Micro light emitting diode chip and display device

Abstract

This invention discloses a miniature light-emitting diode (LED) chip, including, for example, an epitaxial structure. The epitaxial structure includes a first-doped semiconductor layer, a second-doped semiconductor layer, and an active layer located between the first and second-doped semiconductor layers. A patterned structure is provided on the light-emitting side of the first-doped semiconductor layer away from the active layer. The long side *a* of the miniature LED chip, the thickness *b* of the miniature LED chip, and the peak-valley height difference *c* of the patterned structure satisfy the conditions: 0.01 ≤ *b / a* ≤ 6 and 0.01 ≤ *c / b* ≤ 0.3. This invention, by designing the structural dimensions and / or shape of the miniature LED chip, for example, designing the peak-valley height difference of the patterned structure to satisfy the condition 0.01 ≤ *c / b* ≤ 0.3, can reduce the power of laser stripping, increase the process window, and improve light extraction efficiency. This invention also provides a display device using the aforementioned miniature LED chip.

Description

Technical Field

[0001] This invention relates to the field of solid-state light-emitting device technology, and in particular to a micro light-emitting diode chip and a display device using the micro light-emitting diode chip. Background Technology

[0002] Micro-LED chips typically refer to semiconductor light-emitting diode chips whose length, width, and thickness are all less than 100 micrometers (μm). To overcome total internal reflection and improve the light extraction efficiency (or light-emitting efficiency) of Micro-LED chips, related technologies include the use of traditional patterned sapphire substrate (PSS) processes to fabricate Micro-LED chips. However, in the process of laser lift-off (LLO) of traditional patterned sapphire substrates, the required laser energy is high and the process window is small, which can easily lead to low laser lift-off yield, or chip damage or breakage. Summary of the Invention

[0003] Therefore, in order to overcome at least some of the defects and deficiencies of the prior art, embodiments of the present invention provide a micro light-emitting diode chip and a display device using such a micro light-emitting diode chip.

[0004] Specifically, one embodiment of the present invention provides a micro light-emitting diode chip, comprising an epitaxial structure; wherein the epitaxial structure includes a first doped semiconductor layer, a second doped semiconductor layer, and an active layer located between the first doped semiconductor layer and the second doped semiconductor layer, a patterned structure is provided on the light-emitting side of the first doped semiconductor layer away from the active layer, and the long side a of the micro light-emitting diode chip, the thickness b of the micro light-emitting diode chip, and the peak-valley height difference c of the patterned structure satisfy the conditions: 0.01≤b / a≤6 and 0.01≤c / b≤0.3.

[0005] In one embodiment of the present invention, the peak-valley height difference c of the patterned structure satisfies the condition: c < 1 μm.

[0006] In one embodiment of the present invention, the peak-valley height difference c of the patterned structure satisfies the condition: 0.1μm≤c<1μm.

[0007] In one embodiment of the present invention, the peak-valley height difference c of the patterned structure satisfies the condition: c < 0.1 μm.

[0008] In one embodiment of the present invention, the long side a of the micro light-emitting diode chip is less than 100 μm, and the thickness b of the micro light-emitting diode chip is less than 20 μm.

[0009] In one embodiment of the present invention, the patterned structure is a two-dimensional photonic crystal structure.

[0010] In one embodiment of the present invention, the peak-valley height difference of the patterned structure is less than or equal to 1.5 μm.

[0011] In one embodiment of the present invention, the patterned structure is disposed on the light-emitting side of the first doped semiconductor layer away from the active layer via a pattern transfer method using a growth substrate with a patterned structure.

[0012] In one embodiment of the present invention, the patterned structure is disposed on the light-emitting side of the first doped semiconductor layer away from the active layer by dry etching after laser lift-off of the growth substrate.

[0013] Furthermore, another embodiment of the present invention provides a micro light-emitting diode chip, comprising an epitaxial structure with the growth substrate removed and no bonding substrate support. The epitaxial structure includes a first doped semiconductor layer, a second doped semiconductor layer, and an active layer located between the first doped semiconductor layer and the second doped semiconductor layer. A patterned structure is provided on the light-emitting side of the first doped semiconductor layer away from the active layer, and the peak-valley height difference of the patterned structure is less than 1 micrometer. The long side of the micro light-emitting diode chip is less than 100 micrometers, the thickness of the micro light-emitting diode chip is less than or equal to 10 micrometers, and the thickness b of the micro light-emitting diode chip and the peak-valley height difference c of the patterned structure satisfy the condition: 0.01≤c / b≤0.3.

[0014] In addition, an embodiment of the present invention provides a display device comprising: a circuit board having a plurality of electrode structures, each of the electrode structures including a pair of electrodes; and a plurality of micro light-emitting diode chips as described in any of the foregoing embodiments, disposed on the circuit board and electrically connected to the plurality of electrode structures respectively.

[0015] As can be seen from the above, the embodiments of the present invention design the structural dimensions and / or shape of the micro light-emitting diode chip 100. For example, the peak-valley height difference of the patterned structure is designed to meet the condition 0.01≤c / b≤0.3. It can even be combined with photonic crystal design to optimize the light extraction efficiency. This can reduce the power of laser stripping, increase the process window, not damage the chip, and improve the light extraction efficiency. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to the first embodiment of the present invention.

[0018] Figures 2A-2E This is a schematic diagram of the process structure of a method for manufacturing a micro light-emitting diode chip according to the first embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of the structure of a miniature light-emitting diode chip according to the second embodiment of the present invention.

[0020] Figure 4 This is a schematic diagram of the structure of a display device according to the third embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments described in the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0022] It should be noted that all directional indicators (such as up, down, left, right, front, and back) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0023] In the embodiments of this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0024] [First Embodiment]

[0025] See Figure 1The first embodiment of the present invention provides a micro-light-emitting diode chip 100, which includes an epitaxial structure 110 with the growth substrate removed and without bonding substrate support. Here, the bonding substrate typically refers to a substrate connected to the epitaxial structure via a bonding process (e.g., metal bonding). The epitaxial structure 110 includes: a first doped semiconductor layer 112, a second doped semiconductor layer 116, and an active layer 114, such as a multiple quantum well (MQW) layer, located between the first doped semiconductor layer 112 and the second doped semiconductor layer 116. A patterned structure 113, such as a microstructure array, is provided on the side of the first doped semiconductor layer 112 away from the active layer 114 (i.e., the light-emitting side of the micro-light-emitting diode chip 100). It is understood that, in addition to the epitaxial structure 110, the micro-light-emitting diode 100 of this embodiment also includes, for example, a first electrode electrically connected to the first doped semiconductor layer 112. Figure 1 (Not shown) and a second electrode electrically connected to the second doped semiconductor layer 116. Figure 1 (Not shown), but for the sake of focusing on describing the epitaxial structure 110 with the patterned structure 113 in this embodiment of the invention, the specific description of the first electrode and the second electrode will be omitted below. In addition, it is worth mentioning that, taking the blue Micro-LED chip as an example, the epitaxial structure 110 of this embodiment can also be provided with other functional layers according to actual needs, such as an unintentionally doped gallium nitride layer (u-GaN), a stress relief layer located between the N-type semiconductor layer and the multi-quantum well layer, an electron blocking layer (EBL) located between the multi-quantum well layer and the P-type semiconductor layer, etc., and this embodiment of the invention is not limited thereto.

[0026] Taking a blue Micro-LED chip as an example, the first doped semiconductor layer 112 is, for example, an N-type GaN (gallium nitride) layer, the second doped semiconductor layer 116 is, for example, a P-type GaN layer, and the active layer 114 is, for example, an InGaN / GaN multiple quantum well layer. Of course, the micro-LED chip 100 in this embodiment is not limited to a blue Micro-LED chip; it can also be a Micro-LED chip of other colors, such as a green Micro-LED chip, a red Micro-LED chip, etc. Accordingly, the composition and materials of each layer in the epitaxial structure 110 need to be adjusted, but this is a mature existing technology and will not be elaborated further here.

[0027] As mentioned above, regarding the Micro-LED chip fabrication process using a traditional patterned sapphire substrate (PSS) structure with a peak-to-valley height difference greater than 2.5 μm in the microstructure array on the PSS structure, the fabrication of the F-COC (Free-standing Chip on Carrier) structure requires the use of micro-adhesive to temporarily fix the chip surface, followed by laser lift-off to remove the substrate. During this process, because the peak-to-valley height difference of the surface microstructure array in the traditional PSS structure is large, the laser lift-off requires high energy and has a small process window, which easily leads to low laser lift-off yield, chip damage, or breakage. This embodiment aims to reduce the laser lift-off energy and increase the process window to overcome the technical problems of low laser lift-off yield or chip damage or breakage that easily occur in related technologies. The structural dimensions and / or shape of the micro-LED chip 100 are designed accordingly. For example, the long side a of the micro-LED chip 100 (e.g., ...) Figure 1 The length a) in the X direction of the micro LED chip 100 and the thickness b) of the micro LED chip 100 (i.e., Figure 1 The height in the Z direction (not shown) and the peak-valley height difference c of the patterned structure 113 (i.e., Figure 1 The height c in the Z direction satisfies the conditions: 0.01≤b / a≤6, 0.01≤c / b≤0.3; where b is defined as the overall thickness of the micro-LED chip 100 in the Z direction, and b / a mainly describes the size specifications of the micro-LED chip 100 itself (typically, b / a≤1), and the value of the thickness b can be determined by the thickness of the epitaxial structure 110, the electrode thickness of the micro-LED chip 100, and the semiconductor layer etching depth (e.g., Mesa etching depth). The condition 0.01≤b / a≤6 indicates that the long side a of the micro-LED chip 100 can be greater than the thickness b (e.g., 0.01≤b / a<1) so that the shape of the micro-LED chip 100 appears longer but thinner, which is beneficial for the thinning of the display device using this type of micro-LED chip 100, or it can be less than the thickness b (e.g., 1).

[0028] ​Preferably, the specific size of the peak-valley height difference c of the patterned structure 113 is set to be less than or equal to 1.5 μm, more preferably submicron or even nanometer scale. Here, submicron scale refers to the peak-valley height difference c of the patterned structure 113 (i.e., Figure 1 The height difference in the Z-direction, or the surface roughening height difference, satisfies the condition: 0.1μm ≤ c < 1μm. Here, nanometer level refers to the peak-valley height difference c of the patterned structure 113 satisfying the condition: c < 0.1μm (i.e., less than 100 nanometers). For example, in a specific embodiment, a < 100μm (or even less than 10μm), b < 20μm (more specifically, b ≤ 10μm), c ≤ 1.5μm, and the thickness of the epitaxial structure 110 is less than 10μm (specifically, 2-6μm, for example, 3-5μm), but the embodiments of the present invention are not limited thereto.

[0029] Furthermore, each microstructure in the patterned structure 113 can be strip-shaped, dome-shaped, columnar, etc., without specific limitations, as long as it can break total internal reflection to improve the light extraction efficiency (or light emission efficiency) of the micro LED chip 100.

[0030] In addition, to facilitate a clearer understanding of the micro-LED chip 100 of this embodiment, an exemplary fabrication method of the micro-LED chip 100 of this embodiment will be briefly described below using a blue Micro-LED chip as an example. Specifically:

[0031] First, such as Figure 2A As shown, a patterned sapphire substrate 200 is used as the growth substrate. Here, the patterned sapphire substrate 200 refers to a sapphire substrate with a patterned structure 202 formed on its surface.

[0032] Secondly, such as Figure 2B As shown, a buffer layer 1121, an N-type semiconductor layer 1120, an active layer 1140 (e.g., an MQW layer) and a P-type semiconductor layer 1160 are epitaxially grown sequentially on the surface of the patterned sapphire substrate 200 on which the patterned structure 202 is formed.

[0033] Then, Micro-LED chip (COW, chip on wafer) fabrication is performed. For example, using ICP (Inductively Coupled Plasma) dry etching, the Mesa structure is first fabricated, followed by the Isolation structure. Specifically, the P-type semiconductor layer 1160 and the active layer 1140 are etched using ICP until a portion of the N-type semiconductor layer 1120 is removed to form a mesa structure, thereby exposing a portion of the N-type semiconductor layer 1120. Then, ICP etching is used to pattern the bluestone substrate 200 to form the Isolation structure, defining multiple Micro-LED chips. Alternatively, the Isolation structure can be fabricated first, followed by the Mesa structure. After forming the Mesa and Isolation structures, N-electrodes 118a and P-electrodes 118b are formed, respectively, to electrically connect, for example, to the N-type semiconductor layer 1120 (corresponding to the first doped semiconductor layer 112) and the P-type semiconductor layer 1160 (corresponding to the second doped semiconductor layer 116), such as ohmic contacts. Figure 2C As shown.

[0034] Next, the COW structure, which includes the Mesa structure, Isolation structure, and N-electrode 118a and P-electrode 118b, is temporarily fixed to the temporary substrate 400 using a micro-adhesive. Figure 2D As shown.

[0035] Finally, the patterned sapphire substrate 200 is removed using laser lift-off, and the buffer layer 1121 is simultaneously ablated by the laser, thereby obtaining multiple Micro-LED chips temporarily fixed to the temporary substrate 400, that is, multiple micro-light-emitting diode chips 100 temporarily fixed to the temporary substrate 400, such as... Figure 2E As shown; it should be noted here that, Figure 2E The miniature light-emitting diode chip 100 shown is Figure 1 The miniature LED chip 100 shown is the same component, only... Figure 1 The micro LED chip 100 shown omits the drawing of the N-electrode 118a and P-electrode 118b. In this embodiment, the negative pattern of the patterned structure 202 of the patterned sapphire substrate 200 is transferred to the light-emitting side of the N-type semiconductor layer (first doped type semiconductor layer 112) to form the patterned structure 113 (e.g., ...). Figure 1 (or as shown in 2E), and the peak-valley height difference of the patterned structure 113 is preferably less than or equal to 1.5 μm, more preferably submicron or nanometer scale. Furthermore, from Figure 2EAs can be seen from the diagram, the patterned structure 113 and the N-type semiconductor layer 112 are an integral structure, that is, the patterned structure 113 is directly formed on the N-type semiconductor layer 112 and has the same material.

[0036] [Second Embodiment]

[0037] See Figure 3 A second embodiment of the present invention provides a micro-light-emitting diode chip 300, which includes an epitaxial structure 310 with the growth substrate removed and no bonding substrate support. The epitaxial structure 310 includes: a first-doped semiconductor layer 312, a second-doped semiconductor layer 316, and an active layer 314, such as a multiple quantum well layer, located between the first-doped semiconductor layer 312 and the second-doped semiconductor layer 316. A patterned structure 313, such as a two-dimensional photonic crystal structure, is provided on the side of the first-doped semiconductor layer 312 away from the active layer 314 (i.e., the light-emitting side of the micro-light-emitting diode chip 300). It is understood that, in addition to the epitaxial structure 310, the micro-light-emitting diode 300 of this embodiment also includes, for example, a first electrode electrically connected to the first-doped semiconductor layer 312. Figure 3 (Not shown) and a second electrode electrically connected to the second doped semiconductor layer 316. Figure 3 (Not shown), but for the purpose of focusing on describing the epitaxial structure 310 with the patterned structure 313 in this embodiment of the invention, the first electrode and the second electrode (see reference) will be omitted below. Figure 2E The specific description of the N electrode 118a and P electrode 118b in the figure is provided. Furthermore, it is worth mentioning that, taking a blue Micro-LED chip as an example, the epitaxial structure 310 of this embodiment can also be supplemented with other functional layers according to actual needs, such as an unintentionally doped gallium nitride layer (u-GaN), a stress relief layer located between the N-type semiconductor layer and the multi-quantum well layer, an electron blocking layer located between the multi-quantum well layer and the P-type semiconductor layer, etc. This embodiment of the invention is not limited to these.

[0038] Taking a blue Micro-LED chip as an example, the first doped semiconductor layer 312 is, for example, an N-type GaN layer, the second doped semiconductor layer 316 is, for example, a P-type GaN layer, and the active layer 314 is, for example, an InGaN / GaN multiple quantum well layer. Of course, the micro-LED chip 300 in this embodiment is not limited to a blue Micro-LED chip; it can also be a Micro-LED chip of other colors, such as a green Micro-LED chip, a red Micro-LED chip, etc. Accordingly, the composition and materials of each layer in the epitaxial structure 310 need to be adjusted as necessary, but this is a mature existing technology and will not be elaborated further here.

[0039] As described above, this embodiment designs the structural dimensions and / or shape of the micro LED chip 300, for example, the long side a of the micro LED chip 300 (e.g., Figure 3 The length a) in the X direction of the micro LED chip 300 and the thickness b) of the micro LED chip 300. Figure 3 The height in the Z direction (not shown) and the peak-valley height difference c between the patterned structure 313 (two-dimensional photonic crystal structure) and the valley height difference c (i.e. Figure 3 The height c in the Z direction satisfies the conditions: 0.01≤b / a≤6, 0.01≤c / b≤0.3; where b is defined as the overall thickness of the micro-LED chip 300 in the Z direction, and b / a mainly describes the size specifications of the micro-LED chip 300 itself (typically, b / a≤1), and the value of thickness b can be determined by the thickness of the epitaxial structure 310, the electrode thickness of the micro-LED chip 300, and the etching depth of the semiconductor layer (e.g., Mesa etching depth). The condition 0.01≤b / a≤6 indicates that the long side a of the micro-LED chip 300 can be greater than the thickness b (e.g., 0.01≤b / a<1) so that the shape of the micro-LED chip 300 appears longer but thinner, which is beneficial for the thinning of the display device using this type of micro-LED chip 300, or it can be less than the thickness b (e.g., 1).

[0040] Preferably, the peak-valley height difference of the patterned structure 313 (two-dimensional photonic crystal structure) is set to be less than or equal to 1.5 μm, more preferably sub-micron or even nanometer scale. Here, sub-micron scale refers to the peak-valley height difference c of the patterned structure 313 (i.e., Figure 3 The height difference in the Z direction (or the surface roughening height difference) satisfies the condition: 0.1μm≤c<1μm. Here, nanoscale refers to the peak-valley height difference c of the patterned structure 313 satisfying the condition: c<0.1μm.

[0041] ​Furthermore, for the two-dimensional photonic crystal structure 313, its lattice type can be a square lattice, a triangular lattice, or a honeycomb lattice, etc., without specific limitations, as long as it can improve the light extraction efficiency of the micro LED chip 300. It is worth noting that the photonic crystal structure has photon energy levels, which can improve the light extraction efficiency, and can also change / control the light pattern (light emission direction) and control the light wavelength as needed.

[0042] In addition, to facilitate a clearer understanding of the micro-LED chip 300 of this embodiment, an exemplary fabrication method of the micro-LED chip 300 of this embodiment will be briefly described below using a blue Micro-LED chip as an example. Specifically:

[0043] First, a sapphire substrate with a two-dimensional photonic crystal structure is fabricated. Specifically, a silicon dioxide layer is deposited on the sapphire substrate using a CVD process. A two-dimensional photonic crystal pattern is formed on the silicon dioxide layer using electron beam lithography. Then, the silicon dioxide in the periodically distributed micropore regions of the pattern is removed by dry etching to expose the sapphire substrate. In other words, a two-dimensional photonic crystal structure is formed on the sapphire substrate, resulting in a sapphire substrate with a patterned structure (such as a two-dimensional photonic crystal structure) on its surface.

[0044] Secondly, an unintentionally doped GaN layer (u-GaN), an N-type GaN layer, an InGaN / GaN multi-quantum-well layer, and a P-type GaN layer are epitaxially grown sequentially on a sapphire substrate with a two-dimensional photonic crystal structure, wherein the u-GaN first fills the periodically distributed micropore region.

[0045] Next, Micro-LED chip (COW) fabrication is performed. For example, the Mesa structure can be fabricated first using ICP dry etching, followed by the Isolation structure. Specifically, the P-type GaN layer and the InGaN / GaN multi-quantum-well layer can be etched using ICP until a portion of the N-type GaN layer is removed to form a mesa structure, exposing a portion of the N-type GaN layer. Then, ICP etching is used to etch onto a sapphire substrate to form the Isolation structure, defining multiple Micro-LED chips. Alternatively, the Isolation structure can be fabricated first, followed by the Mesa structure. After forming the Mesa and Isolation structures, N-electrodes and P-electrodes are formed, electrically connected to the N-type GaN layer and P-type GaN layer, respectively.

[0046] Next, a micro-adhesive is used to temporarily fix the COW structure, which has the Mesa structure, Isolation structure and NP electrode formed thereon, to a temporary substrate.

[0047] Furthermore, a 248nm KrF excimer laser was used to remove the sapphire substrate to expose the interface where silicon dioxide and u-GaN coexist.

[0048] Finally, dry etching is used to simultaneously remove the u-GaN layer and silicon dioxide layer in the exposed area until the N-type GaN layer is etched down. Specifically, using a different etching ratio of GaN to silicon dioxide (e.g., 6:1), and with the silicon dioxide layer as a mask layer, a light-emitting side of the N-type GaN layer (first doped semiconductor layer 312) is formed. Figure 3 The patterned structure 313 shown allows for the creation of multiple Micro-LED chips that are temporarily fixed to a temporary substrate and have the patterned structure 313 disposed thereon. In other words, multiple chips temporarily fixed to a temporary substrate, such as... Figure 3 The micro-light-emitting diode 300 is shown. In this embodiment, the pattern of the two-dimensional photonic crystal on the sapphire substrate with the two-dimensional photonic crystal structure is transferred to the u-GaN layer located on the light-emitting side of the N-type GaN layer, and the peak-valley height difference of the patterned structure 313 is less than or equal to 1.5 μm, preferably submicron or nanometer scale. Moreover, the patterned structure 313 (two-dimensional photonic crystal structure) and the N-type GaN layer (corresponding to the first doped semiconductor layer 312) are two layers in contact with each other.

[0049] It is worth noting that the aforementioned embodiments of the present invention use a growth substrate (e.g., a sapphire substrate) with a patterned surface to fabricate the micro-LED chip 100 / 300, so as to transfer the pattern of the patterned structure on the surface of the growth substrate to the light-emitting side of the micro-LED chip 100 / 300, that is, to obtain the patterned structure 113 / 313 on the light-emitting side of the micro-LED chip 100 / 300 by using a pattern transfer method; however, the embodiments of the present invention are not limited thereto. A flat substrate can also be used as the growth substrate first, and a semiconductor layer can be epitaxially grown to fabricate a micro-LED chip without a patterned structure. After laser lift-off of the flat substrate, a dry etching method (e.g., ICP etching) can be used to roughen the light-emitting side of the micro-LED chip to form a patterned structure, which can also achieve the same result. Figure 1 or Figure 3 The micro LED chip shown is 100 / 300. The dry etching method used here avoids the technical problems in related technologies, such as the need to use strong acid and alkali solutions for surface roughening, which can damage the micro-adhesive and lead to chip detachment, thus hindering subsequent chip transfer processes. At the same time, it can improve the light extraction efficiency of the micro LED chip.

[0050] Furthermore, it is worth noting that the exemplary manufacturing method of the foregoing embodiments of the present invention is illustrated by example of manufacturing a flip-chip Micro-LED, but the micro-LED chip of the embodiments of the present invention is not limited to a flip-chip Micro-LED, and can also be a vertical structure Micro-LED chip, that is, the P electrode and the N electrode are located above and below the Micro-LED chip respectively.

[0051] [Third Embodiment]

[0052] Figure 4 This is a schematic diagram of the structure of a display device according to a third embodiment of the present invention. Figure 4 As shown, the display device 40 includes a circuit board 41 and a plurality of ( Figure 4 (Only three are shown as examples) Miniature light-emitting diode chips 43. Multiple ( ) are disposed on the circuit board 41. Figure 4 (Only three are shown as examples) Electrode structures, and each of the electrode structures includes a pair of electrodes 411 and 413; the plurality of micro light-emitting diode chips 43 are disposed on the circuit board 41 and are electrically connected to the plurality of electrode structures respectively. More specifically, the circuit substrate 41 is, for example, a complementary metal-oxide-semiconductor (CMOS) substrate, a liquid crystal on silicon (LCOS) substrate, a thin film transistor (TFT) substrate, or other substrates with working circuits, without limitation; the plurality of micro-LED chips 43 may be Micro-LED chips of the same color or Micro-LED chips of multiple different colors (e.g., R, G, B); each of the micro-LED chips 43 is, for example, the micro-LED chip 100 of the first embodiment or the micro-LED chip 300 of the second embodiment, having an N electrode 43a and a P electrode 43b, and the N electrode 43a and the P electrode 43b are electrically connected to the electrodes 411 and 413 in the corresponding electrode structure respectively by solder 42. Furthermore, it is understood that in other embodiments, when the micro-LED chip 43 is made of... Figure 4When the flip-chip Micro-LED shown is replaced with a vertical structure Micro-LED chip, one of its N-electrode and P-electrode can be electrically connected to one of electrodes 411 and 413 in the electrode structure via solder, and the other can be electrically connected to the other of electrodes 411 and 413 in the electrode structure via wire bonding. It is worth noting that the display device 40 of this embodiment, by employing a micro-LED chip with high light extraction efficiency, can achieve high display brightness or low power consumption.

[0053] Furthermore, it is understood that the foregoing embodiments are merely illustrative examples of the present invention. Provided that the technical features do not conflict, the structure is not contradictory, and the purpose of the invention is not violated, the technical solutions of the various embodiments can be arbitrarily combined and used.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A miniature light-emitting diode chip, comprising an epitaxial structure; characterized in that, The epitaxial structure is an epitaxial structure without a growth substrate and without bonding substrate support; the epitaxial structure includes a first doped semiconductor layer, a second doped semiconductor layer, and an active layer located between the first doped semiconductor layer and the second doped semiconductor layer, a patterned structure is provided on the light-emitting side of the first doped semiconductor layer away from the active layer, and the patterned structure is an integral structure with the first doped semiconductor layer; and the long side a of the micro light-emitting diode chip, the thickness b of the micro light-emitting diode chip, and the peak-valley height difference c of the patterned structure satisfy the conditions: 0.01≤b / a≤6, and 0.01≤c / b≤0.

3.

2. The micro light-emitting diode chip as described in claim 1, characterized in that, The peak-valley height difference c of the patterned structure satisfies the condition: c < 1µm.

3. The miniature light-emitting diode chip as described in claim 2, characterized in that, The peak-valley height difference c of the patterned structure satisfies the condition: 0.1µm≤c<1µm.

4. The micro light-emitting diode chip as described in claim 2, characterized in that, The peak-valley height difference c of the patterned structure satisfies the condition: c < 0.1 µm.

5. The micro light-emitting diode chip as described in any one of claims 2 to 4, characterized in that, The long side a of the micro LED chip is less than 100µm, and the thickness b of the micro LED chip is less than 20µm.

6. The miniature light-emitting diode chip as described in claim 1, characterized in that, The patterned structure is a two-dimensional photonic crystal structure.

7. The micro light-emitting diode chip as described in claim 1, characterized in that, The peak-valley height difference of the patterned structure is less than or equal to 1.5µm.

8. The micro light-emitting diode chip as described in claim 1, characterized in that, The patterned structure is formed on the light-emitting side of the first doped semiconductor layer away from the active layer by a pattern transfer method using a growth substrate with a patterned structure.

9. The micro light-emitting diode chip as described in claim 1, characterized in that, The patterned structure is formed on the light-emitting side of the first doped semiconductor layer, away from the active layer, by dry etching after laser lift-off of the substrate.

10. A miniature light-emitting diode chip, characterized in that, The epitaxial structure includes a growth substrate removed and no bonding substrate support. The epitaxial structure includes a first doped semiconductor layer, a second doped semiconductor layer, and an active layer located between the first doped semiconductor layer and the second doped semiconductor layer. A patterned structure is provided on the light-emitting side of the first doped semiconductor layer away from the active layer, and the peak-valley height difference of the patterned structure is less than 1 micrometer. The long side of the micro-light-emitting diode chip is less than 100 micrometers, the thickness of the micro-light-emitting diode chip is less than or equal to 10 micrometers, and the thickness b of the micro-light-emitting diode chip and the peak-valley height difference c of the patterned structure satisfy the condition: 0.01≤c / b≤0.

3.

11. A display device, comprising: A circuit board having multiple electrode structures, each of which includes a pair of electrodes. as well as A plurality of miniature light-emitting diode chips as described in any one of claims 1 to 10 are disposed on the circuit substrate and are electrically connected to the plurality of electrode structures respectively.

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