Miniature light emitting diode and display panel

Abstract

The invention discloses a micro light emitting diode and a display panel. The miniature light-emitting diode comprises a first electric connection layer, a second electric connection layer and an epitaxial laminated layer located between the first electric connection layer and the second electric connection layer, wherein the upper surface of the epitaxial laminated layer comprises an ohmic contact region and a non-ohmic contact region; the non-ohmic contact region at least comprises an outer edge region located on the periphery of the upper surface of the epitaxial laminated layer; the outer edge region is doped with a non-conductive element, and the doping concentration of the non-conductive element is 1E16 / cm < 3 >-1E19 / cm < 3 >; a current expansion layer is arranged between the first electric connection layer and the epitaxial lamination layer, and the current expansion layer is located on the ohmic contact region. The miniature light-emitting diode can realize low-current density efficiency improvement.

Description

Technical Field

[0001] The present invention relates to the field of light emitting diodes, and in particular to a micro light emitting diode and a display panel. Background Art

[0002] Micro LED is a new generation of display technology that inherits the characteristics of light-emitting diodes. It has the advantages of small size, long life, low power consumption, fast response time and strong controllability. The color gamut of micro LEDs can be greater than 120%, and the pixel density (the number of pixels per inch) can exceed 1500.

[0003] The size of a micro-LED is less than 50 μm. At this time, non-radiative recombination is easily generated on the side wall of the core particle, and the thermal effect increases, which will seriously affect the luminous efficiency of the micro-LED. Summary of the invention

[0004] The problem solved by the present invention is to provide a micro light emitting diode and a display panel to improve the luminous efficiency under low current density.

[0005] In order to solve the above problems, the present invention provides a micro light emitting diode, comprising a first electrical connection layer, a second electrical connection layer and an epitaxial stack located between the first electrical connection layer and the second electrical connection layer; the upper surface of the epitaxial stack comprises an ohmic contact region and a non-ohmic contact region, the non-ohmic contact region at least comprises an outer edge region located around the upper surface of the epitaxial stack; the outer edge region is doped with a non-conductive element, and the doping concentration of the non-conductive element is 1E16 / cm 3 ~1E19 / cm 3 There is also a current spreading layer between the first electrical connection layer and the epitaxial stack, and at least part of the current spreading layer is located on the ohmic contact area.

[0006] Optionally, in a top view, the current spreading layer is in the shape of an extended rectangle, the epitaxial stack has an upper step surface, the shape centers of the extended rectangle and the upper step surface coincide, and the side length of the extended rectangle is less than 0.8 of the side length of the upper step surface.

[0007] Optionally, the first electrical connection layer is a first electrode layer, and the second electrical connection layer is a second electrode layer.

[0008] Optionally, the non-conductive element is an inert element.

[0009] Optionally, the non-conductive element is argon, helium or nitrogen; and the doping depth of the non-conductive element is 0.2 μm to 2 μm.

[0010] Optionally, the non-conductive element is doped by ion implantation.

[0011] In order to solve the above problems, the present invention also provides a micro light emitting diode, comprising a first electrical connection layer, a second electrical connection layer and an epitaxial stack located between the first electrical connection layer and the second electrical connection layer; the upper surface of the epitaxial stack comprises an ohmic contact region and a non-ohmic contact region, the non-ohmic contact region at least comprises an outer edge region located around the upper surface of the epitaxial stack; the outer edge region is doped with a non-conductive element, and the doping concentration of the non-conductive element is 1E16 / cm 3 ~1E19 / cm 3 ; The first electrical connection layer covers the ohmic contact area; the upper surface of the epitaxial stack also has a current blocking layer, the current blocking layer is located on the non-ohmic contact area surrounded by the ohmic contact area, and the side and upper surface of the current blocking layer are covered by the first electrical connection layer.

[0012] Optionally, in the top view direction, the shape of the first electrical connection layer is an electrical connection rectangle, the epitaxial stack has an upper step surface, the shape centers of the electrical connection rectangle and the upper step surface coincide, and the side length of the electrical connection rectangle is less than 0.8 of the side length of the upper step surface.

[0013] Optionally, in a top view, the current blocking layer is in the shape of a blocking rectangle, the blocking rectangle coincides with the center of the upper step surface, and the side length of the blocking rectangle is less than 0.5 of the side length of the upper step surface.

[0014] Optionally, the first electrical connection layer directly covers the ohmic contact region; and the side surface and the upper surface of the current blocking layer are covered by the first upper electrical connection layer.

[0015] Optionally, the non-conductive element is an inert element.

[0016] Optionally, the non-conductive element is argon, helium or nitrogen; and the doping depth of the non-conductive element is 0.2 μm to 2 μm.

[0017] Optionally, the non-conductive element is doped by ion implantation.

[0018] In order to solve the above problems, the present invention also provides a micro light emitting diode, comprising a first electrical connection layer, a second electrical connection layer and an epitaxial stack located between the first electrical connection layer and the second electrical connection layer; the upper surface of the epitaxial stack comprises an ohmic contact region and a non-ohmic contact region, the non-ohmic contact region at least comprises an outer edge region located around the upper surface of the epitaxial stack; the outer edge region is doped with a non-conductive element, and the doping concentration of the non-conductive element is 1E16 / cm 3 ~1E19 / cm 3; The first electrical connection layer covers the ohmic contact area; the epitaxial stack is also embedded with a current blocking layer, the upper surface of the current blocking layer is in the same plane as the upper surface of the outer edge area, the upper surface of the current blocking layer is surrounded by the ohmic contact area, and the upper surface of the current blocking layer is also covered by the first electrical connection layer.

[0019] Optionally, in a top view, the first electrical connection layer is shaped like an electrical connection rectangle, the epitaxial stack has an upper step surface, the centers of the electrical connection rectangle and the upper step surface coincide, and the side length of the electrical connection rectangle is less than 0.8 of the side length of the upper step surface.

[0020] Optionally, in a top view, the shape of the current blocking layer is a blocking rectangle, the shape centers of the blocking rectangle and the upper step surface coincide, and the side length of the blocking rectangle is less than 0.5 of the side length of the upper step surface.

[0021] Optionally, the material of the first electrical connection layer is a transparent conductive material.

[0022] Optionally, the first electrical connection layer covers the ohmic contact region, and the upper surface of the current blocking layer is also covered by the first electrical connection layer.

[0023] Optionally, the non-conductive element is an inert element.

[0024] Optionally, the non-conductive element is argon, helium or nitrogen; and the doping depth of the non-conductive element is 0.2 μm to 2 μm.

[0025] Optionally, the non-conductive element is doped by ion implantation.

[0026] In order to solve the above problem, the present invention further provides a display panel, comprising the micro light emitting diode as described above.

[0027] In the micro-LED structure provided by the present invention, the outer edge region of the epitaxial stack surface is designed to be doped with a corresponding concentration of non-conductive elements, so that the conductivity of the outer edge region is reduced, so that the outer edge region will not conduct current regardless of the material layer structure it contacts, that is, the outer edge region is always a non-ohmic contact region. This structure can better prevent the current from diffusing to the edge, and thus avoid the non-radiative recombination problem caused by the current flowing through the side wall area of ​​the mesa structure, so that the photoelectric efficiency can be improved at a low current density. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of a cross-sectional structure of a micro light emitting diode provided by an embodiment of the present invention; Figure 2 yes Figure 1 A schematic diagram of a partial top view of the structure of the micro light emitting diode shown; Figure 3 is a schematic diagram of a cross-sectional structure of another micro light emitting diode provided by another embodiment of the present invention; Figure 4 yes Figure 3 A schematic diagram of a partial top view of the structure of the micro light emitting diode shown; Figure 5 is a schematic diagram of a cross-sectional structure of another micro light emitting diode provided by another embodiment of the present invention; Figure 6 yes Figure 5 A schematic diagram of a partial top view of the structure of the micro light emitting diode shown; Figure 7 is a schematic diagram of a cross-sectional structure of another micro light emitting diode provided by another embodiment of the present invention; Figure 8 yes Figure 7 A schematic diagram of the top view of the micro light emitting diode shown; Fig. 9 is a schematic top view of a micro light emitting diode provided by another embodiment of the present invention; Fig.10 It is a schematic diagram of a display panel provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In solving the technical problems mentioned in the background technology, the existing micro light emitting diodes generally adopt the following two methods: 1. Changing the design of the metal electrode on the current spreading layer to achieve different current diffusion effects. This method will cause the metal electrode to reflect light due to annealing or the high reflectivity of the metal itself, which will reduce the light extraction efficiency. Second, use the transparent electrode of the current spreading layer for patterned conduction. Although this method can change the current path, avoid small currents flowing through the edge of the table, and overcome the non-radiative recombination effect, the effect of relying solely on transparent electrodes for patterned current dispersion is not good, such as the problem of high chip voltage.

[0030] To this end, the present invention provides a new micro light emitting diode and a display panel to solve the above-mentioned existing deficiencies.

[0031] For a clearer representation, the present invention is described in detail below with reference to the accompanying drawings.

[0032] The present invention provides a micro light emitting diode. Figure 1 and Figure 2 , which includes a first electrical connection layer 160 , a second electrical connection layer 100 , and an epitaxial stack (not labeled) located between the first electrical connection layer 160 and the second electrical connection layer 100 .

[0033] like Figure 1 As shown, the epitaxial stack includes: a first conductive semiconductor layer 110, an active layer 120 located on the first conductive semiconductor layer 110, and a second conductive semiconductor layer 130 located on the active layer 120. Each of the above-mentioned layers of the epitaxial stack can be a single-layer structure or a multi-layer stack structure, and the materials and formation processes of each layer structure can be various known selections and combinations, which can refer to the corresponding prior art and will not be described in detail.

[0034] The upper surface of the epitaxial stack includes an ohmic contact region 130B and a non-ohmic contact region (not labeled), the non-ohmic contact region at least including an outer edge region 130A located around the upper surface of the epitaxial stack, the outer edge region 130A is doped with a non-conductive element, and the doping concentration of the non-conductive element is 1E16 / cm 3 ~1E19 / cm 3 .

[0035] The micro-LED provided in this embodiment is designed so that the outer edge region 130A is doped with a corresponding concentration of non-conductive elements, so that the conductivity of the outer edge region 130A decreases, so that the outer edge region 130A will not conduct current regardless of the material layer structure it contacts, that is, the outer edge region 130A is always a non-ohmic contact region. This structure can better prevent the current from diffusing to the edge, and thus avoid the non-radiative recombination problem caused by the current flowing through the sidewall area of ​​the mesa structure, so that the photoelectric efficiency can be improved at a low current density.

[0036] It should be noted that, because the outer edge region 130A is doped with non-conductive elements, the entire outer edge region 130A will not be an ohmic contact region, and the resistivity of the outer edge region 130A is much higher than that when it is not doped. In other words, the ohmic contact region of this embodiment will only be located in the non-outer edge region surrounded by the outer edge region 130A. In this embodiment, the entire non-outer edge region is an ohmic contact region. However, in other embodiments, there may be further non-ohmic contact regions in the non-outer edge region (or in the middle region).

[0037] In this embodiment, the non-conductive element is doped by ion implantation. By ion implantation, the outer edge region 130A (i.e., the non-ohmic contact region) on the upper surface of the epitaxial stack is subjected to ion implantation, so that the conductivity of the outer edge region 130A decreases, so that the current can be better confined to the required position. Figure 1 As shown by the dotted arrow in the figure, the current is diffused in the set direction, thereby increasing the effective current density and improving the luminous efficiency. In other embodiments, other methods can also be used to dope the outer edge region with a corresponding concentration of non-conductive elements.

[0038] The non-conductive element is an inert element, for example, argon (Ar) or helium (He), or both of these elements are doped simultaneously.

[0039] The non-conductive element may also be other elements, such as nitrogen (N), etc. The doping of the non-conductive element may also be a mixed doping of an inert element and a non-inert element.

[0040] In this embodiment, the doping depth of the non-conductive element may be 0.2 μm to 2 μm. In this case, the doping depth may be deeper than that of the active layer 120 .

[0041] Please refer to Figure 1 A current spreading layer 150 is further provided between the first electrical connection layer 160 and the epitaxial stack, and the current spreading layer 150 is located on the ohmic contact region 130B.

[0042] In this embodiment, the first electrical connection layer 160 uses a metal electrode, that is, the first electrical connection layer 160 can be a first electrode layer, and its material is selected from metal materials, such as gold (Au), titanium (Ti), nickel (Ni), chromium (Cr), aluminum (Al) or silver (Ag), and their alloys. The second electrical connection layer 100 can be a second electrode layer, and its material can be the same as that of the first electrical connection layer 160, or different from that of the first electrical connection layer 160. It should be noted that in other embodiments, the first electrical connection layer and the second electrical connection layer can also be other non-metallic conductive material layers.

[0043] The material of the current spreading layer 150 may be a transparent conductive material, specifically indium tin oxide (ITO) or indium zinc oxide (IZO).

[0044] In this embodiment, the thickness of the current spreading layer 150 can range from 10Å to 3000Å, preferably 100Å. The top layer structure of the outer region of the second conductive semiconductor layer 130 is usually highly carbon-doped gallium phosphide for generating red light, or P-GaN for generating blue light. When this top layer structure realizes ohmic contact with the current spreading layer 150, the transparent conductive material of the current spreading layer 150 is mostly ITO. Moreover, the thickness of ITO is usually required to be thick (reaching a certain thickness or more) to form ohmic contact better. Therefore, in this embodiment, the thickness of the current spreading layer 150 is set to 10Å~3000Å.

[0045] It should be noted that Figure 1Although the current spreading layer 150 is only located on the ohmic contact area 130B, the surface of the outer edge area 130A provided in the present invention is a structure that has been treated with ion implantation. Under this structural condition, even if the current spreading layer 150 covers the outer edge area 130A at the same time, it can still be ensured that the ohmic contact is formed only in the area that has not been treated with ion implantation. This is the advantage brought by the ion implantation treatment of the surface of the outer edge area 130A, which also results in more size margins when manufacturing the current spreading layer 150.

[0046] In this embodiment, the area of ​​the first electrical connection layer 160 is consistent with the area of ​​the current spreading layer 150 when viewed from the top. Figure 1 The cross-sectional width of the first electrical connection layer 160 is shown to be the same as the cross-sectional width of the current spreading layer 150, which can be referred to in the following Figure 2 Corresponding content.

[0047] Meanwhile, in this embodiment, the ranges of the outer edge region 130A and the non-ohmic contact region are consistent, that is, the region where the outer edge region 130A is located is the entire non-ohmic contact region on the upper surface of the epitaxial stack.

[0048] Therefore, in this embodiment, the second conductive semiconductor layer 130 of the uppermost epitaxial stack has an ohmic contact area 130B because the surface of the second conductive semiconductor layer 130 in contact with the current spreading layer 150, and a non-ohmic contact area, i.e., an outer edge area 130A, on the outer edge of the second conductive semiconductor layer 130 that is not in contact with the current spreading layer 150. This structure ensures that the performance of the micro light emitting diode is improved.

[0049] The micro light emitting diode of this embodiment further includes an insulating layer 140 for protecting the epitaxial stack and the current spreading layer 150 . The insulating layer 140 covers the side surfaces of the epitaxial stack and the outer edge region 130A.

[0050] In this embodiment, the ion implantation process specifically implants ions into the epitaxial stack at both sides below the current spreading layer 150, and implants high-resistance impurities, such as nitrogen, to reduce the possibility of current being injected into the epitaxial stack from the side. Since nitrogen is used as the implanted non-conductive element, nitrogen gas can be used as the ion source.

[0051] In other embodiments, the outer edge region 130A of the non-ohmic contact region is used as the region to be treated by ion implantation, and an argon (Ar) ion source or a helium (He) ion source may also be used.

[0052] In this embodiment, ion implantation into the outer edge region 130A around the upper surface of the epitaxial stack may include: A silicon dioxide layer (not shown) is formed on the surface of the epitaxial stack, specifically on the upper surface of the outer region of the second conductive type semiconductor layer 130; Then, a photoresist layer (not shown) is formed on the silicon dioxide layer, wherein the photoresist layer exposes the outer edge region 130A, and the photoresist layer may be formed by using a positive photoresist; The ion implantation is performed using the photoresist layer as a mask, i.e., the ion implantation is not performed in the area protected by the photoresist (because the implantation is into the photoresist), while the ion implantation is performed in the area exposed by the opening of the photoresist layer. The opening of the photoresist layer corresponds to the outer edge area 130A, specifically, the silicon dioxide layer on the outer edge area 130A is exposed. The ion implantation uses argon or nitrogen as an ion source.

[0053] The dose, energy and angle used in the ion implantation can be set accordingly as required.

[0054] In this embodiment, the outer edge region 130A is ion-implanted and has an ion-implanted layer after the treatment. The conductivity of the ion-implanted layer structure decreases, so that the outer edge region 130A will not conduct current no matter what material layer structure it contacts.

[0055] The outer edge region 130A of the ion implantation layer in this embodiment can better prevent the current from spreading to the edge, even if the outer edge region 130A is in contact with the current spreading layer 150 or other metal layers (such as a reflective metal layer). Figure 1 No ohmic contact will be formed, and therefore no current will be conducted, thereby avoiding the problem of non-radiative recombination caused by current flowing through the sidewall region of the mesa structure, thereby achieving an improvement in photoelectric efficiency at a low current density.

[0056] On the contrary, an epitaxial stack that has not been treated with ion implantation, that is, a conventional epitaxial stack, even if it does not contact the current spreading layer, however, due to the material of the second conductive semiconductor layer 130 itself, some current still has the opportunity to reach the edge of the mesa, and cannot achieve good diffusion control.

[0057] Figure 1 The arrows in the figure show the flow position of the current in the micro-LED structure, and it can be seen that the current is only conducted at the corresponding position of the ohmic contact area 130B. Therefore, it can be concluded that the micro-LED structure of this embodiment ensures that the current is extended to the required area, ensures the corresponding current density is increased, and improves the performance of the micro-LED.

[0058] As mentioned above, in some embodiments, the area of ​​the first electrical connection layer 160 and the area of ​​the current spreading layer 150 may be consistent. Figure 2The area of ​​the current spreading layer 150 is not shown, but it is easy to know that the area of ​​the first electrical connection layer 160 is the area of ​​the current spreading layer 150. It should be noted that in some embodiments, the area of ​​the first electrical connection layer 160 is slightly larger than the area of ​​the current spreading layer 150 and the first electrical connection layer is in contact with the epitaxial material. Figure 2 The rectangle corresponding to the first electrical connection layer 160 shown in FIG. 1 is the expanded rectangle corresponding to the current spreading layer 150 .

[0059] That is to say, Figure 2 In the top view, the current spreading layer 150 is in the shape of an extended rectangle (i.e. Figure 2 The first electrical connection layer 160 with a smaller area in the middle completely overlaps with the corresponding rectangle), and the epitaxial stack has an upper step surface. In this embodiment, the shape of the upper step surface is an epitaxial rectangle (ie Figure 2 the larger rectangle in the middle).

[0060] In this embodiment, the centers of the extended rectangle and the outer rectangle coincide. The coincidence of the centers indicates that the extended rectangle is located in the central area of ​​the outer rectangle. In addition, in this embodiment, the diagonals of the two rectangles also coincide, that is, the axes of symmetry coincide. At this time, the extended rectangle and the outer rectangle are similar, and because the axes of symmetry coincide, the two sets of opposite sides between the two rectangles are also parallel. In other embodiments, the extended rectangle and the outer rectangle may not be similar.

[0061] It should be noted that in other embodiments, in a top view, the step surface on the epitaxial stack may not be a rectangle, but other polygonal or other shapes.

[0062] In this embodiment, the side length of the extended rectangle is less than 0.8 of the side length of the corresponding side of the extended rectangle. Figure 2 The dimensions in the figure are h10≤0.8h11, h20≤0.8h21. At this time, the length of each side of the current spreading layer 150 is less than 80% of the length of each corresponding side of the chip epitaxial stack.

[0063] The above-mentioned size limitation limits the area where the current spreads to a suitable range, matches the epitaxial stack, and prevents non-radiative recombination of the current.

[0064] It should be noted that in other embodiments, in the top view direction, the shape of the current spreading layer may be other shapes, and the shape of the epitaxial stack may be other shapes, such as rhombus, circle, ellipse, pentagon or hexagon.

[0065] The micro light emitting diode provided in this embodiment improves the luminous efficiency by controlling the size of the current expansion layer 150 to limit the current to only pass through the middle area of ​​the chip structure, rather than the edge area of ​​the chip; on the one hand, the current density is increased, and on the other hand, the influence of edge non-radiative recombination on the luminous efficiency is reduced. At the same time, more importantly, the outer area of ​​the upper surface of the epitaxial stack is treated with high-resistance impurity ion implantation, so that the current further only passes through the middle area of ​​the chip structure, further improving the luminous efficiency and reducing the influence of edge non-radiative recombination on the luminous efficiency.

[0066] Another embodiment of the present invention provides another micro light emitting diode. Figure 3 and Figure 4 , which includes a first electrical connection layer 160, a second electrical connection layer 100 and an epitaxial stack located between the first electrical connection layer 160 and the second electrical connection layer 100, and reference may be made to the corresponding contents of the aforementioned embodiments.

[0067] In this embodiment, the upper surface of the epitaxial stack includes an ohmic contact region 130B and a non-ohmic contact region, and the non-ohmic contact region at least includes an outer edge region 130A located around the upper surface of the epitaxial stack. The surface of the outer edge region 130A is treated by ion implantation.

[0068] The first electrical connection layer 160 covers the ohmic contact region 130B.

[0069] The epitaxial stack also has a current blocking layer 170 on its upper surface. The current blocking layer 170 is located on the non-ohmic contact area surrounded by the ohmic contact area 130B. Figure 3 It is shown as a blocking area 130C, and the side and upper surface of the current blocking layer 170 are covered by the first electrical connection layer 160. Please refer to the corresponding content of the above-mentioned embodiment.

[0070] In this embodiment, the first electrical connection layer 160 is also made of metal material. The current blocking layer 170 is an insulating dielectric layer, and its material may be, for example, silicon dioxide or silicon nitride.

[0071] Please refer to Figure 4 In the top view, the shape of the first electrical connection layer 160 is an electrode rectangle ( Figure 4 The epitaxial stack has an upper step surface, and the shape of the upper step surface is an epitaxial rectangle ( Figure 4 The center of the electrode rectangle coincides with that of the extension rectangle, and the side length of the electrode rectangle is less than 0.8 of the side length of the corresponding side of the extension rectangle. Please refer to the corresponding content of the above-mentioned embodiment.

[0072] Please continue to refer to Figure 4 In the top view direction, the shape of the current blocking layer 170 is a blocking rectangle ( Figure 4The smallest rectangle in Figure 4 In the top view of FIG. 1 , the current blocking layer 170 is blocked by the first electrical connection layer 160. Therefore, Figure 4 The blocking rectangle and the extension rectangle have their centers overlapped, and the side length of the blocking rectangle is less than 0.5 of the side length of the corresponding side of the extension rectangle. In this embodiment, the symmetry axes of the above three rectangles also overlap.

[0073] Combination Figure 4 , the above-mentioned dimensional relationship can be expressed as: h10≤0.8h11, h20≤0.8h21, h30≤0.5h11, h40≤0.5h21. At this time, the length of each side of the first electrical connection layer 160 is less than 80% of the length of each side corresponding to the chip epitaxial stack, and the length of each side of the current blocking layer 170 is less than 50% of the length of each side corresponding to the chip epitaxial stack.

[0074] The difference from the above-mentioned embodiment is that this embodiment performs annealing after the ion implantation. The annealing temperature is controlled at 500° C. to 1000° C. Through annealing, this embodiment can further achieve better diffusion of the implanted ions and reduce the conductivity of the implanted ions in the outer edge region 130A.

[0075] Another embodiment of the present invention provides another micro light emitting diode. Figure 5 and Figure 6 , which includes a first electrical connection layer 180, a second electrical connection layer 100 and an epitaxial stack located between the first electrical connection layer 180 and the second electrical connection layer 100. The upper surface of the epitaxial stack includes an ohmic contact region 130B and a non-ohmic contact region, and the non-ohmic contact region at least includes an outer edge region 130A located around the upper surface of the epitaxial stack (the non-ohmic contact region also includes a barrier region 130C, refer to the following content). The outer edge region 130A is doped with a non-conductive element, and the doping concentration of the non-conductive element is 1E16 / cm 3 ~1E19 / cm 3 The first electrical connection layer 180 covers the ohmic contact region 130B. For these structures, reference may be made to the corresponding contents of the aforementioned embodiments.

[0076] The present embodiment is different from the previous embodiment in that the epitaxial stack is further embedded with a current blocking layer 170, and the material of the current blocking layer 170 is also an insulating dielectric material, which can be formed by first forming a trench in the second conductive semiconductor layer 130, and then filling and flattening. The upper surface of the current blocking layer 170 is in the same plane as the upper surface of the outer edge area 130A, and the upper surface of the current blocking layer 170 is also in the same plane as the upper surface of the ohmic contact area 130B. The upper surface of the current blocking layer 170 is surrounded by the ohmic contact area 130B, and the upper surface of the current blocking layer 170 is also covered by the first electrical connection layer 180. At this time, the upper surface of the current blocking layer 170 contacts the first electrical connection layer 180 to form a blocking area 130C that is also a non-ohmic contact area.

[0077] like Figure 6 In the top view, the first electrical connection layer 180 is in the shape of an electrode rectangle, the epitaxial stack has an upper step surface (i.e., an upper surface), the upper step surface is in the shape of an epitaxial rectangle, the electrode rectangle and the epitaxial rectangle are coincident in center, and the side length of the electrode rectangle is less than 0.8 of the side length of the epitaxial rectangle. In the top view, the current blocking layer 170 is in the shape of a blocking rectangle (shown in a dotted box in the figure), the blocking rectangle and the epitaxial rectangle are coincident in center, and the side length of the blocking rectangle is less than 0.5 of the side length of the epitaxial rectangle.

[0078] Different from the above-mentioned embodiments, in this embodiment, the material of the first electrical connection layer 180 is a transparent conductive material, such as indium tin oxide, indium zinc oxide, etc. That is, in this embodiment, a transparent conductive material is used as an electrode, and no metal electrode is made. This embodiment uses the material selection of the first electrical connection layer 180 and the current blocking layer 170 to better achieve the conduction of current at the corresponding restricted position, which can be referred to Figure 5 The dashed arrow in .

[0079] Please refer to Figure 6 ,and Figure 4 In the present embodiment, the size relationship is the same as that of the first electrical connection layer 180. In other words, the length of each side of the first electrical connection layer 180 is less than 80% of the length of each side of the chip epitaxial stack, and the length of each side of the current blocking layer 170 is less than 50% of the length of each side of the chip epitaxial stack.

[0080] It should be noted that in other embodiments, in the top view direction, the shape of the first electrical connection layer may be other shapes, the shape of the epitaxial stack may be other shapes, the shape of the current blocking layer may be other shapes, and their shapes may be the same or different. Their shapes may be, for example, rhombus, circle, ellipse, pentagon or hexagon, etc.

[0081] Another embodiment of the present invention provides another micro light emitting diode. Figure 7 and Figure 8 , which includes a first electrical connection layer 190, a second electrical connection layer 100 and an epitaxial stack located between the first electrical connection layer 190 and the second electrical connection layer 100. The upper surface of the epitaxial stack includes an ohmic contact region 130B and a non-ohmic contact region, and the non-ohmic contact region at least includes an outer edge region 130A located around the upper surface of the epitaxial stack (the non-ohmic contact region also includes a barrier region 130C, refer to the following content). The outer edge region 130A is doped with a non-conductive element, and the doping concentration of the non-conductive element is 1E16 / cm 3 ~1E19 / cm 3 The first electrical connection layer 190 covers the ohmic contact region 130B. For these structures, reference may be made to the corresponding contents of the aforementioned embodiments.

[0082] The present embodiment is different from the above-mentioned embodiment in that the epitaxial stack is further embedded with a current blocking layer 170, and the material of the current blocking layer 170 is also an insulating dielectric material. The upper surface of the current blocking layer 170 is in the same plane as the upper surface of the outer edge region 130A, and the upper surface of the current blocking layer 170 is also in the same plane as the upper surface of the ohmic contact region 130B. The upper surface of the current blocking layer 170 is surrounded by the ohmic contact region 130B, and the upper surface of the current blocking layer 170 is also covered by the first electrical connection layer 190. At this time, the upper surface of the current blocking layer 170 contacts the first electrical connection layer 190 to form a blocking region 130C that is also a non-ohmic contact region.

[0083] like Figure 8 In the top view direction, similar to the aforementioned embodiment, the shape of the first electrical connection layer 190 is an electrode rectangle, and the shape of the second conductive semiconductor layer 130 is a notch rectangle. The notch itself is also a rectangle, so the notch rectangle of the second conductive semiconductor layer 130 has six sides.

[0084] Figure 7 and Figure 8 It is also shown that a first electrode pad 191 is provided on the first electrical connection layer 190 , and the first electrode pad can be made of a metal material.

[0085] Please refer to Figure 8 , shows a schematic top view of the micro light emitting diode of this embodiment, wherein, Figure 7 The cross-sectional structure shown is Figure 8 The structure shown is a cross-sectional structure obtained by cutting along the double-headed arrow AA'.

[0086] like Figure 8 As shown, in this embodiment, the top view shape of the second electrical connection layer 100 is also rectangular, and is Figure 8In addition, the top view of the second electrical connection layer 100 also shows that the second electrical connection layer 100 has a second electrode pad 101, and the second electrode pad 101 can also be made of metal material.

[0087] Combination Figure 7 and Figure 8 It can be seen that the micro light emitting diode of this embodiment has a vertical packaging structure, and can further be a face-up vertical structure.

[0088] Another embodiment of the present invention provides another micro light emitting diode. Fig. 9 It should be noted that the micro-LED of this embodiment has Figure 7 The same cross-sectional structure, i.e. Figure 7 The cross-sectional structure shown is Fig. 9 The structure shown is a cross-sectional structure obtained by cutting along the bidirectional arrow BB'. Therefore, reference can be made to the corresponding contents of the above-mentioned embodiment. Figure 8 Different top-down structures, including Figure 8 The difference is that its top-down structure is Figure 8 The second electrical connection layer 100 in the embodiment is replaced by the first conductive semiconductor layer 110, and it also has a second electrode pad 111, but now the second electrode pad 111 is located on the first conductive semiconductor layer 110, so its top view structure is as follows: Fig. 9 shown.

[0089] The embodiment of the present invention further provides a display panel 200, please refer to Fig.10 The display panel 200 includes a plurality of micro-light emitting diodes arranged in an array as in any of the above embodiments. Fig.10 A portion of the micro light emitting diode 201 is shown in an enlarged schematic manner.

[0090] In this embodiment, the display panel 200 is a display panel corresponding to the display screen of a smart phone. In other embodiments, the display panel may also be a display panel of other types of electronic products, such as a display panel of a computer display screen, or a display panel of a smart wearable electronic product display screen.

[0091] As the display panel 200 has the micro-LEDs (micro-LEDs 201 ) of the aforementioned embodiments, it has the advantages brought by the micro-LEDs of the aforementioned embodiments.

[0092] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A micro light emitting diode, comprising a first electrical connection layer, a second electrical connection layer, and an epitaxial stack electrically connected to the first electrical connection layer and the second electrical connection layer, characterized in that: The upper surface of the epitaxial stack includes an ohmic contact area and a non-ohmic contact area, wherein the non-ohmic contact area at least includes an outer edge area located around the upper surface of the epitaxial stack; the outer edge area is doped with a non-conductive element, and the doping concentration of the non-conductive element is 1E16 / cm 3 ~1E19 / cm 3 ; A current spreading layer is further provided between the first electrical connection layer and the epitaxial stack, and at least a portion of the current spreading layer is located on the ohmic contact region.

2. The micro light emitting diode according to claim 1, characterized in that: In the top view, the current spreading layer is in the shape of an extended rectangle, the epitaxial stack has an upper step surface, the shape centers of the extended rectangle and the upper step surface coincide, and the side length of the extended rectangle is less than 0.8 of the side length of the upper step surface.

3. The micro light emitting diode according to claim 1, characterized in that: The first electrical connection layer is a first electrode layer, and the second electrical connection layer is a second electrode layer.

4. The micro light emitting diode according to claim 1, characterized in that: The non-conductive element is an inert element.

5. The micro light emitting diode according to claim 1, characterized in that: The non-conductive element is argon, helium or nitrogen; the doping depth of the non-conductive element is 0.2 μm to 2 μm.

6. The micro light emitting diode according to claim 1, characterized in that: The non-conductive element is doped by ion implantation.

7. The micro light emitting diode according to claim 1, characterized in that: The upper surface of the epitaxial stack further has a current blocking layer, which is located on the non-ohmic contact area surrounded by the ohmic contact area, and the side surface and upper surface of the current blocking layer are covered by the first electrical connection layer.

8. The micro light emitting diode according to claim 7, characterized in that: In the top view direction, the shape of the first electrical connection layer is an electrical connection rectangle, the epitaxial stack has an upper step surface, the shape centers of the electrical connection rectangle and the upper step surface coincide, and the side length of the electrical connection rectangle is less than 0.8 of the side length of the upper step surface.

9. The micro light emitting diode according to claim 8, characterized in that: In a top view, the current blocking layer is in the shape of a blocking rectangle, the blocking rectangle coincides with the center of the upper step surface, and the side length of the blocking rectangle is less than 0.5 of the side length of the upper step surface.

10. The micro light emitting diode according to claim 7, characterized in that: The first electrical connection layer directly covers the ohmic contact region; the side surface and the upper surface of the current blocking layer are covered by the first electrical connection layer.

11. The micro light emitting diode according to claim 1, characterized in that: The first electrical connection layer covers the ohmic contact area; the epitaxial stack is also embedded with a current blocking layer, the upper surface of the current blocking layer is in the same plane as the upper surface of the outer edge area, the upper surface of the current blocking layer is surrounded by the ohmic contact area, and the upper surface of the current blocking layer is also covered by the first electrical connection layer.

12. The micro light emitting diode according to claim 1, characterized in that: The material of the first electrical connection layer is a transparent conductive material.

13. The micro light emitting diode according to claim 11, characterized in that: The first electrical connection layer covers the ohmic contact region, and the upper surface of the current blocking layer is also covered by the first electrical connection layer.

14. A display panel, characterized in that: Comprising the micro light emitting diode as claimed in any one of claims 1 to 13.

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