Micro LED

Abstract

A micro light emitting diode (LED) with high light extraction efficiency includes a bottom conductive layer, a light emitting layer on the bottom conductive layer, and a top conductive structure on the light emitting layer. The micro LED also includes a conductive side arm electrically connecting the side wall of the light emitting layer to the bottom conductive layer, and a reflective bottom dielectric layer disposed below the light emitting layer and above the bottom conductive layer. In some embodiments, the micro LED also includes a small area and transparent ohmic contact between the top conductive structure and the light emitting layer, thereby increasing the light exit area and improving the light extraction efficiency.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 965,889, filed on January 25, 2020, entitled “MicroLight Emitting Diode With High Light Extraction Efficiency,” which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to display devices, and more particularly, to systems and methods of manufacturing micro light emitting diodes (LEDs) with high light extraction efficiency. Background Art

[0004] Display technology is becoming increasingly popular in today's commercial electronic devices. These display panels are widely used in fixed large screens such as liquid crystal display televisions (LCD TVs) and organic light-emitting diode televisions (OLED TVs) and portable electronic devices such as personal laptops, smart phones, tablets, and wearable electronic devices. With the development of mini-LED and micro-LED technology in recent years, consumer devices and applications such as augmented reality (AR), projection, head-up displays (HUD), mobile device displays, wearable device displays, and in-vehicle displays require LED panels with higher efficiency and resolution. For example, an AR display integrated into goggles and positioned close to the wearer's eyes can have a size as small as a fingernail, while still requiring HD (1280x720 pixels) or higher resolution.

[0005] Light-emitting diode (LED) is a junction-type light-emitting device. The main structure of LED is PN junction. Under forward bias, PN junction emits visible light or infrared light. The luminous efficiency of LED depends on epitaxial material, ohmic contact electrode, chip structure, geometric shape, etc.

[0006] In current LED technology, the formation of P-type LEDs poses great challenges. For example, there are difficulties in doping P-GaN LEDs due to the lack of high work function metals that match P-GaN. In addition, low ohmic contact resistance is required to control annealing temperature, time, and atmosphere. The electrode is required to be transparent to ensure the transmittance of light from the LED. Typically, Au / Ni alloys are required to form a good ohmic contact. Au is opaque to the emitted wavelength, which causes the metal electrode to shield the outgoing light. Therefore, the electrode cannot be too thick. However, when the electrode is too thin, the thin electrode layer will cause uneven diffusion of the current, which in turn causes overheating in the local area and reduces the transparency of the electrode.

[0007] Many developments in LED displays are aimed at improving the efficiency of LEDs. For example, a flip-chip LED structure is achieved by flipping the LED structure face down and bonding the flipped LED structure to a substrate with electrodes. The flip-chip LED structure has advantages over other structures in terms of efficiency and technological maturity because the flip-chip LED structure can reduce the photons absorbed by the P-type ohmic contact electrode and can avoid the shielding of the electrode on the emitted light. Although flip-chip LEDs have been widely studied, the limitations of the total reflection effect have not yet been overcome, which limits the improvement of light extraction efficiency.

[0008] Although Bragg reflectors are generally used to increase reflectivity, Bragg reflectors have high reflectivity only for normally incident light. Bragg reflectors have low reflectivity for obliquely incident light. In that case, total reflection cannot be achieved.

[0009] In addition, when a back reflector structure is added to the flip-chip LED structure, the contact area between the metal electrode and the semiconductor material is reduced, resulting in a sharp increase in ohmic contact resistance. The back contact formed in the back reflector structure reduces the reflection area of ​​the back reflector structure, thereby reducing the reflectivity of the reflector structure and the light extraction efficiency of the LED.

[0010] In addition, in the flip-chip LED structure, the electrode needs a low work function metal to achieve N-GaN ohmic contact. Since the area left after the etching process is limited, it is very difficult to prepare N-type ohmic contact. Summary of the invention

[0011] Improved display designs are needed that improve upon and help address shortcomings of conventional LED systems and structures, such as those described above. In particular, there is a need for display panels with efficient micro-LED structures having good ohmic contacts, high extraction areas, high reflectivity, and high extraction efficiency.

[0012] Various embodiments include a display panel that includes an array of pixel light sources (eg, LEDs, OLEDs) electrically coupled to corresponding pixel drive circuits (eg, FETs).

[0013] In some embodiments, a micro-LED with high light extraction efficiency includes: a bottom conductive layer; a light-emitting layer located on the bottom conductive layer; a top conductive structure located on the light-emitting layer; a bottom dielectric layer located between the bottom conductive layer and the light-emitting layer; and a conductive side arm connecting the bottom layer sidewall of the light-emitting layer to the bottom conductive layer.

[0014] In some embodiments, the micro light emitting diode further includes: an ohmic contact layer between the top conductive structure and the light emitting layer.

[0015] In some embodiments, the lateral width of the ohmic contact layer is much smaller than the lateral width of the light emitting layer.

[0016] In some embodiments, the top conductive structure directly covers the ohmic contact layer, and a majority of the light emitting layer is not shielded by the ohmic contact layer.

[0017] In some embodiments, the ohmic contact layer is a metal film.

[0018] In some embodiments, the thickness of the ohmic contact layer is less than 20 nm, and the lateral width of the ohmic contact layer is less than 0.5 μm.

[0019] In some embodiments, the material of the ohmic contact layer includes at least one or more selected from the group consisting of Group I, Group II, Group III, Group IV, Group VI, and Group VIII metals in the periodic table.

[0020] In some embodiments, the top conductive structure is transparent and the ohmic contact layer is transparent.

[0021] In some embodiments, the bottom dielectric layer is a composite reflective layer.

[0022] In some embodiments, the composite reflective layer includes multiple layers, the multiple layers including at least an insulating reflective dielectric layer and a composite metal reflective layer, the composite metal reflective layer is located at the bottom of the insulating reflective dielectric layer and contacts the bottom conductive layer.

[0023] In some embodiments, the composite metal reflective layer has multiple layers.

[0024] In some embodiments, the insulating reflective dielectric layer further includes a top insulating dielectric layer and a bottom Bragg reflector.

[0025] In some embodiments, the top insulating dielectric layer has no less than three layers.

[0026] In some embodiments, the material of the top insulating dielectric layer is metal oxide.

[0027] In some embodiments, the lateral width of the bottom conductive layer is greater than the lateral width of the bottom dielectric layer, so that the bottom conductive layer has a protruding top extending beyond the bottom dielectric layer; one end of the conductive side arm is connected to the bottom layer of the light-emitting layer, and at least a portion of the other end of the conductive side arm is connected to the protruding top of the bottom conductive layer and supported on the protruding top of the bottom conductive layer.

[0028] In some embodiments, the lateral width of the bottom dielectric layer is not less than the width of the bottom of the light emitting layer.

[0029] In some embodiments, the light emitting layer further includes a first type semiconductor layer, an active layer, and a second type semiconductor layer in order from top to bottom. In some embodiments, the second type semiconductor layer has a protruding top extending beyond the active layer and the first type semiconductor layer, one end of the conductive side arm covers and contacts the protruding top of the second type semiconductor layer, and the other end of the conductive side arm contacts the bottom conductive layer.

[0030] In some embodiments, the lateral width of the bottom conductive layer is greater than the lateral width of the second type semiconductor layer and the lateral width of the bottom dielectric layer, so that the bottom conductive layer has a protruding top extending beyond the second type semiconductor layer and the bottom dielectric layer. In some embodiments, at least a portion of the conductive side arm is supported on the protruding top of the bottom conductive layer.

[0031] In some embodiments, the lateral width of the bottom conductive layer is less than 2 μm.

[0032] In some embodiments, a width of a protruding top of the bottom conductive layer is no greater than a width of a protruding top of the second type semiconductor layer.

[0033] In some embodiments, the second type semiconductor layer further includes a second type top semiconductor layer and a second type bottom semiconductor layer, the second type bottom semiconductor layer extending outward relative to the second type top semiconductor layer to form a protruding top.

[0034] In some embodiments, the material of the second type top semiconductor layer is different from the material of the second type bottom semiconductor layer.

[0035] In some embodiments, the second type top semiconductor layer is AlGaInP, the second type bottom semiconductor layer is GaP; and the first type semiconductor layer is AlInP.

[0036] In some embodiments, the end of the conductive side arm is in electrical contact with the protruding top of the second type bottom semiconductor layer, not in electrical contact with the second type top semiconductor layer, and not in electrical contact with the light emitting layer and the first type semiconductor layer.

[0037] In some embodiments, the lateral width of the first type semiconductor layer is equal to or greater than the lateral width of the active layer.

[0038] In some embodiments, the lateral width of the first type semiconductor layer is much smaller than the lateral width of the active layer.

[0039] In some embodiments, the conductive side arm has an inverted L-shape.

[0040] In some embodiments, the conductive side arms are attached to and connected to the sidewalls of the bottom dielectric layer.

[0041] In some embodiments, a lateral width of the bottom conductive layer is greater than a lateral width of the bottom dielectric layer, and a sidewall of the bottom conductive layer protrudes beyond a sidewall of the conductive side arm.

[0042] In some embodiments, the micro-light emitting diode also includes: a transparent isolation layer, which covers at least the protruding top of the second type of semiconductor layer, the top and side walls of the conductive side arms, the side walls of the light emitting layer, and the side walls of the first type of semiconductor layer, and the top conductive structure is located on the top of the transparent isolation layer.

[0043] In some embodiments, the material of the conductive side arms is a conductive metal.

[0044] In some embodiments, the first type semiconductor layer is an N-type semiconductor layer, and the second type semiconductor layer is a P-type semiconductor layer.

[0045] In some embodiments, the first type semiconductor layer is a P-type semiconductor layer, and the second type semiconductor layer is an N-type semiconductor layer.

[0046] In some embodiments, the material of the bottom conductive layer includes one or more conductive metals.

[0047] In some embodiments, the micro light emitting diode further includes a circuit substrate located at the bottom of the bottom conductive layer, wherein the bottom conductive layer serves as a bonding layer bonded to a surface of the circuit substrate.

[0048] In some embodiments, the circuit substrate includes at least a driving circuit for controlling light emission of the light emitting layer.

[0049] In some embodiments, the micro light emitting diodes have a light extraction efficiency of at least 20%.

[0050] In some embodiments, the micro light emitting diodes have a light extraction efficiency of at least 40%.

[0051] In some embodiments, the micro light emitting diodes have a light extraction efficiency of at least 60%.

[0052] It should be noted that the various embodiments described above may be combined with any other embodiments described herein. The features and advantages described in the specification are not all-inclusive, and in particular, many additional features and advantages will be apparent to those of ordinary skill in the art from the drawings, the specification, and the claims. Furthermore, it should be noted that the language used in the specification is selected primarily for readability and instructional purposes, and is not selected to delineate or limit the subject matter of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order that the present disclosure can be understood in more detail, the present disclosure may be described in more detail by referring to the features of various embodiments, some of which are shown in the accompanying drawings. However, these drawings only illustrate the relevant features of the present disclosure and are therefore not to be considered restrictive, as the description may allow for other effective features.

[0054] Figure 1 is a cross-sectional view of a micro LED structure according to the first embodiment.

[0055] Figure 2 is a cross-sectional view of a micro LED structure according to a second embodiment.

[0056] Figure 3 is a cross-sectional view of a micro LED structure according to a third embodiment.

[0057] Figure 4 Depicted is a cross-sectional view of a bottom dielectric layer structure of a micro LED structure according to some embodiments.

[0058] Figure 5 Depicted is a cross-sectional view of a bottom dielectric layer structure of a micro LED structure according to some embodiments.

[0059] Figure 6 is a cross-sectional view of a micro LED structure according to a fourth embodiment.

[0060] Figure 7 is a cross-sectional view of a micro LED structure according to a fifth embodiment.

[0061] Figure 8 is a cross-sectional view of a micro LED structure according to a sixth embodiment.

[0062] Fig. 9 is a cross-sectional view of a micro LED structure according to a seventh embodiment.

[0063] Fig.10 is a cross-sectional view of a micro LED structure according to an eighth embodiment.

[0064] Fig.11 is a cross-sectional view of a micro LED structure according to a ninth embodiment.

[0065] Fig.12 is a top view of a micro LED display panel 1200 according to some embodiments.

[0066] According to common practice, the various features illustrated in the drawings may not be drawn to scale. Therefore, for clarity, the sizes of various features may be arbitrarily expanded or reduced. In addition, some drawings may not depict all components of a given system, method, or device. Finally, the same reference numerals may be used to represent similar features throughout the specification and drawings. DETAILED DESCRIPTION

[0067] Many details are described herein in order to provide a thorough understanding of the example embodiments shown in the accompanying drawings. However, some embodiments may be practiced without many of the specific details, and the scope of the claims is limited only by those features and aspects specifically detailed in the claims. In addition, well-known methods, components, and materials are not described in detail so as not to unnecessarily obscure the relevant aspects of the embodiments described herein. Reference will now be made in detail to the preferred embodiments to provide a further understanding of the present invention. The specific embodiments and drawings discussed are only used to illustrate specific ways to make and use the present invention and do not limit the scope of the present invention or the appended claims.

[0068] Embodiments consistent with the present disclosure include a display panel and a method of manufacturing the display panel, the display panel including a substrate having a pixel driver circuit array, an LED array having the following structure formed above the substrate. The display panel with high light extraction efficiency can overcome the shortcomings of conventional display systems.

[0069] Figure 1 is a cross-sectional view of a micro LED structure according to the first embodiment. Figure 1 The illustrated micro-LED structure 100 has a high light extraction efficiency. In some embodiments, the light extraction efficiency is at least 20%. In some embodiments, the light extraction efficiency is at least 30%. In some embodiments, the light extraction efficiency is at least 40%. In some embodiments, the micro-LED includes a bottom conductive layer 102, a light emitting layer 106 on the bottom conductive layer 102, and a top conductive structure 108 on the light emitting layer 106. In some embodiments, the micro-LED also includes a bottom dielectric layer 104 disposed between the bottom conductive layer 102 and the light emitting layer 106. In some embodiments, the bottom dielectric layer 104 is part of the light emitting layer 106. In some embodiments, the light emitting layer 106 includes many different layers. In some embodiments, the conductive side arm 110 connects the bottom or bottom ( Figure 1 The conductive side arms 110 are located on both sides of the micro LED structure. In some embodiments, the top conductive structure 108 forms a top conductive structure, which is not limited by the scope of this embodiment. In some embodiments, the top conductive structure is in the shape of a line, a square, a rectangle, or some other shape.

[0070] Figure 2 is a cross-sectional view of a micro LED structure according to a second embodiment. Figure 2The illustrated micro-LED structure 200 has a high light extraction efficiency. In some embodiments, the light extraction efficiency is at least 20%. In some embodiments, the light extraction efficiency is at least 30%. In some embodiments, the light extraction efficiency is at least 40%. In some embodiments, the light extraction efficiency is at least 50%. In some embodiments, Figure 2 The micro LED structure 200 is based on Figure 1 The micro-LED structure 100 in FIG. Figure 1 In the micro LED structure 100, the micro LED structure 200 includes a bottom conductive layer 202, a light emitting layer 206, a bottom dielectric layer 204, a top conductive structure 208, and a conductive side arm 210. In addition, in some embodiments, the bottom conductive layer 202 connected to the conductive side arm 210 has a protruding bottom 202-1, so that the bottom of the conductive side arm 210 is at least partially or alternatively completely supported by the protruding bottom 202-1 of the bottom conductive layer 202. For example, the sidewalls of the conductive side arm 210 are aligned with the sidewalls of the protruding bottom 202-1 of the bottom conductive layer 202, such as Figure 2 As shown. In addition, in some embodiments, an ohmic contact layer 212 is disposed between the top conductive structure 208 and the light emitting layer 206. In some embodiments, the ohmic contact layer 212 is a metal film. The composition of the metal film of the ohmic contact layer 212 is at least selected from one or more of Group I, Group II, Group III, Group IV, Group VI and Group VIII in the periodic table and combinations thereof, such as Au, Cr, Be, Zn, Pt, Ti, Ge, Ni, In and combinations thereof. In some embodiments, when light is emitted from the top of the LED 200, a top conductive structure that is transparent to the emitted light is used as the top conductive structure 208, such as an indium tin oxide (ITO) transparent conductive film. In some embodiments, the ohmic contact layer 212 is transparent to the emitted light. Preferably, when the thickness of the ohmic contact layer 212 is less than 20 nm, the ohmic contact layer 212 may be transparent to the emitted light.

[0071] Figure 3 is a cross-sectional view of a micro LED structure according to a third embodiment. Figure 3 The illustrated micro-LED structure 300 has a high light extraction efficiency. In some embodiments, the light extraction efficiency is at least 20%. In some embodiments, the light extraction efficiency is at least 30%. In some embodiments, the light extraction efficiency is at least 40%. In some embodiments, the light extraction efficiency is at least 50%. In some embodiments, the light extraction efficiency is at least 60%. In some embodiments, Figure 3 The micro-LED structure 300 is based on Figure 2 The micro-LED structure 200 in FIG. Figure 2In the micro LED structure 200, the micro LED structure 300 includes a bottom conductive layer 302, a light emitting layer 306, a bottom dielectric layer 304, a top conductive structure 308, a conductive side arm 310, a protruding bottom 302-1 of the bottom conductive layer 302 located below the conductive side arm 310, and an ohmic contact layer 312. In some embodiments, the width of the ohmic contact layer 312 is much narrower than the width of the light emitting layer 306 to form an ohmic contact point. The top conductive structure 308 covers the ohmic contact layer 312, and the light emitting layer 306 is not completely shielded by the ohmic contact layer 312. In some embodiments, in order to improve the light extraction efficiency, the lateral width of the ohmic contact layer 312 is less than 1 μm, preferably, less than 0.5 μm. In some embodiments, in order to improve the transmittance of the ohmic contact layer 312, the thickness of the ohmic contact layer 312 is less than 20 nm. In some embodiments, the material of the ohmic contact layer 312 depends on the type of the light emitting layer 306 and the material of the top conductive structure 308. In some embodiments, the material of the ohmic contact layer 312 is metal. In some preferred embodiments, the ohmic contact layer 312 has a Figure 2 The ohmic contact layer 212 is formed of a multilayer of composite metal materials.

[0072] Figure 4 A cross-sectional view of a bottom dielectric layer structure of a micro LED structure according to some embodiments is depicted. The bottom dielectric layer 404 may be used as Figures 1 to 3 The bottom dielectric layer 404 is reflective. In some embodiments, the bottom dielectric layer 404 has a reflectivity greater than 50%. In some embodiments, the bottom dielectric layer 404 has a reflectivity greater than 70%. In some embodiments, the bottom dielectric layer 404 has a reflectivity greater than 90%. In some preferred embodiments, the bottom dielectric layer 404 is a composite reflective layer, which increases the reflection area and improves the reflection efficiency. Figure 4 As shown, the composite reflective layer 404 has multiple layers, including at least an insulating reflective dielectric layer 404-1 and a composite metal reflective layer 404-2. In some embodiments, the composite metal reflective layer 404-2 is disposed at the bottom of the insulating reflective dielectric layer 404-1. In some embodiments, the composite metal reflective layer 404-2 contacts the Figures 1 to 3 In some embodiments, the material of the composite metal reflective layer 404-2 is similar to or the same as that of the bottom conductive layer, such as Cr and / or Au, etc., and it is not only used as a reflective layer, but also as a buffer layer between the insulating reflective dielectric layer 404-1 and the bottom conductive layer. The composite metal reflective layer 404-2 further increases the adhesion between the insulating reflective dielectric layer 404-1 and the bottom conductive layer, so that the insulating reflective dielectric layer 404-1 and the bottom conductive layer are firmly bonded together.

[0073] Figure 5A cross-sectional view of a bottom dielectric layer structure of a micro LED structure according to some embodiments is depicted. The bottom dielectric layer 504 may be used as Figures 1 to 4 In some embodiments, the bottom dielectric layer 504 includes an insulating reflective dielectric layer 504-1 and a composite metal reflective layer 504-2. In some embodiments, Figure 4 The insulating reflective dielectric layer 504-1 shown in the figure includes a top insulating dielectric layer 504-11 and a bottom distributed Bragg reflector (DBR) 504-12. In some embodiments, the material of the top insulating dielectric layer 504-11 is a metal oxide. In some cases, the material of the top insulating dielectric layer 504-11 also includes Si, In, or / and Sn, etc. In some embodiments, a multilayer Bragg reflector (DBR) is used as the bottom DBR 504-12, which is well known to those skilled in the art and will not be described in detail here. In some embodiments, the top insulating dielectric layer 504-11 can increase the transmittance and refractive index of light so that the light effectively enters the bottom DBR 504-12. In some embodiments, the top insulating dielectric layer 504-11 includes multiple layers, such as more than or equal to three layers.

[0074] Figure 6 is a cross-sectional view of a micro LED structure according to a fourth embodiment. Figure 6 The illustrated micro-LED structure 600 has a high light extraction efficiency. In some embodiments, the light extraction efficiency is at least 20%. In some embodiments, the light extraction efficiency is at least 30%. In some embodiments, the light extraction efficiency is at least 40%. In some embodiments, the light extraction efficiency is at least 50%. In some embodiments, the light extraction efficiency is at least 60%. In some embodiments, Figure 6 The micro-LED structure 600 is based on Figure 3 The micro-LED structure 300 in FIG. Figure 3 In the micro LED structure 300, the micro LED structure 600 includes a bottom conductive layer 602, a light emitting layer 606, a bottom dielectric layer 604, a top conductive structure 608, a conductive side arm 610, and an ohmic contact layer 612, which is much narrower than the light emitting layer 606 to form an ohmic contact point. In some embodiments, as Figure 6 As shown, the lateral width of the bottom conductive layer 602 is greater than the lateral width of the composite reflective layer (bottom dielectric layer 604), so that the bottom conductive layer 602 has a protruding top 602-2 protruding outward. In some embodiments, one end of the conductive side arm 610 is connected to the bottom or bottom of the light emitting layer 606 ( Figure 6 (not shown separately), and at least a portion of the other end of the conductive side arm 610 is connected to the protruding top 602-2 of the bottom conductive layer 602. Figure 6As shown, a portion of the bottom of the conductive side arm 610 is supported on the protruding top 602-2 of the bottom conductive layer 602. In some embodiments, to ensure high extraction efficiency of the micro LED structure 600, the lateral width of the bottom conductive layer 602 is less than 2 μm, preferably in the range of 0.3-2 μm.

[0075] Figure 7 is a cross-sectional view of a micro LED structure according to a fifth embodiment. Figure 7 The illustrated micro-LED structure 700 has a high light extraction efficiency. In some embodiments, the light extraction efficiency is at least 20%. In some embodiments, the light extraction efficiency is at least 30%. In some embodiments, the light extraction efficiency is at least 40%. In some embodiments, the light extraction efficiency is at least 50%. In some embodiments, the light extraction efficiency is at least 60%. In some embodiments, Figure 7 The micro-LED structure 700 is based on Figure 6 The micro-LED structure 600 in FIG. is similar to Figure 6 The micro LED structure 600 in the embodiment of the present invention includes a bottom conductive layer 702, a light emitting layer 706, a bottom dielectric layer 704, a top conductive structure 708, a conductive side arm 710, and an ohmic contact layer 712, which is much narrower than the light emitting layer 706 to form an ohmic contact point. The lateral width of the bottom conductive layer 702 is greater than the lateral width of the composite reflective layer (bottom dielectric layer 704), so that the bottom conductive layer 702 has a protruding top 702-2 that protrudes outward. In some embodiments, the bottom conductive layer 702 has a protruding top 702-2 that protrudes outward relative to the bottom dielectric layer 704, so that the bottom of the conductive side arm 710 is at least partially or alternatively completely supported on the protruding top 702-2 of the bottom conductive layer 702. In one example, the sidewalls of the conductive side arm 710 are aligned with the sidewalls of the bottom conductive layer 702, such as Figure 7 shown.

[0076] for Figure 6 and Figure 7 In the embodiment shown, in some examples, the lateral width of the bottom dielectric layer 704 is not less than the width of the bottom of the light emitting layer 706, and the sidewall of the light emitting layer 706 is vertical or inclined. In another example, the lateral width of the bottom dielectric layer 704 can be less than the width of the bottom of the light emitting layer 706, and the shape of the conductive side arm 710 is L-shaped.

[0077] Figure 8 is a cross-sectional view of a micro LED structure according to a sixth embodiment. Figure 8The illustrated micro-LED structure 800 has a high light extraction efficiency. In some embodiments, the light extraction efficiency is at least 20%. In some embodiments, the light extraction efficiency is at least 30%. In some embodiments, the light extraction efficiency is at least 40%. In some embodiments, the light extraction efficiency is at least 50%. In some embodiments, the light extraction efficiency is at least 60%. In some embodiments, Figure 8 The micro-LED structure in 800 is based on Figure 7 The micro-LED structure 700 in FIG. Figure 7 In the micro LED structure 700, the micro LED structure 800 includes a bottom conductive layer 802, a light emitting layer 806, a bottom dielectric layer 804, a top conductive structure 808, a conductive side arm 810, and an ohmic contact layer 812, which is much narrower than the light emitting layer 806 to form an ohmic contact point. The lateral width of the bottom conductive layer 802 is greater than the lateral width of the composite reflective layer (bottom dielectric layer 804), so that the bottom conductive layer 802 has a protruding top 802-2 protruding outward, and the bottom of the conductive side arm 810 is at least partially or alternatively completely supported on the protruding top 802-2 of the bottom conductive layer 802. In one example, the sidewalls of the conductive side arm 810 are aligned with the sidewalls of the bottom conductive layer 802, such as Figure 8 In some embodiments, the bottom lateral width of the light emitting layer 806 is less than the lateral width of the bottom dielectric layer 804. In some embodiments, the conductive side arm 810 has an inverted L shape. The conductive side arm 810 includes a horizontal portion 810-1 and a vertical portion 810-2. The end of the horizontal portion 810-1 extends to and contacts the bottom or bottom of the light emitting layer 806 ( Figure 8 802), and the end of the vertical portion 810-2 extends to and contacts the bottom conductive layer 802.

[0078] Fig. 9 is a cross-sectional view of a micro LED structure according to a seventh embodiment. Fig. 9 The illustrated micro-LED structure 900 has a high light extraction efficiency. In some embodiments, the light extraction efficiency is at least 20%. In some embodiments, the light extraction efficiency is at least 30%. In some embodiments, the light extraction efficiency is at least 40%. In some embodiments, the light extraction efficiency is at least 50%. In some embodiments, the light extraction efficiency is at least 60%. In some embodiments, the light extraction efficiency is at least 70%. In some embodiments, Fig. 9 The micro-LED structure in 900 is based on Figure 8 The micro-LED structure in 800. Similar to Figure 8In the micro LED structure 800, the micro LED structure 900 includes a bottom conductive layer 902, a light emitting layer 906, a bottom dielectric layer 904, a top conductive structure 908, a conductive side arm 910 and an ohmic contact layer 912, which is much narrower than the light emitting layer 906 to form an ohmic contact point. In addition, the lateral width of the bottom conductive layer 902 is greater than the lateral width of the composite reflective layer (bottom dielectric layer 904), so that the bottom conductive layer 902 has a protruding top 902-2 protruding outward, and the bottom of the conductive side arm 910 is at least partially or alternatively completely supported on the protruding top 902-2 of the bottom conductive layer 902. In one example, the sidewalls of the conductive side arm 910 are aligned with the sidewalls of the bottom conductive layer 902, such as Fig. 9 In some embodiments, the conductive side arm 910 has an inverted L shape. The conductive side arm 910 includes a horizontal portion 910-1 and a vertical portion 910-2.

[0079] like Fig. 9 As shown, in some embodiments, the light emitting layer 906 includes a first type semiconductor layer 906-1, an active layer 906-2, and a second type semiconductor layer 906-3 from top to bottom. In some embodiments, the lateral width of the second type semiconductor layer 906-3 is greater than the lateral width of the first type semiconductor layer 906-1 and the lateral width of the active layer 906-2, so a protruding top 906-3-3 is formed at the edge of the second type semiconductor layer 906-3. In some embodiments, the lateral width of the first type semiconductor layer 906-1 is the same as the lateral width of the active layer 906-2. In some embodiments, the lateral width of the first type semiconductor layer 906-1 is the same as the lateral width of the top conductive structure 908.

[0080] In some embodiments, an end of the horizontal portion 910 - 1 of the conductive side arm 910 covers and contacts the protruding top 906 - 3 - 3 of the second type semiconductor layer 906 - 3 , and the other end of the vertical portion 910 - 2 of the conductive side arm 910 contacts the bottom conductive layer 902 .

[0081] In some embodiments, the first type semiconductor layer 906-1 is an N-type semiconductor layer and the second type semiconductor layer 906-3 is a P-type semiconductor layer. Alternatively, in some embodiments, the first type semiconductor layer 906-1 is a P-type semiconductor layer and the second type semiconductor layer 906-3 is an N-type semiconductor layer. In some embodiments, the material of the N-type semiconductor is N-type AlInP or N-type GaAs, or a composite material of various N-type semiconductor layers. In some embodiments, the material of the P-type semiconductor layer is P-type GaP or P-type AlGaInP.

[0082] In some embodiments, the lateral width of the bottom conductive layer 902 is greater than the lateral width of the second type semiconductor layer 906-3. In some embodiments, the lateral width of the second type semiconductor layer 906-3 is equal to the lateral width of the bottom dielectric layer 904. The bottom conductive layer 902 has a protruding top 902-2 that extends outwardly relative to the second type semiconductor layer 906-3 and the bottom dielectric layer 904. In some embodiments, at least a portion of the conductive side arm 910 is at least partially or alternatively completely supported on the protruding top 902-2 of the bottom conductive layer 902. In some embodiments, as Fig. 9 As shown, the entire bottom of the conductive side arm 910 is supported on the protruding top 902 - 2 of the bottom conductive layer 902 .

[0083] In some embodiments, the end of the conductive side arm 910 connected to the protruding top 906-3-3 of the second type semiconductor layer 906-3 is not directly connected to the active layer 906-2. Fig. 9 As shown, there is a gap between the vertical sidewall of the horizontal portion 910-1 of the conductive side arm 910 and the active layer 906-2. In some preferred embodiments, the lateral width of the protruding top 902-2 of the bottom conductive layer 902 (the width of the portion extending only outside the bottom dielectric layer 904) is equal to or less than the lateral width of the protruding top 906-3-3 of the second type semiconductor layer 906-3 (the width of the portion extending only outside the active layer 906-2). Such a width arrangement ensures that the bottom end of the conductive side arm 910 is located on the bottom conductive layer 902, and avoids the upper end of the conductive side arm 910 from contacting the active layer 906-2, thereby forming a stable and reliable electrical contact structure.

[0084] Fig.10 is a cross-sectional view of a micro LED structure according to an eighth embodiment. Fig.10 The illustrated micro-LED structure 1000 has a high light extraction efficiency. In some embodiments, the light extraction efficiency is at least 20%. In some embodiments, the light extraction efficiency is at least 30%. In some embodiments, the light extraction efficiency is at least 40%. In some embodiments, the light extraction efficiency is at least 50%. In some embodiments, the light extraction efficiency is at least 60%. In some embodiments, the light extraction efficiency is at least 70%. In some embodiments, the light extraction efficiency is at least 80%. In some embodiments, Fig.10 The micro-LED structure in 1000 is based on Fig. 9 The micro-LED structure in 900. Similar to Fig. 9The micro LED structure 900 in FIG. 1 includes a bottom conductive layer 1002, a light emitting layer 1006, a bottom dielectric layer 1004, a top conductive structure 1008, a conductive side arm 1010 having an inverted L shape, and an ohmic contact layer 1012, which is much narrower than the light emitting layer 1006 to form an ohmic contact point. In some embodiments, the light emitting layer 1006 includes, from top to bottom, a first type semiconductor layer 1006-1, an active layer 1006-2, and a second type semiconductor layer 1006-3.

[0085] like Fig.10 As shown, in some embodiments, the second type semiconductor layer 1006-3 includes a second type top semiconductor layer 1006-31 and a second type bottom semiconductor layer 1006-32. The second type bottom semiconductor layer 1006-32 extends outward relative to the second type top semiconductor layer 1006-31, so that the extended portion of the second type bottom semiconductor layer 1006-32 serves as a protruding top 1006-32-1. In some embodiments, the material of the second type top semiconductor layer 1006-31 and the material of the second type bottom semiconductor layer 1006-32 can be the same or different. In some embodiments, the second type top semiconductor layer 1006-31 is AlGaInP, and the second type bottom semiconductor layer 1006-32 is GaP. In addition, in some embodiments, the first type semiconductor layer 1006-1 has one or more layers. For example, the first type semiconductor layer 1006-1 includes N-type AlInP and N-type GaAs from top to bottom. In another example, the first type semiconductor layer 1006-1 has only N-type AlInP. In some embodiments, N-type AlInP is directly below and in contact with the ohmic contact layer 1012 and the top conductive structure 1008. In a preferred embodiment, the light emitting layer 1006 includes N-type AlInP, a quantum active layer, P-type AlGaInP, and P-type GaP arranged in order from top to bottom.

[0086] like Fig.10 As shown, in some embodiments, the horizontal portion 1010-1 of the conductive side arm 1010 covers and directly contacts the second type bottom semiconductor layer 1006-32, and the end of the horizontal portion 1010-1 is not directly connected to the second type top semiconductor layer 1006-31, the active layer 1006-2 and / or the first type semiconductor layer 1006-1. In some embodiments, the lateral width of the bottom conductive layer 1002 is greater than the lateral width of the bottom dielectric layer 1004. In some embodiments, the sidewalls of the bottom conductive layer 1002 protrude beyond the sidewalls of the conductive side arm 1010 (at Fig.10 In some embodiments, the material of the conductive side arm 1010 is conductive metal or other conductive materials.

[0087] Similar to Figures 1 to 9 In some embodiments, Fig.10 Each side of the micro-LED structure 1000 in FIG. 1 has a conductive side arm 1010. In addition, similar to Figures 1 to 9 In some embodiments, the conductive side arm 1010 may be attached to and contact Fig.10 In an alternative embodiment, the shape of the conductive side arm 1010 can be changed to another shape that does not contact the side wall of the bottom dielectric layer 1004 ( Fig.10 ), and equivalent embodiments or variations may be implemented by those skilled in the art.

[0088] Fig.11 is a cross-sectional view of a micro LED structure according to a ninth embodiment. Fig.11 The illustrated micro-LED structure 1100 has a high light extraction efficiency. In some embodiments, the light extraction efficiency is at least 20%. In some embodiments, the light extraction efficiency is at least 30%. In some embodiments, the light extraction efficiency is at least 40%. In some embodiments, the light extraction efficiency is at least 50%. In some embodiments, the light extraction efficiency is at least 60%. In some embodiments, the light extraction efficiency is at least 70%. In some embodiments, the light extraction efficiency is at least 80%. In some embodiments, the light extraction efficiency is at least 90%. In some embodiments, Fig.11 The micro-LED structure 1100 is based on Fig.10 The micro-LED structure 1000 in FIG. is similar to Fig.10 The micro LED structure 1000 in the embodiment of the present invention includes a bottom conductive layer 1102, a light emitting layer 1106, a bottom dielectric layer 1104, a top conductive structure 1108, a conductive side arm 1110 having an inverted L shape, and an ohmic contact layer 1112, which is much narrower than the light emitting layer 1106 to form an ohmic contact point. In some embodiments, the light emitting layer 1106 includes, from top to bottom, a first type semiconductor layer 1106-1, an active layer 1106-2, and a second type semiconductor layer 1106-3. In some embodiments, the second type semiconductor layer 1106-3 includes a second type top semiconductor layer 1106-31 and a second type bottom semiconductor layer 1106-32.

[0089] according to Fig.11, the micro LED structure 1100 with high light extraction efficiency also includes a transparent isolation layer 1114. In some embodiments, each side of the micro LED structure 1100 has a transparent isolation layer 1114. In some embodiments, the transparent isolation layer 1114 directly covers at least a portion of the gap between the conductive side arm 1110 and the sidewall of the light emitting layer 1106, located within the protruding top 1106-32-1 of the second type bottom semiconductor layer 1106-32, or alternatively, covers the entire gap. The transparent isolation layer 1114 also directly covers the exposed sidewalls of the second type top semiconductor layer 1106-31, the top of the conductive side arm 1110 and the sidewall facing the micro LED structure 1100, the sidewalls of the active layer 1106-2, and at least most of the sidewalls of the first type semiconductor layer 1106-1 from bottom to top. In some embodiments, most of the sidewalls of the first type semiconductor layer 1106-1 from bottom to top are at least 50% of the sidewalls. In some embodiments, the majority of the sidewalls of the first type semiconductor layer 1106 - 1 from bottom to top are at least 70% of the sidewalls. In some embodiments, the majority of the sidewalls of the first type semiconductor layer 1106 - 1 from bottom to top are at least 90% of the sidewalls.

[0090] In some embodiments, the top conductive structure 1108 is arranged on the sidewall and the top of the ohmic contact layer 1112, the protruding top of the first type semiconductor layer 1106-1, and the top of the transparent isolation layer 1114. In some embodiments, the top of the transparent isolation layer 1114 covers at least a portion of the top of the first type semiconductor layer 1106-1 ( Fig.11 ) without covering the top of the ohmic contact layer 1112.

[0091] In some embodiments, the material of the bottom conductive layer 1102 includes one or more types of conductive metals, such as Cr, Pt, Au, Sn, etc. The multi-layer composite conductive layer used as the bottom conductive layer 1102 is made of these metals. In some embodiments, the bottom conductive layer 1102 is also used as a bonding layer, bonded to the circuit substrate 1116 ( Fig.11 The circuit substrate 1116 includes at least a driving circuit that controls the light emitting layer 1106 to emit light.

[0092] In some embodiments, the bottom of the conductive side arm 1110 extends downward but does not contact the circuit substrate 1116. In some embodiments, when the bottom of the conductive side arm 1110 extends downward to contact the circuit substrate 1116, the contact electrode in the circuit substrate 1116 is connected to the bottom of the conductive side arm 1110, and other areas below the bottom of the conductive side arm 1110 that are not in contact with the contact electrode are insulated. In some embodiments, the bottom of the conductive side arm 1110 is also bonded to the surface of the circuit substrate 1116.

[0093] As above Figures 1 to 11 As described above, in the LED structure with high light extraction efficiency disclosed herein, the light emitting layer uses the bottom conductive layer to achieve downward electrical contact and uses the top conductive structure to achieve upward electrical contact. In addition, the conductive side arm electrically connects the side wall of the light emitting layer to both sides of the bottom conductive layer. When the bottom of the conductive side arm extends downward to contact the circuit substrate, the conductive side arm further electrically connects the light emitting layer to the circuit substrate, which increases the light emitting area and improves the light extraction efficiency.

[0094] In addition, by utilizing the conductive side arms to electrically connect the side walls of the light-emitting layer and the bottom conductive layer, the reflective area of ​​the composite reflective layer (bottom dielectric layer) is expanded, further improving the light extraction efficiency of the LED.

[0095] In addition, the ohmic contact layer formed between the top conductive structure and the light-emitting layer can be made very small and thin, such as a transparent metal film. This structure ensures good ohmic contact between the light-emitting layer and the top conductive structure, increases the light emitting area, and improves the light extraction efficiency.

[0096] Although the detailed description contains many details, these should not be construed as limiting the scope of the invention, but merely as illustrating different examples and aspects of the invention. It should be understood that the scope of the invention includes other embodiments not discussed in detail above. For example, micro-LED structures and layers with different shapes and thicknesses, such as square bases or other polygonal bases, may also be used. Various other modifications, changes and variations that are obvious to those skilled in the art may be made to the arrangement, operation and details of the methods and apparatus of the invention disclosed herein without departing from the spirit and scope of the invention as defined in the appended claims. Therefore, the scope of the invention shall be determined by the appended claims and their legal equivalents.

[0097] Other embodiments also include Figures 1 to 11 Various subsets of the above-described embodiments shown in FIG. 1 may be combined or otherwise rearranged in various other embodiments.

[0098] Fig.121 is a top view of a micro LED display panel 1200 according to some embodiments. The display panel 1200 includes a data interface 1210, a control module 1220, and a pixel area 1250. The data interface 1210 receives data that defines an image to be displayed. The source and format of this data will vary depending on the application. The control module 1220 receives input data and converts it into a form suitable for driving pixels in the display panel. The control module 1220 may include: digital logic and / or a state machine to convert from the received format to a format suitable for the pixel area 1250; a shift register or other type of buffer and memory to store and transmit data; a digital-to-analog converter and a level converter; and a scan controller including a clock circuit.

[0099] The pixel area 1250 includes a pixel array. The pixels include Figures 1 to 11 The structure described in the embodiment of the present invention is integrated with a micro-LED 1234 of a pixel driver in some examples. In this example, the display panel 1200 is a color RGB display panel. It includes red, green and blue pixels. In each pixel, LED 1234 is controlled by a pixel driver. According to some embodiments, the pixel is in contact with a power supply voltage (not shown), in contact with ground through a ground pad 1236, and also in contact with a control signal. Although in Fig.12 Not shown, the P electrode of LED1234 and the output of the driving transistor are electrically connected. The LED current drive signal connection (between the P electrode of the LED and the output of the pixel driver), the ground connection (between the n electrode and the system ground), the power supply voltage Vdd connection (between the source of the pixel driver and the system Vdd), and the control signal connection to the pixel driver gate are made according to various embodiments.

[0100] Fig.12 The drawings are representative only. Other designs will be apparent. For example, the colors do not have to be red, green, and blue. Nor do they have to be arranged in rows or strips. As an example, Fig.12 In addition to the square matrix arrangement of pixels shown in , a hexagonal matrix arrangement of pixels may also be used to form the display panel 1200 .

[0101] In some applications, a fully programmable rectangular pixel array is not necessary. Other designs of display panels and displays with a variety of shapes can also be formed using the device structures described herein. One class of examples is special applications, including signage and automotive applications. For example, multiple pixels can be arranged in a star or spiral shape to form a display panel, and different patterns on the display panel can be generated by turning LEDs on and off. Another professional example is automotive headlights and smart lighting, where certain pixels are grouped together to form various lighting shapes, and each group of LED pixels can be turned on or off or otherwise adjusted by individual pixel drivers.

[0102] Different types of display panels can be manufactured. For example, the resolution of display panels can typically range from 8×8 to 3840x2160. Common display resolutions include QVGA with a resolution of 320x240 and an aspect ratio of 4:3, XGA with a resolution of 1024x768 and an aspect ratio of 4:3, D with a resolution of 1280x720 and an aspect ratio of 16:9, FHD with a resolution of 1920×1080 and an aspect ratio of 16:9, UHD with a resolution of 3840x2160 and an aspect ratio of 16:9, and 4K with a resolution of 4096×2160. There can also be a wide variety of pixel sizes, ranging from sub-micron and below to 10mm and above. The size of the overall display area can also vary widely, ranging from as small as a few tens of microns or less on the diagonal to hundreds of inches or more.

[0103] Example applications include display screens, light engines for home / office projectors and portable electronics such as smartphones, laptops, wearable electronics, AR and VR glasses, and retinal projection. Power consumption can range from as low as a few milliwatts for retinal projectors to as high as kilowatts for large-screen outdoor displays, projectors, and smart car headlights. In terms of frame rate, due to the fast response of inorganic LEDs (nanoseconds), the frame rate can be as high as KHz, or even MHz for small resolutions.

[0104] Other embodiments also include Figures 1 to 12 Various subsets of the above-described embodiments shown in FIG. 1 may be combined or otherwise rearranged in various other embodiments.

[0105] Although the specific description contains many details, these should not be construed as limiting the scope of the invention, but merely illustrating different examples and aspects of the invention. It should be understood that the scope of the invention includes other embodiments not discussed in detail above. For example, the above method can be applied to the integration of non-LED and OLED functional devices with non-pixel driver control circuits. Examples of non-LED devices include vertical cavity surface emitting lasers (VCSELs), photodetectors, micro-electromechanical systems (MEMS), silicon photonic devices, power electronic devices, and distributed feedback lasers (DFBs). Examples of other control circuits include current drivers, voltage drivers, transimpedance amplifiers, and logic circuits.

[0106] The foregoing description of the disclosed embodiments is provided to enable making or using the embodiments described herein and variations thereof. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the subject matter disclosed herein. Therefore, the present disclosure is not intended to be limited to the embodiments shown herein, but will conform to the widest scope consistent with the following claims and the principles and novel features disclosed herein.

[0107] Features of the present invention can be implemented by using a computer program product or with the help of a computer program product, such as a storage medium (multiple media) or a computer-readable storage medium (multiple media), wherein or thereon instructions are stored, and these instructions can be used to program a processing system to perform any features presented herein. Storage media can include, but are not limited to, high-speed random access memory, such as DRAM, SRAM, DDRRAM or other random access solid-state memory devices, and can include non-volatile memory, such as one or more magnetic disk storage devices, optical disk storage devices, flash memory devices or other non-volatile solid-state storage devices. Memory optionally includes one or more storage devices located away from the CPU. Memory or optionally non-volatile memory devices in memory include non-temporary computer-readable storage media.

[0108] Features of the present invention stored on any machine-readable medium(s) may be embodied in software and / or firmware for controlling the hardware of a processing system and for enabling the processing system to interact with other mechanisms utilizing the results of the present invention. Such software or firmware may include, but is not limited to, application code, device drivers, operating systems, and execution environments / containers.

[0109] It should be understood that although the terms "first", "second", etc. may be used herein to describe various elements or steps, these elements or steps should not be limited by these terms. These terms are only used to distinguish one element or step from another element or step.

[0110] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the claims. As used in the description of the embodiments and the appended claims, the singular forms "one", "an" and "the" are intended to also include multiple forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and includes any and all possible combinations of one or more related listed items. It should also be understood that the terms "including" and / or "comprising" when used in this specification specify the presence of said features, integers, steps, operations, elements and / or parts, but do not prevent the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups.

[0111] The foregoing description for purposes of illustration has been described with reference to specific embodiments. However, the above illustrative discussion is not intended to be exhaustive or to limit the claims to the precise forms disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments are chosen and described in order to best explain the principles of practical application and operation to enable others skilled in the art to realize.

Claims

1. A micro light emitting diode with high light extraction efficiency, comprising: a bottom conductive layer; The light emitting layer is located on the bottom conductive layer; A top conductive structure is located on the light emitting layer; a bottom dielectric layer, located between the bottom conductive layer and the light emitting layer; as well as A conductive side arm connecting the side wall of the bottom layer of the light-emitting layer and the bottom conductive layer; in, The lateral width of the bottom conductive layer is greater than the lateral width of the bottom dielectric layer, so that the bottom conductive layer has a protruding top extending beyond the bottom dielectric layer; One end of the conductive side arm is connected to the bottom layer of the light emitting layer, and at least a portion of the other end of the conductive side arm is connected to and supported on the protruding top of the bottom conductive layer. 2 . The micro light emitting diode according to claim 1 , further comprising an ohmic contact layer between the top conductive structure and the light emitting layer.

3. The micro light emitting diode according to claim 2, wherein: The lateral width of the ohmic contact layer is smaller than the lateral width of the light emitting layer.

4. The micro light emitting diode according to any one of claims 2 to 3, wherein: The top conductive structure directly covers the ohmic contact layer, and a majority of the light emitting layer is not shielded by the ohmic contact layer.

5. The micro light emitting diode according to claim 2, wherein: The ohmic contact layer is a metal film.

6. The micro light emitting diode according to claim 2, wherein: The thickness of the ohmic contact layer is less than 20 nm, and the lateral width of the ohmic contact layer is less than 0.5 μm.

7. The micro light emitting diode according to claim 2, wherein: The material of the ohmic contact layer includes at least one or more selected from the group consisting of metals of Group I, Group II, Group III, Group IV, Group VI, and Group VIII in the periodic table.

8. The micro light emitting diode according to claim 2, wherein: The top conductive structure is transparent, and the ohmic contact layer is transparent.

9. The micro light emitting diode according to any one of claims 1 to 3 and 5 to 8, wherein: The bottom dielectric layer is a composite reflective layer.

10. The micro light emitting diode according to claim 9, wherein: The composite reflective layer includes multiple layers, which at least include an insulating reflective dielectric layer and a composite metal reflective layer. The composite metal reflective layer is located at the bottom of the insulating reflective dielectric layer and contacts the bottom conductive layer.

11. The micro light emitting diode according to claim 10, wherein: The composite metal reflective layer has multiple layers.

12. The micro light emitting diode according to claim 10, wherein: The insulating reflective dielectric layer further includes a top insulating dielectric layer and a bottom Bragg reflector.

13. The micro light emitting diode according to claim 12, wherein: The top insulating dielectric layer has no less than three layers.

14. The micro light emitting diode according to claim 12, wherein: The material of the top insulating dielectric layer is metal oxide.

15. The micro light emitting diode according to claim 1, wherein: The lateral width of the bottom dielectric layer is not less than the width of the bottom of the light emitting layer.

16. The micro light emitting diode according to claim 15, wherein: The light emitting layer also includes a first type semiconductor layer, an active layer and a second type semiconductor layer from top to bottom. The second type semiconductor layer has a protruding top extending beyond the active layer and the first type semiconductor layer, and One end of the conductive side arm covers and contacts the protruding top of the second type semiconductor layer, and the other end of the conductive side arm contacts the bottom conductive layer.

17. The micro-light emitting diode according to claim 16, wherein: The lateral width of the bottom conductive layer is greater than the lateral width of the second type semiconductor layer and the lateral width of the bottom dielectric layer, so that the bottom conductive layer has a protruding top extending beyond the second type semiconductor layer and the bottom dielectric layer, and At least a portion of the conductive side arm is supported on the protruding top of the bottom conductive layer.

18. The micro light emitting diode according to claim 17, wherein: The lateral width of the bottom conductive layer is less than 2 μm.

19. The micro light emitting diode according to claim 17, wherein: A width of the protruding top of the bottom conductive layer is not greater than a width of the protruding top of the second type semiconductor layer.

20. The micro light emitting diode according to claim 19, wherein: The second type semiconductor layer further includes a second type top semiconductor layer and a second type bottom semiconductor layer, wherein the second type bottom semiconductor layer extends outward relative to the second type top semiconductor layer to form a protruding top portion.

21. The micro light emitting diode according to claim 20, wherein: The material of the second type top semiconductor layer is different from the material of the second type bottom semiconductor layer.

22. The micro light emitting diode according to claim 21, wherein: The second type top semiconductor layer is AlGaInP, the second type bottom semiconductor layer is GaP; the first type semiconductor layer is AlInP.

23. The micro light emitting diode according to claim 20, wherein: The end of the conductive side arm: in electrical contact with said protruding top portion of said second type bottom semiconductor layer, is not in electrical contact with the top semiconductor layer of the second type, and There is no electrical contact with the light emitting layer and the first type semiconductor layer.

24. The micro-light emitting diode according to any one of claims 16 to 23, wherein: The lateral width of the first type semiconductor layer is equal to or greater than the lateral width of the active layer.

25. The micro light emitting diode according to claim 16, wherein: The lateral width of the first type semiconductor layer is smaller than the lateral width of the active layer.

26. The micro light emitting diode according to claim 1, wherein: The conductive side arm has an inverted L-shape.

27. The micro-light emitting diode according to claim 1, wherein: The conductive side arms are attached to and connected to the sidewalls of the bottom dielectric layer.

28. The micro light emitting diode according to claim 1, wherein: The lateral width of the bottom conductive layer is greater than the lateral width of the bottom dielectric layer, and the sidewall of the bottom conductive layer protrudes beyond the sidewall of the conductive side arm.

29. The micro-light emitting diode according to claim 16, further comprising: a transparent isolation layer covering at least the protruding top of the second type semiconductor layer, the top and sidewalls of the conductive side arm, the sidewalls of the light emitting layer and the sidewalls of the first type semiconductor layer, and The top conductive structure is located on the top of the transparent isolation layer.

30. The micro-light emitting diode according to claim 1, wherein: The conductive side arm is made of conductive metal.

31. The micro-light emitting diode according to claim 16, wherein: The first type semiconductor layer is an N-type semiconductor layer, and the second type semiconductor layer is a P-type semiconductor layer.

32. The micro-light emitting diode according to claim 16, wherein: The first type semiconductor layer is a P type semiconductor layer, and the second type semiconductor layer is an N type semiconductor layer.

33. The micro-light emitting diode according to claim 1, wherein: The material of the bottom conductive layer includes one or more conductive metals.

34. The micro light emitting diode according to claim 1, further comprising a circuit substrate located at the bottom of the bottom conductive layer, wherein the bottom conductive layer serves as a bonding layer bonded to a surface of the circuit substrate.

35. The micro-light emitting diode according to claim 34, wherein: The circuit substrate includes at least a driving circuit for controlling light emission of the light emitting layer.

36. The micro-light emitting diode according to claim 1, wherein: The micro light emitting diode has a light extraction efficiency of at least 20%.

37. The micro-light emitting diode according to claim 1, wherein: The micro light emitting diode has a light extraction efficiency of at least 40%.

38. The micro-light emitting diode according to claim 1, wherein: The micro light emitting diode has a light extraction efficiency of at least 60%.

Images