WO2021115470A1

WO2021115470A1 - Light-emitting diode

Info

Publication number: WO2021115470A1
Application number: PCT/CN2020/136033
Authority: WO
Inventors: 闫春辉; 蒋振宇
Original assignee: 深圳第三代半导体研究院
Priority date: 2019-12-13
Filing date: 2020-12-14
Publication date: 2021-06-17
Also published as: CN112993108A; CN112993108B

Abstract

Disclosed in the present application is a light-emitting diode, comprising a substrate, a light-emitting epitaxial layer, a first electrode, and a plurality of second electrodes. The light-emitting epitaxial layer comprises a first semiconductor layer, an active light-emitting layer and a second semiconductor layer sequentially stacked on one another and disposed on the substrate. The first electrode is electrically connected to one of the first semiconductor layer and the second semiconductor layer, and the second electrode is electrically connected to the other of the first semiconductor layer and the second semiconductor layer. The first electrode is a planar electrode. The projection of the plurality of second electrodes on the substrate falls within the projection of the first electrode on the substrate and the plurality of second electrodes are disposed to be spaced apart from one another. The sum of the shortest distances between the projection of any of light-emitting points in at least part of light-emitting regions of the light-emitting epitaxial layer on the substrate and the projections of the two adjacent second electrodes on the substrate is not greater than a transverse critical electrode spacing. The above configuration of the present application can effectively improve the distribution uniformity of electrical currents and thus increase lumen density and lumen efficiency of light-emitting diodes, thereby reducing lumen costs.

Description

A light-emitting diode

【Technical Field】

This application relates to the field of semiconductors, especially a light-emitting diode.

【Background technique】

Light-emitting diodes are solid-state components that convert electrical energy into light. Light-emitting diodes have the advantages of small size, high efficiency, and long life, and are widely used in traffic indications, outdoor full-color displays and other fields. In particular, the use of high-power light-emitting diodes can realize semiconductor solid-state lighting, which has caused a revolution in the history of human lighting, and has gradually become a research hotspot in the current electronics field.

At present, the current of the light-emitting diode is generally injected into the active light-emitting layer by a lateral diffusion method, and this lateral diffusion method has a natural non-uniform current distribution characteristic, resulting in excessive current density in a local area. Excessive current density in a local area can easily cause two problems:

1. Excessive local current can easily cause the electro-optical conversion efficiency to drop, resulting in a drop in lumen efficiency and lumen density;

2. Excessive local current can easily cause local overheating, leading to a decrease in the service life and reliability of the light-emitting diode, and it is necessary to achieve heat dissipation through a complex package design, which increases the cost of lumen.

[Summary of the invention]

The present application provides a light emitting diode that can improve the uniformity of current distribution, so that the light emitting diode can withstand a higher working current, thereby improving the lumen efficiency and lumen density of the light emitting diode, and reducing the lumen cost.

In one aspect, the present application provides a light-emitting diode, including: a substrate; a light-emitting epitaxial layer, including a first semiconductor layer, an active light-emitting layer, and a second semiconductor layer that are sequentially stacked on the substrate; A second electrode, the first electrode is electrically connected to one of the first semiconductor layer and the second semiconductor layer, and the plurality of second electrodes are electrically connected to the other of the first semiconductor layer and the second semiconductor layer; wherein, the first The electrode is a surface electrode, and the projections of multiple second electrodes on the substrate fall within the projections of the first electrodes on the substrate and are spaced apart from each other. The shortest distance between two adjacent second electrodes is not greater than the lateral threshold. Electrode spacing, the horizontal critical electrode spacing refers to the shortest when the dynamic slope of the change curve of the working voltage of the light-emitting diode with the average current density in a certain working current section where the ^{average current density is greater than 1A/mm 2} ^{is not greater than 0.18Ω·mm 2} The maximum allowable value of the sum of the separation distance, the light-emitting diode works in the operating current section, and the first semiconductor layer and the second semiconductor layer are made of materials based on the three-nitride system; the materials based on the three-nitride system include GaN , At least one of _{Alx 1} Gay ₁ N, InGaN, Alx ₂ Iny ₂ Gaz _{2 N.}

On the other hand, the present application provides a light-emitting diode, including: a substrate; a light-emitting epitaxial layer, including a first semiconductor layer, an active light-emitting layer, and a second semiconductor layer stacked on the substrate in sequence; a first electrode and A plurality of second electrodes, the first electrode is electrically connected to one of the first semiconductor layer and the second semiconductor layer, and the plurality of second electrodes are electrically connected to the other of the first semiconductor layer and the second semiconductor layer; wherein, the first electrode is electrically connected to one of the first semiconductor layer and the second semiconductor layer; One electrode is a surface electrode, the projections of the multiple second electrodes on the substrate fall inside the projections of the first electrode on the substrate and are arranged at intervals. Any light-emitting point in at least part of the light-emitting area of the light-emitting epitaxial layer is on the substrate. The sum of the shortest distance between the projection on the bottom and the projection of the two adjacent second electrodes on the substrate is not greater than the lateral critical electrode spacing. The lateral critical electrode spacing refers to ensuring that the operating voltage of the light-emitting diode changes with the average current density When the dynamic slope of the curve in a certain working current section with an average current density greater than 1A/mm ² is not greater than 0.18Ω·mm ² the maximum allowable value of the sum of the shortest separation distances, the light emitting diode works in the working current section, and the first Both the semiconductor layer and the second semiconductor layer are made of materials based on the Group III nitride system.

In another aspect, the present application provides a light emitting diode, including: a substrate; a light emitting epitaxial layer, including a first semiconductor layer, an active light emitting layer, and a second semiconductor layer stacked on the substrate in sequence; a first electrode and A plurality of second electrodes, the first electrode is electrically connected to one of the first semiconductor layer and the second semiconductor layer, and the plurality of second electrodes are electrically connected to the other of the first semiconductor layer and the second semiconductor layer; wherein, the first electrode is electrically connected to one of the first semiconductor layer and the second semiconductor layer; One electrode is a surface electrode, the projections of multiple second electrodes on the substrate fall inside the projections of the first electrodes on the substrate and are spaced apart from each other, and the shortest distance between two adjacent second electrodes is not greater than the lateral Critical electrode spacing, horizontal critical electrode spacing means to ensure that the dynamic slope of the light-emitting diode operating voltage with the average current density in a certain operating current section where the ^{average current density is greater than 1A/mm 2} ^{is not greater than 0.18Ω·mm 2} The maximum allowable value of the sum of the shortest separation distance, the light emitting diode works in the operating current section, and the first semiconductor layer and the second semiconductor layer are both made of materials based on the group III nitride system.

The beneficial effect of the present application is: different from the state of the art, the present application sets a lateral critical electrode spacing based on the slope of the change of the working voltage with the average current density, and sets any light-emitting point in at least a part of the light-emitting area of the light-emitting epitaxial layer The sum of the shortest distance between the projection on the substrate and the projection of the two adjacent second electrodes on the substrate is not greater than the lateral critical electrode spacing, which effectively improves the uniformity of current distribution so that the light-emitting diode can withstand higher The working current can improve the lumen efficiency and lumen density of the light-emitting diode. At the same time, the life and reliability of the light-emitting diode are high, and no complicated package design is required for heat dissipation, which reduces the lumen cost of the light-emitting diode.

【Explanation of the drawings】

In order to more clearly describe the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings that need to be used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work. among them:

Fig. 1 is a top view of a light emitting diode according to a first embodiment of the present application;

Fig. 2 is a schematic partial cross-sectional view taken along the A1-A1 direction of Fig. 1;

FIG. 3 is a schematic diagram showing the variation of the operating voltage with the average current density of the blue light emitting diode adopting the structure shown in FIG. 1 under different lengths of L1+L2;

Fig. 4 is a schematic diagram showing the change of the dynamic slope of each change curve shown in Fig. 3 with the average current density;

Fig. 5 is a top view of a light emitting diode according to a second embodiment of the present application;

Fig. 6 is a schematic partial cross-sectional view along the A2-A2 direction of Fig. 5;

Fig. 7 is a top view of a light emitting diode according to a third embodiment of the present application;

Fig. 8 is a schematic partial cross-sectional view taken along the A3-A3 direction of Fig. 7;

Fig. 9 is a top view of a light emitting diode according to a fourth embodiment of the present application;

Fig. 10 is a schematic partial cross-sectional view taken along the B-B direction of Fig. 5.

【Detailed ways】

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of this application.

As shown in FIGS. 1 and 2, the light-emitting diode according to the first embodiment of the present application includes a substrate 11, a light-emitting epitaxial layer 12, a first electrode 13 and a second electrode 14. The light-emitting epitaxial layer 12 further sequentially stacks a first semiconductor layer 121, an active light-emitting layer 122 and a second semiconductor layer 123 disposed on the substrate 11. In this embodiment, the substrate 11 can be made of conductive materials such as Si, Ge, Cu, and CuW. The first semiconductor layer 121 is a P-type semiconductor layer (for example, P-type GaN), and the corresponding first electrode 13 is also referred to as a P-type electrode. The second semiconductor layer 123 is an N-type semiconductor layer (for example, N-type GaN), and the corresponding second electrode 14 is also referred to as an N-type electrode. In other embodiments, the first semiconductor layer 121 and the second semiconductor layer 123 may be a single-layer or multi-layer structure of any other suitable material having different conductivity types.

Further, as shown in FIGS. 1 and 2, the first electrode 13 is a surface electrode, and the plurality of second electrodes 14 are strip-shaped electrodes, and the projections on the substrate 11 fall on the first electrode 13 on the substrate 11. The projections inside and spaced apart from each other. Specifically, in this embodiment, the second electrodes 14 are finger electrodes extending along the first direction D1 and spaced apart from each other along the second direction D2 perpendicular to the first direction D1, so that the second electrodes 14 are The projections on the substrate 11 are spaced apart from each other along the second direction D2. The first electrode 13 and the second electrode 14 are further connected to a first pad (not shown) and a second pad 16, and are further connected to an external circuit through the first pad and the second pad 16.

Furthermore, in this embodiment, the light-emitting diode is a vertical light-emitting diode, and the second electrode 14 and the first electrode 13 are respectively located on opposite sides of the light-emitting epitaxial layer 120. Wherein, the second electrode 14 is disposed on the side of the second semiconductor layer 123 away from the active light emitting layer 122, and the second electrode 14 is electrically connected to the second semiconductor layer 123. For example, in this embodiment, the second electrode 14 is connected to the second semiconductor layer 123. The two semiconductor layers 123 are electrically connected by direct contact.

The first electrode 13 is arranged on the side of the substrate 11 away from the light-emitting epitaxial layer 12 and forms an electrical connection with the first semiconductor layer 121 through the substrate 11. Furthermore, a reflector 18 and a metal bonding layer 17 may be further provided between the substrate 11 and the first semiconductor layer 121. The reflector 18 is used to reflect the light generated by the active light-emitting layer 122, and further remove the light from the second semiconductor layer. Light is emitted from the side where the layer 123 is located, and the metal bonding layer 17 is used to improve the adhesion with the substrate 11.

In this embodiment, the projection of the second electrode 14 on the substrate 11 and the projection of the first electrode 13 on the substrate 11 overlap each other, and then fall within the projection of the first electrode 13 on the substrate 11. It is worth noting here that the inside of the projection of the first electrode 13 on the substrate 11 referred to in the present application includes both the overlap with the projection of the first electrode 13 on the substrate 11 shown in FIG. 2 and the subsequent The one shown in Figures 9-10 is surrounded by the projection of the first electrode on the substrate.

With the above structure, the current formed by holes is directly injected into the active light-emitting layer 122 from the first electrode 13 through the substrate 11, the mirror 18, and the metal bonding layer 17 along the stacking direction, and the current formed by electrons is from the second The electrode 14 is injected into the second semiconductor layer 123 and diffuses laterally along the second semiconductor layer 123 and injected into the active light emitting layer 122. The electrons and holes undergo radiation recombination in the active light-emitting layer 122 and generate photons, thereby forming light emission.

As can be seen from the above structure, the distance at which the current in the light-emitting epitaxial layer 12 spreads laterally is determined by the lateral distance between adjacent second electrodes 14. In the prior art, the lateral spacing between adjacent second electrodes 14 is set too large, resulting in poor uniformity of the current density distribution of the current injected into the active light-emitting layer 122, which in turn leads to the above-mentioned background art. Describe the problem.

In this embodiment, the shortest distance between the projection of any light-emitting point A in at least part of the light-emitting area of the light-emitting epitaxial layer 12 on the substrate 11 and the projection of the two adjacent second electrodes 14 on the substrate 11 They are L1 and L2 respectively. The sum of the two shortest separation distances is L1+L2.

The physical definition of the lateral critical electrode spacing Lc will be described in detail below. Specifically, this embodiment has determined the influence of the average current density on the operating voltage through a large number of experiments, and defined the key parameter that affects the performance of the LED chip: "lateral critical electrode spacing Lc", and the shortest distance is determined by the lateral critical electrode spacing Lc. The sum of the separation distance L1+L2 is limited, so that the performance of the LED chip is greatly improved.

The lateral critical electrode spacing Lc in the blue light emitting diode will be described in detail below with reference to FIGS. 3 and 4. In this application, a blue light emitting diode refers to a light emitting diode with a peak wavelength between 440 nm and 480 nm during operation.

FIG. 3 shows a schematic diagram of the variation of the operating voltage of the blue light emitting diode with the average current density under different L1+L2, and FIG. 4 shows the schematic diagram of the dynamic slope of each variation curve shown in FIG. 3 as a function of the average current density. In Figures 3 and 4, the selected values of L1+L2 include 230 micrometers, 105 micrometers, 80 micrometers, 50 micrometers, and 30 micrometers, and _{the unit of the working voltage V F} is volts (ie, V), and the average current density The unit of J is ampere per square millimeter (ie, A/mm ² ), and the dynamic slope S _d =dV _F /dJ. At this time, the unit of the dynamic slope of the change curve shown in Figure 4 is ohm square millimeter (ie, Ω· mm ² ). The average current density J is the ratio between the working current of the light-emitting diode and the light-emitting area of the light-emitting diode. Furthermore, in order to reflect the difference between the dynamic slopes of the various change curves in FIG. 4, the Y axis in FIG. 4 is expressed in logarithmic coordinates.

First, as shown in Figure 3, when L1+L2=230 microns, it can be seen from the corresponding change curve that the working voltage V _F rises sharply with the increase of the average current density J, and it can be seen from Figure 4 It can be seen that the dynamic slope in all ranges of the change curve is not less than 0.19Ω·mm ² . However, when L1+L2 drops to 105 microns, it can be seen from Figure 3 that _{the rising trend of the working voltage V F} with the average current density J obviously slows down, and it can be seen from Figure 4 that the average current density J When the value is greater than a certain value, the dynamic slope of the curve drops to 0.18Ω·mm ² , and with the increase of the average current density J, it continues to remain below 0.18Ω·mm ² within a certain range, and can drop to 0.07Ω·mm ² . When L1+L2 drops to 80 microns, _{the rising trend of the working voltage V F} with the average current density J further slows down, and when the average current density J is greater than a certain value, the dynamic slope of the curve drops to 0.18Ω·mm ² , And with the increase of the average current density J, it is continuously maintained below 0.18Ω·mm ² within a certain range, and can be reduced to 0.05Ω·mm ² . When L1+L2 drops to 50 and 30 microns, _{the rising trend of the working voltage V F} with the average current density J further slows down, and when the average current density J is greater than a certain value, the dynamic slope of the curve drops to 0.18Ω·mm ² , And with the increase of the average current density J, it has been continuously maintained below 0.18Ω·mm ² and can be reduced to below 0.02Ω·mm ² and 0.005Ω·mm ² . It can be seen that as the length of L1+L2 decreases, the dynamic slope of the LED decreases rapidly with the increase of current density, and the current density for effective operation also increases rapidly. Therefore, the lumen output per unit area of the LED chip can be increased, thereby reducing the lumen. cost.

Therefore, in this embodiment, the lateral critical electrode spacing Lc is defined as ensuring that the operating voltage V _{F of the} light emitting diode varies with the average current density J within a certain operating current section where the average current density J is greater than 1A/mm ² The maximum allowable value of the sum of the above-mentioned shortest separation distances L1+L2 when the dynamic slope S _{d is} not greater than 0.18Ω·mm ^2.

In other embodiments, the lateral critical electrode spacing can be defined as the maximum allowable value of the sum of the shortest separation distances L1+L2 when the dynamic slope in the above-mentioned operating current section is not greater than 0.15Ω·mm ^{2, and it can even be further defined as} no greater than the maximum allowable value 0.1,0.06,0.03Ω · mm ² in.

Since the light-emitting diode is a constant current component, its working voltage is directly related to the lumen density and lumen efficiency. Therefore, when L1+L2 is set to be no greater than Lc and the light-emitting diode works in the above-mentioned operating current range, the performance of the light-emitting diode begins to be greatly improved, and the greater the operating current, the more obvious the improvement effect. At the same time, due to the significant reduction of the operating voltage, the thermal effect is also significantly reduced, so that light-emitting diodes with better life and reliability can be obtained, thereby increasing the lumen cost of the light-emitting diodes.

It should be further clarified that the 230 microns, 105 microns, 80 microns, 50 microns, and 30 microns mentioned above are parameters used in the design of specific light-emitting epitaxial layer structures and materials, and cannot be used as critical parameters for the lateral direction. The actual limit of the electrode spacing Lc. In practical applications, the lateral critical electrode spacing Lc varies with the specific structure and specific material of the light-emitting diode.

In this embodiment, at least part of the light-emitting area constrained by Lc covers the entire light-emitting area of the light-emitting epitaxial layer 12. In other embodiments, the above-mentioned at least part of the light-emitting area is a partial area of the entire light-emitting area of the light-emitting epitaxial layer 12. In a specific embodiment, the area ratio of the set of all at least part of the light-emitting regions that meet the above constraint conditions to the total light-emitting regions on the light-emitting epitaxial layer 12 is not less than 50%. In other specific embodiments, the area ratio of the set of all at least part of the light-emitting regions that meet the above constraint conditions to the total light-emitting regions on the light-emitting epitaxial layer 12 may be further not less than 60%, 70%, 80%, or 90%.

Furthermore, as shown in FIGS. 3 and 4, the greater the operating current, the more obvious the improvement effect of the light-emitting diode performance. Therefore, the restriction method for the sum of the shortest separation distances L1+L2 in this embodiment is particularly suitable for high-power light-emitting diodes. In a specific embodiment, the average current density J during operation of the light emitting diode is set to be not less than 1A/mm ² . In other specific embodiments, the average current density J during operation of the light emitting diode can be further set to not less than 1.5, ^{2, 3, 5,} 10, 20 A/mm 2.

It should be noted that the first semiconductor layer and the second semiconductor layer of the blue light-emitting diode described in FIGS. 1-2 above are both based on Group III nitride system materials. Therefore, the lateral critical electrode spacing Lc is also applicable to light-emitting diodes of other wavelengths based on the III-nitride system, such as 365nm-400nm, 400nm-440nm, 440nm-480nm, 480nm-540nm, 540nm-560nm, 560nm-600nm or 600nm- 700nm.

It should be noted that the sum of the shortest separation distances L1+L2 in this embodiment is actually limited by the shortest separation distance between the projections of two adjacent second electrodes 14 on the substrate 11. Therefore, in this embodiment and In other embodiments, the shortest separation distance between the projections of two adjacent second electrodes 14 on the substrate 11 can be restricted by using Lc. Specifically, the shortest distance between the projections of two adjacent second electrodes 14 on the substrate 11 is set to be no greater than the lateral critical electrode spacing, which refers to ensuring that the operating voltage of the light emitting diode varies with the average current The maximum allowable value of the shortest separation distance when the dynamic slope of the density change curve in a certain operating current section where the average current density is greater than 1A/mm ² ^{is not greater than 0.18Ω·mm 2} or the maximum allowable value under the above-mentioned other dynamic slope limits .

In summary, through the above arrangement, the uniformity of the current distribution is effectively improved, so that the light-emitting diode can withstand a higher working current, thereby improving the lumen efficiency and lumen density of the light-emitting diode. At the same time, the life and reliability of the light-emitting diode are high, and no complicated package design is required for heat dissipation, which reduces the lumen cost of the light-emitting diode.

In the following, light-emitting diodes of other structures that are also applicable to the above-mentioned lateral critical electrode spacing constraint will be described.

As shown in FIGS. 5 and 6, the light emitting diode according to the second embodiment of the present application is a modification of the vertical light emitting diode shown in FIGS. 1 and 2. In this embodiment, the light-emitting diode also includes a first electrode 23, a substrate 21, a mirror 28, a metal bonding layer 27, a first semiconductor layer 221, and an active layer similar to the light-emitting diode shown in FIG. 1 and FIG. The light emitting layer 222, the second semiconductor layer 223, and the second electrode 24. The difference between this embodiment and the light-emitting diode shown in FIG. 1 and FIG. 2 is:

The first semiconductor layer 221, the second semiconductor layer 123 and the active light emitting layer 122 are provided with trenches 224, and the trenches 224 arrange the first semiconductor layer 221, the second semiconductor layer 223 and the active light emitting layer 222 at intervals. Mesa structure (Mesa) 225. An insulating layer 291 and a current diffusion layer 292 are formed in the sidewall of the mesa structure 225 and the exposed area of the mesa structure 225. Two adjacent second electrodes 242 are respectively disposed in the trenches 224 on both sides of the mesa structure 225, and are electrically connected to the second semiconductor layer 223 through the current diffusion layer 292. At this time, as shown in FIG. 6, any light-emitting point A'in at least a part of the light-emitting region of the light-emitting epitaxial layer formed by the first semiconductor layer 221, the second semiconductor layer 123 and the active light-emitting layer 122 is on the substrate 11 The shortest distance between the projection on the upper surface and the projection of the two adjacent second electrodes 24 on the substrate 21 are respectively L1' and L2'. The sum of the two shortest separation distances is L1'+L2'.

Furthermore, as shown in FIGS. 7 and 8, the light emitting diode according to the third embodiment of the present application is a further modification of the vertical type light emitting diode shown in FIGS. 5 and 6. In this embodiment, the light-emitting diode also includes a first electrode 33, a substrate 31, a mirror 38, a metal bonding layer 37, a first semiconductor layer 321, and an active layer similar to the light-emitting diode shown in FIG. 5 and FIG. The light emitting layer 322, the second semiconductor layer 323, and the second electrode 34. In addition, the first semiconductor layer 321, the active light emitting layer 322, and the second semiconductor layer 323 are also divided into mesa structures 325 spaced from each other by the trenches 324, and are formed on the sidewalls of the mesa structures 325 and the exposed regions of the mesa structures 325 There is an insulating layer 391. The difference between this embodiment and the light emitting diode shown in FIG. 5 and FIG. 6 is:

A part of the second electrode 34 is disposed in the trench 324 in the form of a main electrode 343, and another part of the second electrode 34 is extended to the top of the mesa structure 325 in the form of a branch electrode 344, and is in contact with the second semiconductor layer 323 and formed Electric connection. At this time, as shown in FIG. 8, any light-emitting point A" in at least a part of the light-emitting region of the light-emitting epitaxial layer formed by the first semiconductor layer 321, the second semiconductor layer 323 and the active light-emitting layer 322 is on the substrate 11 The shortest distance between the projection on the upper surface and the projection of the two adjacent second electrodes 24 on the substrate 21 are respectively L1" and L2'. The sum of the two shortest separation distances is L1"+L2".

As shown in FIGS. 9 and 10, the light-emitting diode according to the fourth embodiment of the present application is a flip-chip light-emitting diode, which includes a substrate 41, a light-emitting epitaxial layer 42, a first electrode 43 and a second electrode 44. The first electrode 43 is a surface electrode, the number of the second electrode 44 is multiple, and the two are located on the same side of the light emitting diode. The light-emitting epitaxial layer 42 further sequentially stacks a first semiconductor layer 421, an active light-emitting layer 422, and a second semiconductor layer 423 disposed on the substrate 41. The first electrode 43 is disposed on a side of the second semiconductor layer 423 away from the substrate 41 and is electrically connected to the second semiconductor layer 423. A mirror 49 is further provided between the first electrode 43 and the second semiconductor layer 423 to reflect the light generated by the active light-emitting layer 422, and then emit light from the side where the substrate 41 is located. The surface of the first electrode 43 is provided with a plurality of grooves 424, and the grooves 424 extend to the first semiconductor layer 421 via the mirror 49, the second semiconductor layer 423 and the active light emitting layer 422. The plurality of second electrodes 44 are respectively disposed in the corresponding grooves 424 and are electrically connected to the first semiconductor layer 421. In this embodiment, the first semiconductor layer 421 is an N-type semiconductor layer (for example, N-type GaN), and the corresponding second electrode 44 is also called an N-type electrode. The second semiconductor layer 423 is a P-type semiconductor layer (for example, P-type GaN), and the corresponding first electrode 43 is also referred to as a P-type electrode. In other embodiments, the first semiconductor layer 421 and the second semiconductor layer 423 may be a single-layer or multi-layer structure of any other suitable materials with different conductivity types. In this embodiment, the projection of any light-emitting point A"' in at least part of the light-emitting area of the light-emitting epitaxial layer 42 on the substrate 41 and the projection of the two adjacent second electrodes 44 on the substrate 41 are the shortest The separation distances are respectively L1”' and L2”'. The sum of the two shortest separation distances is L1”'+L2”'.

The sums of the two shortest separation distances L1'+L2', L1"+L2" and L1"'+L2"' of the above-mentioned several light-emitting diode structures and other similar structures are all affected by the above-mentioned lateral critical electrode spacing Lc.

It should be noted that the first electrode and the second electrode of the first embodiment and the second embodiment of the present application are in a grid-like structure, which improves performance while reducing production line upgrade costs. However, the third embodiment and the fourth embodiment of the present application have a uniform dot structure, which can improve the uniformity of lateral current spreading.

In other embodiments, the shapes of the first electrode and the second electrode are not limited, and can be selected according to actual needs. Both the first electrode and the second electrode are composed of conductive materials, and the materials are aluminum, copper, tungsten, molybdenum, gold, titanium, silver, nickel, palladium or any combination thereof. The first electrode and the second electrode have at least one layer structure . Wherein, the first electrode may be a P-type electrode, and the second electrode may be an N-type electrode; or, the first electrode may be an N-type electrode, and the second electrode may be a P-type electrode.

The active light-emitting layer formed between the first semiconductor layer and the second semiconductor layer can emit light with a certain energy according to the recombination of electrons and holes, and can have a multiple quantum well (MQW) structure in which quantum wells and quantum barriers are alternately superimposed . For example, the active light-emitting layer may have _{a multi-quantum InGaN/GaN formed by injecting trimethylgallium gas (TMGa), ammonia (NH 3} ), nitrogen (N ₂ ), trimethyl indium gas (TMIn), etc. Well structure. At the same time, the first and second semiconductor layers and the active light-emitting layer can be formed by using semiconductor layer growth processes known in the art, such as metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), hydride vapor phase Epitaxy (HVPE) and so on. And has an energy determined by the intrinsic energy band of the active light-emitting layer material.

The Group III nitride material mentioned above may specifically include GaN, Al _x1 Ga _y1 N, InGaN, Al _x2 In _y2 Ga _z2 N. The mole fractions x1 and x2 of Al are respectively less than 10%.

The above are only implementations of this application, and do not limit the scope of this application. Any equivalent structure or equivalent process transformation made using the content of the description and drawings of this application, or directly or indirectly applied to other related technical fields, The same reasoning is included in the scope of patent protection of this application.

Claims

A light emitting diode, wherein the light emitting diode includes:

Substrate

The light-emitting epitaxial layer includes a first semiconductor layer, an active light-emitting layer, and a second semiconductor layer stacked on the substrate in sequence;

A first electrode and a plurality of second electrodes, the first electrode is electrically connected to one of the first semiconductor layer and the second semiconductor layer, and the plurality of second electrodes are connected to the first semiconductor layer and the second semiconductor layer. Another electrical connection in the semiconductor layer;

Wherein, the first electrode is a surface electrode, and the projections of the plurality of second electrodes on the substrate fall within the projections of the first electrodes on the substrate and are spaced apart from each other. The shortest distance between the two second electrodes is not greater than the lateral critical electrode spacing. The lateral critical electrode spacing refers to ensuring that the operating voltage of the light-emitting diode varies with the average current density curve when the average current density is greater than 1A. /mm 2 when the dynamic slope in a certain working current section is not greater than 0.18Ω·mm 2 the maximum allowable value of the sum of the shortest separation distance, the light emitting diode works in the working current section, and the first Both the first semiconductor layer and the second semiconductor layer are made of materials based on the Group III nitride system;

The group III nitride system-based material includes at least one of GaN, Al x1 Ga y1 N, InGaN, and Al x2 In y2 Ga z2 N.
A light emitting diode, wherein the light emitting diode includes:

Substrate

The light-emitting epitaxial layer includes a first semiconductor layer, an active light-emitting layer, and a second semiconductor layer stacked on the substrate in sequence;

A first electrode and a plurality of second electrodes, the first electrode is electrically connected to one of the first semiconductor layer and the second semiconductor layer, and the plurality of second electrodes are connected to the first semiconductor layer and the second semiconductor layer. Another electrical connection in the semiconductor layer;

Wherein, the first electrode is a surface electrode, the projections of the plurality of second electrodes on the substrate fall within the projections of the first electrodes on the substrate and are spaced apart from each other, and the light-emitting The sum of the shortest distance between the projection of any light-emitting point on the substrate and the projection of the two adjacent second electrodes on the substrate in at least part of the light-emitting area of the epitaxial layer is not greater than the lateral critical The electrode spacing, the horizontal critical electrode spacing refers to ensuring that the dynamic slope of the light-emitting diode operating voltage with the average current density variation curve in a certain operating current section where the average current density is greater than 1A/mm 2 is not greater than 0.18 Ω·mm 2 is the maximum allowable value of the sum of the shortest separation distance, the light-emitting diode works in the operating current section, and the first semiconductor layer and the second semiconductor layer are both based on three groups Nitride system materials.
The light-emitting diode according to claim 2, wherein the peak wavelength of the light-emitting diode during operation is between 365nm-400nm, 400nm-440nm, 440nm-480nm, 480nm-540nm, 540nm-560nm, 560nm-600nm, or 600nm- 700nm.
The light emitting diode according to claim 2, wherein the lateral critical electrode spacing refers to the maximum allowable value of the sum of the shortest separation distance when ensuring that the dynamic slope in the operating current section is not greater than 0.15Ω·mm 2 .
The light emitting diode according to claim 2, wherein the lateral critical electrode spacing refers to the maximum allowable value of the sum of the shortest separation distance when ensuring that the dynamic slope in the operating current section is not greater than 0.1Ω·mm 2 .
The light-emitting diode according to claim 2, wherein the lateral critical electrode spacing refers to the maximum allowable value of the sum of the shortest separation distance when ensuring that the dynamic slope in the operating current section is not greater than 0.06Ω·mm 2 .
The light emitting diode according to claim 2, wherein the lateral critical electrode spacing refers to the maximum allowable value of the sum of the shortest separation distance when ensuring that the dynamic slope in the operating current section is not greater than 0.03Ω·mm 2 .
The light emitting diode of claim 2, wherein the light emitting diode is a vertical light emitting diode, the first electrode is located on a side of the first semiconductor layer away from the active light emitting layer, and the second electrode is located The second semiconductor layer is far away from the active light-emitting layer, or the second semiconductor layer and the active light-emitting layer are provided with grooves, and the grooves connect the second semiconductor layer and the active light-emitting layer. The active light-emitting layer is divided into at least two mesa structures spaced apart from each other, and a part of the first semiconductor layer is exposed, and the second electrode is at least partially disposed in the trench and electrically connected by a branch electrode or a current diffusion layer To the second semiconductor layer, the projections of the plurality of second electrodes on the substrate overlap with the projections of the first electrodes on the substrate.
The light-emitting diode according to claim 2, wherein the light-emitting diode is a flip-chip light-emitting diode, the first electrode is disposed on a side of the second semiconductor layer away from the substrate, and the first electrode is A plurality of grooves extending to the first semiconductor layer are provided, the plurality of second electrodes are arranged in the corresponding grooves and are electrically connected to the second semiconductor layer, the plurality of second electrodes The projection on the substrate falls inside the projection of the groove on the substrate.
3. The light emitting diode according to claim 2, wherein the area ratio of the set of all the at least part of the light emitting regions on the light emitting epitaxial layer to all the light emitting regions on the light emitting epitaxial layer is not less than 50%.
3. The light emitting diode according to claim 2, wherein the area ratio of the set of all the at least part of the light emitting regions on the light emitting epitaxial layer to all the light emitting regions on the light emitting epitaxial layer is not less than 60%.
3. The light emitting diode according to claim 2, wherein the area ratio of the collection of all the at least part of the light emitting regions on the light emitting epitaxial layer to all the light emitting regions on the light emitting epitaxial layer is not less than 70%.
The light-emitting diode according to claim 2, wherein the area ratio of the collection of all the at least part of the light-emitting regions on the light-emitting epitaxial layer to the total light-emitting regions on the light-emitting epitaxial layer is not less than 80%.
3. The light emitting diode according to claim 2, wherein the area ratio of the collection of all the at least part of the light emitting regions on the light emitting epitaxial layer to all the light emitting regions on the light emitting epitaxial layer is not less than 90%.
The light emitting diode according to claim 2, wherein the average current density when the light emitting diode is in operation is not less than 1 A/mm 2 .
The light emitting diode according to claim 2, wherein the average current density when the light emitting diode is in operation is not less than 2A/mm 2 .
The light emitting diode according to claim 2, wherein the average current density when the light emitting diode is in operation is not less than 5A/mm 2 .
The light emitting diode according to claim 2, wherein the average current density when the light emitting diode is in operation is not less than 10 A/mm 2 .
The light emitting diode according to claim 2, wherein the average current density when the light emitting diode is in operation is not less than 20 A/mm 2 .
A light emitting diode, wherein the light emitting diode includes:

Substrate

The light-emitting epitaxial layer includes a first semiconductor layer, an active light-emitting layer, and a second semiconductor layer stacked on the substrate in sequence;

A first electrode and a plurality of second electrodes, the first electrode is electrically connected to one of the first semiconductor layer and the second semiconductor layer, and the plurality of second electrodes are connected to the first semiconductor layer and the second semiconductor layer. Another electrical connection in the semiconductor layer;

Wherein, the first electrode is a surface electrode, and the projections of the plurality of second electrodes on the substrate fall within the projections of the first electrodes on the substrate and are spaced apart from each other. The shortest distance between the two second electrodes is not greater than the lateral critical electrode spacing. The lateral critical electrode spacing refers to ensuring that the operating voltage of the light-emitting diode varies with the average current density curve when the average current density is greater than 1A. /mm 2 when the dynamic slope in a certain working current section is not greater than 0.18Ω·mm 2 the maximum allowable value of the sum of the shortest separation distance, the light emitting diode works in the working current section, and the first Both the first semiconductor layer and the second semiconductor layer are made of materials based on the Group III nitride system.