to partially remove sapphire material, and most of them are removed in the entire layer. Therefore, a semiconductor material is selected as a substrate, and the substrate can be partially removed in the subsequent process, and the remaining substrate is used to prepare a constant current unit to achieve integration. In this embodiment, the material of the semiconductor growth substrate 100 is specifically silicon, for example.

[0096] Optionally, the preparation method further includes: forming a buffer layer (not shown) on the second surface 102. Thus, the buffer layer reduces defects and interlayer stress caused by lattice differences between subsequent semiconductor epitaxial layers and semiconductor growth substrate 100, improves crystal quality, and ensures light-emitting effects.

[0097] Next, please continue to refer to Figure 2, step S102 is performed: epitaxially growing a semiconductor epitaxial layer 110 on the second surface 102 side, the semiconductor epitaxial layer 110 includes a third surface 103 connected to the semiconductor growth substrate 100, and the semiconductor epitaxial layer 110 includes a first semiconductor epitaxial layer 111, a light-emitting layer 113, and a second semiconductor epitaxial layer 115 stacked in sequence in a direction away from the semiconductor growth substrate 100, and the first semiconductor epitaxial layer 111, the light-emitting layer 113, and the second semiconductor epitaxial layer 115 are used to constitute a light-emitting unit. In this embodiment, the light-emitting unit includes a light-emitting structure, and the first semiconductor epitaxial layer 111, the light-emitting layer 113, and the second semiconductor epitaxial layer 115 constitute a light-emitting structure.

[0098] The process of epitaxially growing the semiconductor epitaxial layer 110 may include an electron beam evaporation process, a physical vapor deposition (PVD) process, a chemical vapor deposition (CVD) process, a pulsed laser deposition (PLD) process, a dual-type thermal evaporation process, a sputtering process, a metal organic chemical vapor deposition (MOCVD) process, and a hydride vapor phase epitaxy (HVPE) process, etc. This embodiment does not limit this.

[0099] Specifically, epitaxially growing the semiconductor epitaxial layer 110 on the second surface 102 side may include: epitaxially growing a first semiconductor epitaxial layer 111 on the second surface 102 side; growing a light emitting layer 113 on the first semiconductor epitaxial layer 111 ; and growing a second semiconductor epitaxial layer 115 on the light emitting layer 113 .

[0100] The material of the first semiconductor epitaxial layer 111 may include a III-V compound semiconductor material, such as at least one of GaN, InN, AlN, InGaN, AlGaN and InAlGaN, which is not limited in this embodiment.

[0101] The material of the second semiconductor epitaxial layer 115 may include a III-V compound semiconductor material, such as at least one of GaN, InN, AlN, InGaN, AlGaN and InAlGaN, which is not limited in this embodiment.

[0102] The first semiconductor epitaxial layer 111 has a first conductivity type, and the second semiconductor epitaxial layer 115 has a second conductivity type different from the first conductivity type. In the light emitting structure, the first semiconductor epitaxial layer 111 and the second semiconductor epitaxial layer 115 serve as an electron injection layer and a hole injection layer, respectively.

[0103] Specifically, when the first semiconductor epitaxial layer 111 is an N-type semiconductor layer, the second semiconductor epitaxial layer 115 is a P-type semiconductor layer; conversely, when the first semiconductor epitaxial layer 111 is a P-type semiconductor layer, the second semiconductor epitaxial layer 115 is an N-type semiconductor layer. The doping ions include P-type doping ions and N-type doping ions, the P-type doping ions may include one or more of Mg, Zn, Ca, Sr and Ba, and the N-type doping ions may include one or more of Si, Ge, Sn, Se and Te, which is not limited in this embodiment.

[0104] The light-emitting layer 113 may be a single quantum well (SQW) structure or a multiple quantum well (MQW) structure. Specifically, the light-emitting layer 113 may be formed by a cycle of a well layer and a barrier layer using a III-V compound semiconductor material. For example, the light-emitting layer 113 may be formed by a cycle of an InGaN well layer and a GaN barrier layer, or by a cycle of an AlGaN well layer and a GaN barrier layer.

[0105] It can be understood that the material of the light emitting layer 113 can be adjusted according to the band gap energy of the wavelength of the light to be emitted. The material of the light emitting layer 113 can include a material that emits light in the visible light region with blue, red and green wavelengths. For example, if the light emitting layer 113 emits blue light with a wavelength in the range of 450nm to 470nm, the light emitting layer 113 can be formed into a SQW structure or an MQW structure with a periodic cycle of InGaN well layers and GaN barriers. The material of the light emitting layer 113 can also include a material that emits light in invisible light regions such as ultraviolet and infrared. For example, if the light emitting layer 113 emits ultraviolet light with a wavelength in the range of 200nm to 365nm, the light emitting layer 113 can be formed into a SQW structure or an MQW structure with a periodic cycle of GaN well layers and AlGaN barriers.

[0106] In some other embodiments, before forming the light emitting layer 113, a first conductive coating (not shown in the figure) is formed on the first semiconductor epitaxial layer 111; and / or, before forming the second semiconductor epitaxial layer 115, a second conductive coating (not shown in the figure) is formed on the light emitting layer 113. It can be understood that in the light emitting structure, the first semiconductor epitaxial layer 111 and the second semiconductor epitaxial layer 115 serve as electron injection and hole injection layers, respectively, thereby forming a conductive coating (not shown in the figure) above and / or below the light emitting layer 113 to protect the light emitting layer 113.

[0107] Optionally, the material of the conductive cladding layer includes AlGaN.

[0108] Please refer to Figure 3After executing step S102, the preparation method further includes: forming a channel layer 121 and a current blocking layer 122 on the second semiconductor epitaxial layer 115, the channel layer 121 is located in the boundary area of ​​the second semiconductor epitaxial layer 115, and extends to cover the cutting path, the channel layer 121 and the current blocking layer 122 are arranged at intervals, and the channel layer 121 and the current blocking layer 122 cover part of the second semiconductor epitaxial layer 115. The channel layer 121 extends to cover the cutting path, and when an independent light-emitting unit is subsequently cut to form, the channel layer 121 can be used as an etching stop layer. Since the light generated under the electrode under the action of the current will be blocked by the electrode, the current blocking layer 122 is set, and an electrode layer corresponding to the current blocking layer 122 in position is formed in the subsequent steps to hinder the current transmission under the electrode, avoid generating light here, and finally improve the light-emitting efficiency of the light-emitting unit.

[0109] The material of the channel layer 121 may include a conductive material or a non-conductive material. The conductive material may include a transparent conductive oxide or a metal material; the transparent conductive oxide layer may include at least one of indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO) and gallium zinc oxide (GZO); the metal material may include at least one of Ti, Ni, Pt, Pd, Rh, Ir and W. The non-conductive material may include SiO x 、SiO x N y , Si3N4, Al2O3 or TiO2.

[0110] In the thickness direction of the semiconductor growth substrate 100, the channel layer 121 partially overlaps with the projection of the semiconductor epitaxial layer 110; the material of the channel layer 121 is an insulating material. Therefore, if the electrode formed subsequently is located in the boundary region of the first semiconductor epitaxial layer 111, the channel layer 121 can also play the same current blocking effect as the current blocking layer 122.

[0111] The process of forming the channel layer 121 may include an atomic layer deposition process, an electron beam evaporation process, a physical vapor deposition process, a chemical vapor deposition process, a pulsed laser deposition process, and the like.

[0112] The material of the current blocking layer 122 may include a non-conductive material, such as SiO x 、SiO x N y , Si3N4, Al2O3 or TiO2.

[0113] The process of forming the current blocking layer 122 may include an atomic layer deposition process, an electron beam evaporation process, a physical vapor deposition process, a chemical vapor deposition process, a pulsed laser deposition process, and the like.

[0114] In some embodiments, the channel layer 121 and the current blocking layer 122 are made of the same material and can be prepared in the same process.

[0115] Please refer to Figure 4 After forming the channel layer 121 and the current blocking layer 122, the preparation method further includes: forming an ohmic layer 131 on the second semiconductor epitaxial layer 115, the ohmic layer 131 is located between the channel layer 121 and the current blocking layer 122, and the ohmic layer 131 covers the remaining second semiconductor epitaxial layer 115. It can be understood that the second semiconductor epitaxial layer 115 has a low doping concentration and a high contact resistance, and thus exhibits a degraded ohmic characteristic, and the ohmic layer 131 effectively reduces the ohmic contact resistance.

[0116] The process of forming the ohmic layer 131 may include an electron beam evaporation process, a physical vapor deposition process, a chemical vapor deposition process, a pulsed laser deposition process, a dual-type thermal evaporation process, a sputtering process, and the like.

[0117] The material of the ohmic layer 131 may include at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf; or at least one of ITO, IZO, IZTO, IAZO, IGZO, IGTO, AZO, and ATO.

[0118] Next, please refer to Figure 5 A reflective layer 132 is formed on the ohmic layer 131 . The reflective layer 132 is located between the channel layer 121 and the current blocking layer 122 . The reflective layer 132 may partially or completely cover the channel layer 121 and the current blocking layer 122 .

[0119] The material of the reflective layer 132 includes a material having a high reflectivity for light emitted from the light emitting layer 113, such as at least one of Ag, Ni, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt, Au, and Hf, so as to effectively reflect the light emitted from the light emitting layer 113 and significantly improve the light extraction efficiency of the light emitting unit.

[0120] The process of forming the reflective layer 132 may include an electron beam evaporation process, a physical vapor deposition process, a chemical vapor deposition process, a pulsed laser deposition process, a dual-type thermal evaporation process, a sputtering process, and the like.

[0121] Please refer to Figure 6 , a blocking layer 133 is formed, and the blocking layer 133 covers the channel layer 121 , the current blocking layer 122 and the reflective layer 132 .

[0122] The material of the barrier layer 133 includes a conductive material with a high melting point and good stability, which can effectively block metal migration and mutual diffusion between materials. For example, it can include at least one of gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), titanium (Ti), aluminum (Al), copper (Cu), lead (Pd), ruthenium (Ru), molybdenum (Mo), iridium (Ir), rhodium (Rh), tantalum (Ta), hafnium (Hf), zirconium (Zr), niobium (Nb), and vanadium (V). It can be understood that a bonding layer will be formed on the channel layer 121, the current blocking layer 122 and the reflective layer 132 to combine the conductive support member with the light-emitting unit, but the material of the bonding layer is usually a material with a low melting point and high diffusion such as tin or its alloy. The metal will diffuse to the reflective layer 132, affecting the function of the reflective layer 132. Therefore, preparing a barrier layer 133 with a high melting point and stable chemical properties can effectively avoid damage to the reflective layer 132 and the ohmic layer 131.

[0123] In some embodiments, the barrier layer 133 may be a single-layer structure or a multi-layer structure.

[0124] The process of forming the blocking layer 133 may include an electron beam evaporation process, a physical vapor deposition process, a chemical vapor deposition process, a pulsed laser deposition process, a dual-type thermal evaporation process, a sputtering process, and the like.

[0125] Next, please refer to Figure 7 , a bonding layer 134 is formed on the barrier layer 133 .

[0126] The process of forming the bonding layer 134 may include an electron beam evaporation process, a physical vapor deposition process, a chemical vapor deposition process, a pulsed laser deposition process, a dual-type thermal evaporation process, a sputtering process, and the like.

[0127] The material of the bonding layer 134 may include at least one of indium (In), tin (Sn), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), titanium (Ti), aluminum (Al), germanium (Ge), copper (Cu), lead (Pd), ruthenium (Ru), molybdenum (Mo), iridium (Ir), rhodium (Rh), tantalum (Ta), hafnium (Hf), zirconium (Zr), niobium (Nb), and vanadium (V).

[0128] The bonding layer 134 may be a single-layer structure or a multi-layer structure.

[0129] Next, the conductive support member 140 is provided.

[0130] The material of the conductive support member 140 may include one or more combinations of metal materials such as gold (Au), nickel (Ni), tungsten (W), molybdenum (Mo), copper (Cu), aluminum (Al), tantalum (Ta), silver (Ag), platinum (Pt), chromium (Cr), and alloys thereof; or one or more semiconductor materials such as gallium nitride (GaN), silicon carbide (SiC), zinc oxide (ZnO), silicon (Si), germanium (Ge), gallium phosphide (GaP), indium phosphide (InP), silicon germanium (SiGe), gallium arsenide (GaAs), and gallium oxide (Ga2O3). The conductive support member 140 has good electrical and thermal conductivity and support properties.

[0131] The thickness of the conductive support member 140 may range from 30 μm to 1000 μm. It is understood that in actual preparation, the thickness may be changed according to the design requirements of the light emitting device.

[0132] In some other embodiments, the bonding layer 134 may be formed on the surface of the conductive support member 140 .

[0133] Please refer to Figure 8 The conductive support member 140 is bonded to the light emitting unit through the bonding layer 134 by a thermal compression bonding process. Thus, the light emitting unit can be conductively led out through the conductive support member 140, and the conductive support member 140 also becomes the cathode of the light emitting device.

[0134] Optionally, the temperature range of the thermal compression bonding may be 80° C. to 600° C.; the pressure range may be 0.1 MPa to 100 MPa.

[0135] Please refer to Fig. 9 , perform step S103: remove part of the semiconductor growth substrate 100 from the first surface 101 side to expose part of the third surface 103, the third surface 103 is the light-emitting surface of the light-emitting unit. Thus, the light-emitting function of the light-emitting unit is ensured.

[0136] Specifically, removing a portion of the semiconductor growth substrate 100 from the first surface 101 side may include: forming a patterned mask (not shown) on the first surface 101 side; and removing a portion of the semiconductor growth substrate 100 using the patterned mask as a mask to expose a portion of the third surface 103 .

[0137] The process of removing a portion of the semiconductor growth substrate 100 may include a physical grinding process, a chemical stripping process, an etching process or a combination thereof.

[0138] Specifically, the etching process may be a dry etching process. Further, it may be an ICP-RIE (Inductively Coupled Plasma-Reactive Ion Etching) process. This process can process micro-patterns at the micron and nanometer levels, provide high etching rate, high selectivity and low damage processing, and is conducive to improving production efficiency and precision.

[0139] It is understandable that the remaining semiconductor growth substrate 100 includes a predetermined thickness, length, and width, which can be set according to actual needs, and this embodiment does not limit this.

[0140] Optionally, the remaining semiconductor growth substrate 100 is located in the boundary area of ​​the light-emitting unit. It can be understood that in the subsequent steps, the remaining semiconductor growth substrate 100 is used to prepare the constant current unit, and the constant current unit and the light-emitting unit need to be conductively connected. Setting it in the boundary area of ​​the light-emitting unit can reduce the impact of subsequent processes on the light-emitting surface of the light-emitting unit and ensure the light-emitting efficiency of the light-emitting unit.

[0141] Please refer to Fig.10 The preparation method further includes: using an etching process to etch the first semiconductor epitaxial layer 111 from the third surface 103 to form a rough structure 150. Thus, the rough structure 150 is used to improve the light extraction efficiency of the light emitting unit.

[0142] Optionally, in the thickness direction of the semiconductor epitaxial layer, the height of the roughness structure 150 ranges from 50 nm to 3000 nm; the width of the roughness structure 150 ranges from 50 nm to 3000 nm.

[0143] Furthermore, the height of the roughness structure 150 ranges from 300 nm to 1000 nm; the width of the roughness structure 150 ranges from 300 nm to 1000 nm.

[0144] The cross-sectional shape of the roughness structure 150 may include a regular shape and / or an irregular shape, such as a pyramid shape, a polygon shape, a concave lens shape or a random shape, which is not limited in this embodiment.

[0145] Specifically, the etching process may include a wet etching process or a dry etching process; wherein the wet etching process may be a chemical etching process; and the dry etching process may be an ICP-RIE process.

[0146] Please refer to Fig.14 , a mesa etching process is performed to form a first opening, and the first opening extends from the third surface 103 through the semiconductor epitaxial layer 110 to the channel layer 121. Thus, independent light-emitting units are separated.

[0147] Specifically, the mesa etching process may be a dry etching process or a wet etching process.

[0148] Next, step S104 is performed: ion doping is performed in the remaining semiconductor growth substrate 100 to form a plurality of ion doping regions to form a constant current unit. Thus, the constant current unit is integrated on the light-emitting unit, so that the light-emitting unit can work under constant current drive, thereby improving stability; the constant current unit is prepared by using the remaining semiconductor growth substrate 100 on the light-emitting unit, and the light-emitting unit and the constant current unit are integrated in the preparation process of a single light-emitting device, thereby avoiding the need to additionally set up a constant current device and integrate it with the light-emitting device in the packaging stage, which is conducive to device miniaturization.

[0149] Please refer to Fig.11 Optionally, ion doping is performed in the remaining semiconductor growth substrate 100 to form a plurality of ion doped regions, including: forming a second doping layer 220 and a first doping layer 210 stacked in sequence in a direction away from the semiconductor epitaxial layer in the remaining semiconductor growth substrate 100; forming a first doping region 211, a second doping region 212 and a third doping region 213 arranged in sequence in a direction perpendicular to the thickness direction of the semiconductor epitaxial substrate in a surface layer of the first doping layer 210 away from the semiconductor epitaxial layer 110; wherein the first doping layer 210, the first doping region 211 and the third doping region 213 have a first conductivity type, the second doping layer 220 and the second doping region 212 have a second conductivity type different from the first conductivity type, the bottom surface of the second doping region 212 is spaced from the bottom surface of the first doping layer 210, the bottom surface of the second doping region 212 is a surface of the second doping region 212 close to the second doping layer 220, and the bottom surface of the first doping layer 210 is a surface of the first doping layer 210 close to the second doping layer 220.

[0150] In this embodiment, the first conductivity type is specifically N-type, and the second conductivity type is specifically P-type.

[0151] In this embodiment, the first doping region 211 , the second doping region 212 , and the third doping region 213 are arranged at intervals, with a certain gap remaining between them.

[0152] Please refer to Figures 14 to 17 Optionally, after forming the constant current unit, the preparation method further includes: forming a first electrode 270, the first electrode 270 covers the first doping region 211 to conductively lead out the first doping region 211; forming a second electrode 280, the second electrode 280 covers the second doping region 212 and the third doping region 213, and extends along the side wall of the constant current unit toward the direction close to the light-emitting unit to conductively connect the second doping region 212, the third doping region 213 and the second doping layer 220; wherein the first electrode 270 is used for conductive connection with the light-emitting unit, and the second electrode 280 is used for conductive connection with the negative electrode of the power supply.

[0153] In this embodiment, the first doping region 211 is the drain region of the constant current unit, the second doping region 212 and the second doping layer 220 are the gate region of the constant current unit, the third doping region 213 is the source region of the constant current unit, the first electrode 270 is the drain electrode, and the second electrode 280 realizes the gate-source short circuit. Therefore, when a high potential is applied to the first electrode 270 and a low potential is applied to the second electrode 280, a reverse biased PN junction is formed between the second doping region 212 and the first doping layer 210, and a depletion region is formed at the bottom surface of the second doping region 212. A reverse biased PN junction is also formed between the first doping layer 210 and the second doping layer 220, and a depletion region is formed at the bottom surface of the first doping layer 210. Please refer to Fig.18 As the applied voltage increases, the electrons flow from the second electrode 280 to the first electrode 270 under the drive of the voltage, and the depletion region gradually increases. However, the change in the width of the depletion layer has almost no effect on the flow of electrons, and the resistance of the conductive channel hardly changes, so the current in the channel increases almost linearly. As the applied voltage continues to increase, the two PN junctions gradually increase the width of the depletion region under the action of the reverse voltage drop until they contact each other to pinch off the current channel. The voltage at this time is called the pinch-off voltage V P ; As the applied voltage continues to increase, at V P -V B In this voltage range, the width of the depletion layer continues to increase and overlap, so that the pinch-off point moves toward the source end with the increase of voltage. At this time, the channel has been pinched off. In other words, the first doping layer 210 between the two gate regions has been completely depleted, so that the voltage drop in the effective channel remains unchanged, and the current passing through the channel remains basically unchanged, outputting a constant current I H When the applied voltage increases to the point where the reverse biased PN junction undergoes avalanche breakdown, the voltage at this point is called the breakdown voltage V B After breakdown occurs, the operating current increases rapidly, and the device is prone to overheating and damage.

[0154] Therefore, when performing ion doping, it is necessary to control the spacing between the bottom surface of the second doping region 212 and the bottom surface of the first doping layer 210. The first doping layer 210 between the bottom surface of the second doping region 212 and the bottom surface of the first doping layer 210 is used to form a depletion region. If a certain gap is not retained between the two, the depletion region cannot be formed, and then the constant current effect cannot be achieved. It can be understood that in actual preparation, the spacing distance between the two can be designed according to the device requirements, and this embodiment does not limit this.

[0155] For further information, please refer to Fig.11, ion doping is performed in the remaining semiconductor growth substrate 100 to form a plurality of ion doped regions, and further includes: forming a third doping layer 230 in the remaining semiconductor growth substrate 100, the third doping layer 230 being located on a side of the second doping layer 220 away from the first doping layer 210; wherein the third doping layer 230 has a second conductivity type, and the doping concentration of the third doping layer 230 is higher than the doping concentration of the second doping layer 220; the second electrode 280 extends along the side wall of the constant current unit toward the direction close to the light-emitting unit to conductively connect the second doping region 212, the third doping region 213 and the second doping layer 220, including: the second electrode 280 extends along the side wall of the constant current unit toward the direction close to the light-emitting unit to connect with the third doping layer 230, so as to conductively connect the second doping region 212, the third doping region 213 and the second doping layer 220. Thus, a third doping layer 230 is prepared on the side of the second doping layer 220 away from the first doping layer 210, and the second electrode 280 is conductively connected to the third doping layer 230. The third doping layer 230 has a better doping concentration, a higher carrier concentration, and a better current diffusion capability, which can provide better current injection for the constant current unit and improve the ohmic contact.

[0156] Specifically, ion doping is performed in the remaining semiconductor growth substrate 100 to form a plurality of ion doped regions, including: injecting first conductive type doping ions into the remaining semiconductor growth substrate 100 to form a highly doped third doping layer 230 in the bottom region of the remaining semiconductor growth substrate 100; injecting first conductive type doping ions into the remaining semiconductor growth substrate 100 to form a second doping layer 220 on the third doping layer 230; injecting second conductive type doping ions into the remaining semiconductor growth substrate 100 to form a second doping layer 220 on the second doping layer 220. A first doping layer 210; a first patterned mask (not shown in the figure) is formed on the top surface of the remaining semiconductor growth substrate 100, ion doping is performed using the first patterned mask as a mask, and a first doping region 211 and a third doping region 213 are formed in the surface layer of the first doping layer 210 away from the semiconductor epitaxial layer 110; a second patterned mask (not shown in the figure) is formed on the top surface of the remaining semiconductor growth substrate 100, ion doping is performed using the second patterned mask as a mask, and a second doping region 212 is formed in the surface layer of the first doping layer 210 away from the semiconductor epitaxial layer 110.

[0157] In some other embodiments, forming the second doping region 212 may include: forming a second patterned mask on the top surface of the remaining semiconductor growth substrate 100, performing an etching process using the second patterned mask as a mask, and forming a concave step on the surface of the first doping layer 210 away from the semiconductor epitaxial layer 110; and forming a filling layer having the first conductivity type in the concave step. Thus, the filling layer is the second doping region 212. The material of the filling layer may include low-temperature polysilicon.

[0158] Specifically, please refer to Fig.12 , forming the second electrode 280 includes: forming a second groove 250, the second groove 250 is located on the side wall of the constant current unit close to the third doping region 213, and extends from the first doping layer 210 to the third doping layer 230; the second electrode 280 covers the second doping region 212 and the third doping region 213, and fills the second groove 250. Thus, the second electrode 280 is extended along the side wall of the constant current unit toward the direction close to the light-emitting unit, so as to conductively connect the second doping region 212, the third doping region 213 and the second doping layer 220.

[0159] The material of the first electrode 270 may include at least one of gold (Au), titanium (Ti), aluminum (Al), nickel (Ni), platinum (Pt), ruthenium (Ru), iridium (Ir), rhodium (Rh), tantalum (Ta), molybdenum (Mo), silver (Ag), tungsten (W), copper (Cu), chromium (Cr), palladium (Pd), vanadium (V), cobalt (Co), niobium (Nb), zirconium (Zr), indium tin oxide (ITO), aluminum zinc oxide (AZO), and indium zinc oxide (IZO). The material of the second electrode 280 may be the same as the material of the first electrode 270, or may be different from the material of the first electrode 270, which is not limited in this embodiment.

[0160] The process of forming the first electrode 270 may include at least one of an electron beam evaporation process, a physical vapor deposition process, a chemical vapor deposition process, a pulsed laser deposition process, a dual-type thermal evaporation process, and a sputtering process. The process of forming the second electrode 280 may be the same as the process of forming the first electrode 270, or may be different from the process of forming the first electrode 270, which is not limited in this embodiment.

[0161] Please refer to Fig.16 and Fig.17 Before forming the first electrode 270, the preparation method further includes: forming a first isolation layer 261, one end of the first isolation layer 261 extends to the first doping region 211 to cover part of the first doping layer 210, and the other end of the first isolation layer 261 extends to the second surface 102 to cover at least part of the side wall of the constant current unit; the first electrode 270 includes a first part 271 and a second part 272, the first part 271 covers the top surface of the first isolation layer 261 and the second doping region 212, and the second part 272 covers the side surface of the first isolation layer 261; after forming the first electrode 270, the preparation method further includes: forming a third electrode 160, the third electrode 160 covers part of the third surface 103 and is conductively connected to the second part 272, and the light-emitting unit and the constant current unit are conductively connected through the first electrode 270 and the third electrode 160. Thus, Fig.16As shown, the first electrode 270 extends to the side wall of the constant current unit to facilitate conductive connection with the third electrode 160, so that the current can be from the second electrode 280 to the constant current unit, and then through the first electrode 270 and the second electrode 280 to the light-emitting unit, thereby realizing the series connection of the light-emitting unit and the constant current unit. On this basis, before preparing the first electrode 270, a first isolation layer 261 is prepared to electrically insulate the first electrode 270 from the first doping layer 210, the second doping layer 220 and the third doping layer 230, so that the first electrode 270 is only conductively connected to the first doping region 211.

[0162] Optionally, the material of the first isolation layer 261 includes an insulating material, such as SiO x 、SiO x N y , Si3N4, Al2O3 or TiO2 and other non-conductive materials.

[0163] The process of forming the first isolation layer 261 may include an atomic layer deposition process, an electron beam evaporation process, a physical vapor deposition process, a chemical vapor deposition process, or a pulsed laser deposition process, which is not limited in this embodiment.

[0164] The first isolation layer 261 may have a single-layer structure or a multi-layer structure.

[0165] The material of the third electrode 160 may be the same as that of the first electrode 270 , which is not limited in this embodiment; the process of forming the third electrode 160 may be the same as that of forming the first electrode 270 , which is not limited in this embodiment.

[0166] Please refer to Figures 13 to 17 Optionally, the line width of the second portion 272 is smaller than the width of the side wall of the constant current unit. It can be understood that Fig.13 Below the second electrode 280 is a constant current unit. Fig.14 and Fig.16 The structure in the middle circle includes a constant current unit. On the cross section of line AA', if Fig.15 The sidewall of the structure shown in the figure is also formed with a first electrode 270. The light nearby may be directly absorbed by the first electrode 270, which affects the light-emitting efficiency. In order to realize the conductive connection between the second portion 272 and the third electrode 160, the third electrode 160 needs to cross a portion of the third surface 103 (for example, Fig.14 The portion of the third surface 103 located between the third electrode 160 and the constant current unit reduces the light-emitting surface and affects the light-emitting efficiency of the light-emitting unit.

[0167] Optionally, the line width of the second portion 272 is less than or equal to the line width of the third electrode 160. Thus, while ensuring the conductive connection between the first electrode 270 and the third electrode 160, the line width of the second portion 272 is further reduced, and the absorption of light by the first electrode 270 is further reduced.

[0168] Optionally, before forming the first isolation layer 261, the preparation method further includes: forming a first groove 240, the sidewall of the first groove 240 is adjacent to the first doping region 211; the first isolation layer 261 fills the first groove 240, the top surface of the first isolation layer 261 is coplanar with the top surface of the semiconductor growth substrate 100, and the top surface of the semiconductor growth substrate 100 is the surface of the semiconductor growth substrate 100 away from the semiconductor epitaxial layer 110. Thus, the first groove 240 is formed in the first doping layer 210, and the top surface of the first isolation layer 261 is coplanar with the top surface of the semiconductor growth substrate 100, so that the first electrode 270 and other structures prepared in the subsequent steps can be prepared on a flat surface, reducing the process difficulty and avoiding the occurrence of faults or cracks in the structures prepared subsequently.

[0169] Optionally, the remaining semiconductor growth substrate 100 is located in the boundary area of ​​the light-emitting unit; the first isolation layer 261 covers at least part of the side wall of the constant current unit, including: the first isolation layer 261 covers at least part of the inner side wall of the constant current unit, and the inner side wall of the constant current unit is the side wall of the constant current unit close to the center of the third surface 103. Thus, the prepared constant current unit is located in the boundary area of ​​the light-emitting unit, and the first isolation layer 261 is set on the inner side wall close to the center of the constant current unit, so that the second part 272 of the first electrode 270 is also located on this side wall, which makes it easier to realize the conductive connection between the second part 272 and the third electrode 160, reduces the process difficulty, and reduces the degree of shielding of the third surface 103 (light-emitting surface), thereby ensuring the light-emitting efficiency of the light-emitting unit.

[0170] Please refer to Fig.17 After forming the first electrode 270, the preparation method further includes: forming a second isolation layer 262, the second isolation layer 262 covers the top surface and the inner surface of the first electrode 270, the inner surface of the first electrode 270 is the side surface of the first electrode 270 close to the second doping region 212; the second electrode 280 covers the second isolation layer 262. Thus, the second isolation layer 262 is disposed on the top and around the first electrode 270, so that the first electrode 270 is electrically insulated from the second electrode 280, the second doping region 212 and the third doping region 213.

[0171] Optionally, the material of the second isolation layer 262 includes an insulating material, such as SiO x 、SiO x N y, Si3N4, Al2O3 or TiO2, etc. The material of the second isolation layer 262 can be the same as that of the first isolation layer 261, which is not limited in this embodiment.

[0172] The process for forming the second isolation layer 262 may include an atomic layer deposition process, an electron beam evaporation process, a physical vapor deposition process, a chemical vapor deposition process, or a pulsed laser deposition process. The process for forming the second isolation layer 262 may be the same as the process for forming the first isolation layer 261, which is not limited in this embodiment.

[0173] The second isolation layer 262 may be a single-layer structure or a multi-layer structure.

[0174] In this embodiment, the material of the third electrode 160 is the same as that of the second electrode 280, and the second electrode 280 and the third electrode 160 can be prepared in the same process, thereby reducing the preparation process and the cost.

[0175] Please refer to Fig.13 The third electrode 160 is located in the boundary area and the middle area of ​​the light-emitting unit; the remaining semiconductor growth substrate 100 is located in the boundary area of ​​the light-emitting unit. This is more conducive to achieving the conductive connection between the first electrode 270 and the third electrode 160, and reducing the impact on the light-emitting surface of the light-emitting unit.

[0176] Furthermore, the third electrode 160 includes an electrode pad, which is located in the boundary area of ​​the light-emitting unit; in the thickness direction of the semiconductor growth substrate 100, the projections of the remaining semiconductor growth substrate 100 and the electrode pad overlap. It can be understood that when the electrode is prepared on the light-emitting unit, the electrode pad is usually prepared at the same time, so that the light-emitting unit can be conductively led out through the electrode pad later. In this embodiment, the remaining semiconductor growth substrate 100 is located at the position of the electrode pad to avoid affecting the light-emitting surface of the light-emitting unit. In this case, the portion of the second electrode 280 located on the top surface of the remaining semiconductor growth substrate 100 can be understood as an electrode pad, so as to conductively lead out the prepared constant current driven light-emitting device and conductively connect it to the negative electrode of the power supply.

[0177] The present application also provides a constant current driving light emitting device, please refer to Figures 14 to 17 , the light emitting device comprises:

[0178] The semiconductor growth substrate 100 includes a first surface 101 and a second surface 102 opposite to each other;

[0179] The semiconductor epitaxial layer is located on the second surface 102 side. The semiconductor epitaxial layer 110 includes a first semiconductor epitaxial layer 111, a light-emitting layer 113, and a second semiconductor epitaxial layer 115 stacked in sequence in a direction away from the semiconductor growth substrate 100. The first semiconductor epitaxial layer 111, the light-emitting layer 113, and the second semiconductor epitaxial layer 115 are used to constitute a light-emitting unit; wherein,

[0180] The semiconductor growth substrate 100 covers a portion of the semiconductor epitaxial layer 110 ;

[0181] The surface of the semiconductor epitaxial layer 110 that is not covered by the semiconductor growth substrate 100 is the third surface 103 , and the third surface 103 is the light emitting surface of the light emitting unit;

[0182] The semiconductor growth substrate 100 includes a plurality of ion-doped regions, and the plurality of ion-doped regions are used to form a constant current unit.

[0183] Thus, a constant current unit is integrated on the light-emitting unit, so that the light-emitting unit can work under constant current drive, thereby improving stability; the constant current unit is formed by using a semiconductor growth substrate, and the light-emitting unit is formed by using a semiconductor epitaxial layer obtained by epitaxial growth on the semiconductor growth substrate, so that a single light-emitting device itself has a constant current drive, and there is no need to add a constant current device to the circuit in actual use, thereby reducing costs, reducing light absorption caused by adding components to the circuit, and improving light extraction efficiency; avoiding the integration of the light-emitting device and the constant current device at the packaging stage, which is conducive to device miniaturization.

[0184] Fig.19 It is a schematic diagram of the light-emitting module circuit. As shown in the figure, the light-emitting module is formed by connecting a plurality of light-emitting devices in parallel and then in series. When the constant current DC (Direct Current) provides a constant current to drive the light-emitting module, each individual light-emitting device will evenly divide the DC current. For conventional light-emitting modules, a constant current unit is not integrated in each individual light-emitting device. Once a light-emitting device is damaged and short-circuited, other light-emitting devices connected in parallel with it will share the DC current, thereby increasing the current passing through other light-emitting devices and causing them to burn, until a group of light-emitting devices connected in parallel are all burned and short-circuited, causing the entire light-emitting module to be completely short-circuited and unable to work normally. In this embodiment, a constant current unit is integrated on the light-emitting unit in each light-emitting device. Even if some light-emitting devices are short-circuited, causing the DC current that needs to be shared by other light-emitting devices to increase, the current value actually passing through the light-emitting device is still the constant current output by the constant current unit, which will not cause other light-emitting devices to burn and short-circuit, ensuring that the light-emitting module can still work normally.

[0185] Optionally, the semiconductor growth substrate 100 is located in the boundary region of the light emitting unit. Fig.14 and Fig.15As shown, in the device, the semiconductor growth substrate 100 is located in the boundary region of the semiconductor epitaxial layer 110, thereby reducing the impact on the light-emitting surface and ensuring the light-emitting efficiency of the light-emitting unit.

[0186] Optionally, the semiconductor growth substrate 100 includes multiple ion-doped regions, including: a first doping layer 210 and a second doping layer 220 stacked in sequence from the first surface 101 to the second surface 102; the first doping layer 210 is formed with a surface layer away from the semiconductor epitaxial layer 110, and a first doping region 211, a second doping region 212 and a third doping region 213 are arranged in sequence along a direction perpendicular to the thickness of the constant current unit; wherein the first doping layer 210, the first doping region 211 and the third doping region 213 have a first conductivity type, the second doping layer 220 and the second doping region 212 have a second conductivity type different from the first conductivity type, the bottom surface of the second doping region 212 is spaced from the bottom surface of the first doping layer 210, the bottom surface of the second doping region 212 is the surface of the second doping region 212 close to the second doping layer 220, and the bottom surface of the first doping layer 210 is the surface of the first doping layer 210 close to the second doping layer 220.

[0187] Please refer to Fig.15 and Fig.17 The light-emitting device further includes: a first electrode 270, covering the first doping region 211 to conductively lead out the first doping region 211; a second electrode 280, covering the second doping region 212 and the third doping region 213, and extending from the first surface 101 to the second surface 102 to conductively connect the second doping region 212, the third doping region 213 and the second doping layer 220; wherein the first electrode 270 is used for conductive connection with the light-emitting unit, and the second electrode 280 is used for conductive connection with the negative electrode of the power supply.

[0188] In this embodiment, the first doping region 211 is the drain region of the constant current unit, the second doping region 212 and the second doping layer 220 are the gate region of the constant current unit, the third doping region 213 is the source region of the constant current unit, the first electrode 270 is the drain electrode, and the second electrode 280 realizes the gate-source short circuit. Therefore, when a high potential is applied to the first electrode 270 and a low potential is applied to the second electrode 280, a reverse biased PN junction is formed between the second doping region 212 and the first doping layer 210, and a depletion region is formed at the bottom surface of the second doping region 212. A reverse biased PN junction is also formed between the first doping layer 210 and the second doping layer 220, and a depletion region is formed at the bottom surface of the first doping layer 210. Please refer to Fig.18As the applied voltage increases, the electrons flow from the second electrode 280 to the first electrode 270 under the drive of the voltage, and the depletion region gradually increases. However, the change in the width of the depletion layer has almost no effect on the flow of electrons, and the resistance of the conductive channel hardly changes, so the current in the channel increases almost linearly. As the applied voltage continues to increase, the two PN junctions gradually increase the width of the depletion region under the action of the reverse voltage drop until they contact each other to pinch off the current channel. The voltage at this time is called the pinch-off voltage V P ; As the applied voltage continues to increase, at V P -V B In this voltage range, the width of the depletion layer continues to increase and overlap, so that the pinch-off point moves toward the source end with the increase of voltage. At this time, the channel has been pinched off. In other words, the first doping layer 210 between the two gate regions has been completely depleted, so that the voltage drop in the effective channel remains unchanged, and the current passing through the channel remains basically unchanged, outputting a constant current I H When the applied voltage increases to the point where the reverse biased PN junction undergoes avalanche breakdown, the voltage at this point is called the breakdown voltage V B After breakdown occurs, the operating current increases rapidly, and the device is prone to overheating and damage.

[0189] Further, the semiconductor growth substrate 100 includes a plurality of ion doping regions, and further includes: a third doping layer 230, which is located on a side of the second doping layer 220 away from the first doping layer 210; wherein the third doping layer 230 has a second conductivity type, and the doping concentration of the third doping layer 230 is higher than the doping concentration of the second doping layer 220; the second electrode 280 extends from the first surface 101 to the second surface 102 to electrically connect the second doping region 212, the third doping region 213 and the second doping layer 220, including: the second electrode 280 extends from the first surface 101 to the second surface 102 to connect with the third doping layer 230, so as to electrically connect the second doping region 212, the third doping region 213 and the second doping layer 220. The third doping layer 230 has a higher doping concentration, a higher carrier concentration, and a better current diffusion capability, and can provide a better current injection for the constant current unit, thereby improving the ohmic contact.

[0190] Optionally, the device also includes: a first isolation layer 261, one end of the first isolation layer 261 extends to the first doping region 211 to cover a portion of the first doping layer 210, and the other end of the first isolation layer 261 extends to the second surface 102 to cover at least a portion of the side wall of the constant current unit; the first electrode 270 includes a first part 271 and a second part 272, the first part 271 covers the top surface of the first isolation layer 261 and the first doping region 211, and the second part 272 covers the side surface of the first isolation layer 261; the device also includes: a third electrode 160, covering a portion of the third surface 103 and being conductively connected to the second part 272, and the light-emitting unit and the constant current unit are conductively connected through the first electrode 270 and the third electrode 160. Thus, the first electrode 270 extends to the side wall of the constant current unit to facilitate conductive connection with the third electrode 160, and through the first isolation layer 261, the first electrode 270 can be electrically insulated from the first doping layer 210, the second doping layer 220 and the third doping layer 230, so that the first electrode 270 is only conductively connected to the first doping region 211.

[0191] Optionally, the line width of the second portion 272 is smaller than the width of the side wall of the constant current unit. It can be understood that light near the electrode may be directly absorbed by the electrode. Therefore, the line width of the second portion 272 of the first electrode 270 is set to be smaller than the width of the side wall of the constant current unit, that is, the second portion 272 covers part of the side wall of the constant current unit, reducing the absorption of light by the first electrode 270, and the second portion 272 is conductively connected to the third electrode 160. The line width of the second portion 272 is smaller, which can also reduce the coverage of the third surface 103 (light-emitting surface) by the third electrode 160 connected thereto, thereby improving the light-emitting efficiency of the light-emitting unit.

[0192] Optionally, the line width of the second portion 272 is less than or equal to the line width of the third electrode 160. Thus, while ensuring the conductive connection between the first electrode 270 and the third electrode 160, the line width of the second portion 272 is further reduced, and the absorption of light by the first electrode 270 is further reduced.

[0193] Optionally, the top surface of the first isolation layer 261 is coplanar with the first surface 101. Thus, the first electrode 270 and other structures on the first isolation layer 261 can be formed on a flat surface, reducing the process difficulty and avoiding faults or cracks in the structure.

[0194] Optionally, the semiconductor growth substrate 100 is located in the boundary area of ​​the light-emitting unit; the first isolation layer 261 covers at least part of the side wall of the constant current unit, including: the first isolation layer 261 covers at least part of the inner side wall of the constant current unit, and the inner side wall of the constant current unit is the side wall of the constant current unit close to the center of the third surface 103. Thus, the constant current unit is located in the boundary area of ​​the light-emitting unit, and the first isolation groove is set on the inner side wall close to the center of the constant current unit, so that the second part 272 of the first electrode 270 is also located on this side wall, which makes it easier to realize the conductive connection between the second part 272 and the third electrode 160, reduces the process difficulty, and reduces the degree of shielding of the third surface 103 (light-emitting surface), thereby ensuring the light-emitting efficiency of the light-emitting unit.

[0195] Optionally, the device further includes: a second isolation layer 262, covering the top surface and the inner surface of the first electrode 270, the inner surface of the first electrode 270 being the side surface of the first electrode 270 close to the second doping region 212. Thus, the second isolation layer 262 is disposed on the top and around the first electrode 270, so that the first electrode 270 is electrically insulated from the second electrode 280, the second doping region 212 and the third doping region 213.

[0196] Please refer to Fig.13 and Fig.14 The third electrode 160 is located at the boundary area and the central area of ​​the light emitting unit; the semiconductor growth substrate 100 is located at the boundary area of ​​the light emitting unit. This is more conducive to achieving the conductive connection between the first electrode 270 and the third electrode 160, and reducing the impact on the light emitting surface of the light emitting unit.

[0197] Furthermore, the third electrode 160 includes an electrode pad, which is located in the boundary area of ​​the light-emitting unit; in the thickness direction of the semiconductor growth substrate 100, the projections of the semiconductor growth substrate 100 and the electrode pad overlap. It can be understood that when the electrode is prepared on the light-emitting unit, the electrode pad is usually prepared at the same time, so that the light-emitting unit can be conductively led out through the electrode pad later. In this embodiment, the semiconductor growth substrate 100 is located at the position of the electrode pad, which is more conducive to avoiding the influence on the light-emitting surface of the light-emitting unit. In this case, the portion of the second electrode 280 located on the top surface of the semiconductor growth substrate 100 can be understood as an electrode pad to conductively lead out the constant current driven light-emitting device and conductively connect it to the negative pole of the power supply.

[0198] Optionally, an electrode reflective layer (not shown) is formed between the third electrode 160 and the third surface 103. It is understandable that light near the third electrode 160 may be absorbed by the third electrode 160. The electrode reflective layer is provided so that this part of light can be reflected to improve the luminous efficiency.

[0199] The light-emitting unit further includes a channel layer 121 and a current blocking layer 122 located on the side of the second semiconductor epitaxial layer 115 away from the light-emitting layer 113; the channel layer 121 is located in the boundary region of the second semiconductor epitaxial layer 115 and extends to cover the cutting road; the channel layer 121 and the current blocking layer 122 are arranged at intervals; in the thickness direction of the semiconductor growth substrate 100, the projections of the current blocking layer 122 and the third electrode 160 overlap. Since the light generated under the electrode under the action of the current will be blocked by the electrode, therefore, the current blocking layer 122 is arranged to correspond to the third electrode 160, which can hinder the current transmission under the third electrode 160, avoid the generation of light here, and finally improve the light-emitting efficiency of the light-emitting unit.

[0200] Optionally, the material of the channel layer 121 includes an insulating material; in the thickness direction of the semiconductor growth substrate 100, the projection of the channel layer 121 covers the projection of the first electrode 270 and the projection of the second electrode 280. Thus, light is also avoided from being generated at the first electrode 270 and the second electrode 280, thereby improving the light emitting efficiency of the light emitting unit.

[0201] Please refer to Fig.14 The light-emitting unit further includes: an ohmic layer 131, which is located on a side of the second semiconductor epitaxial layer 115 away from the light-emitting layer 113 and between the channel layer 121 and the current blocking layer 122. It can be understood that the second semiconductor epitaxial layer 115 has a low doping concentration and a high contact resistance, and thus exhibits a degraded ohmic characteristic, and the ohmic layer 131 effectively reduces the ohmic contact resistance.

[0202] The light emitting unit further includes a reflective layer 132 located on a side of the ohmic layer 131 away from the second semiconductor epitaxial layer 115 to improve the light extraction efficiency of the light emitting unit.

[0203] The light emitting unit further includes a blocking layer 133 located on a side of the channel layer 121 , the current blocking layer 122 and the reflective layer 132 away from the second semiconductor epitaxial layer 115 .

[0204] The material of the barrier layer 133 includes a conductive material with a high melting point and good stability, which can effectively block metal migration and mutual diffusion between materials. For example, it can include at least one of gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), titanium (Ti), aluminum (Al), copper (Cu), lead (Pd), ruthenium (Ru), molybdenum (Mo), iridium (Ir), rhodium (Rh), tantalum (Ta), hafnium (Hf), zirconium (Zr), niobium (Nb), and vanadium (V). It can be understood that a bonding layer will be formed on the channel layer 121, the current blocking layer 122 and the reflective layer 132 to combine the conductive support member with the light-emitting unit, but the material of the bonding layer is usually a material with a low melting point and high diffusion such as tin or its alloy. The metal will diffuse to the reflective layer 132, affecting the function of the reflective layer 132. Therefore, preparing a barrier layer 133 with a high melting point and stable chemical properties can effectively avoid damage to the reflective layer 132 and the ohmic layer 131.

[0205] Please refer to Fig.14 The light emitting device further includes a bonding layer 134 and a conductive support member 140 which are sequentially stacked in a direction away from the second semiconductor epitaxial layer 115. The bonding layer 134 can realize bonding the light emitting structure and related structures to the conductive support member 140, thereby realizing the transfer of the light emitting structure and the peeling of the semiconductor growth substrate 100, thereby manufacturing a vertical structure light emitting device.

[0206] It should be noted that the constant current driven light emitting device embodiment provided in the present application and the method for preparing the constant current driven light emitting device embodiment belong to the same concept; the technical features in the technical solutions recorded in the embodiments can be arbitrarily combined without conflict. However, it should be further noted that the constant current driven light emitting device provided in the embodiment of the present application, the combination of its various technical features can already solve the technical problem to be solved by the present application; therefore, the constant current driven light emitting device provided in the embodiment of the present application may not be limited by the method for preparing the constant current driven light emitting device provided in the embodiment of the present application, and any constant current driven light emitting device prepared by the preparation method that can form the constant current driven light emitting device structure provided in the embodiment of the present application is within the scope of protection of the present application.

[0207] It should be understood that the above embodiments are exemplary and are not intended to include all possible implementations included in the claims. Various modifications and changes may be made on the basis of the above embodiments without departing from the scope of the present disclosure. Similarly, the various technical features of the above embodiments may be arbitrarily combined to form other embodiments of the present application that may not be explicitly described. Therefore, the above embodiments only express several implementations of the present application and do not limit the scope of protection of the patent of this application.

Claims

1. A method for preparing a constant current driven light emitting device, characterized in that: include: providing a semiconductor growth substrate, the semiconductor growth substrate comprising a first surface and a second surface opposite to each other; epitaxially growing a semiconductor epitaxial layer on the second surface side, the semiconductor epitaxial layer comprising a third surface connected to the semiconductor growth substrate, the semiconductor epitaxial layer comprising a first semiconductor epitaxial layer, a light emitting layer and a second semiconductor epitaxial layer sequentially stacked in a direction away from the semiconductor growth substrate, the first semiconductor epitaxial layer, the light emitting layer and the second semiconductor epitaxial layer being used to constitute a light emitting unit; Removing a portion of the semiconductor growth substrate from the first surface side to expose a portion of the third surface, wherein the third surface is a light emitting surface of the light emitting unit; Ion doping is performed in the remaining semiconductor growth substrate to form a plurality of ion doping regions to form a constant current unit.

2. The method for preparing a constant current driven light emitting device according to claim 1, characterized in that: The remaining semiconductor growth substrate is located in a boundary region of the light emitting unit.

3. The method for preparing a constant current driven light emitting device according to claim 1, characterized in that: The step of performing ion doping in the remaining semiconductor growth substrate to form a plurality of ion doped regions comprises: forming a second doping layer and a first doping layer sequentially stacked in a direction away from the semiconductor epitaxial layer in the remaining semiconductor growth substrate; Forming a first doping region, a second doping region and a third doping region in sequence arranged along a direction perpendicular to the thickness of the semiconductor epitaxial substrate on a surface layer of the first doping layer away from the semiconductor epitaxial layer; Among them, the first doping layer, the first doping region and the third doping region have a first conductivity type, the second doping layer and the second doping region have a second conductivity type different from the first conductivity type, the bottom surface of the second doping region is spaced apart from the bottom surface of the first doping layer, the bottom surface of the second doping region is the surface of the second doping region close to the second doping layer, and the bottom surface of the first doping layer is the surface of the first doping layer close to the second doping layer.

4. The method for preparing a constant current driven light emitting device according to claim 3, characterized in that: After forming the constant current unit, the preparation method further comprises: forming a first electrode, wherein the first electrode covers the first doped region to electrically lead out the first doped region; forming a second electrode, wherein the second electrode covers the second doping region and the third doping region and extends along the side wall of the constant current unit toward the light emitting unit to conductively connect the second doping region, the third doping region and the second doping layer; The first electrode is used for conductive connection with the light emitting unit, and the second electrode is used for conductive connection with the negative electrode of the power supply.

5. The method for preparing a constant current driven light emitting device according to claim 4, characterized in that: The step of performing ion doping in the remaining semiconductor growth substrate to form a plurality of ion doped regions further comprises: forming a third doping layer in the remaining semiconductor growth substrate, the third doping layer being located on a side of the second doping layer away from the first doping layer; wherein the third doping layer has a second conductivity type, and a doping concentration of the third doping layer is higher than a doping concentration of the second doping layer; The second electrode extends along the side wall of the constant current unit toward the light emitting unit to conductively connect the second doping region, the third doping region and the second doping layer, including: The second electrode extends along the side wall of the constant current unit toward the light emitting unit to connect with the third doping layer, so as to conductively connect the second doping region, the third doping region and the second doping layer.

6. The method for preparing a constant current driven light emitting device according to claim 4, characterized in that: Before forming the first electrode, the preparation method further comprises: forming a first isolation layer, wherein one end of the first isolation layer extends to the first doped region to cover a portion of the first doped layer, and the other end of the first isolation layer extends to the second surface to cover at least a portion of the side wall of the constant current unit; The first electrode includes a first portion and a second portion, the first portion covers the top surface of the first isolation layer and the second doping region, and the second portion covers the side surface of the first isolation layer; After forming the first electrode, the preparation method further comprises: A third electrode is formed, wherein the third electrode covers a portion of the third surface and is conductively connected to the second portion, and the light emitting unit and the constant current unit are conductively connected through the first electrode and the third electrode.

7. The method for preparing a constant current driven light emitting device according to claim 6, characterized in that: A line width of the second portion is smaller than or equal to a line width of the third electrode.

8. The method for preparing a constant current driven light emitting device according to claim 6, characterized in that: After forming the first electrode, the preparation method further comprises: forming a second isolation layer, wherein the second isolation layer covers a top surface and an inner side surface of the first electrode, wherein the inner side surface of the first electrode is a side surface of the first electrode close to the second doping region; The second electrode covers the second isolation layer.

9. The method for preparing a constant current driven light emitting device according to claim 6, characterized in that: Before forming the first isolation layer, the preparation method further comprises: forming a first groove, wherein a sidewall of the first groove is adjacent to the first doped region; The first isolation layer fills the first groove, and a top surface of the first isolation layer is coplanar with a top surface of the semiconductor growth substrate. The top surface of the semiconductor growth substrate is a surface of the semiconductor growth substrate away from the semiconductor epitaxial layer.

10. The method for preparing a constant current driven light emitting device according to claim 6, characterized in that: The remaining semiconductor growth substrate is located in a boundary region of the light emitting unit; The first isolation layer covers at least part of the side wall of the constant current unit, including: the first isolation layer covers at least part of the inner side wall of the constant current unit, and the inner side wall of the constant current unit is the side wall of the constant current unit close to the center of the third surface.

11. A constant current driven light emitting device, characterized in that: include: A semiconductor growth substrate including a first surface and a second surface opposite to each other; A semiconductor epitaxial layer, located on the second surface side, the semiconductor epitaxial layer includes a first semiconductor epitaxial layer, a light-emitting layer, and a second semiconductor epitaxial layer stacked in sequence in a direction away from the semiconductor growth substrate, the first semiconductor epitaxial layer, the light-emitting layer, and the second semiconductor epitaxial layer are used to constitute a light-emitting unit; wherein, The semiconductor growth substrate covers a portion of the semiconductor epitaxial layer; A surface of the semiconductor epitaxial layer that is not covered by the semiconductor growth substrate is a third surface, and the third surface is a light-emitting surface of the light-emitting unit; The semiconductor growth substrate includes a plurality of ion doping regions, and the plurality of ion doping regions are used to form a constant current unit.

12. The constant current driven light emitting device according to claim 11, characterized in that: The semiconductor growth substrate is located in a boundary region of the light emitting unit.

13. The constant current driven light emitting device according to claim 11, characterized in that: The semiconductor growth substrate includes a plurality of ion doping regions, including: A first doping layer and a second doping layer sequentially stacked from the first surface to the second surface; The first doping layer is formed with a first doping region, a second doping region and a third doping region arranged in sequence along a direction perpendicular to the thickness of the constant current unit on a surface away from the semiconductor epitaxial layer; Among them, the first doping layer, the first doping region and the third doping region have a first conductivity type, the second doping layer and the second doping region have a second conductivity type different from the first conductivity type, the bottom surface of the second doping region is spaced apart from the bottom surface of the first doping layer, the bottom surface of the second doping region is the surface of the second doping region close to the second doping layer, and the bottom surface of the first doping layer is the surface of the first doping layer close to the second doping layer.

14. The constant current driven light emitting device according to claim 13, characterized in that: The device further comprises: a first electrode, covering the first doped region to electrically lead the first doped region out; a second electrode, covering the second doping region and the third doping region, and extending from the first surface to the second surface to conductively connect the second doping region, the third doping region and the second doping layer; The first electrode is used for conductive connection with the light emitting unit, and the second electrode is used for conductive connection with the negative electrode of the power supply.

15. The constant current driven light emitting device according to claim 14, characterized in that: The semiconductor growth substrate includes a plurality of ion doped regions, and further includes: a third doped layer located on a side of the second doped layer away from the first doped layer; wherein the third doped layer has a second conductivity type, and a doping concentration of the third doped layer is higher than a doping concentration of the second doped layer; The second electrode extends from the first surface to the second surface to conductively connect the second doping region, the third doping region and the second doping layer, including: The second electrode extends from the first surface to the second surface to connect with the third doping layer, so as to conductively connect the second doping region, the third doping region and the second doping layer.

16. The constant current driven light emitting device according to claim 14, characterized in that: The device further comprises: a first isolation layer, wherein one end of the first isolation layer extends to the first doping region to cover a portion of the first doping layer, and the other end of the first isolation layer extends to the second surface to cover at least a portion of a side wall of the constant current unit; The first electrode includes a first portion and a second portion, the first portion covers the top surface of the first isolation layer and the first doping region, and the second portion covers the side surface of the first isolation layer; The device further comprises: A third electrode covers a portion of the third surface and is conductively connected to the second portion. The light-emitting unit and the constant current unit are conductively connected through the first electrode and the third electrode.

17. The constant current driven light emitting device according to claim 16, characterized in that: A line width of the second portion is smaller than or equal to a line width of the third electrode.

18. The constant current driven light emitting device according to claim 16, characterized in that: The device further comprises: The second isolation layer covers the top surface and the inner side surface of the first electrode, wherein the inner side surface of the first electrode is the side surface of the first electrode close to the second doping region.

19. The constant current driven light emitting device according to claim 16, characterized in that: A top surface of the first isolation layer is coplanar with the first surface.

20. The constant current driven light emitting device according to claim 16, characterized in that: The semiconductor growth substrate is located in the boundary region of the light emitting unit; The first isolation layer covers at least part of the side wall of the constant current unit, including: the first isolation layer covers at least part of the inner side wall of the constant current unit, and the inner side wall of the constant current unit is the side wall of the constant current unit close to the center of the third surface.

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