Resonant cavity light emitting diode, manufacturing method thereof and light emitting array structure
By using patterned mask layer and epitaxial growth technology in the resonant cavity light emitting diode, the dislocation density is reduced and the resonant cavity is formed, which solves the problem of low device reliability and improves crystal quality and spectral purity.
Patent Information
- Application Number
- CN202311068399.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-23
- Publication Date
- 2025-02-28
AI Technical Summary
In the prior art, the device reliability of the resonant cavity light emitting diode is low, mainly due to the complex process and poor stability of the oxide layer, which causes stress to occur at the openings of the oxide layer, reducing device reliability.
A patterned mask layer is used to form a window on the growth substrate, and a first type semiconductor layer is formed epitaxially inside and outside the window, and then an active layer, a second type semiconductor layer and a first reflective layer are formed thereon, and an inverted surface is placed on the carrier substrate, the growth substrate and the mask layer are removed, an oblique wall is formed, and a second reflective layer is formed thereon to form a resonant cavity.
By reducing the dislocation density of the first type of semiconductor layer, the crystal quality is improved, the device reliability is improved, and the light resonance effect is improved through the design of the resonant cavity, the spectral purity and directionality and collimation of light exit are improved.
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Figure CN119546021A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a resonant cavity light emitting diode and a manufacturing method thereof, and a light emitting array structure. Background Art
[0002] With the development of big data and the fifth generation of mobile communication technology, optical network information processing is increasing and high-density broadband communication is improving. As laser light sources, resonant cavity light emitting diodes (RCLED) and vertical cavity surface emitting lasers (VCSEL) are attracting more and more attention.
[0003] An oxide layer with openings is often used in laser light sources to perform lateral control of electrons and photons. However, due to the high complexity and poor stability of the oxidation process, it is difficult to accurately control the oxidation depth. In addition, there is a difference in the thermal expansion coefficients of oxides and semiconductors, which causes stress at the openings in the oxide layer, reducing device reliability. Summary of the invention
[0004] In view of this, the embodiments of the present application provide a resonant cavity light emitting diode and a manufacturing method thereof, and a light emitting array structure to solve the technical problem of low device reliability in the prior art.
[0005] According to one aspect of the present application, a method for manufacturing a resonant cavity light-emitting diode is provided, comprising: forming a patterned mask layer on a growth substrate, the patterned mask layer having a window exposing the growth substrate, and the cross-sectional area of the window gradually increasing along the arrangement direction of the growth substrate and the patterned mask layer; epitaxially manufacturing a first type semiconductor layer in the window; epitaxially manufacturing an active layer, a second type semiconductor layer and a first reflective layer on the first type semiconductor layer; inverting the first type semiconductor layer on a carrier substrate; removing the growth substrate and the patterned mask layer, and the cross-sectional area of the first type semiconductor layer gradually decreasing along the arrangement direction of the carrier substrate and the first type semiconductor layer; the first type semiconductor layer comprises an inclined wall and an upper surface away from the carrier substrate, the inclined wall matches the shape of the window, a second reflective layer is manufactured on the inclined wall, and the upper surface is a light outlet.
[0006] According to another aspect of the present application, a resonant cavity light emitting diode manufactured by the above-mentioned manufacturing method is provided, comprising: a first reflective layer, a second type semiconductor layer, an active layer and a first type semiconductor layer stacked in sequence on a carrier substrate; the first type semiconductor layer comprises an inclined wall and an upper surface away from the side of the carrier substrate, and the cross-sectional area of the first type semiconductor layer gradually decreases along the arrangement direction of the carrier substrate and the first type semiconductor layer; the second reflective layer at least covers the inclined wall, and the upper surface is a light outlet.
[0007] According to another aspect of the present application, a light-emitting array structure is provided, comprising: a first light-emitting area and a second light-emitting area adjacent to each other, wherein the first light-emitting area comprises the above-mentioned resonant cavity light-emitting diode; and the pixel structure of the second light-emitting area comprises any one of LED pixels, OLED pixels and LCD pixels.
[0008] One of the above technical solutions has the following beneficial effects:
[0009] The present application provides a method for manufacturing a resonant cavity light emitting diode, wherein the cross-sectional area of a window of a patterned mask layer gradually increases, a first type semiconductor layer is firstly epitaxially manufactured from a growth substrate of a smaller area, and then the window is laterally epitaxially filled, thereby reducing the dislocation density of the first type semiconductor layer, improving the crystal quality, and improving the reliability of the device; and there is no need to adopt a process of etching the entire first type semiconductor layer to form a patterned unit, thereby avoiding an etching process for the first type semiconductor layer, thereby ensuring that the crystal quality of the first type semiconductor layer is not reduced; then an active layer, a second type semiconductor layer, and a first reflective layer are sequentially epitaxially manufactured, and are inverted on a carrier substrate, and the area of the first type semiconductor layer gradually decreases in a direction away from the carrier substrate, and a second reflective layer is manufactured on an inclined wall of the first type semiconductor layer, and the first reflective layer and the second reflective layer constitute a resonant cavity, and light is reflected multiple times in the resonant cavity, thereby improving the light resonance effect, so that the light has a narrower wavelength peak, and the spectral purity is improved; the upper surface of the first type semiconductor layer away from the carrier substrate is a light outlet, and the light outlet area is the smallest, which can improve the directionality and collimation of light emission. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Figure 1 A schematic flow chart of a method for manufacturing a resonant cavity light emitting diode provided in one embodiment of the present application;
[0011] Figures 2 to 8 A schematic diagram of the structure of a resonant cavity light emitting diode provided for manufacturing an embodiment of the present application;
[0012] Fig. 9 A schematic diagram of an intermediate structure of a resonant cavity light emitting diode provided in one embodiment of the present application;
[0013] Fig.10 A schematic diagram of an intermediate structure of a resonant cavity light emitting diode provided in one embodiment of the present application;
[0014] Fig.11 A schematic diagram of the structure of a resonant cavity light emitting diode provided in one embodiment of the present application;
[0015] Fig.12 A schematic diagram of the structure of another resonant cavity light emitting diode provided in one embodiment of the present application;
[0016] Fig.13 A schematic diagram of the structure of another resonant cavity light emitting diode provided in one embodiment of the present application;
[0017] Fig.14 A schematic diagram of the structure of another resonant cavity light emitting diode provided in one embodiment of the present application;
[0018] Fig.15 A schematic diagram of the structure of another resonant cavity light emitting diode provided in one embodiment of the present application;
[0019] Fig.16 A schematic diagram of the structure of another resonant cavity light emitting diode provided in one embodiment of the present application;
[0020] Fig.17 A schematic diagram of the structure of another resonant cavity light emitting diode provided in one embodiment of the present application;
[0021] Fig.18 A schematic diagram of a three-dimensional structure of a resonant cavity light emitting diode provided in one embodiment of the present application;
[0022] Fig.19 A schematic diagram of the structure of another resonant cavity light emitting diode provided in one embodiment of the present application;
[0023] Fig. 20 for Fig.12 A top view of a resonant cavity light emitting diode is provided;
[0024] Fig.21 A schematic diagram of the structure of another resonant cavity light emitting diode provided in one embodiment of the present application;
[0025] Fig. 22 A resonant cavity light emitting diode arrangement diagram provided in one embodiment of the present application;
[0026] Fig.23 Another resonant cavity light emitting diode arrangement diagram provided in one embodiment of the present application;
[0027] Fig.24 Another resonant cavity light emitting diode arrangement diagram provided in one embodiment of the present application;
[0028] Fig.25 A schematic diagram of a light emitting array structure provided in one embodiment of the present application;
[0029] Fig.26 A schematic diagram of another light emitting array structure provided in one embodiment of the present application;
[0030] Fig. 27 A schematic diagram of the structure of another light-emitting array structure provided in one embodiment of the present application. DETAILED DESCRIPTION
[0031] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0032] To improve light extraction efficiency, Figure 1 A schematic diagram of a process for manufacturing a resonant cavity light emitting diode provided in one embodiment of the present application. Figures 2 to 8 A schematic diagram of the structure of a resonant cavity light emitting diode provided in one embodiment of the present application is shown in FIG. Figure 1 As shown, the present application provides a method for manufacturing a resonant cavity light emitting diode, comprising:
[0033] Step S1, such as Figure 2 As shown, a patterned mask layer 12 is formed on a growth substrate 11 , and the patterned mask layer 12 has a window 121 exposing the growth substrate 11 . Along the arrangement direction of the growth substrate 11 and the patterned mask layer 12 , the cross-sectional area of the window 121 gradually increases.
[0034] Specifically, the patterned mask layer 12 is SiO 2 or SiN, and a patterned structure is formed by photolithography of SiO 2 or SiN, and the cross-sectional area of the window 121 left in the photolithography region is gradually increased in parallel to the plane where the growth substrate 11 is located.
[0035] Alternatively, if Figure 2 As shown, the sidewall shape of the window 121 is a curve convex away from the growth substrate 11; alternatively, the sidewall shape of the window 121 is a curve or a straight line concave toward the growth substrate.
[0036] Optionally, the growth substrate 11 includes any one of sapphire, silicon, silicon carbide, silicon germanium, GaN or GaAs.
[0037] It should be noted that Figure 2Only three windows 121 are illustrated to manufacture three resonant cavity light emitting diodes; optionally, the embodiment of the present application does not limit the number of resonant cavity light emitting diodes.
[0038] Step S2, such as Figure 3 As shown, the first type semiconductor layer 21 is epitaxially produced in the window 121. It should be noted that the cross-sectional area of the first type semiconductor layer 21 gradually increases in the direction away from the growth substrate 11, that is, the first type semiconductor layer 21 is first epitaxially grown on the growth substrate 11 with a smaller area, and the window 121 is laterally epitaxially filled. Taking the material of the first type semiconductor layer 21 as GaN as an example, the dislocation of GaN is mainly a linear dislocation in the
[0001] crystal direction, that is, a linear dislocation extending along the thickness direction of the growth substrate 11. At this time, the smaller the epitaxial growth area of the first type semiconductor layer 21, the lower the dislocation density of GaN, thereby improving the crystal quality of the first type semiconductor layer 21. In addition, by patterning the mask layer 12 by photolithography, the specific shape of the first type semiconductor layer 21 can be controlled to obtain a resonant cavity diode of a specific shape, and the process is relatively simple.
[0039] Optionally, before forming the first type semiconductor layer 21 , a nucleation layer and a buffer layer are first formed by epitaxial growth at the bottom of the window 121 ; when the first type semiconductor layer 21 is a GaN-based material, the material of the nucleation layer is AlN, and the material of the buffer layer is GaN.
[0040] Step S3, such as Figure 4 As shown, an active layer 22 , a second type semiconductor layer 23 and a first reflective layer 31 are epitaxially produced on the first type semiconductor layer 21 .
[0041] Optionally, when the first type semiconductor layer 21 is a GaN-based material, the material of the active layer 22 includes a combination of any two of GaN, InGaN, AlGaN and AlInGaN, and the second type semiconductor layer 23 is a GaN-based material with a conductivity type opposite to that of the first type semiconductor layer 21 .
[0042] Optionally, when the first type semiconductor layer 21 and the second type semiconductor layer 23 are GaAs-based materials, the active layer 22 includes a combination of any two of GaAs, InGaAs, AlGaAs and AlInGaAs.
[0043] Optionally, when the first type semiconductor layer 21 and the second type semiconductor layer 23 are GaP-based materials, the active layer 22 includes a combination of any two of GaP, InGaP, AlGaP and AlInGaP.
[0044] Optionally, the material of the first reflective layer 21 is a metal or metal alloy with high reflectivity. Optionally, the material of the first reflective layer 21 is a distributed Bragg reflector composed of oxide material pairs such as TiO2 / SiO2, Ti3O5 / SiO2, Ta2O5 / SiO2, Ti3O5 / Al2O3, ZrO2 / SiO2 or TiO2 / Al2O3.
[0045] Step S4, such as Figure 5 As shown, it is placed upside down on the supporting substrate 13.
[0046] Optionally, the carrier substrate 13 is a driving circuit board, including a driving circuit for providing a driving signal for the resonant cavity light emitting diode finally manufactured. Optionally, before step S4, a second electrode electrically connected to the second type semiconductor layer 23 is manufactured; in step S5, the second electrode is electrically connected to the driving circuit board (carrier substrate 13).
[0047] Step S5, such as Figure 6 As shown, the growth substrate 11 and the patterned mask layer 12 are removed, and the cross-sectional area of the first type semiconductor layer 21 gradually decreases along the arrangement direction of the carrier substrate 13 and the first type semiconductor layer 21 .
[0048] It should be noted that the shape of the first type semiconductor layer 21 formed in the window 121 is consistent with the shape of the window 121 , and therefore, the cross-sectional area of the first type semiconductor layer 21 gradually decreases in a direction away from the carrier substrate 13 .
[0049] Optionally, the growth substrate 11 is removed by laser lift-off. Optionally, the patterned mask layer 12 is removed by etching.
[0050] In one embodiment, Figure 7 As shown, after removing the growth substrate 11 and the patterned mask layer 12, the method further includes: forming a passivation layer 41 on the sidewalls of the first type semiconductor layer 21, the active layer 22 and the second type semiconductor layer 23. Optionally, the passivation layer 41 is an insulating material, such as SiO2, Al2O3, SiN, polyimide, photoresist or other photo-patternable polymers.
[0051] Optionally, the passivation layer 41 covers the upper surface of the first type semiconductor layer 21 away from the carrier substrate 13. Optionally, the passivation layer 41 covers the side surface of the first reflective layer 31.
[0052] Step S6, as Figure 8 As shown, the first type semiconductor layer 21 includes an inclined wall A1 and an upper surface A2 away from the supporting substrate 13. The inclined wall A1 matches the shape of the window 121. The second reflective layer 32 is made on the inclined wall A1, and the upper surface A2 is a light outlet.
[0053] It can be understood that the first type semiconductor layer 21 is epitaxially produced from a growth substrate with a smaller area, which improves the crystal quality of the first type semiconductor layer and improves the reliability of the device; and the first type semiconductor layer 21 replicates the shape of the window 121 of the patterned mask layer 12, and forms a resonant cavity light emitting diode at one time, without the need to use a process of etching the entire layer to form a patterned unit of the first type semiconductor layer, avoiding the etching process for the first type semiconductor layer, thereby ensuring that the crystal quality of the first type semiconductor layer is not reduced. Secondly, the first reflective layer 31 and the second reflective layer 32 constitute the resonant cavity of the resonant cavity light emitting diode, and the light is reflected multiple times in the resonant cavity, which improves the light resonance effect, makes the light have a narrower wavelength peak, and improves the spectral purity; the second reflective layer 32 replicates the shape of the window 121 of the patterned mask layer 12, so that the upper surface A2 is the position with the smallest cross-sectional area of the first type semiconductor layer, that is, the light outlet area is the smallest, which can improve the directionality and collimation of the light emission.
[0054] Optionally, the reflectivity of the second reflective layer 32 is lower than that of the first reflective layer 31 , so that the upper surface A2 serves as a light outlet.
[0055] In one embodiment, the first type semiconductor layer 21 is N-type doped, and the second type semiconductor layer 23 is P-type doped.
[0056] In one embodiment, Fig. 9 A schematic diagram of an intermediate structure of a resonant cavity light emitting diode provided in one embodiment of the present application is shown in FIG. Fig. 9 As shown, before being inverted on the carrier substrate, it also includes: etching the first reflective layer 31 and a portion of the second type semiconductor layer 23 to form a second via hole, depositing an insulating layer 51 on the inner wall of the second via hole, and making a second electrode 62 electrically connected to the second type semiconductor layer in the second via hole, the second electrode 62 is electrically connected to the driving circuit on the carrier substrate 13, and provides a driving signal for the second type semiconductor layer 23.
[0057] In one embodiment, Fig.10 This is a schematic diagram of an intermediate structure of a resonant cavity light emitting diode provided in one embodiment of the present application. Fig.11 A schematic diagram of the structure of a resonant cavity light emitting diode provided in one embodiment of the present application is shown in FIG. Fig.10 As shown, while etching the second via hole, the first reflective layer 31, the second type semiconductor layer 23, the active layer 22 and part of the first type semiconductor layer 21 are etched to form the first via hole, and the insulating layer 51 is deposited on the inner wall of the first via hole and the inner wall of the second via hole; a first electrode 61 electrically connected to the first type semiconductor layer 21 is made in the first via hole, and a second electrode 62 electrically connected to the second type semiconductor layer 23 is made in the second via hole. After being inverted onto the carrier substrate 13, the following is obtained. Fig.11In the resonant cavity light emitting diode shown, the first electrode 61 and the second electrode 62 provide driving signals to the first type semiconductor layer 21 and the second type semiconductor layer 23 respectively.
[0058] In one embodiment, Fig.12 A schematic diagram of the structure of another resonant cavity light emitting diode provided in an embodiment of the present application is shown in FIG. Fig.12 As shown, after the second electrode 62 is manufactured and inverted onto the carrier substrate 13, the manufacturing method of the resonant cavity light emitting diode further includes: etching the first type semiconductor layer 21 from the inclined wall A1 to form a first via hole, and manufacturing a first electrode 61 in the first via hole that is electrically connected to the first type semiconductor layer 21. Optionally, it also includes an electrode connection line 63 located on the side wall of each resonant cavity light emitting diode, and the first type semiconductor layer 21 is electrically connected to the driving circuit on the carrier substrate 13 through the first electrode 61 and the electrode connection line 63.
[0059] Optionally, the second electrode 62 is an interconnected common electrode, and the first electrode 61 is an independent electrode that provides an electrical signal to each resonant cavity light emitting diode; or, the first electrode 61 is an interconnected common electrode, and the second electrode 62 is an independent electrode.
[0060] In one embodiment, Fig.13 A schematic diagram of the structure of another resonant cavity light emitting diode provided in an embodiment of the present application is shown in FIG. Fig.13 As shown, in the resonant cavity light emitting diode, the second electrode 62 is located on the terrace of the second type semiconductor layer 23 , and the first electrode 61 is located on the inclined wall A1 of the first type semiconductor layer 21 .
[0061] Based on the same inventive concept, the embodiment of the present application also provides a resonant cavity light emitting diode manufactured by any of the above manufacturing methods, such as Figure 8 As shown, the resonant cavity light emitting diode includes: a first reflective layer 31, a second type semiconductor layer 23, an active layer 22 and a first type semiconductor layer 21 stacked in sequence on a carrier substrate 13; the first type semiconductor layer 21 includes an inclined wall A1 and an upper surface A2 on a side away from the carrier substrate 13, and the cross-sectional area of the first type semiconductor layer 21 gradually decreases along the arrangement direction of the carrier substrate 13 and the first type semiconductor layer 21; the second reflective layer 32 at least covers the inclined wall A1, and the upper surface A2 is a light outlet.
[0062] It should be noted that, in the manufacture method provided in the embodiment of the present application, a resonant cavity light-emitting diode is manufactured. First, the first type semiconductor layer is first epitaxially grown on a growth substrate with a smaller area, and the window is laterally epitaxially filled to reduce the dislocation density and improve the crystal quality of the first type semiconductor layer. Secondly, to form a resonant cavity light-emitting diode, there is no need to use a process of etching the entire layer of the first type semiconductor layer to form a patterned unit, thereby avoiding the etching process for the first type semiconductor layer, thereby ensuring that the crystal quality of the first type semiconductor layer is not reduced. Furthermore, the first reflective layer and the second reflective layer constitute the resonant cavity of the resonant cavity light-emitting diode, and the light is reflected multiple times in the resonant cavity, thereby improving the light resonance effect, making the light have a narrower wavelength peak, and improving the spectral purity. Finally, the second reflective layer replicates the shape of the window of the patterned mask layer, so that the upper surface is the position with the smallest cross-sectional area of the first type semiconductor layer, that is, the light outlet area is the smallest, thereby improving the directionality and collimation of the light emission.
[0063] In one embodiment, in a direction perpendicular to the carrier substrate 13, the cross-sectional shape of the inclined wall A1 includes any one or a combination of a curve that is concave toward the carrier substrate 13, a curve that is convex away from the carrier substrate 13, and a straight line. Figure 8 As shown, the cross-sectional shape of the inclined wall A1 is a curve that is concave toward the supporting substrate 13. It can be understood that the closer to the light exit, the greater the tangent slope of the inclined wall A1 is, and the first type semiconductor layer 21 shows a trend of gradually converging. After being reflected by the side wall, the light is more easily directed upward and toward the light exit, which can accelerate the escape of photons from the light exit and improve the light extraction efficiency. Fig.14 A schematic diagram of the structure of another resonant cavity light emitting diode provided in an embodiment of the present application is shown in FIG. Fig.14 As shown, the cross-sectional shape of the inclined wall A1 is a curve convex away from the supporting substrate 13 . Fig.15 A schematic diagram of the structure of another resonant cavity light emitting diode provided in an embodiment of the present application is shown in FIG. Fig.15 As shown, the cross-sectional shape of the inclined wall A1 is a straight line.
[0064] Optionally, Fig.16 A schematic diagram of the structure of another resonant cavity light emitting diode provided in an embodiment of the present application is shown in FIG. Fig.16 As shown, the sidewalls of the first type semiconductor layer 21 include an inclined wall A1 and a vertical sidewall A3. It can be understood that in the manufacturing process, the first type semiconductor layer portion in the window of the patterned mask layer is firstly epitaxially grown, and then the first type semiconductor layer portion including the vertical sidewall A3 is epitaxially grown. At this time, the surface of the second type semiconductor layer away from the growth substrate is relatively flat, and then the film layers of other semiconductor materials, such as the active layer 22 and the second type semiconductor layer 23, are epitaxially grown, which can improve the crystal quality of the film layers of other semiconductor materials, thereby improving the photoelectric characteristics of the resonant cavity light emitting diode.
[0065] In one embodiment, Fig.17 A schematic diagram of the structure of another resonant cavity light emitting diode provided in an embodiment of the present application is shown in FIG. Fig.17 As shown in the figure, along the arrangement direction of the carrier substrate 11 and the first type semiconductor layer 21, the cross-sectional areas of the second type semiconductor layer 23, the active layer 22 and the first type semiconductor layer 21 gradually decrease. Specifically, the closer to the light outlet, the second type semiconductor layer 23, the active layer 22 and the first type semiconductor layer 21 as a whole show a trend of gradually converging, so that the light is more easily directed upward and toward the light outlet after being reflected by the side wall, which can accelerate the escape of photons from the light outlet and improve the light extraction efficiency.
[0066] In one embodiment, Figure 8 As shown, the area of the upper surface A2 of the first type semiconductor layer 21 is 0.05 to 0.5 times the cross-sectional area of the active layer 22. Specifically, the area of the upper surface A2 is the area of the light outlet, and the area of the active layer 22 is close to the projection area of the resonant cavity on the carrier substrate 13. The area of the light outlet is as small as possible to improve the directionality and collimation of the light emission; the area of the active layer 22 is as large as possible to increase the number of photons, improve the internal quantum efficiency, and improve the light extraction efficiency after multiple reflections in the resonant cavity. Optionally, the area of the upper surface A2 is 0.1 times, 0.2 times, 0.3 times or 0.4 times the area of the active layer 22.
[0067] In one embodiment, the shape of the upper surface A2 of the first type semiconductor layer 21 includes any one of a circular shape, an elliptical shape, or a polygonal shape, and the shape of the surface of the second type semiconductor layer 23 close to the carrier substrate 13 is a hexagonal shape. Fig.18 A schematic diagram of a three-dimensional structure of a resonant cavity light emitting diode provided in one embodiment of the present application is shown in FIG. Fig.18 As shown, the shape of the upper surface A2 is circular, and the shape of the surface of the second type semiconductor layer 23 close to the carrier substrate 13 is hexagonal. It can be understood that, taking the epitaxial growth process of GaN as an example, GaN belongs to the hexagonal crystal system, and when there is no window restriction of the patterned mask layer, the shape of GaN will gradually grow into a hexagon. It should be noted that Fig.18 Only the carrier substrate 13 , the first reflective layer 31 , the second type semiconductor layer 23 , the active layer 22 and the first type semiconductor layer 21 are illustrated.
[0068] In one embodiment, Fig.19 A schematic diagram of the structure of another resonant cavity light emitting diode provided in an embodiment of the present application is shown in FIG. Fig.19As shown, the second reflective layer 32 also covers the upper surface A2 of the first type semiconductor layer 21, the sidewalls of the second type semiconductor layer 23, and the sidewalls of the active layer 22. Specifically, the second reflective layer 32 and the first reflective layer 31 form a nearly fully enclosed resonant cavity, which reduces the leakage of light from the sidewalls of the second type semiconductor layer 23 and the active layer 22, increases the number of reflections of light in the resonant cavity, improves the light resonance effect, makes the light have a narrower wavelength peak, and improves the spectral purity.
[0069] In one embodiment, Fig.19 As shown, the reflectivity of the second reflective layer located at the inclined wall A1 is higher than the reflectivity of the second reflective layer located at the upper surface A2. Specifically, the upper surface A2 with lower reflectivity is a light outlet, and the light is reflected multiple times in the resonant cavity formed by the first reflective layer 31 and the second reflective layer 32, and finally emerges from the upper surface A2. Optionally, the second reflective layer 32 is a distributed Bragg reflector composed of oxide material pairs, and the number of periods of material pairs of the second reflective layer located at the inclined wall A1 is greater than the number of periods of material pairs of the second reflective layer located at the upper surface A2. Optionally, the material of the second reflective layer located at the inclined wall A1 is different from the material of the second reflective layer located at the upper surface A2, wherein the reflectivity of the second reflective layer located at the inclined wall A1 is higher.
[0070] In one embodiment, Fig.11 As shown, the resonant cavity light emitting diode also includes a driving circuit (not shown) located on the supporting substrate 13; the second electrode 62 is located in a second via hole that penetrates part of the second type semiconductor layer 23 and the first reflective layer 31, and the second electrode 62 is used to electrically connect the second type semiconductor layer 23 and the driving circuit.
[0071] Alternatively, if Fig.11 As shown, the resonant cavity light emitting diode also includes a first electrode 61, which is located in a first via hole that penetrates the first reflective layer 31, the second type semiconductor layer 23, the active layer 22 and a portion of the first type semiconductor layer 21, and the first electrode 61 is used to electrically connect the first type semiconductor layer 21 and the driving circuit. Specifically, the first via hole for setting the first electrode 61 and the second via hole for setting the second electrode 62 can be etched and formed at the same time, the process is simple, and the first electrode 61 and the second electrode 62 do not affect the light outlet, thereby improving the light extraction efficiency. It should be noted that the first via hole and the second via hole are first formed into an insulating layer 51, and then the electrode structure is made.
[0072] In one embodiment, Fig.12As shown, the second electrode of the resonant cavity light emitting diode is located in the second via hole between the second type semiconductor layer 23 and the carrier substrate 13, and further includes: a first electrode 61 located in the first via hole of the oblique wall A1; an electrode connection line 63 located on the oblique wall A1, the side wall of the active layer 22 and the side wall of the second type semiconductor layer 23, and the first type semiconductor layer 21 is electrically connected to the driving circuit through the first electrode 61 and the electrode connection line 63. Specifically, the electrode structure does not penetrate the active layer 22, does not reduce the area of the active layer, fully reserves the space where electrons and holes can be excited, and improves the light extraction efficiency.
[0073] Optionally, Fig. 20 for Fig.12 A top view of a resonant cavity light emitting diode is provided, such as Fig. 20 As shown, in order to reduce the contact resistance between the first electrode 61 and the first type semiconductor layer 21, the first electrode 61 is an arc shape exceeding 180 degrees; the first electrode 61 is then electrically connected to the driving circuit on the carrier substrate 13 through the electrode connection line 63. It should be noted that Fig. 20 The outer contour of the illustrated second reflective layer 32 is a hexagon, that is, the projection shape of the second type semiconductor layer 23 on the carrier substrate 13 is a hexagon; the projection shape of the upper surface A2 of the first type semiconductor layer 21 on the carrier substrate 13 is a circle.
[0074] In one embodiment, Fig.21 A schematic diagram of the structure of another resonant cavity light emitting diode provided in an embodiment of the present application is shown in FIG. Fig.21 As shown, the first type semiconductor layer 21 includes a lower surface A4 close to the active layer 22, and the areas of the lower surfaces A4 of at least two resonant cavity light emitting diodes are different, so that the emission wavelengths of the two resonant cavity light emitting diodes are different. It should be noted that, taking the material of the active layer 22 as InGaN / GaN as an example, the areas of the lower surfaces A4 of the two resonant cavity light emitting diodes are different, and the areas of the subsequent epitaxial active layers 22 are different. Due to the different doping rates of the In component in the active layers of different areas, the emission wavelengths of the two resonant cavity light emitting diodes finally produced are different. Optionally, the larger the area of the lower surface A4, the shorter the emission wavelength of the resonant cavity light emitting diode.
[0075] Optionally, Fig. 22 A resonant cavity light emitting diode arrangement diagram provided in one embodiment of the present application, such as Fig. 22 As shown, the resonant cavity light emitting diodes R100 / G100 / B100 emit red light, green light and blue light respectively, and each pixel unit U1 includes 1 R100, 1 G100 and 1 B100, and form a delta arrangement. Optionally, the resonant cavity light emitting diodes can also form any one of a standard RGB arrangement and a diamond arrangement.
[0076] Optionally, considering that the luminous efficiency of red light is lower than that of green light and blue light, one pixel unit includes a plurality of resonant cavity light emitting diodes emitting red light to balance the proportions of the three colors in one pixel unit. Fig.23 Another resonant cavity light emitting diode arrangement diagram provided in an embodiment of the present application is shown in FIG. Fig.24 Another resonant cavity light emitting diode arrangement diagram provided in an embodiment of the present application is as follows: Fig.23 and Fig.24 As shown, the resonant cavity light emitting diodes R100 / G100 / B100 emit red light, green light and blue light respectively, and each pixel unit U2 includes 2 R100, 1 G100 and 1 B100. Fig.23 As shown, in a pixel unit U2, two R100, one G100 and one B100 are arranged in a staggered manner; Fig.23 As shown, in a pixel unit U2, 2 R100, 1 G100 and 1 B100 are arranged in a standard RGB configuration.
[0077] Based on the same inventive concept, the embodiment of the present application further provides a light emitting array structure, Fig.25 A schematic diagram of a light emitting array structure provided in one embodiment of the present application is shown in FIG. Fig.25 As shown, the light emitting array structure includes: adjacent first light emitting area R1 and second light emitting area R2, the first light emitting area R1 includes the above-mentioned resonant cavity light emitting diode 100, and the pixel structure 200 of the second light emitting area R2 includes any one of LED pixels, OLED pixels and LCD pixels.
[0078] Optionally, the resonant cavity light emitting diode emits visible light, and the pixel structure is used as a display screen. The arrangement of the resonant cavity light emitting diode 100 and the arrangement of the pixel structure 200 include any one of a standard RGB arrangement, a delta arrangement, and a diamond arrangement. Compared with LED pixels, OLED pixels, and LCD pixels, the resonant cavity light emitting diode disclosed in the present application can improve light extraction efficiency, brightness, and color. In a traditional light emitting array structure, there is a problem of low brightness in the border area. The light emitting array structure provided in the present application can set the first light emitting area in the border area and the second light emitting area in the center area to improve the brightness uniformity of the light emitting array structure.
[0079] Optionally, LED (Light-Emitting Diode) pixels include micro-LED pixels, mini-LED pixels or conventional LED pixels, and OLED (Organic Light-Emitting Diode) pixels include PMOLED (Passive-matrix OLED) pixels or AMOLED (Active-matrix OLED) pixels, etc.
[0080] Optionally, Fig.26 A schematic diagram of another light emitting array structure provided in an embodiment of the present application is shown in FIG. Fig.26 As shown, the first light-emitting region R1 includes resonant cavity light-emitting diodes 101 / 102 / 103 that emit blue light, green light, and red light, respectively, and the second light-emitting region R2 includes pixel structures 201 / 202 / 203 that emit blue light, green light, and red light, respectively. The color arrangement of the resonant cavity light-emitting diodes 101 / 102 / 103 is the same as the color arrangement of the pixel structures 201 / 202 / 203 and belongs to the standard RGB arrangement.
[0081] Optionally, Fig. 27 A schematic diagram of another light emitting array structure provided in an embodiment of the present application is shown in FIG. Fig. 27 As shown, the first light emitting region R1 and the second light emitting region R2 are arranged alternately in the row direction, and a resonant cavity light emitting diode 100 is disposed on one side of each pixel structure 200 to improve the problem of low brightness of the pixel structure 200. Fig. 27 As shown, the blue light sub-pixel 104 includes a resonant cavity light emitting diode 100 emitting blue light and a pixel structure 200 emitting blue light, the green light sub-pixel 105 includes a resonant cavity light emitting diode 100 emitting green light and a pixel structure 200 emitting green light, and the red light sub-pixel 106 includes a resonant cavity light emitting diode 100 emitting red light and a pixel structure 200 emitting red light.
[0082] Optionally, the light-emitting array structure is applied to a display device, such as a mobile phone, wherein the resonant cavity light-emitting diode emits infrared light for fingerprint unlocking, and the pixel structure emits visible light for displaying images.
[0083] In the absence of contradiction, those skilled in the art may combine and combine the different embodiments or examples and the features of the different embodiments or examples described in this specification. The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A method for manufacturing a resonant cavity light emitting diode, characterized in that: include: forming a patterned mask layer on a growth substrate, wherein the patterned mask layer has a window exposing the growth substrate, and a cross-sectional area of the window gradually increases along an arrangement direction of the growth substrate and the patterned mask layer; Epitaxially fabricating a first type semiconductor layer in the window; epitaxially fabricating an active layer, a second type semiconductor layer and a first reflective layer on the first type semiconductor layer; Place it upside down on a carrier substrate; The growth substrate and the patterned mask layer are removed, and the cross-sectional area of the first type semiconductor layer gradually decreases along the arrangement direction of the carrier substrate and the first type semiconductor layer; The first type semiconductor layer includes an inclined wall and an upper surface away from the carrier substrate. The inclined wall matches the shape of the window. A second reflective layer is formed on the inclined wall. The upper surface is a light outlet.
2. The method according to claim 1, characterized in that: After removing the growth substrate and the patterned mask layer, the method further includes: A passivation layer is formed on the side walls of the first type semiconductor layer, the active layer and the second type semiconductor layer.
3. The method according to claim 1, characterized in that: Before being inverted on the carrier substrate, the method further comprises: The first reflective layer and a portion of the second type semiconductor layer are etched to form a second via hole, an insulating layer is deposited on an inner wall of the second via hole, and a second electrode electrically connected to the second type semiconductor layer is fabricated in the second via hole.
4. The method according to claim 3, characterized in that: While etching the second via hole, the first reflective layer, the second type semiconductor layer, the active layer and a portion of the first type semiconductor layer are etched to form a first via hole. Depositing an insulating layer on an inner wall of the first via hole and an inner wall of the second via hole; A first electrode electrically connected to the first type semiconductor layer is fabricated in the first via hole, and a second electrode electrically connected to the second type semiconductor layer is fabricated in the second via hole.
5. The manufacturing method according to claim 3, characterized in that: Also includes: The first type semiconductor layer is etched from the oblique wall to form a first via hole, and a first electrode electrically connected to the first type semiconductor layer is fabricated in the first via hole.
6. A resonant cavity light emitting diode manufactured according to the manufacturing method according to any one of claims 1 to 5, characterized in that: include: A first reflective layer, a second type semiconductor layer, an active layer and a first type semiconductor layer are sequentially stacked on a carrier substrate; The first type semiconductor layer comprises an inclined wall and an upper surface away from the carrier substrate, and along the arrangement direction of the carrier substrate and the first type semiconductor layer, the cross-sectional area of the first type semiconductor layer gradually decreases; The second reflective layer at least covers the inclined wall, and the upper surface is a light outlet.
7. The resonant cavity light emitting diode according to claim 6, characterized in that: In a direction perpendicular to the carrier substrate, a cross-sectional shape of the inclined wall includes any one of a curve recessed toward the carrier substrate, a curve protruding away from the carrier substrate, and a straight line, or a combination thereof.
8. The resonant cavity light emitting diode according to claim 6, characterized in that: Along the arrangement direction of the carrier substrate and the first type semiconductor layer, the cross-sectional areas of the second type semiconductor layer, the active layer and the first type semiconductor layer gradually decrease.
9. The resonant cavity light emitting diode according to claim 6, characterized in that: An area of the upper surface of the first-type semiconductor layer is 0.05 to 0.5 times a cross-sectional area of the active layer.
10. The resonant cavity light emitting diode according to claim 6, characterized in that: The shape of the upper surface of the first type semiconductor layer includes any one of a circle, an ellipse or a polygon, and the shape of the surface of the second type semiconductor layer close to the carrier substrate is a hexagon.
11. The resonant cavity light emitting diode according to claim 6, characterized in that: The second reflective layer also covers the upper surface of the first type semiconductor layer, the sidewall of the second type semiconductor layer, and the sidewall of the active layer.
12. The resonant cavity light emitting diode according to claim 11, characterized in that: The reflectivity of the second reflective layer located on the inclined wall is higher than the reflectivity of the second reflective layer located on the upper surface.
13. The resonant cavity light emitting diode according to claim 6, characterized in that: Also includes: a driving circuit located on the carrier substrate; The second electrode is located in a second via hole that penetrates a portion of the second-type semiconductor layer and the first reflective layer, and the second electrode is used to electrically connect the second-type semiconductor layer and the driving circuit.
14. The light emitting diode according to claim 13, characterized in that: Also includes: The first electrode is located in a first via hole that penetrates the first reflective layer, the second type semiconductor layer, the active layer and a portion of the first type semiconductor layer, and is used to electrically connect the first type semiconductor layer and the driving circuit.
15. The resonant cavity light emitting diode according to claim 13, characterized in that: Also includes: A first electrode is located in a first via hole of the inclined wall; The electrode connection line is located on the inclined wall, the side wall of the active layer and the side wall of the second type semiconductor layer. The first type semiconductor layer is electrically connected to the driving circuit through the first electrode and the electrode connection line.
16. The resonant cavity light emitting diode according to claim 6, characterized in that: The first type semiconductor layer includes a lower surface close to the active layer, At least two of the resonant cavity light emitting diodes have different areas of the lower surfaces, so that the light emission wavelengths of the two resonant cavity light emitting diodes are different.
17. A light emitting array structure, characterized in that: include: The adjacent first light emitting area and the second light emitting area, The first light emitting region comprises a resonant cavity light emitting diode as claimed in any one of claims 6 to 16; The pixel structure of the second light emitting area includes any one of LED pixels, OLED pixels and LCD pixels.