LED structure and preparation method thereof

Abstract

The invention discloses an LED structure and a preparation method thereof, the LED structure comprises a substrate structure, a first semiconductor layer, a quantum well structure and a second semiconductor layer which are stacked in sequence, and the conduction types of the first semiconductor layer and the second semiconductor layer are opposite; the quantum well structure comprises a potential well layer and a barrier layer located on one side, far away from the substrate structure, of the potential well layer; wherein the potential well layer comprises a plurality of potential well sub-layers which are arranged in a stacked mode, the potential well layer comprises In components, the In components of at least three potential well sub-layers in the plurality of potential well sub-layers are different, and the light-emitting wavebands of the at least three potential well sub-layers corresponding to the different In components comprise a red light waveband, a green light waveband and a blue light waveband. According to the invention, the potential well sub-layers with different In components are integrated on the single-layer potential well layer for gathering, so that the luminous efficiency of the LED structure can be improved, light with different wave bands is emitted, and full-color display is realized.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to an LED structure and a preparation method thereof. Background Art

[0002] In a traditional GaN-based light-emitting diode (LED) on sapphire, the In component in the InGaN alloy material in the multi-quantum well active layer is adjusted, that is, the emission wavelength is adjusted by changing the bandgap width of the InGaN material. However, in the preparation of a multi-wavelength light source for white backlight or a full-color LED structure, since a long-wavelength quantum well structure requires a high In component to be realized, a high In component will introduce a large stress, resulting in a poor crystal quality of the quantum well structure, affecting the light extraction efficiency, and even causing the consequences of fragmentation and chipping. Summary of the Invention

[0003] The present invention provides an LED structure and a preparation method thereof, which can improve the light extraction efficiency, emit light in different wavelength bands, and realize full-color display.

[0004] According to one aspect of the present invention, an LED structure is provided, including:

[0005] A substrate structure, a first semiconductor layer, a quantum well structure, and a second semiconductor layer stacked in sequence, wherein the first semiconductor layer and the second semiconductor layer have opposite conduction types;

[0006] The quantum well structure includes a well layer and a barrier layer located on the side of the well layer away from the substrate structure;

[0007] Wherein, the well layer includes multiple stacked well sub-layers, the well layer includes an In component, and at least three of the multiple well sub-layers have different In components, and the emission wavelength bands of the multiple well sub-layers include a red light band, a green light band, and a blue light band.

[0008] Optionally, along the direction from the substrate structure to the quantum well structure, the In components in the multiple well sub-layers change in a predetermined trend, and the predetermined trend change of the In components in the multiple well sub-layers includes gradually decreasing, gradually increasing, gradually decreasing and then gradually increasing, or gradually increasing and then gradually decreasing.

[0009] Optionally, the change of the In components in the multiple well sub-layers in a predetermined trend includes linear change, step change, or periodic change.

[0010] Optionally, the quantum well structure further includes at least one insertion layer; each insertion layer is disposed between two adjacent well sub-layers with different In components.

[0011] Optionally, the material of the insertion layer is a group III nitride material, and the material of the insertion layer includes any one of AlInN, AlInGaN, AlN, and AlGaN.

[0012] Optionally, the LED structure further includes:

[0013] An electron blocking layer; the electron blocking layer is located between the quantum well structure and the second semiconductor layer.

[0014] Optionally, the proportion of In component in the quantum well sublayer is 10%-60%.

[0015] Optionally, along the direction from the substrate structure to the quantum well structure, the thickness of the multi-layer quantum well sublayers remains unchanged, gradually increases, gradually decreases, first increases and then decreases, or first decreases and then increases.

[0016] Optionally, the LED structure further includes:

[0017] A stress release layer, the stress release layer is located between the first semiconductor layer and the quantum well structure.

[0018] Optionally, the LED structure includes a plurality of quantum well structures, and the plurality of quantum well structures are sequentially stacked between the first semiconductor layer and the second semiconductor layer.

[0019] Optionally, along the direction from the substrate structure to the quantum well structure, the average In component of the plurality of quantum well structures remains unchanged or gradually increases.

[0020] Optionally, along the direction from the substrate structure to the quantum well structure, the thickness of the plurality of quantum well structures remains unchanged or gradually increases.

[0021] According to another aspect of the present invention, there is provided a method for manufacturing an LED structure, including:

[0022] Providing a substrate structure;

[0023] Forming a first semiconductor layer on the substrate structure;

[0024] Forming a quantum well structure on the side of the first semiconductor layer away from the substrate structure;

[0025] Forming a second semiconductor layer on the side of the quantum well structure away from the first semiconductor layer; wherein, the first semiconductor layer and the second semiconductor layer have opposite conductivity types; forming the quantum well structure includes forming a quantum well layer and a barrier layer located on the side of the quantum well layer away from the substrate structure; forming the quantum well layer includes forming a plurality of stacked quantum well sublayers, the quantum well layer includes In component, and at least three quantum well sublayers in the plurality of quantum well sublayers have different In components, and the emission wavelength bands of the plurality of quantum well sublayers are the red wavelength band, the green wavelength band, and the blue wavelength band.

[0026] Optionally, along the direction from the substrate structure towards the quantum well structure, the In composition in the multi-layer potential well sub-layers changes in a predetermined trend, and the predetermined trend change of the In composition in the multi-layer potential well sub-layers includes gradually decreasing, gradually increasing, gradually decreasing and then gradually increasing, or gradually increasing and then gradually decreasing.

[0027] Optionally, forming a quantum well structure on the side of the first semiconductor layer away from the substrate structure includes:

[0028] Forming an insertion layer between each two adjacent potential well sub-layers with different In compositions.

[0029] Optionally, before forming the second semiconductor layer on the side of the quantum well structure away from the first semiconductor layer, it further includes:

[0030] Forming an electron blocking layer on the side of the quantum well structure away from the first semiconductor layer.

[0031] Optionally, before forming the quantum well structure on the side of the first semiconductor layer away from the substrate structure, it further includes:

[0032] Forming a stress release layer on the side of the first semiconductor layer away from the substrate structure.

[0033] Optionally, forming the quantum well structure on the side of the first semiconductor layer away from the substrate structure further includes:

[0034] Forming a plurality of quantum well structures on the side of the first semiconductor layer away from the substrate structure, and the plurality of quantum well structures are sequentially stacked between the first semiconductor layer and the second semiconductor layer.

[0035] Optionally, along the direction from the substrate structure towards the quantum well structure, the average In composition of the plurality of quantum well structures remains unchanged or gradually increases.

[0036] Optionally, along the direction from the substrate structure towards the quantum well structure, the thickness of the plurality of quantum well structures remains unchanged or gradually increases.

[0037] The LED structure provided by the technical solution of the embodiment of the present invention includes: a substrate structure, a first semiconductor layer, a quantum well structure, and a second semiconductor layer that are stacked in sequence. The first semiconductor layer and the second semiconductor layer have opposite conduction types; the quantum well structure includes a well layer and a barrier layer located on the side of the well layer away from the substrate structure; wherein, the well layer includes multiple stacked well sub-layers, the well layer includes In components, at least two of the multiple well sub-layers have different In components, and at least two of the multiple well sub-layers have different emission wavelength bands. By setting at least two of the multiple well sub-layers to have different In components, it is possible to concentrate light with different emission wavelength bands in a single well layer, enabling the LED structure to emit light of different wavelength bands, achieving full-color display. Moreover, since each well sub-layer has a different In component, the average In component in the well layer can be reduced, the stress difference between the well layer and the barrier layer can be decreased, the crystal quality can be improved, and thus the light extraction efficiency of the device can be enhanced.

[0038] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present invention, nor is it used to limit the scope of the present invention. Other features of the present invention will become easily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0040] Figure 1 is a schematic diagram of an LED structure provided by Embodiment 1 of the present invention.

[0041] Figures 2a - 2c is a graph showing the change trend of the In component in the multiple well sub-layers provided by Embodiment 1 of the present invention.

[0042] Figures 3a - 3f is a graph showing the corresponding relationship between the change trend of the In component in the multiple well sub-layers 311 provided by Embodiment 1 and the emission wavelength band of the LED structure.

[0043] Figure 4 is a schematic structural diagram of another LED structure provided by Embodiment 1 of the present invention.

[0044] Figure 5 is a schematic diagram of yet another LED structure provided by Embodiment 1 of the present invention.

[0045] Figure 6 is a schematic diagram of yet another LED structure provided by Embodiment 1 of the present invention.

[0046] Figure 7 It is a schematic diagram of an LED structure provided by the second embodiment of the present invention.

[0047] Figure 8 It is a schematic diagram of another LED structure provided by the second embodiment of the present invention.

[0048] Figure 9 It is a schematic diagram of an LED structure provided by the third embodiment of the present invention.

[0049] Figure 10 It is a flowchart of a preparation method of an LED structure provided by the fourth embodiment of the present invention. Detailed implementation manners

[0050] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0051] It should be noted that the terms "first", "second", etc. in the specification of the present invention are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0052] Embodiment 1

[0053] The embodiment of the present invention provides an LED structure. Figure 1 It is a schematic diagram of an LED structure provided by the first embodiment of the present invention. Refer to Figure 1, the LED structure includes: a substrate structure 10, a first semiconductor layer 20, a quantum well structure 30, and a second semiconductor layer 40, which are sequentially stacked. The first semiconductor layer 20 and the second semiconductor layer 40 have opposite conduction types; the quantum well structure 30 includes a quantum well layer 31 and a barrier layer 32 located on the side of the quantum well layer 31 away from the substrate structure 10; wherein, the quantum well layer 31 includes multiple stacked quantum well sub-layers 311, the quantum well layer 31 includes In component, and at least three of the multiple quantum well sub-layers 311 have different In components. The emission wavelength bands corresponding to at least three quantum well sub-layers 311 with different In components include a red wavelength band, a green wavelength band, and a blue wavelength band.

[0054] Among them, the material of the substrate structure 10 can be any one of substrates such as Si, SiC, Al2O3, AlN, or GaN. Optionally, the substrate structure 10 can further include a substrate and a buffer layer structure formed on the substrate; the first semiconductor layer 20 can be an N-type semiconductor layer, and the second semiconductor layer 40 can be a P-type semiconductor layer; alternatively, the first semiconductor layer 20 can be a P-type semiconductor layer, and the second semiconductor layer 40 can be an N-type semiconductor layer; the materials of the first semiconductor layer 20 and the second semiconductor layer 40 are group III nitride materials. Optionally, the materials of the first semiconductor layer 20 and the second semiconductor layer 40 are GaN-based materials. In this embodiment, the materials of the first semiconductor layer 20 and the second semiconductor layer 40 are GaN, and this embodiment is not limited herein. The materials of the quantum well layer 31 and the barrier layer 32 can be group III nitride materials. Optionally, the material of the quantum well layer 31 can be InGaN material, and the material of the barrier layer 32 can be gallium nitride material. The In components of each of the multiple quantum well sub-layers 311 are different, and the In component of each quantum well sub-layer 311 can be between 10% and 60%; the In components of the multiple quantum well sub-layers 311 can change in a predetermined trend. The In component of each quantum well sub-layer 311 is a relatively fixed ratio, and at least two of the multiple quantum well sub-layers 311 have different emission wavelength bands. Exemplarily, when the In component accounts for 25%, the LED structure emits blue light; when the In component accounts for 40%, the LED structure emits green light; when the In component accounts for 55%, the LED structure emits red light. By setting at least three of the multiple quantum well sub-layers 311 to have different In components, lights with three different emission wavelength bands of red, green, and blue can be concentrated in one quantum well layer 31, so that the LED structure can emit lights with different wavelength bands and achieve full-color display.

[0055] From an extrinsic perspective, when the well layer 31 is made of InGaN material and the barrier layer 32 is made of GaN material, the lattice constant of InGaN is greater than that of GaN. Then, the barrier layer 32 will apply compressive stress to the well layer 31, and this compressive stress will cause crystal quality problems in the InGaN material of the well layer 31, making it impossible to fabricate a high-quality well layer 31. Especially when the In composition accounts for 55% in the LED structure emitting red light, the higher the In composition, the larger the lattice constant and the greater the compressive stress. By setting different In compositions in at least two well sub-layers 311 and integrating the well sub-layers 311 with different In compositions corresponding to different emission wavelength bands of red, green, and blue light in a single well layer 31, the average In composition in the single well layer 31 can be reduced, the stress difference between the well layer 31 and the substrate structure 10 and between the well layer 31 and the barrier layer 32 can be decreased, and the crystal quality of the well layer 31 and the barrier layer 32 can be improved, thereby enhancing the light extraction efficiency of the device.

[0056] The LED structure provided by the technical solution of the embodiment of the present invention includes: a substrate structure 10, a first semiconductor layer 20, a quantum well structure 30, and a second semiconductor layer 40 that are sequentially stacked. The first semiconductor layer 20 and the second semiconductor layer 40 have opposite conductivity types; the quantum well structure 30 includes a well layer 31 and a barrier layer 32 located on the side of the well layer 31 away from the substrate structure 10; wherein, the well layer 31 includes multiple stacked well sub-layers 311, the well layer 31 includes an In composition, and at least three of the multiple well sub-layers 311 have different In compositions. The emission wavelength bands of the multiple well sub-layers 311 corresponding to different In compositions include a red light band, a green light band, and a blue light band. By setting at least three of the multiple well sub-layers 311 to have different In compositions, light of different emission wavelength bands can be concentrated in a single well layer 31, enabling the LED structure to emit light of different wavelength bands and achieve full-color display. Moreover, since at least three of the well sub-layers 311 have different In compositions, that is, the well sub-layers 311 with different In compositions corresponding to different emission wavelength bands are integrated in a single well layer 31, the average In composition in the single well layer 31 can be reduced, thereby decreasing the stress difference between the well layer 31 and the substrate structure 10 and between the well layer 31 and the barrier layer 32, and improving the crystal quality of the well layer 31 and the barrier layer 32, thereby enhancing the light extraction efficiency of the device.

[0057] Optionally, referring to Figure 1 , along the direction from the substrate structure 10 to the quantum well structure 30, the In composition in the multiple well sub-layers 311 changes in a predetermined trend. The predetermined trend change of the In composition in the multiple well sub-layers 311 includes gradually decreasing, gradually increasing, gradually decreasing and then gradually increasing, or gradually increasing and then gradually decreasing.

[0058] Among them, by setting the In component in the multi-layer potential well sub-layer 311 to gradually decrease, or gradually increase, or gradually decrease and then gradually increase, or gradually increase and then gradually decrease, the jump of the In component can be reduced, the epitaxial crystal quality of the potential well layer 31 can be improved, and thus the light extraction efficiency of the device can be improved.

[0059] Optionally, referring to Figure 1 , the change of the In component in the multi-layer potential well sub-layer 311 shows a predetermined trend, including linear change, step change or periodic change.

[0060] Among them, along the direction from the substrate structure 10 to the quantum well structure 30, when the predetermined trend is gradually increasing, for example, Figures 2a - 2c is the change trend diagram of the In component in the multi-layer potential well sub-layer provided in the first embodiment of the present invention. Referring to Figure 2a , the predetermined trend of the In component in the multi-layer potential well sub-layer 311 in FIG. 2 shows a linear increasing change; referring to Figure 2b , Figure 2b , the predetermined trend of the In component in the multi-layer potential well sub-layer 311 in [[ ]] shows a stepwise increasing change; referring to Figure 2c , Figure 2c , the predetermined trend of the In component in the multi-layer potential well sub-layer 311 in [[ ]] shows a periodic increasing change, and every two potential well sub-layers can be an oscillation period.

[0061] In [[ ]] Figures 2a - 2c , the horizontal axis direction is the thickness direction of the multi-layer potential well sub-layer 311, that is, the direction from the substrate structure 10 to the quantum well structure 30. The abscissa d represents the thickness distance between the potential well sub-layer 311 and the substrate structure 10, and the ordinate is the In component of the potential well sub-layer 311. The starting point is the In component of the potential well sub-layer 311 adjacent to the substrate structure 10. In this embodiment, Figures 2a - 2c only the case where the In component in the multi-layer potential well sub-layer 311 gradually increases along the direction from the substrate structure 10 to the quantum well structure 30 is shown. It can be understood that along the direction from the substrate structure 10 to the quantum well structure 30, the In component in the multi-layer potential well sub-layer 311 can gradually decrease, first increase and then decrease, or first decrease and then increase with the same change trend. The change of the In component in the multi-layer potential well sub-layer 311 shows a predetermined trend, including linear change, step change or periodic change, which can realize light sources with multiple wavelengths or mixed light for use as white light backlight.

[0062] Referring to Figures 3a - 3f , Figures 3a - 3fIt is a diagram showing the correspondence between the change trend of the In composition in the multi-layer potential well sub-layer 311 provided in the first embodiment and the light-emitting band of the LED structure. The light-emitting bands of at least three potential well sub-layers (311) corresponding to different In compositions include a red light band, a green light band, and a blue light band. That is, along the direction from the substrate structure 10 to the quantum well structure 30, the In composition in the multi-layer potential well sub-layer 311 changes in a predetermined trend to correspond to different light-emitting bands.

[0063] Optionally, along the direction from the substrate structure 10 to the quantum well structure 30, as Figure 3a shown, the In composition in the multi-layer potential well sub-layer 311 gradually increases. That is, the light-emitting bands of the multi-layer potential well sub-layer 311 are successively the blue light band, the green light band, and the red light band; as Figure 3b shown, the In composition in the multi-layer potential well sub-layer 311 gradually decreases. That is, the light-emitting bands of the multi-layer potential well sub-layer 311 are successively the red light band, the green light band, and the blue light band; as Figures 3c - 3d shown, the In composition in the multi-layer potential well sub-layer 311 first decreases and then increases. That is, the light-emitting bands of the multi-layer potential well sub-layer 311 are successively the red light band, the blue light band, and the green light band or successively the green light band, the blue light band, and the red light band; as Figures 3e - 3f shown, the In composition in the multi-layer potential well sub-layer 311 first increases and then decreases. That is, the light-emitting bands of the multi-layer potential well sub-layer 311 are successively the blue light band, the red light band, and the green light band or successively the green light band, the red light band, and the blue light band. Among them, the potential well sub-layer 311 corresponding to each of the red, green, and blue light-emitting bands can be one layer or multiple layers. Optionally, the In compositions of the multi-layer potential well sub-layers 311 are similar, and the average In composition of the stacked structure formed by them is constant so that the stacked structures formed by them emit red, green, or blue light bands respectively.

[0064] Optionally, as Figure 4 shown, Figure 4 is a schematic structural diagram of another LED structure provided in the first embodiment of the present invention. Along the direction from the substrate structure 10 to the quantum well structure 30, the thickness of the multi-layer potential well sub-layer 311 gradually increases to gradually buffer the stress in the multi-layer potential well sub-layer 311 and improve the crystal quality. In other embodiments, the thickness of the multi-layer potential well sub-layer 311 can also remain unchanged, gradually decrease, first increase and then decrease, or first decrease and then increase. This embodiment does not make a limitation here.

[0065] Optionally, Figure 5 is a schematic diagram of still another LED structure provided in the first embodiment of the present invention. Referring to Figure 5 , the quantum well structure 30 further includes at least one insertion layer 50; each insertion layer 50 is disposed between two adjacent potential well sub-layers 311 with different In compositions.

[0066] Among them, the insertion layer 50 is a high-potential layer. Each insertion layer 50 is disposed between two adjacent quantum well sub-layers 311 with different In components, which can improve the electron-hole recombination ability in the quantum well layer 31, thereby improving the light extraction efficiency. Moreover, the insertion layer 50 can also serve as a protective layer to prevent the precipitation of In elements, ensure the fixation of the In component in each quantum well sub-layer 311, and improve the light extraction stability and light extraction efficiency of the LED structure.

[0067] Optionally, referring to Figure 5 , the material of the insertion layer 50 is a group III nitride material, and the material of the insertion layer 50 includes any one of AlInN, AlInGaN, AlN, and AlGaN.

[0068] Among them, the material preparation processes of AlInN, AlInGaN, AlN, and AlGaN are mature. At the same time, they can improve the electron-hole recombination ability in the quantum well layer 31, thereby improving the light extraction efficiency. They can also prevent the precipitation of In elements and ensure the fixation of the In component in each quantum well sub-layer 311.

[0069] Optionally, referring to Figure 5 , the thickness of the insertion layer 50 is less than 1 nm.

[0070] Preferably, the thickness range of the insertion layer 50 is 0.2 nm - 0.5 nm, which is convenient for device integration and has a simple process.

[0071] Optionally, Figure 6 is a schematic diagram of another LED structure provided by Embodiment 1 of the present invention. Referring to Figure 1 and Figure 6 , the LED structure further includes: an electron blocking layer 60; the electron blocking layer 60 is located between the quantum well structure 30 and the second semiconductor layer 40.

[0072] Among them, the electron blocking layer 60 can be used to block the transmission of electrons between different parts and prevent crosstalk.

[0073] Optionally, referring to Figure 6 , the proportion of the In component in the quantum well sub-layer 311 is 10% - 60%.

[0074] Among them, different proportions of the In component can emit light of different wavelengths to achieve full-color display.

[0075] Among them, optionally, when the In component in the quantum well sub-layer 311 is higher, the thickness of the corresponding quantum well sub-layer 311 is smaller to reduce the stress influence of the quantum well sub-layer 311 with a high In component, improve the crystal quality, and thus improve the light extraction efficiency of the quantum well structure.

[0076] Optionally, referring to Figure 6 , the thickness of the quantum well sub-layer 311 is less than 2 nm.

[0077] Among them, if the thickness of the potential well sub-layer 311 is greater than 2 nm, it is not conducive to the miniaturization of the device. Preferably, the thickness of the potential well sub-layer 311 is 0.2 nm - 1.5 nm, which is convenient for device integration and has a simple process.

[0078] Optionally, referring to Figure 1 and Figure 6 , the LED structure further includes: a stress release layer 70, and the stress release layer 70 is located between the first semiconductor layer 20 and the quantum well structure 30.

[0079] Among them, the stress release layer 70 can release the stress of the potential well layer 31 with a high In component, reduce the lattice defects of the potential well layer 31, improve the crystal quality of the potential well layer 31, and improve the light extraction efficiency of the LED structure.

[0080] Embodiment 2

[0081] The content of Embodiment 2 is substantially the same as that of Embodiment 1, and the difference is only that, referring to Figure 7 , Figure 7 is a schematic diagram of an LED structure provided by Embodiment 2 of the present invention. The LED structure includes a plurality of quantum well structures 30, and the plurality of quantum well structures 30 are sequentially stacked between the first semiconductor layer 20 and the second semiconductor layer 40.

[0082] Among them, each of the plurality of quantum well structures 30 in the plurality of quantum well structures 30 can emit light of different red, green, and blue wavelength bands to achieve full-color display. Compared with the single quantum well structure, the multi-quantum well structure further releases the stress of the potential well layer 31, further improves the crystal quality, thereby improving the light extraction efficiency of the device, and the multi-quantum well structure includes a plurality of light-emitting layers, thereby increasing the light emission intensity of the LED.

[0083] Optionally, referring to Figure 7 , along the direction from the substrate structure 10 to the quantum well structure 30, the average In component of the plurality of quantum well structures 30 remains unchanged or gradually increases.

[0084] Among them, optionally, along the direction from the substrate structure 10 to the quantum well structure 30, the average In component of the plurality of quantum well structures 30 gradually increases, and the stress can be gradually released along the direction from the substrate structure 10 to the quantum well structure 30 to further improve the crystal quality of the quantum well structure 30, thereby improving the light extraction efficiency of the LED structure.

[0085] Optionally, referring to Figure 8 , Figure 8 is a schematic structural diagram of another LED structure provided by Embodiment 2 of the present invention. Along the direction from the substrate structure 10 to the quantum well structure 30, the thickness of the plurality of quantum well structures 30 can gradually increase.

[0086] Among them, along the direction from the substrate structure 10 to the quantum well structure 30, the thicknesses of multiple quantum well structures 30 gradually increase, so that stress can be gradually released along the direction from the substrate structure 10 to the quantum well structure 30, thereby further improving the crystal quality of the quantum well structure 30 and thus improving the light extraction efficiency of the LED structure. Along the direction from the substrate structure 10 to the quantum well structure 30, the thicknesses of multiple quantum well structures 30 gradually increasing may include: along the direction from the substrate structure 10 to the quantum well structure 30, the thickness of the potential well sub-layer 311 in each quantum well structure 30 gradually increases; and / or, along the direction from the substrate structure 10 to the quantum well structure 30, the number of potential well sub-layers 311 in each quantum well structure 30 gradually increases.

[0087] Embodiment III

[0088] The content of Embodiment III is substantially the same as that of Embodiment I or Embodiment II, and the difference is only that, Figure 9 As a schematic diagram of an LED structure provided in Embodiment III of the present invention, the first semiconductor layer 20 has a partial surface not covered by the quantum well structure 30 and the second semiconductor layer 40. The LED structure further includes a first electrode 80 located on the partial surface of the first semiconductor 20 not covered by the quantum well structure 30 and the second semiconductor layer 40, and a second electrode 90 located on the side of the second semiconductor layer 40 away from the substrate structure 10. As Figure 9 shown, optionally, the substrate structure 10 may further include a substrate 11, a nucleation layer 12, and a buffer layer 13 stacked in sequence, and the first semiconductor layer 20 is formed on the side of the buffer layer 13 away from the substrate 11.

[0089] Embodiment IV

[0090] On the basis of the above embodiments, the present invention provides a method for manufacturing an LED structure. Figure 10 As a flowchart of a method for manufacturing an LED structure provided in Embodiment IV of the present invention, referring to Figure 10 , the manufacturing method includes:

[0091] S110. Provide a substrate structure.

[0092] S120. Form a first semiconductor layer on the substrate structure.

[0093] S130. Form a quantum well structure on the side of the first semiconductor layer away from the substrate structure.

[0094] S140. Form a second semiconductor layer on the side of the quantum well structure away from the first semiconductor layer.

[0095] Among them, the conduction types of the first semiconductor layer and the second semiconductor layer are opposite; forming a quantum well structure includes forming a well layer and a barrier layer located on the side of the well layer away from the substrate structure; forming a well layer includes forming multiple stacked well sub-layers, the well layer includes an In component, and the In components of at least three well sub-layers among the multiple well sub-layers are different, and the emission wavelength bands of the at least three well sub-layers corresponding to different In components include a red wavelength band, a green wavelength band, and a blue wavelength band.

[0096] In the method for preparing an LED structure provided by an embodiment of the present invention, by setting different In components for at least three well sub-layers among the multiple well sub-layers, light of different emission wavelength bands can be concentrated in one well layer, so that the LED structure can emit light of the red wavelength band, the green wavelength band, and the blue wavelength band respectively, realizing full-color display. And because the In components of at least three well sub-layers are different, that is, the well sub-layers with different In components corresponding to different red, green, and blue emission wavelength bands are integrated in a single well layer, the average In component in the single well layer can be reduced, thereby reducing the stress difference between the well layer and the substrate structure and between the well layer and the barrier layer, improving the crystal quality of the well layer and the barrier layer, and thus improving the light extraction efficiency of the device.

[0097] Optionally, referring to Figure 1 , along the direction from the substrate structure 10 to the quantum well structure 30, the In component in the multiple well sub-layers 311 changes in a predetermined trend, where the predetermined trend change of the In component in the multiple well sub-layers 311 includes gradually decreasing, gradually increasing, gradually decreasing and then gradually increasing, or gradually increasing and then gradually decreasing.

[0098] Optionally, along the direction from the substrate structure 10 to the quantum well structure 30, as Figure 3a shown, the In component in the multiple well sub-layers 311 gradually increases, that is, the emission wavelength bands of the multiple well sub-layers 311 are the blue wavelength band, the green wavelength band, and the red wavelength band in sequence; as Figure 3b shown, the In component in the multiple well sub-layers 311 gradually decreases, that is, the emission wavelength bands of the multiple well sub-layers 311 are the red wavelength band, the green wavelength band, and the blue wavelength band in sequence; as Figures 3c - 3d shown, the In component in the multiple well sub-layers 311 first decreases and then increases, that is, the emission wavelength bands of the multiple well sub-layers 311 are the red wavelength band, the blue wavelength band, and the green wavelength band in sequence or the green wavelength band, the blue wavelength band, and the red wavelength band in sequence; as Figures 3e - 3fAs shown, the In composition in the multi-layer potential well sub-layer 311 first increases and then decreases, that is, the light-emitting bands of the multi-layer potential well sub-layer 311 are the blue light band, the red light band, and the green light band in sequence, or the green light band, the red light band, and the blue light band in sequence. Among them, the potential well sub-layer 311 corresponding to each of the different light-emitting bands of red, green, and blue can be one layer or multiple layers. Optionally, the In compositions of the multi-layer potential well sub-layers 311 are similar, and the average In composition of the stacked structure formed by them is constant, so that the stacked structures formed by them emit red light bands, green light bands, or blue light bands respectively.

[0099] Optionally, referring to Figure 5 , a quantum well structure 30 is formed on the side of the first semiconductor layer 20 away from the substrate structure 10, including: an insertion layer 50 is formed between each two adjacent potential well sub-layers 311 with different In compositions.

[0100] Optionally, referring to Figure 6 , before forming the second semiconductor layer 40 on the side of the quantum well structure 30 away from the first semiconductor layer 20, it further includes: an electron blocking layer 60 is formed on the side of the quantum well structure 30 away from the first semiconductor layer 20.

[0101] Optionally, the proportion of the In composition in the potential well sub-layer 311 is 10%-60%.

[0102] Optionally, referring to Figure 6 , before forming the quantum well structure 30 on the side of the first semiconductor layer 20 away from the substrate structure 10, it further includes: a stress release layer 70 is formed on the side of the first semiconductor layer 20 away from the substrate structure 10.

[0103] Optionally, referring to Figure 7 , forming the quantum well structure 30 on the side of the first semiconductor layer 20 away from the substrate structure 10 includes: forming a plurality of quantum well structures 30 on the side of the first semiconductor layer 20 away from the substrate structure 10, and the plurality of quantum well structures 30 are sequentially stacked between the first semiconductor layer 20 and the second semiconductor layer 40.

[0104] Optionally, referring to Figure 7 , along the direction from the substrate structure 10 to the quantum well structure 30, the average In composition of the plurality of quantum well structures 30 remains unchanged or gradually increases.

[0105] Optionally, referring to Figure 8 , along the direction from the substrate structure 10 to the quantum well structure 30, the thickness of the plurality of quantum well structures 30 remains unchanged or gradually increases.

[0106] Optionally, referring to Figure 9, after the second semiconductor layer 40 is formed on the side of the quantum well structure 30 away from the first semiconductor layer 20, it further includes: etching the second semiconductor layer 40 and the quantum well structure to expose the surface of a part of the first semiconductor layer 20; preparing a first electrode 80 on the surface of the part of the first semiconductor 20 not covered by the quantum well structure 30 and the second semiconductor layer 40, and preparing a second electrode 80 on the side of the second semiconductor layer 40 away from the substrate structure 10.

[0107] The preparation method of the LED structure provided by the technical solution of the embodiment of the present invention has the same beneficial effects as the LED structure provided by any embodiment of the present invention, and will not be elaborated here.

[0108] It should be understood that various forms of the processes shown above can be used, reordering, adding or deleting steps. For example, the steps described in the present invention can be executed in parallel, sequentially or in a different order, as long as the desired results of the technical solution of the present invention can be achieved, and no limitation is made herein.

[0109] The above specific embodiments do not constitute a limitation on the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. An LED structure, characterized in that, Comprising: A substrate structure (10), a first semiconductor layer (20), a quantum well structure (30), and a second semiconductor layer (40) which are stacked in sequence, wherein the first semiconductor layer (20) and the second semiconductor layer (40) have opposite conductivity types; The quantum well structure (30) includes a quantum well layer (31) and a barrier layer (32) located on a side of the quantum well layer (31) away from the substrate structure (10); Wherein, the quantum well layer (31) includes multiple stacked quantum well sub-layers (311), the quantum well layer (31) includes In component, and at least three of the multiple quantum well sub-layers (311) have different In components, and the emission wavelength bands of at least three quantum well sub-layers (311) corresponding to different In components include a red light wavelength band, a green light wavelength band, and a blue light wavelength band.

2. The LED structure according to claim 1, wherein: Along the direction from the substrate structure (10) to the quantum well structure (30), the In component in the multiple quantum well sub-layers (311) changes in a predetermined trend, and the In component in the multiple quantum well sub-layers (311) gradually decreases, gradually increases, first decreases and then increases, or first increases and then decreases.

3. The LED structure according to claim 2, characterized in that Along the direction from the substrate structure (10) to the quantum well structure (30): The In component in the multiple quantum well sub-layers (311) gradually decreases, and the emission wavelength bands of the multiple quantum well sub-layers (311) are a red light wavelength band, a green light wavelength band, and a blue light wavelength band in sequence; Or, the In component in the multiple quantum well sub-layers (311) gradually increases, and the emission wavelength bands of the multiple quantum well sub-layers (311) are a blue light wavelength band, a green light wavelength band, and a red light wavelength band in sequence; Or, the In component in the multiple quantum well sub-layers (311) first decreases and then increases, and the emission wavelength bands of the multiple quantum well sub-layers (311) are a red light wavelength band, a blue light wavelength band, and a green light wavelength band in sequence; Or, the In component in the multiple quantum well sub-layers (311) first decreases and then increases, and the emission wavelength bands of the multiple quantum well sub-layers (311) are a green light wavelength band, a blue light wavelength band, and a red light wavelength band in sequence; Or, the In component in the multiple quantum well sub-layers (311) first increases and then decreases, and the emission wavelength bands of the multiple quantum well sub-layers (311) are a blue light wavelength band, a red light wavelength band, and a green light wavelength band in sequence; Or, the In component in the multiple quantum well sub-layers (311) first increases and then decreases, and the emission wavelength bands of the multiple quantum well sub-layers (311) are a green light wavelength band, a red light wavelength band, and a blue light wavelength band in sequence.

4. The LED structure according to claim 2, wherein: The change of the In component in the multiple quantum well sub-layers (311) in a predetermined trend includes linear change, step change, or periodic change.

5. The LED structure according to claim 1, wherein: The quantum well structure (30) further includes at least one insertion layer (50); each insertion layer (50) is disposed between two adjacent quantum well sub-layers (311) with different In components.

6. The LED structure according to claim 1, characterized in that, Also comprising: An electron blocking layer (60); the electron blocking layer (60) is located between the quantum well structure (30) and the second semiconductor layer (40).

7. The LED structure according to claim 1, wherein: The proportion of In component in the potential well sub-layer (311) is 10%-60%.

8. The LED structure according to claim 1, wherein: Along the direction from the substrate structure (10) to the quantum well structure (30), the thickness of the multiple potential well sub-layers (311) remains unchanged, gradually increases, gradually decreases, first increases and then decreases, or first decreases and then increases.

9. The LED structure according to claim 1, wherein, Further comprising: A stress release layer (70), the stress release layer (70) is located between the first semiconductor layer (20) and the quantum well structure (30).

10. The LED structure according to any one of claims 1-9, wherein: The LED structure includes multiple quantum well structures (30), and the multiple quantum well structures (30) are sequentially stacked between the first semiconductor layer (20) and the second semiconductor layer (40).

11. The LED structure according to claim 10, wherein: Along the direction from the substrate structure (10) to the quantum well structure (30), the average In component of the multiple quantum well structures (30) remains unchanged or gradually increases.

12. The LED structure according to claim 11, wherein: Along the direction from the substrate structure (10) to the quantum well structure (30), the thickness of the multiple quantum well structures (30) remains unchanged or gradually increases.

13. A method for preparing an LED structure, characterized in that, Comprising: Providing a substrate structure (10); Forming a first semiconductor layer (20) on the substrate structure (10); Forming a quantum well structure (30) on a side of the first semiconductor layer (20) away from the substrate structure (10); Forming a second semiconductor layer (40) on a side of the quantum well structure (30) away from the first semiconductor layer (20); wherein, the first semiconductor layer (20) and the second semiconductor layer (40) have opposite conduction types; forming the quantum well structure (30) includes forming a potential well layer (31) and a barrier layer (32) located on a side of the potential well layer (31) away from the substrate structure (10); forming the potential well layer (31) includes forming multiple stacked potential well sub-layers (311), the potential well layer (31) includes an In component, and at least three of the multiple potential well sub-layers (311) have different In components, and the emission wavelength bands of at least three potential well sub-layers (311) corresponding to different In components include a red light band, a green light band, and a blue light band.

14. The method for manufacturing the LED structure according to claim 13, wherein: In the direction from the substrate structure (10) towards the quantum well structure (30), the In composition in the multiple quantum well sub-layers (311) changes in a predetermined trend, and the In composition in the multiple quantum well sub-layers (311) gradually decreases, gradually increases, first decreases and then increases, or first increases and then decreases; wherein, the direction from the substrate structure (10) towards the quantum well structure (30): The In composition in the multiple quantum well sub-layers (311) gradually decreases, and the emission bands of the multiple quantum well sub-layers (311) are successively a red light band, a green light band, and a blue light band; Or, the In composition in the multiple quantum well sub-layers (311) gradually increases, and the emission bands of the multiple quantum well sub-layers (311) are successively a blue light band, a green light band, and a red light band; Or, the In composition in the multiple quantum well sub-layers (311) first decreases and then increases, and the emission bands of the multiple quantum well sub-layers (311) are successively a red light band, a blue light band, and a green light band; Or, the In composition in the multiple quantum well sub-layers (311) first decreases and then increases, and the emission bands of the multiple quantum well sub-layers (311) are successively a green light band, a blue light band, and a red light band; Or, the In composition in the multiple quantum well sub-layers (311) first increases and then decreases, and the emission bands of the multiple quantum well sub-layers (311) are successively a blue light band, a red light band, and a green light band; Or, the In composition in the multiple quantum well sub-layers (311) first increases and then decreases, and the emission bands of the multiple quantum well sub-layers (311) are successively a green light band, a red light band, and a blue light band.

15. The manufacturing method of the LED structure according to claim 13, wherein, Forming a quantum well structure (30) on the side of the first semiconductor layer (20) away from the substrate structure (10), including: Forming an insertion layer (50) between every two adjacent quantum well sub-layers (311) with different In compositions.

16. The manufacturing method of the LED structure according to claim 13, wherein, Before forming the second semiconductor layer (40) on the side of the quantum well structure (30) away from the first semiconductor layer (20), further including: Forming an electron blocking layer (60) on the side of the quantum well structure (30) away from the first semiconductor layer (20).

17. The manufacturing method of the LED structure according to claim 13, wherein, Before forming the quantum well structure (30) on the side of the first semiconductor layer (20) away from the substrate structure (10), further including: Forming a stress release layer (70) on the side of the first semiconductor layer (20) away from the substrate structure (10).

18. The method for preparing the LED structure according to claim 13, wherein, Forming a quantum well structure (30) on the side of the first semiconductor layer (20) away from the substrate structure (10), further including: Forming a plurality of quantum well structures (30) on the side of the first semiconductor layer (20) away from the substrate structure (10), and the plurality of quantum well structures (30) are sequentially stacked between the first semiconductor layer (20) and the second semiconductor layer (40).

19. The method for preparing the LED structure according to claim 18, wherein: In the direction from the substrate structure (10) towards the quantum well structure (30), the average In composition of the plurality of quantum well structures (30) remains unchanged or gradually increases.

20. The preparation method of the LED structure according to claim 19, wherein: Along the direction from the substrate structure (10) to the quantum well structure (30), the thicknesses of the multiple quantum well structures (30) remain unchanged or gradually increase.

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