Light emitting diode and light emitting device

Abstract

According to the light-emitting diode and the light-emitting device, a concave structure is formed in a P-type current expansion layer in a semiconductor epitaxial laminated layer, extends towards the direction of an N-type semiconductor layer, can further extend to a P-type limiting layer, and is projected on a plane where a light-emitting surface is located; the projection of the first electrode is located in the projection range of the concave structure. The recessed structure enables the resistance of the P-type semiconductor layer in the surrounding area to be increased, so that the current passing through the corresponding active layer below the first electrode surrounded by the recessed structure is reduced, and the light emitted by the corresponding active layer below the first electrode can be reduced. In this way, light which can enter the ohmic contact interface of the first electrode and the first N-type semiconductor layer is reduced, light absorption of the ohmic contact interface is reduced, and the light emitting efficiency of the light emitting diode can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices and apparatuses, and particularly to a light-emitting diode and a light-emitting device. Background Art

[0002] A light-emitting diode (LED) has advantages such as high luminous intensity, high efficiency, small size, and long service life, and is considered to be one of the most potential light sources at present. In recent years, LEDs have been widely used in daily life, such as in the fields of lighting, signal display, backlight, vehicle lamps, and large-screen display. At the same time, these applications also put forward higher requirements for the brightness and luminous efficiency of LEDs.

[0003] A light-emitting diode realizes at least providing electrons or holes respectively through n-type doping or p-type doping of a first-type semiconductor layer and a second-type semiconductor layer, and electrons and holes radiatively recombine and emit light in an active layer. Metal electrodes are respectively formed on the N-type semiconductor layer and the P-type semiconductor layer. In order to facilitate backend packaging, an ohmic contact is formed at the contact interface between the metal electrode and the semiconductor layer to reduce the contact resistance, thereby reducing the power consumption of the light-emitting diode. However, the interface of the ohmic contact formed between the metal electrode and the semiconductor layer is usually rough and has many defects. Therefore, when the light emitted from the active layer is incident on the interface of the ohmic contact, most of the light will be absorbed, and only a small part of the light will be reflected back into the semiconductor by the metal electrode and absorbed again. Summary of the Invention

[0004] In view of the deficiencies in the light extraction efficiency of light-emitting diodes in the prior art, the present invention provides a light-emitting diode and a light-emitting device to solve one or more of the above problems.

[0005] An embodiment of the present application provides a light-emitting diode, which at least includes:

[0006] A semiconductor epitaxial stack including an N-type semiconductor layer, an active layer, and a P-type semiconductor layer stacked in sequence; the P-type semiconductor layer includes a P-type current spreading layer and a P-type confinement layer, the P-type confinement layer is located between the active layer and the P-type current spreading layer, and the side of the N-type semiconductor layer away from the active layer is the light-emitting surface of the light-emitting diode;

[0007] An electrode structure including a first electrode located on the light-emitting surface and electrically connected to the first semiconductor layer;

[0008] Wherein, the P-type current spreading layer is formed with a concave structure extending in the direction towards the N-type semiconductor layer, and in the projection on the plane where the light-emitting surface is located, the projection of the first electrode is within the projection range of the concave structure.

[0009] Another embodiment of the present application provides a light-emitting device, which includes a circuit board and a light-emitting element disposed on the circuit board, and the light-emitting element includes the light-emitting diode provided by the present application.

[0010] As described above, the light-emitting diode and the light-emitting device of the present application have the following beneficial effects:

[0011] In the semiconductor epitaxial stack of the light-emitting diode of the present application, a recessed structure is formed in the P-type current spreading layer. The recessed structure extends in the direction towards the N-type semiconductor layer and can further extend to the P-type confinement layer. Projected on the plane where the light-emitting surface is located, the projection of the first electrode is within the projection range of the recessed structure. The above-mentioned recessed structure will increase the resistance of the P-type semiconductor layer surrounded by it. Therefore, the current passing through the active layer corresponding to the lower part of the first electrode surrounded by it is reduced, thereby reducing the light emitted by the active layer corresponding to the lower part of the first electrode, and also reducing the light that can be incident on the interface of the ohmic contact between the first electrode and the first N-type semiconductor layer, and reducing the light absorption at the ohmic contact interface, which can improve the light-emitting efficiency of the light-emitting diode. In addition, the recessed structure itself has a certain reflection effect, especially its side wall can reflect part of the light incident thereon, thereby further improving the light extraction efficiency of the light-emitting diode. Correspondingly, the brightness and light-emitting efficiency of the light-emitting device including the light-emitting diode can also be improved accordingly. Description of the Drawings

[0012] Figure 1 Shows a schematic structural diagram of a light-emitting diode in the prior art.

[0013] Figure 2 Shows a top-view structural diagram of the light-emitting diode provided in Embodiment 1 of the present invention.

[0014] Figure 3 Shows Figure 2 A schematic cross-sectional structural diagram of the shown light-emitting diode along the A-A direction.

[0015] Figure 4 Shows Figure 2 An SEM image of the shown light-emitting diode.

[0016] Figure 5 Shows a top-view structural diagram of the light-emitting diode provided in Embodiment 2 of the present invention.

[0017] Figure 6 Shows Figure 5 A schematic cross-sectional structural diagram of the shown light-emitting diode along the A-A direction.

[0018] Figure 7 Shows Figure 5 An SEM image of the shown light-emitting diode.

[0019] Figure 8 It shows a schematic structural diagram of the light-emitting device provided in the second embodiment of the present invention.

[0020] Element number description

[0021] 10. Light-emitting diode; 11. N-type semiconductor layer; 12. Active layer; 13. P-type semiconductor layer; 14. N electrode;

[0022] 100. Light-emitting diode; 110. Semiconductor epitaxial stack; 111. First semiconductor layer; 112. Active layer; 113. Second semiconductor layer; 1130. Concave structure; 1131. P-type confinement layer; 1132. P-type current spreading layer; 120. Dielectric layer; 121. Through hole; 130. Metal reflective layer; 140. Substrate; 151. First electrode; 1511. Pad area, 1512. Extension bar; 152. Second electrode; 153. N-type ohmic contact layer; 160. Insulating reflective layer; 170. Insulating protective layer; 180. Bonding layer;

[0023] 200. Light-emitting device; 201. Circuit board; 202. Light-emitting diode. Detailed implementation manners

[0024] The following uses specific specific examples to illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0025] As Figure 1 shown, in the prior art, a vertical-structured light-emitting diode 10 includes an N-type semiconductor layer, an active layer, and a P-type semiconductor layer stacked in sequence from top to bottom. The side of the N-type semiconductor layer away from the active layer is the light-emitting surface, and an N electrode is formed thereon. This N electrode is usually a metal electrode, such as Au, AuGeNi, Ge, Ni, Pt, Pd, etc. This metal electrode has a certain light absorption effect and will absorb the light radiated from the active layer, thereby reducing the light emitted from the light-emitting surface and affecting the light extraction efficiency and brightness of the light-emitting diode.

[0026] Aiming at the problem of reduced brightness of the light-emitting diode caused by light absorption of the metal electrode in the prior art, an embodiment of the present application provides a light-emitting diode, which at least includes:

[0027] A semiconductor epitaxial stack includes an N-type semiconductor layer, an active layer, and a P-type semiconductor layer stacked in sequence; the P-type semiconductor layer includes a P-type current spreading layer and a P-type confinement layer, the P-type confinement layer is located between the active layer and the P-type current spreading layer, and the side of the N-type semiconductor layer away from the active layer is the light-emitting surface of the light-emitting diode;

[0028] An electrode structure includes a first electrode located on the light-emitting surface and electrically connected to the first semiconductor layer;

[0029] Wherein, the P-type current spreading layer is formed with a recess structure that extends in the direction towards the N-type semiconductor layer, and in the projection on the plane where the light-emitting surface is located, the projection of the first electrode is within the projection range of the recess structure.

[0030] The above-mentioned recess structure will increase the resistance of the P-type semiconductor layer surrounded by it. Therefore, the current passing through the corresponding active layer under the first electrode is reduced, thereby reducing the light emitted by the corresponding active layer under the first electrode, reducing the light that can be incident on the interface of the ohmic contact between the first electrode and the first N-type semiconductor layer, reducing the light absorption at the ohmic contact interface, and improving the light-emitting efficiency of the light-emitting diode. In addition, the recess structure itself has a certain reflection effect, especially its sidewalls can reflect part of the incident light, thereby further improving the light extraction efficiency of the light-emitting diode. Correspondingly, the brightness and light-emitting efficiency of the light-emitting device including the light-emitting diode can also be improved accordingly.

[0031] Optionally, the projection of the recess structure and the projection of the first electrode have the same projection profile.

[0032] Optionally, the recess structure is arranged to surround the first electrode to form a closed structure.

[0033] The recess structure having the same profile as the first electrode can ensure that the above-mentioned recess structure exists around the corresponding area of the first electrode, ensuring that the current passing through the corresponding area of the active layer under the first electrode is minimized, reducing the light that may be at the ohmic contact interface between the first electrode and the N-type semiconductor layer, which is beneficial to improving the light extraction efficiency.

[0034] Optionally, in the projection on the plane where the light-emitting surface is located, the spacing distance between the recess structure and the first electrode is between 3 μm and 15 μm.

[0035] Optionally, the width of the recess structure is between 3 μm and 15 μm.

[0036] Optionally, the longitudinal cross-section of the recessed structure is triangular, trapezoidal or rectangular. The definition of the above-mentioned morphological characteristics of the recessed structure enables a relatively thick P-type semiconductor layer to remain around it, thereby increasing the contact area between the semiconductor epitaxial stack and the bonding layer, improving the reliability of the light-emitting diode, especially improving the wire bonding resistance of the light-emitting diode.

[0037] Optionally, the bottom of the recessed structure is located in the P-type current spreading layer;

[0038] Alternatively, the bottom of the recessed structure is located in the P-type confinement layer and is lower than the interface between the P-type semiconductor layer and the active layer.

[0039] As described above, the bottom of the recessed structure can be located in the P-type current spreading layer, or further penetrate the P-type current spreading layer and extend into the P-type confinement layer, while controlling its bottom to be lower than the interface between the active layer and the P-type layer, thereby reducing non-radiative recombination caused by sidewall defects of the active layer and improving the light-emitting efficiency of the chip.

[0040] Optionally, the light-emitting diode further includes an insulating reflective layer formed on the light-emitting surface, spaced from the first electrode and surrounding the first electrode to form a closed structure.

[0041] A part of the light emitted from the semiconductor epitaxial stack is directed towards the first electrode. The above-mentioned insulating reflective layer is arranged around the first electrode, so it can reflect this part of the light. A part of the reflected light can be directly emitted, and another part may be reflected back to the semiconductor epitaxial stack and finally emitted from the light-emitting surface after being reflected again. Thereby improving the light extraction efficiency of the light-emitting diode and increasing its brightness.

[0042] Optionally, the height of the insulating reflective layer is less than or equal to the height of the first electrode.

[0043] Optionally, the spacing distance between the insulating reflective layer and the first electrode is between 1 μm and 10 μm. Optionally, the width of the insulating reflective layer is between 1 μm and 5 μm.

[0044] The height of the insulating reflective layer is less than or equal to the height of the first electrode, and there is the above-mentioned spacing distance from the first electrode. On the premise of reflecting the incident light, it can ensure that the subsequent wire bonding and other operations at the first electrode are not affected, thereby improving the reliability of the light-emitting diode. The setting of the width of the insulating reflective layer can minimize its area ratio on the light-emitting surface as much as possible, which is beneficial to ensuring that the light-emitting diode has sufficient light-emitting area and improving its light-emitting efficiency. The material of the insulating reflective layer is any one or more of SiO2, Si3N4, Al2O3, TiO2, ZnO, and HfO2. The above materials are materials with high reflectivity and high transparency. Therefore, by increasing the material selection of the insulating reflective layer, the material can be selected according to the actual design needs of the light-emitting diode.

[0045] Optionally, when projected onto the plane where the light-emitting surface is located, the projection of the first electrode is within the projection range of the insulating reflective layer, the projection of the insulating reflective layer is within the projection range of the recessed structure, and the projection of the insulating reflective layer and the projection of the first electrode have the same projection contour.

[0046] The projection of the first electrode being within the projection range of the insulating reflective layer and the insulating reflective layer and the first electrode having the same contour can ensure that the insulating reflective layer is provided around the first electrode, increasing the reflection of light around the electrode and being beneficial to improving the light-emitting efficiency.

[0047] Optionally, the light-emitting diode further includes:

[0048] A dielectric layer formed on the side of the second semiconductor layer away from the active layer, and through holes are formed in the dielectric layer;

[0049] A metal reflective layer formed on the side of the dielectric layer away from the second semiconductor layer and filling the through holes;

[0050] A bonding layer formed on the side of the metal reflective layer away from the dielectric layer;

[0051] A substrate formed on the side of the bonding layer away from the metal reflective layer.

[0052] As described above, the light-emitting diode of the present application is preferably a vertical structure. The above-mentioned dielectric layer and metal reflective layer can form a total reflection structure, reflecting the light radiated by the active layer to the light-emitting surface side, and cooperating with the insulating reflective layer on the light-emitting surface side to increase the light-emitting efficiency and brightness of the light-emitting diode.

[0053] Optionally, when projected onto the plane where the light-emitting surface is located, the through holes are distributed in the area outside the projection range of the recessed structure.

[0054] The above - mentioned setting of the through - hole avoids the accumulation of current in the area corresponding to the first electrode, improves the current uniformity of the light - emitting diode, and further improves its light - emitting efficiency.

[0055] Another embodiment of the present invention provides a light - emitting device, which includes the light - emitting diode provided in this application. Since the light - emitting device includes the light - emitting diode of this application, good light - emitting efficiency and brightness can be achieved.

[0056] Embodiment 1

[0057] This embodiment provides a light - emitting diode. As Figure 2 and Figure 3 shown, the light - emitting diode 100 at least includes a semiconductor epitaxial stack 110. The epitaxial stack 110 includes a first semiconductor layer 111, an active layer 112, and a second semiconductor layer 113 stacked in sequence. The semiconductor epitaxial stack 110 can be any semiconductor epitaxial stack that can emit light under the action of voltage. In this embodiment, the above - mentioned semiconductor epitaxial stack 110 is preferably an AlGaInP - based epitaxial structure. The first semiconductor layer 111 can be an N - type semiconductor layer. Correspondingly, the second semiconductor layer 113 is a P - type semiconductor layer, and vice versa. In this embodiment, an example is given where the first semiconductor layer 111 is an N - type semiconductor layer and the second semiconductor layer 113 is a P - type semiconductor layer.

[0058] In an alternative embodiment, the first semiconductor layer 111 is an N - type AlInP layer for providing electrons. The N - type AlInP layer provides electrons by doping with n - type impurities. The n - type impurities can be, for example, Si, Ge, Sn, Se, and Te, etc. In this embodiment, the n - type impurity is preferably Si, and the Si doping concentration is between 1×10 18 Atoms / cm3 and 2×10 18 Atoms / cm3 to provide electrons for radiative recombination. The second semiconductor layer 113 is a P - type AlInP layer that provides holes by doping with P - type impurities. The P - type impurities can be Mg, Zn, Ca, Sr, C, Ba, etc. In this embodiment, the P - type impurity is preferably Mg or C. The active layer 112 is a multi - quantum well layer, for example, a multi - quantum well layer formed by AlGaInP / AlInP. Among them, the number of periods of the active layer 112 is 2 - 100, the thickness of the well layer is 2nm - 25nm, the thickness of the barrier layer is 2nm - 25nm, and the thicknesses of the well layer and the barrier layer can be the same or different, which can be set according to actual needs. The active layer 112 emits light with a wavelength of 550nm - 950nm.

[0059] Combined again with Figure 3, the above-mentioned P-type semiconductor layer includes a P-type confinement layer 1131 and a P-type current spreading layer 1132. The P-type confinement layer 1131 can be a P-type AlInP carrier confinement layer, which is used to prevent holes and electrons from escaping from the active layer 112 to the P-type semiconductor layer or the N-type semiconductor layer, ensuring efficient recombination and light emission of electrons and holes within the active layer 112. The P-type current spreading layer 1132 can be a P-type AlGaInP layer, a GaP layer, etc. In this embodiment, the P-type current spreading layer is preferably a P-type GaP layer. This P-type current spreading layer 1132 can reduce resistance and make the current evenly distributed throughout the P-type semiconductor layer instead of being concentrated near the electrode. In this embodiment, the P-type current spreading layer 1132 is formed with a recessed structure 1130, which extends in the direction towards the N-type semiconductor layer. At the same time, the recessed structure 1130 does not extend to the interface between the P-type semiconductor layer and the active layer, that is, the bottom of the recessed structure 1130 is located within the P-type current spreading layer 1132; alternatively, the recessed structure 1130 penetrates through the P-type current spreading layer 1132 to its bottom located within the P-type confinement layer 1131 and is lower than the interface between the P-type semiconductor layer and the active layer 112. The above setting of the recessed structure 1130 can reduce non-radiative recombination caused by sidewall defects of the active layer 112 and improve the light-emitting efficiency of the chip. In an alternative embodiment, the shape of the longitudinal cross-section of the above-mentioned recessed structure 1130 can be any suitable shape, such as a rectangle, a triangle, a trapezoid, etc.

[0060] As Figure 3 shown, in this embodiment, the side of the first semiconductor layer 111 away from the active layer 112 is formed as the light-emitting surface of the light-emitting diode 100. A first electrode 151 in the electrode structure of the light-emitting diode 100 is formed on this light-emitting surface, and an N-type ohmic contact layer 153 is further formed between the first electrode 151 and the first semiconductor layer 111. As Figure 2 shown, when projected onto the plane where the light-emitting surface is located, the projection of the first electrode 151 is within the projection range of the recessed structure 1130. Further, referring again to Figure 2 , the above-mentioned first electrode 151 has a pad area 1511 and an extension bar 1512. The extension bar 1512 extends from the pad area 1511 to other areas of the light-emitting surface to improve the current diffusion effect and uniformity on one side of the first semiconductor layer 111. In an alternative embodiment, the above-mentioned extension bar 1512 is formed as a finger-shaped extension bar 1512, and the first electrode 151 can include one or more of the above-mentioned extension bars 1512. When projected onto the plane where the light-emitting surface is located, that is, in the Figure 2 top-down direction, the projection of the first electrode 151 completely falls within the projection range of the recessed structure 1130. As Figure 2As shown, the recessed structure 1130 is formed around the pad region 1511 and the extended strip 1512 of the first electrode 151 to form a closed figure along the contours of the pad region 1511 and the extended strip 1512, such that both the pad region 1511 and the extended strip 1512 of the first electrode 151 are surrounded by the recessed structure 1130. The above arrangement of the recessed structure 1130 increases the resistance of the P-type semiconductor layer 113 it surrounds, reducing the current passing through the corresponding active layer 112 under the first electrode 151, thereby reducing the light emitted by the corresponding active layer 112 under the first electrode 151, reducing the light incident on the interface of the ohmic contact between the first electrode 151 and the N-type semiconductor layer, reducing the light absorption at the ohmic contact interface, and improving the light-emitting efficiency of the light-emitting diode. Additionally, the recessed structure 1130 itself has a certain reflection effect, especially its sidewalls can reflect part of the incident light, thereby further improving the light extraction efficiency of the light-emitting diode.

[0061] Optionally, as Figure 2 shown, the width W1 of the recessed structure 1130 satisfies: 3μm ≤ W1 ≤ 15μm, for example, W1 = 2μm; W1 = 3μm; W1 = 5μm, etc. The width limitation of the recessed structure 1130 enables a certain thickness of the P-type semiconductor layer to be retained around it, thereby increasing the contact area between the semiconductor epitaxial stack 110 and the bonding layer 180, improving the reliability of the light-emitting diode, especially improving the wire bonding resistance of the light-emitting diode. Optionally, in combination with Figure 3 and Figure 4 , the recessed structure 1130 does not extend to the interface between the P-type semiconductor layer and the active layer 112, that is, the recessed structure 1130 is located in the P-type current spreading layer 1132; or, the recessed structure 1130 penetrates through the P-type current spreading layer 1132 to its bottom located in the P-type confinement layer 1131 and is lower than the interface between the P-type semiconductor layer and the active layer 112. That is, the recessed depth H3 of the above recessed structure 1130 is less than or equal to the thickness H5 of the P-type current spreading layer 1132: H3 ≤ H5; or the recessed depth H3 of the above recessed structure 1130, the thickness H5 of the P-type current spreading layer 1132, and the thickness H4 of the P-type confinement layer 1131 satisfy: H5 ≤ H3 ≤ H4. For example, in an optional embodiment, the thickness H4 of the above P-type confinement layer 1131 is between 400nm and 600nm, the thickness of the P-type current spreading layer 1132 is between 2000nm and 3000nm, and the recessed height H3 of the recessed structure 1130 is between 2500nm and 3500nm. Additionally, as also Figure 2As shown in the figure, when projected onto the plane where the light-emitting surface is located, the recessed structure 1130 and the first electrode 151 are arranged at intervals, and the interval distance D1 between the recessed structure 1130 and the first electrode 151 satisfies: 3μm ≤ D1 ≤ 15μm. For example, D1 = 3μm; D1 = 5μm; D1 = 7μm; D1 = 10μm, D1 = 15μm, etc. The bottom of the recessed structure 1130 is located in the P-type current spreading layer 1132 or in the P-type confinement layer 1131, and does not extend to the interface between the active layer 112 and the P-type layer, thereby reducing non-radiative recombination caused by sidewall defects of the active layer 112 and improving the light-emitting efficiency of the chip.

[0062] Referring again to Figure 3 , the light-emitting diode 100 of this embodiment further includes a substrate 140, and the semiconductor epitaxial stack 110 is bonded to the substrate 140 from one side of the second semiconductor layer 113. A bonding layer 180 is formed between the semiconductor epitaxial stack 110 and the substrate 140, and the bonding layer 180 bonds the semiconductor epitaxial stack 110 and the substrate 140 together. The above substrate 140 can be an insulating substrate, a semiconductor substrate, a metal substrate, etc. In this embodiment, the substrate 110 is a silicon (Si) substrate, a germanium (Ge) substrate, a silicon carbide (SiC) substrate, a gallium nitride (GaN) substrate, an aluminum nitride (AlN) substrate, a gallium phosphide (GaP) substrate, or a gallium arsenide (GaAs) substrate, etc. Optionally, the bonding layer 180 is a metal bonding layer, such as Cu, Al, Sn, Au, Ag, Pb, Ti, Ni, In, Pt or W, etc. A dielectric layer 120 and a metal reflective layer 130 are further formed between the bonding layer 180 and the semiconductor epitaxial stack 110, and the metal reflective layer 130 is formed between the dielectric layer 120 and the bonding layer 180. Specifically, the dielectric layer 120 is formed on the side of the second semiconductor layer 113 away from the active layer 112, and the metal reflective layer 130 is formed on the side of the dielectric layer 120 away from the second semiconductor layer 113. The bonding layer 180 covers the metal reflective layer 130.

[0063] In an alternative embodiment, through holes 121 are formed in the dielectric layer 120, and the metal reflective layer 130 fills the through holes 121, thereby realizing electrical connection with the second semiconductor layer 113. Further, the above through holes 121 are distributed in a region outside the region corresponding to the closed structure formed by the recessed structure 1130. That is, when projected onto the plane where the light-emitting surface is located, the projection of the above through holes 121 is located outside the projection range of the recessed structure 1130, and within the projection range of the recessed structure 1130, it is covered by the above dielectric layer 120, thereby preventing the aggregation of current in the region corresponding to the first electrode 151, improving the current uniformity of the light-emitting diode, and further improving its light-emitting efficiency.

[0064] The dielectric layer 120 can be a single-layer structure formed of one of SiO2, SiN, SiON, TiO2, etc., or a multi-layer structure formed by a combination of any several of them. Optionally, it is a DBR structure with a reflection effect, such as a DBR structure formed of SiO2 and TiO2. Optionally, the metal reflective layer can be an alloy of one or more of Ag, Al, Cu, Sn, Au, etc. In this embodiment, the dielectric layer 120 is a DBR structure, and the metal reflective layer 130 is an Ag mirror. The dielectric layer 120 and the metal reflective layer 130 form a total reflection structure, increasing the reflection of the light radiated by the active layer 112 and enhancing the light extraction efficiency of the light-emitting diode 100. In addition, as described above, both the metal reflective layer 130 and the bonding layer 180 are metal layers, so the adhesion between them is good, which is beneficial to improving the reliability of the light-emitting diode. On the other side of the substrate 140 opposite to the semiconductor epitaxial stack 110, a back gold layer is formed, and this back gold layer can serve as the second electrode 152 electrically connected to the second semiconductor layer 113.

[0065] Referring to Figure 3 , to further increase the light extraction efficiency of the light-emitting diode 100, in this embodiment, after forming the first electrode 151, the surface of the first semiconductor layer 111 outside the area covered by the first electrode 151 is roughened to form a roughened surface, thereby increasing the light extraction rate. At the same time, an insulating protective layer 170 is also formed on the exposed sidewalls of the light-emitting diode 100 to protect the light-emitting diode 100 from damage by external moisture and impurities. Optionally, the insulating protective layer 170 can also extend from the sidewalls to cover the edge area of the light-emitting surface.

[0066] Embodiment 2

[0067] This embodiment also provides a light-emitting diode. As Figure 5 and Figure 6 shown, the light-emitting diode 100 also at least includes a semiconductor epitaxial stack 110, and the epitaxial stack 110 includes a first semiconductor layer 111, an active layer 112, and a second semiconductor layer 113 stacked in sequence. The semiconductor epitaxial stack 110 can be any semiconductor epitaxial stack 110 that can emit light under the action of voltage. In this embodiment, the above semiconductor epitaxial stack 110 is preferably an AlGaInP-based epitaxial structure. The above first semiconductor layer 111 can be an N-type semiconductor layer, and correspondingly, the second semiconductor layer 113 is a P-type semiconductor layer, and vice versa is also feasible. This embodiment takes the first semiconductor layer 111 as an N-type semiconductor layer and the second semiconductor layer 113 as a P-type semiconductor layer as an example.

[0068] The same parts as those in Embodiment 1 will not be described again. The differences are as follows: As Figure 5 and Figure 6As shown, in this embodiment, an insulating reflective layer 160 is formed on the light-emitting surface of the light-emitting diode and is spaced apart from the first electrode 151. The insulating reflective layer 160 is spaced apart from the first electrode 151 and is disposed around the first electrode 151. That is, the insulating reflective layer 160 has the same contour as the first electrode 151 and forms a closed figure around the first electrode 151. In an alternative embodiment, the shape of the longitudinal cross-section of the insulating reflective layer 160 may be any suitable shape, such as a rectangle, a triangle, a trapezoid, etc., which is easy to operate and can enable the insulating reflective layer 160 to have a good reflection effect.

[0069] Specifically, as Figure 5 shown, the first electrode 151 has a pad region 1511 and an extension bar 1512. The extension bar 1512 extends from the pad region 1511 to other regions of the light-emitting surface to improve the current diffusion effect and uniformity on the side of the first semiconductor layer 111. In an alternative embodiment, the extension bar 1512 is formed as a finger-shaped extension bar 1512, and the first electrode 151 may include one or more of the above extension bars 1512. Projected onto the plane of the light-emitting surface, that is, in Figure 5 the top-down direction of, the projection of the first electrode 151 completely falls within the projection range of the insulating reflective layer 160. Further, the projection of the insulating reflective layer 160 completely falls within the projection range of the recessed structure 1130. As Figure 5 shown, the insulating reflective layer 160 forms a closed figure along the contours of the pad region 1511 and the extension bar 1512 of the first electrode 151, so that both the pad region 1511 and the extension bar 1512 of the first electrode 151 are surrounded by the insulating reflective layer 160.

[0070] Optionally, as Figure 5 shown, the width of the insulating reflective layer 160 satisfies: 1 μm ≤ W2 ≤ 5 μm, for example, W2 = 2 μm; W2 = 3 μm; W2 = 5 μm, etc. The width limitation of the insulating reflective layer 160 ensures that it does not cover too much of the light-emitting surface, avoiding light-emitting surface loss caused by excessive coverage and affecting the light-emitting efficiency. Combining Figure 6 and Figure 7, the height of the insulating reflective layer 160 protruding on the light-emitting surface is not higher than the height of the first electrode 151, that is, the height H2 of the insulating reflective layer 160 is less than or equal to the height H1 of the first electrode 151. Further, the height H1 of the first electrode 151 satisfies: 2μm ≤ H1 ≤ 5μm, and the height H2 of the insulating reflective layer 160 satisfies: 1μm ≤ H2 ≤ 5μm. In addition, the spacing distance D2 between the first electrode 151 and the insulating reflective layer 160 satisfies: 1μm ≤ D2 ≤ 10μm, for example, D2 = 2μm; D2 = 5μm; D2 = 7μm; D2 = 10μm, etc. The limitation of the height of the insulating reflective layer 160 and the first electrode 151 and the spacing distance therebetween can ensure that the insulating reflective layer 160 has a good reflection effect on the incident light, and at the same time ensure that the insulating reflective layer 160 will not affect the subsequent wire bonding and other processes of the first electrode 151, especially the pad area 1511, and ensure the reliability of the light-emitting diode 100.

[0071] Optionally, the insulating reflective layer 160 may be a single-layer structure or a multi-layer structure. Further, the insulating reflective layer 160 is a transparent material layer, for example, it may be any one or a combination of materials with high reflectivity and high transparency such as SiO2, Si3N4, Al2O3, TiO2, ZnO, HfO2, etc. Further, the insulating reflective layer 160 may be formed into a DBR structure with a total reflection effect, for example, a DBR structure formed by SiO2 and TiO2. The material of the insulating reflective layer 160 can be selected according to the actual design requirements of the light-emitting diode 100 to increase its scope of application.

[0072] As described above, the insulating reflective layer 160 and the concave structure 1130 can cooperate to further improve the light extraction efficiency of the light-emitting diode.

[0073] Embodiment III

[0074] This embodiment provides a light-emitting device, as Figure 8 shown, the light-emitting device 200 includes a circuit board 201 and at least one light-emitting diode 202 fixed to the circuit board 201, and the light-emitting diode includes the light-emitting diode provided in the above Embodiment I of the present application. Since the light-emitting device includes the light-emitting diode provided in Embodiment I or Embodiment II, it has good light extraction efficiency and better reliability.

[0075] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A light emitting diode, characterized in that: At least: A semiconductor epitaxial stack, comprising an N-type semiconductor layer, an active layer and a P-type semiconductor layer stacked in sequence; the P-type semiconductor layer comprises a P-type current spreading layer and a P-type limiting layer, the P-type limiting layer is located between the active layer and the P-type current spreading layer, and the side of the N-type semiconductor layer away from the active layer is the light emitting surface of the light emitting diode; an electrode structure, comprising a first electrode located on the light emitting surface and electrically connected to the first semiconductor layer; The P-type current spreading layer is formed with a recessed structure, the recessed structure extends toward the N-type semiconductor layer, and when projected on the plane where the light emitting surface is located, the projection of the first electrode is within the projection range of the recessed structure.

2. The light emitting diode according to claim 1, characterized in that: The projection of the recessed structure and the projection of the first electrode have the same projection profile.

3. The light emitting diode according to claim 1, characterized in that: The recessed structure is disposed around the first electrode to form a closed structure.

4. The light emitting diode according to claim 1, characterized in that: Projected on the plane where the light emitting surface is located, the spacing distance between the recessed structure and the first electrode is between 3 μm and 15 μm.

5. The light emitting diode according to claim 1, characterized in that: The width of the concave structure is between 3 μm and 15 μm. μm.

6. The light emitting diode according to claim 1, characterized in that: The longitudinal cross section of the recessed structure is triangular, trapezoidal or rectangular.

7. The light emitting diode according to claim 1, characterized in that: The bottom of the recessed structure is located in the P-type current spreading layer; Alternatively, the bottom of the recessed structure is located in the P-type confinement layer and is lower than an interface between the P-type semiconductor layer and the active layer.

8. The light emitting diode according to claim 1, characterized in that: It also includes an insulating reflective layer, which is formed on the light-emitting surface, spaced apart from the first electrode and surrounds the first electrode to form a closed structure.

9. The light emitting diode according to claim 8, characterized in that: A height of the insulating reflective layer is less than or equal to a height of the first electrode.

10. The light emitting diode according to claim 8, characterized in that: The spacing distance between the insulating reflective layer and the first electrode is between 1 μm and 10 μm, and the width of the insulating reflective layer is between 1 μm and 5 μm.

11. The light emitting diode according to claim 8, characterized in that: Projected on the plane where the light emitting surface is located, the projection of the first electrode is located within the projection range of the insulating reflective layer, the projection of the insulating reflective layer is located within the projection range of the recessed structure, and the projection of the insulating reflective layer and the projection of the first electrode have the same projection contour.

12. The light emitting diode according to claim 1, characterized in that: Also includes: a dielectric layer formed on a side of the P-type current spreading layer away from the active layer, wherein a through hole is formed in the dielectric layer; and a metal reflective layer formed on a side of the dielectric layer away from the P-type current spreading layer and filling the through hole; A bonding layer is formed on a side of the metal reflective layer away from the dielectric layer; The substrate is formed on a side of the bonding layer away from the metal reflective layer.

13. The light emitting diode according to claim 12, characterized in that: When projected onto the plane where the light emitting surface is located, the through holes are distributed in a region outside the projection range of the recessed structure.

14. A light emitting device, characterized in that: The invention comprises a circuit substrate and a light emitting element arranged on the circuit substrate, wherein the light emitting element comprises the light emitting diode according to any one of claims 1 to 13.

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