Light emitting epitaxial structure, light emitting diode chip and display device
By inserting an AlGaP improvement layer into the P-type GaP window layer of Micro LED, the lattice matching problem of the GaP window layer is solved, the performance of the light-emitting epitaxial structure and the light-emitting diode chip is improved, and the color gamut and color saturation of the display device are enhanced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- XIAMEN FUTURE DISPLAY TECH RES INST CO LTD
- Filing Date
- 2025-06-25
- Publication Date
- 2026-06-26
AI Technical Summary
In existing Micro LED technology, GaP, the window layer material for red light epitaxial structures, suffers from lattice matching problems, current spread, and numerous crystal growth defects, which affect the color gamut and color saturation of display devices.
Insert at least one AlGaP improvement layer into the P-type GaP window layer to optimize the luminescent epitaxial structure. The lattice constant of the AlGaP improvement layer is closer to that of other stacked layers, serving as a buffer structure to reduce stress and dislocation density caused by lattice mismatch.
This improved the growth quality of the light-emitting epitaxial structure and the performance of the light-emitting diode chip, thereby enhancing the stability and color performance of the display device.
Smart Images
Figure CN224419205U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of semiconductor light-emitting device technology, and more specifically, to a light-emitting epitaxial structure, a light-emitting diode chip, and a display device. Background Technology
[0002] Micro LED (Micro Light Emitting Diode) technology, as a leading candidate for next-generation display technology, has attracted widespread attention due to its self-emissive, high-brightness, low-power, and long-life characteristics. In the development of Micro LED technology, the optimization of the red epitaxial structure is particularly crucial, directly affecting the color gamut and color saturation of display devices. The window layer material for red epitaxial structures is mostly GaP, which is widely used in current red epitaxial production and R&D due to its non-light-absorbing properties and ease of fabrication. However, GaP still suffers from problems such as lattice matching issues, current spread, and numerous crystal growth defects. Therefore, optimizing the window layer of the red epitaxial structure not only helps improve the performance of Micro LED chips but also promotes the development of the entire display technology. Utility Model Content
[0003] In view of this, this application provides a light-emitting epitaxial structure, a light-emitting diode chip, and a display device, which effectively solves the technical problems existing in the prior art. By optimizing the P-type GaP window layer by inserting at least one AlGaP improvement layer, the growth quality of the light-emitting epitaxial structure is improved, and the performance of the light-emitting diode chip is also improved.
[0004] To achieve the above objectives, the technical solution provided in this application is as follows:
[0005] A light-emitting epitaxial structure, comprising:
[0006] A substrate, an N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer are stacked sequentially.
[0007] A layer of AlGaP improvement is inserted into the P-type GaP window layer; or, at least two layers of AlGaP improvement are inserted into the P-type GaP window layer, and the at least two layers of AlGaP improvement are spaced apart in the direction from the substrate to the P-type GaP window layer.
[0008] Optionally, the Al composition of the at least two AlGaP improvement layers is different in each AlGaP improvement layer.
[0009] Optionally, in the at least two AlGaP improvement layers, and in the direction from the substrate to the P-type GaP window layer, the Al composition of the AlGaP improvement layer tends to increase.
[0010] Alternatively, in the at least two AlGaP improvement layers, and in the direction from the substrate to the P-type GaP window layer, the Al composition of the AlGaP improvement layer tends to decrease.
[0011] Optionally, the P-type GaP window layer includes a first surface facing away from the substrate and a second surface facing towards the substrate.
[0012] In at least one AlGaP improvement layer, the first distance between the AlGaP improvement layer and the first surface is less than the second distance between the same AlGaP improvement layer and the second surface.
[0013] Optionally, the light-emitting epitaxial structure further includes:
[0014] A corrosion stop layer located between the substrate and the N-type confinement layer;
[0015] And / or, an N-type current spreading layer located between the substrate and the N-type confinement layer;
[0016] And / or, a buffer layer located between the substrate and the N-type confinement layer;
[0017] And / or, an N-type ohmic contact layer located between the substrate and the N-type confinement layer;
[0018] And / or, an N-type waveguide layer located between the N-type confinement layer and the active layer;
[0019] And / or, a P-type waveguide layer located between the active layer and the P-type confinement layer.
[0020] Based on the same inventive concept, this application also provides a light-emitting diode chip, comprising:
[0021] An N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer are sequentially superimposed.
[0022] A layer of AlGaP improvement is inserted into the P-type GaP window layer; or, at least two layers of AlGaP improvement are inserted into the P-type GaP window layer, and the at least two layers of AlGaP improvement are spaced apart in the direction from the N-type confinement layer to the P-type confinement layer.
[0023] Optionally, the light-emitting diode includes an N-electrode and a P-electrode, wherein the N-electrode is located on the side of the N-type confinement layer opposite to the active layer, and the P-electrode is located on the side of the P-type GaP window layer opposite to the active layer.
[0024] Optionally, the Al composition of the at least two AlGaP improvement layers is different in each AlGaP improvement layer.
[0025] Optionally, in the at least two AlGaP improvement layers, and in the direction from the N-type confinement layer to the P-type confinement layer, the Al composition of the AlGaP improvement layer tends to increase;
[0026] Alternatively, in the at least two AlGaP improvement layers, and in the direction from the N-type confinement layer to the P-type confinement layer, the Al composition of the AlGaP improvement layer tends to decrease.
[0027] Optionally, the P-type GaP window layer includes a first surface facing away from the N-type confinement layer and a second surface facing the N-type confinement layer.
[0028] In at least one AlGaP improvement layer, the first distance between the AlGaP improvement layer and the first surface is less than the second distance between the same AlGaP improvement layer and the second surface.
[0029] Optionally, the light-emitting diode chip further includes:
[0030] An N-type current spread layer located on the side of the N-type confinement layer opposite to the active layer;
[0031] And / or, an N-type ohmic contact layer located on the side of the N-type confinement layer opposite to the active layer;
[0032] And / or, an N-type waveguide layer located between the N-type confinement layer and the active layer;
[0033] And / or, a P-type waveguide layer located between the active layer and the P-type confinement layer.
[0034] Based on the same inventive concept, this application also provides a display device, which includes the above-described light-emitting diode chip.
[0035] Compared with existing technologies, the technical solution provided in this application has at least the following advantages:
[0036] This application provides a light-emitting epitaxial structure, a light-emitting diode chip, and a display device. The light-emitting epitaxial structure includes: a substrate, an N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer, which are sequentially stacked. An AlGaP improvement layer is inserted into the P-type GaP window layer; or, at least two AlGaP improvement layers are inserted into the P-type GaP window layer, and the at least two AlGaP improvement layers are spaced apart in the direction from the substrate to the P-type GaP window layer. As can be seen from the above, the lattice constant of the AlGaP improvement layer provided in this application is closer to the lattice constant of the other stacked layers in the light-emitting epitaxial structure, allowing the AlGaP improvement layer to act as an effective buffer structure. Therefore, optimizing the P-type GaP window layer by inserting at least one AlGaP improvement layer can reduce the stress caused by lattice mismatch in the P-type GaP window layer, while simultaneously reducing the dislocation density in the P-type GaP window layer, improving the crystal quality of the P-type GaP window layer, improving the growth quality of the light-emitting epitaxial structure, making the light-emitting epitaxial structure more stable, and improving the performance of the light-emitting diode chip. Attached Figure Description
[0037] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0038] Figure 1 This is a schematic diagram of a light-emitting epitaxial structure provided in an embodiment of this application;
[0039] Figure 2 This is a schematic diagram of another light-emitting epitaxial structure provided in an embodiment of this application;
[0040] Figure 3 A schematic diagram of another light-emitting epitaxial structure provided in the embodiments of this application;
[0041] Figure 4 A schematic diagram of another light-emitting epitaxial structure provided in the embodiments of this application;
[0042] Figure 5 This is a schematic diagram of the structure of a light-emitting diode chip provided in an embodiment of this application;
[0043] Figure 6 This is a schematic diagram of another light-emitting diode chip provided in an embodiment of this application;
[0044] Figure 7This is a schematic diagram of the structure of another light-emitting diode chip provided in the embodiments of this application;
[0045] Figure 8 This is a schematic diagram of the structure of another light-emitting diode chip provided in the embodiments of this application;
[0046] Figure 9 This is a schematic diagram of the structure of another light-emitting diode chip provided in the embodiments of this application;
[0047] Figure 10 This is a schematic diagram of the structure of another light-emitting diode chip provided in an embodiment of this application.
[0048] Figure label:
[0049] 100 - Substrate; 200 - Etching cutoff layer; 300 - N-type current spreading layer; 400 - N-type confinement layer; 500 - Active layer; 600 - P-type confinement layer; 700 - P-type GaP window layer; 701 - First surface; 702 - Second surface; 703 - Step region; 710 - AlGaP improvement layer; 711 - First AlGaP improvement layer; 712 - Second AlGaP improvement layer; 713 - Third AlGaP improvement layer; 810 - Buffer layer; 820 - N-type ohmic contact layer; 830 - N-type waveguide layer; 840 - P-type waveguide layer; 910 - N-electrode; 920 - P-electrode. Detailed Implementation
[0050] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0051] As described in the background section, Micro LED technology, as a leading candidate for next-generation display technology, has attracted widespread attention due to its self-emissive nature, high brightness, low power consumption, and long lifespan. In the development of Micro LED technology, the optimization of the red epitaxial structure is particularly crucial, directly affecting the color gamut and color saturation of display devices. The window layer material for red epitaxial structures is mostly GaP, which is widely used in current red epitaxial production and R&D due to its non-light absorption and ease of fabrication. However, GaP still suffers from problems such as lattice matching issues, current spread, and numerous crystal growth defects. Therefore, optimizing the window layer of the red epitaxial structure not only helps improve the performance of Micro LED chips but also promotes the development of the entire display technology.
[0052] Based on this, embodiments of this application provide a light-emitting epitaxial structure, a light-emitting diode chip, and a display device, effectively solving the technical problems existing in the prior art. By optimizing the p-type GaP window layer by inserting at least one AlGaP improvement layer, the growth quality of the light-emitting epitaxial structure is improved, and the performance of the light-emitting diode chip is also enhanced. It should be noted that the light-emitting epitaxial structure provided in this application can be a corresponding light-emitting epitaxial structure for Micro LEDs, and the light-emitting diode chip can be a Micro LED chip; furthermore, the light-emitting epitaxial structure and light-emitting diode chip provided in this application can be corresponding to red light emission, and this application does not impose specific limitations in this regard.
[0053] To achieve the above objectives, the technical solutions provided in this application are as follows, in specific combination with... Figures 1 to 10 The technical solutions provided in the embodiments of this application will be described in detail.
[0054] Combination Figure 1 and Figure 2 As shown, Figure 1 This is a schematic diagram of a light-emitting epitaxial structure provided in an embodiment of this application. Figure 2 This is a schematic diagram of another light-emitting epitaxial structure provided in an embodiment of this application. For example... Figure 1 As shown, the light-emitting epitaxial structure provided in this application embodiment includes: a substrate 100, an N-type confinement layer 400, an active layer 500, a P-type confinement layer 600, and a P-type GaP window layer 700 stacked sequentially; an AlGaP improvement layer 710 is inserted into the P-type GaP window layer 700; that is, in the direction from the substrate 100 to the P-type GaP window layer 700, the AlGaP improvement layer 710 divides the P-type GaP window layer 700 into two sub-layers.
[0055] Or such as Figure 2 As shown, the light-emitting epitaxial structure provided in this application embodiment includes: a substrate 100, an N-type confinement layer 400, an active layer 500, a P-type confinement layer 600, and a P-type GaP window layer 700 stacked sequentially; at least two AlGaP improvement layers 710 are inserted into the P-type GaP window layer 700, and the at least two AlGaP improvement layers 710 are spaced apart in the direction from the substrate 100 to the P-type GaP window layer 700; that is, in the direction from the substrate 100 to the P-type GaP window layer 700, at least two AlGaP improvement layers 710 divide the P-type GaP window layer 700 into multiple sub-layer portions, and any two adjacent AlGaP improvement layers 710 are separated by a sub-layer portion of the P-type GaP window layer 700.
[0056] As can be seen from the above, the lattice constant of the AlGaP improvement layer 710 provided in this application embodiment is closer to the lattice constant of the other stacked layers in the light-emitting epitaxial structure, making the AlGaP improvement layer 710 an effective buffer structure. Therefore, by inserting at least one AlGaP improvement layer 710 into the P-type GaP window layer 700 for optimization, the stress caused by lattice mismatch in the P-type GaP window layer 700 can be reduced, the dislocation density in the P-type GaP window layer 700 can be reduced, the crystal quality of the P-type GaP window layer 700 can be improved, the growth quality of the light-emitting epitaxial structure can be improved, the light-emitting epitaxial structure can be made more stable, and the performance of the light-emitting diode chip can be improved.
[0057] In particular, the light-emitting epitaxial structure provided in this application embodiment can be a red-light AlGaInP-based light-emitting epitaxial structure. As the latest generation technology, red-light AlGaInP-based Micro LED technology is currently in the early stages of development and application, and further development and maturity are needed for technology development, product yield, and market application. For the epitaxial structure of red-light Micro LED, AlGaInP quaternary material is usually deposited on a GaAs substrate 100, and the outermost window layer is a P-type GaP window layer 700. In the manufacturing process of the light-emitting diode chip (such as a red-light Micro LED chip), the P-type GaP window layer 700 is bonded to the electrode of the chip, forming current extension in the P-type GaP window layer 700. However, due to the large difference between the lattice constant of GaP material and the GaAs substrate 100 and the underlying AlGaInP material (such as the N-type current extension layer 300), there is a certain lattice mismatch problem. Therefore, at least one AlGaP improvement layer 710 is inserted into the P-type GaP window layer 700 for optimization. The lattice constant of the AlGaP improvement layer 710 is closer to that of GaAs and AlGaInP materials, making the AlGaP improvement layer 710 an effective buffer structure. This reduces the stress caused by lattice mismatch in the P-type GaP window layer 700 and lowers the dislocation density in the P-type GaP window layer 700, effectively improving the stability of the light-emitting epitaxial structure and enhancing the performance of the light-emitting diode chip.
[0058] In some embodiments, the Al composition of the at least two AlGaP improvement layers 710 provided in this application is different. That is, in the light-emitting epitaxial structure including at least two AlGaP improvement layers 710, all materials are Al... x Ga 1-x In the P-type GaP improvement layer, different improvement layers have different X values, thereby controlling the current expansion direction in the P-type GaP window layer 700 to adapt to different current operating scenarios of LED chips of the same size.
[0059] In one aspect, in the at least two AlGaP improvement layers 710 provided in the embodiments of this application, and in the direction from the substrate 100 to the P-type GaP window layer 700, the Al composition of the AlGaP improvement layer 710 shows an increasing trend. Specifically... Figure 2 Taking the P-type GaP window layer 700 shown as an example, which has three AlGaP improvement layers 710 inserted in it, in the direction from the substrate 100 to the P-type GaP window layer 700, the three AlGaP improvement layers 710 are defined as the first AlGaP improvement layer 711, the second AlGaP improvement layer 712 and the third AlGaP improvement layer 713, respectively. The Al composition of the first AlGaP improvement layer 711 is X1, the Al composition of the second AlGaP improvement layer 712 is X2 and the Al composition of the third AlGaP improvement layer 713 is X3. The relationship between X1, X2 and X3 is that X1 is less than X2 and X2 is less than X3. Inserting an AlGaP improvement layer 710 into the P-type GaP window layer 700 is equivalent to adding an Al component to the corresponding region of the P-type GaP window layer 700. Since the etching concentration ratio required for different Al components in the P-type GaP window layer 700 varies, by adjusting the solution ratio and etching method, a corresponding structure can be achieved where the Al component of the first AlGaP improvement layer 711, the second AlGaP improvement layer 712, and the third AlGaP improvement layer 713 shows an increasing trend. After adding an Al component to the P-type GaP window layer 700, the material potential energy decreases, making it easier for electrons to pass through. When electrodes are fabricated on the P-type GaP window layer 700, the current below the non-electrode extends laterally to the area below the electrode, emitting light. Therefore, in the light-emitting epitaxial structure fabricated with an increasing Al component in the AlGaP improvement layer 710 in the direction from the substrate 100 to the P-type GaP window layer 700, this structure has a large saturation current, requiring high scalability for the high-current operation of the light-emitting diode chip.
[0060] Alternatively, in the at least two AlGaP improvement layers 710, and in the direction from the substrate 100 to the p-type GaP window layer 700, the Al composition of the AlGaP improvement layer 710 tends to decrease. Similarly... Figure 2Taking the example of a P-type GaP window layer 700 with three AlGaP improvement layers 710 inserted, in the direction from the substrate 100 to the P-type GaP window layer 700, the three AlGaP improvement layers 710 are defined as a first AlGaP improvement layer 711, a second AlGaP improvement layer 712, and a third AlGaP improvement layer 713, respectively. The Al composition of the first AlGaP improvement layer 711 is X1, the Al composition of the second AlGaP improvement layer 712 is X2, and the Al composition of the third AlGaP improvement layer 713 is X3. The relationship between X1, X2, and X3 is that X1 is greater than X2, and X2 is greater than X3. When an electrode is fabricated on the P-type GaP window layer 700, this structure is not conducive to the current spread below the electrode. Only the current below the electrode can spread vertically through the AlGaP improvement layer 710 to enter the electrode and emit light. It can be seen that in the light-emitting epitaxial structure prepared by the Al GaP improvement layer 710 with a decreasing Al composition in the direction of the substrate 100 pointing to the P-type GaP window layer 700, the saturation current of this structure is small. Corresponding to the low current operation scenario of the light-emitting diode chip, the current needs to be more concentrated to enter the electrode to emit light.
[0061] refer to Figure 3 The diagram shows a schematic of another light-emitting epitaxial structure provided in this application embodiment. The P-type GaP window layer 700 provided in this application embodiment includes a first surface 701 facing away from the substrate 100 and a second surface 702 facing the substrate 100. In at least one AlGaP improvement layer 710, the first distance d1 between the AlGaP improvement layer 710 and the first surface is less than the second distance d2 between the same AlGaP improvement layer 710 and the second surface. This allows the AlGaP improvement layer 710 to be fabricated in the region of the P-type GaP window layer 700 away from the substrate 100, making the AlGaP improvement layer 710 closer to the electrode and enabling more timely current propagation.
[0062] Based on the above-described light-emitting epitaxial structure, the embodiments of this application can further optimize the stacked layers of the light-emitting epitaxial structure to improve the performance of the light-emitting diode chip fabricated by the light-emitting epitaxial structure. Specifically, as follows... Figure 4The diagram shows another light-emitting epitaxial structure provided in this application embodiment. The light-emitting epitaxial structure further includes: an etching stop layer 200 located between the substrate 100 and the N-type confinement layer 400; an N-type current spreading layer 300 located between the substrate 100 and the N-type confinement layer 400, wherein when other structural layers are included between the substrate 100 and the N-type confinement layer 400, the N-type current spreading layer 300 is preferably in adjacent contact with the N-type confinement layer 400; and a buffer layer 810 located between the substrate 100 and the N-type confinement layer 400, wherein when other structural layers are included between the substrate 100 and the N-type confinement layer 400, the buffer layer 810 is preferably in adjacent contact with the substrate 100. This improves the stress release effect during the growth of the light-emitting epitaxial structure and enhances the crystal growth quality of the light-emitting epitaxial structure. The N-type ohmic contact layer 820 located between the substrate 100 and the N-type confinement layer 400 is adjacent to the N-type confinement layer 400 when there is no N-type current spreading layer 300 between the substrate 100 and the N-type confinement layer 400; and adjacent to the N-type current spreading layer 300 when the substrate 100 and the N-type confinement layer 400 are also present. This achieves a lower resistance and more stable current injection channel to the N-type confinement layer 400, improving the performance of the light-emitting epitaxial structure. The N-type waveguide layer 830 located between the N-type confinement layer 400 and the active layer 500 confines and guides the light generated by the active layer 500 to propagate in a direction perpendicular to the junction, increasing the probability of photons escaping from the edge or surface and improving light extraction efficiency. Furthermore, the P-type waveguide layer 840 located between the active layer 500 and the P-type confinement layer 600 constrains and guides the light generated by the active layer 500 to propagate in a direction perpendicular to the junction, thereby increasing the probability of photons escaping from the edge or surface and further improving the light extraction efficiency.
[0063] It should be noted that the optimized stacked layers of the light-emitting epitaxial structure provided in this application embodiment are not limited to the buffer layer 810, etch stop layer 200, N-type ohmic contact layer 820, N-type current spreading layer 300, N-type waveguide layer 830, and P-type waveguide layer 840 described above. In some other embodiments, the optimized stacked layers may also be other functional layers, and this application does not impose specific limitations on this. Furthermore, the light-emitting epitaxial structure provided in this application embodiment may include only one of the following: buffer layer 810, etch stop layer 200, N-type ohmic contact layer 820, N-type current spreading layer 300, N-type waveguide layer 830, and P-type waveguide layer 840. Alternatively, the light-emitting epitaxial structure provided in this application embodiment may include a combination of at least two of the following: buffer layer 810, etch stop layer 200, N-type ohmic contact layer 820, N-type current spreading layer 300, N-type waveguide layer 830, and P-type waveguide layer 840. In other words, the light-emitting epitaxial structure provided in this application embodiment further includes: an etch stop layer 200 located between the substrate 100 and the N-type confinement layer 400; and / or, an N-type current spreading layer 300 located between the substrate 100 and the N-type confinement layer 400; and / or, a buffer layer 810 located between the substrate 100 and the N-type confinement layer 400; and / or, an N-type ohmic contact layer 820 located between the substrate 100 and the N-type confinement layer 400; and / or, an N-type waveguide layer 830 located between the N-type confinement layer 400 and the active layer 500; and / or, a P-type waveguide layer 840 located between the active layer 500 and the P-type confinement layer 600. Optionally, the substrate 100 provided in this embodiment can be a GaAs substrate, the buffer layer 810 can be a GaAs buffer layer, the etching stop layer 200 can be an N-type GaInP etching stop layer, the N-type ohmic contact layer 820 can be an N-type GaAs ohmic contact layer, the N-type current spreading layer 300 can be an N-type AlGaInP current spreading layer, the N-type confinement layer 400 can be an N-type AlInP confinement layer, the N-type waveguide layer 830 can be an N-type AlGaInP waveguide layer, the active layer 500 can be an MQW (Multiple Quantum Well) active layer, the P-type waveguide layer 840 can be a P-type AlGaInP waveguide layer, and the P-type confinement layer 600 can be a P-type AlInP confinement layer. This application does not impose specific limitations on these aspects.
[0064] Based on the same inventive concept, embodiments of this application also provide a light-emitting diode chip. Combined with... Figure 5 and Figure 6 As shown, Figure 5 This is a schematic diagram of the structure of a light-emitting diode chip provided in an embodiment of this application. Figure 6 This is a schematic diagram of another light-emitting diode chip provided in an embodiment of this application. Figure 5As shown, the light-emitting diode chip provided in this application embodiment includes: an N-type confinement layer 400, an active layer 500, a P-type confinement layer 600, and a P-type GaP window layer 700 stacked sequentially; an AlGaP improvement layer 710 is inserted into the P-type GaP window layer 700; that is, in the direction from the N-type confinement layer 400 to the P-type confinement layer 600, the AlGaP improvement layer 710 divides the P-type GaP window layer 700 into two sub-layers.
[0065] Or such as Figure 6 As shown, the light-emitting diode chip provided in this embodiment includes: an N-type confinement layer 400, an active layer 500, a P-type confinement layer 600, and a P-type GaP window layer 700 stacked sequentially; at least two AlGaP improvement layers 710 are inserted into the P-type GaP window layer 700, and the at least two AlGaP improvement layers 710 are spaced apart in the direction from the N-type confinement layer 400 to the P-type confinement layer 600. That is, in the direction from the N-type confinement layer 400 to the P-type confinement layer 600, the at least two AlGaP improvement layers 710 divide the P-type GaP window layer 700 into multiple sub-layer portions, and any two adjacent AlGaP improvement layers 710 are separated by a sub-layer portion of the P-type GaP window layer 700.
[0066] In some embodiments, the light-emitting diode chip provided in this application includes an N-electrode 910 and a P-electrode 920, wherein the N-electrode 910 and the P-electrode 920 can be located on opposite sides of the chip. Specifically, as shown... Figure 7 The diagram shown is a structural schematic of another light-emitting diode chip provided in an embodiment of this application. Figure 5 Taking the light-emitting diode chip shown as an example, the light-emitting diode includes an N electrode 910 and a P electrode 920. The N electrode 910 is located on the side of the N-type confinement layer 400 away from the active layer 500, and the P electrode 920 is located on the side of the P-type GaP window layer 700 away from the active layer 500.
[0067] Alternatively, the light-emitting diode chip provided in this application embodiment includes an N-electrode 910 and a P-electrode 920, wherein the N-electrode 910 and the P-electrode 920 can be located on the same side of the chip. Specifically, as shown... Figure 8 The diagram shown is a structural schematic of another light-emitting diode chip provided in an embodiment of this application. Figure 5Taking the illustrated light-emitting diode (LED) chip as an example, the LED includes an N-electrode 910 and a P-electrode 920. The P-type GaP window layer 700, facing the active layer 500, includes a stepped region 703 exposing the surface of the P-type GaP window layer 700. The P-electrode 920 is located in the stepped region 703 and on the side of the P-type GaP window layer 700 facing the active layer 500. The N-electrode 910 is located on the side of the N-type confinement layer 400 away from the active layer 500. Alternatively, the LED includes an N-electrode 910 and a P-electrode 920. The P-type confinement layer 600, facing the active layer 500, includes a stepped region 703 exposing the surface of the P-type confinement layer 600. The P-electrode 920 is located in the stepped region 703 and on the side of the P-type confinement layer 600 facing the active layer 500. The N-electrode 910 is located on the side of the N-type confinement layer 400 away from the active layer 500.
[0068] As can be seen from the above, the lattice constant of the AlGaP improvement layer 710 provided in this application embodiment is closer to the lattice constant of the other stacked layers in the light-emitting diode chip, so that the AlGaP improvement layer 710 can serve as an effective buffer structure. Therefore, by inserting at least one AlGaP improvement layer 710 into the P-type GaP window layer 700 for optimization, the stress caused by lattice mismatch in the P-type GaP window layer 700 can be reduced, the dislocation density in the P-type GaP window layer 700 can be reduced, the crystal quality of the P-type GaP window layer 700 can be improved, and the performance of the light-emitting diode chip can be improved.
[0069] In particular, the light-emitting diode chip provided in this application embodiment can be a red AlGaInP-based light-emitting diode chip. As the latest generation technology, red AlGaInP-based Micro LED technology is currently in the early stages of development and application, and further development and maturity are needed for technology development, product yield, and market application. For the epitaxial structure of red Micro LED, AlGaInP quaternary material is usually deposited on a GaAs substrate 100, and the outermost window layer is a P-type GaP window layer 700. In the manufacturing process of the light-emitting diode chip (such as a red Micro LED chip), the P-type GaP window layer 700 is combined with the P electrode 920 of the chip, forming current extension in the P-type GaP window layer 700. However, since the lattice constant of GaP material differs significantly from that of GaAs and AlGaInP materials, there is a certain lattice mismatch problem. Therefore, at least one AlGaP improvement layer 710 is inserted into the P-type GaP window layer 700 for optimization. The lattice constant of the AlGaP improvement layer 710 is closer to that of GaAs and AlGaInP materials, which makes the AlGaP improvement layer 710 an effective buffer structure. This reduces the stress caused by lattice mismatch in the P-type GaP window layer 700 and also reduces the dislocation density in the P-type GaP window layer 700, effectively improving the performance of the light-emitting diode chip.
[0070] In some embodiments, the Al composition of the at least two AlGaP improvement layers 710 provided in this application is different. That is, in a light-emitting diode chip including at least two AlGaP improvement layers 710, all materials are Al... x Ga 1-x In the P-type GaP improvement layer, different improvement layers have different X values, thereby controlling the current expansion direction in the P-type GaP window layer 700 to adapt to different current operating scenarios of LED chips of the same size.
[0071] In one aspect, in the at least two AlGaP improvement layers 710 provided in the embodiments of this application, and in the direction from the N-type confinement layer 400 to the P-type confinement layer 600, the Al composition of the AlGaP improvement layer 710 shows an increasing trend. Specifically... Figure 6Taking the example of a P-type GaP window layer 700 with three AlGaP improvement layers 710 inserted therein, in the direction from the N-type confinement layer 400 to the P-type confinement layer 600, the three AlGaP improvement layers 710 are defined as the first AlGaP improvement layer 711, the second AlGaP improvement layer 712, and the third AlGaP improvement layer 713, respectively. The Al composition of the first AlGaP improvement layer 711 is X1, the Al composition of the second AlGaP improvement layer 712 is X2, and the Al composition of the third AlGaP improvement layer 713 is X3. The relationship between X1, X2, and X3 is that X1 is less than X2, and X2 is less than X3. Inserting an AlGaP improvement layer 710 into the P-type GaP window layer 700 is equivalent to adding an Al component to the corresponding region of the P-type GaP window layer 700. Since the etching concentration ratio required for different Al components in the P-type GaP window layer 700 varies, by adjusting the solution ratio and etching method, a corresponding structure can be achieved where the Al component of the first AlGaP improvement layer 711, the second AlGaP improvement layer 712, and the third AlGaP improvement layer 713 shows an increasing trend. After adding an Al component to the P-type GaP window layer 700, the material potential energy decreases, making it easier for electrons to pass through. This allows the current below the non-electrode to enter below the P-electrode 920 in a laterally extended manner, resulting in light emission. Therefore, in the LED chip where the Al component of the AlGaP improvement layer 710 shows an increasing trend in the direction from the N-type confinement layer 400 to the P-type confinement layer 600, this chip structure has a larger saturation current, requiring high scalability for high-current operation scenarios. Alternatively, in the at least two AlGaP improvement layers 710, and in the direction from the N-type confinement layer 400 to the P-type confinement layer 600, the Al composition of the AlGaP improvement layer 710 tends to decrease. Similarly... Figure 6Taking the example of a P-type GaP window layer 700 with three AlGaP improvement layers 710 inserted, in the direction from the N-type confinement layer 400 to the P-type confinement layer 600, the three AlGaP improvement layers 710 are defined as a first AlGaP improvement layer 711, a second AlGaP improvement layer 712, and a third AlGaP improvement layer 713, respectively. The Al composition of the first AlGaP improvement layer 711 is X1, the Al composition of the second AlGaP improvement layer 712 is X2, and the Al composition of the third AlGaP improvement layer 713 is X3. The relationship between X1, X2, and X3 is that X1 is greater than X2, and X2 is greater than X3. This structure is not conducive to the current spread below the non-electrode; only the current below the P-electrode 920 can spread vertically through the AlGaP improvement layer 710 to enter the P-electrode 920 and emit light. As can be seen, in the direction from the N-type confinement layer 400 to the P-type confinement layer 600, the Al composition of the AlGaP improvement layer 710 shows a decreasing trend. In the corresponding light-emitting diode chip, the saturation current of this chip structure is relatively small. Corresponding to the low-current operation scenario of the light-emitting diode chip, the current needs to be more concentrated to enter the P electrode 920 to emit light.
[0072] refer to Figure 9 The diagram shows a schematic of another light-emitting diode chip provided in this application embodiment. The P-type GaP window layer 700 provided in this application embodiment includes a first surface 701 facing away from the N electrode 910 and a second surface 702 facing the N electrode 910. In at least one AlGaP improvement layer 710, the first distance d1 between the AlGaP improvement layer 710 and the first surface is less than the second distance d2 between the same AlGaP improvement layer 710 and the second surface. This allows the AlGaP improvement layer 710 to be fabricated in the region of the P-type GaP window layer 700 away from the substrate 100, making the AlGaP improvement layer 710 closer to the P electrode 920 and enabling more timely current guidance.
[0073] Based on the aforementioned LED chip, embodiments of this application can further optimize the stacked layers of the LED chip to improve its performance. Specifically, as follows... Figure 10The diagram shown illustrates the structure of another light-emitting diode (LED) chip provided in this embodiment. Taking the N-electrode 910 and P-electrode 920 of the LED as examples where they are located on opposite sides of the chip, i.e., the N-electrode 910 is located on the side of the N-type confinement layer 400 away from the active layer 500, and the P-electrode 920 is located on the side of the P-type GaP window layer 700 away from the active layer 500. The LED chip provided in this embodiment further includes an N-type current spreading layer 300 located on the side of the N-type confinement layer 400 away from the active layer 500. When other structural layers are present between the N-type confinement layer 400 and the N-electrode 910, the N-type current spreading layer 300 is preferably adjacent to and in contact with the N-type confinement layer 400. An N-type ohmic contact layer 820 is located on the side of the N-type confinement layer 400 facing away from the active layer 500. When other structural layers are included between the N-type confinement layer 400 and the N-electrode 910, the N-type ohmic contact layer 820 is preferably in adjacent contact with the N-electrode 910. This achieves a lower resistance and more stable current injection channel to the N-type confinement layer 400, improving the performance of the light-emitting epitaxial structure. An N-type waveguide layer 830 is located between the N-type confinement layer 400 and the active layer 500, constraining and guiding the light generated by the active layer 500 to propagate in a direction perpendicular to the junction, increasing the probability of photons escaping from the edge or surface, and improving light extraction efficiency. Similarly, a P-type waveguide layer 840 is located between the active layer 500 and the P-type confinement layer 600, constraining and guiding the light generated by the active layer 500 to propagate in a direction perpendicular to the junction, increasing the probability of photons escaping from the edge or surface, and further improving light extraction efficiency.
[0074] It should be noted that the optimized stacked layers of the light-emitting diode (LED) chip provided in this application are not limited to the aforementioned N-type ohmic contact layer 820, N-type current spreading layer 300, N-type waveguide layer 830, and P-type waveguide layer 840. In some other embodiments, the optimized stacked layers may also be other functional layers, and this application does not impose specific limitations on this. Furthermore, the LED chip provided in this application may include only one of the N-type ohmic contact layer 820, N-type current spreading layer 300, N-type waveguide layer 830, and P-type waveguide layer 840. Alternatively, the LED chip provided in this application may include a combination of at least two of the N-type ohmic contact layer 820, N-type current spreading layer 300, N-type waveguide layer 830, and P-type waveguide layer 840. In other words, the light-emitting diode chip provided in this application embodiment further includes: an N-type current spreading layer 300 located on the side of the N-type confinement layer 400 away from the active layer 500; and / or an N-type ohmic contact layer 820 located on the side of the N-type confinement layer 400 away from the active layer 500; and / or an N-type waveguide layer 830 located between the N-type confinement layer 400 and the active layer 500; and / or a P-type waveguide layer 840 located between the active layer 500 and the P-type confinement layer 600. Optionally, the N-type ohmic contact layer 820 provided in this application embodiment can be an N-type GaAs ohmic contact layer; the N-type current spreading layer 300 can be an N-type AlGaInP current spreading layer; the N-type confinement layer 400 can be an N-type AlInP confinement layer; the N-type waveguide layer 830 can be an N-type AlGaInP waveguide layer; the active layer 500 can be an MQW active layer; the P-type waveguide layer 840 can be a P-type AlGaInP waveguide layer; and the P-type confinement layer 600 can be a P-type AlInP confinement layer. This application does not impose specific limitations on these aspects.
[0075] Based on the same inventive concept, this application also provides a display device, which includes the light-emitting diode chip provided in any of the above embodiments.
[0076] In summary, embodiments of this application provide a light-emitting epitaxial structure, a light-emitting diode chip, and a display device. The light-emitting epitaxial structure includes: a substrate, an N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer stacked sequentially; an AlGaP improvement layer is inserted into the P-type GaP window layer; or, at least two AlGaP improvement layers are inserted into the P-type GaP window layer, and the at least two AlGaP improvement layers are spaced apart in the direction from the substrate to the P-type GaP window layer. As can be seen from the above, the technical solution provided in this application provides that the lattice constant of the AlGaP improvement layer is closer to that of the other stacked layers in the light-emitting epitaxial structure, making the AlGaP improvement layer an effective buffer structure. Therefore, by inserting at least one AlGaP improvement layer into the P-type GaP window layer for optimization, the stress caused by lattice mismatch in the P-type GaP window layer can be reduced, while the dislocation density in the P-type GaP window layer can be reduced, thereby improving the crystal quality of the P-type GaP window layer, improving the growth quality of the light-emitting epitaxial structure, making the light-emitting epitaxial structure more stable, and improving the performance of the light-emitting diode chip.
[0077] In the description of the embodiments of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and other terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.
[0078] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of embodiments of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0079] In the embodiments of this application, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0080] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0081] In the embodiments of this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0082] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.
Claims
1. A light-emitting epitaxial structure, characterized in that, include: A substrate, an N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer are stacked sequentially. A layer of AlGaP improvement is inserted into the P-type GaP window layer; or, at least two layers of AlGaP improvement are inserted into the P-type GaP window layer, and the at least two layers of AlGaP improvement are spaced apart in the direction from the substrate to the P-type GaP window layer.
2. The light-emitting epitaxial structure according to claim 1, characterized in that, In the at least two AlGaP improvement layers, the Al composition of each AlGaP improvement layer is different.
3. The light-emitting epitaxial structure according to claim 2, characterized in that, In the at least two AlGaP improvement layers, and in the direction from the substrate to the P-type GaP window layer, the Al composition of the AlGaP improvement layer tends to increase. Alternatively, in the at least two AlGaP improvement layers, and in the direction from the substrate to the P-type GaP window layer, the Al composition of the AlGaP improvement layer tends to decrease.
4. The light-emitting epitaxial structure according to claim 1, characterized in that, The P-type GaP window layer includes a first surface facing away from the substrate and a second surface facing the substrate. In at least one AlGaP improvement layer, the first distance between the AlGaP improvement layer and the first surface is less than the second distance between the same AlGaP improvement layer and the second surface.
5. The light-emitting epitaxial structure according to claim 1, characterized in that, The light-emitting epitaxial structure further includes: A corrosion stop layer located between the substrate and the N-type confinement layer; And / or, an N-type current spreading layer located between the substrate and the N-type confinement layer; And / or, a buffer layer located between the substrate and the N-type confinement layer; And / or, an N-type ohmic contact layer located between the substrate and the N-type confinement layer; And / or, an N-type waveguide layer located between the N-type confinement layer and the active layer; And / or, a P-type waveguide layer located between the active layer and the P-type confinement layer.
6. A light-emitting diode chip, characterized in that, include: An N-type confinement layer, an active layer, a P-type confinement layer, and a P-type GaP window layer are sequentially superimposed. A layer of AlGaP improvement is inserted into the P-type GaP window layer; or, at least two layers of AlGaP improvement are inserted into the P-type GaP window layer, and the at least two layers of AlGaP improvement are spaced apart in the direction from the N-type confinement layer to the P-type confinement layer.
7. The light-emitting diode chip according to claim 6, characterized in that, The light-emitting diode includes an N-electrode and a P-electrode. The N-electrode is located on the side of the N-type confinement layer opposite to the active layer, and the P-electrode is located on the side of the P-type GaP window layer opposite to the active layer.
8. The light-emitting diode chip according to claim 6, characterized in that, In the at least two AlGaP improvement layers, the Al composition of each AlGaP improvement layer is different.
9. The light-emitting diode chip according to claim 8, characterized in that, In the at least two AlGaP improvement layers, and in the direction from the N-type confinement layer to the P-type confinement layer, the Al composition of the AlGaP improvement layer tends to increase. Alternatively, in the at least two AlGaP improvement layers, and in the direction from the N-type confinement layer to the P-type confinement layer, the Al composition of the AlGaP improvement layer tends to decrease.
10. The light-emitting diode chip according to claim 6, characterized in that, The P-type GaP window layer includes a first surface facing away from the N-type confinement layer and a second surface facing the N-type confinement layer. In at least one AlGaP improvement layer, the first distance between the AlGaP improvement layer and the first surface is less than the second distance between the same AlGaP improvement layer and the second surface.
11. The light-emitting diode chip according to claim 6, characterized in that, The light-emitting diode chip also includes: An N-type current spread layer located on the side of the N-type confinement layer opposite to the active layer; And / or, an N-type ohmic contact layer located on the side of the N-type confinement layer opposite to the active layer; And / or, an N-type waveguide layer located between the N-type confinement layer and the active layer; And / or, a P-type waveguide layer located between the active layer and the P-type confinement layer.
12. A display device, characterized in that, The display device includes a light-emitting diode chip as described in any one of claims 6-11.