A semiconductor light emitting element

Abstract

The application provides a semiconductor light emitting element, comprising: a first conductive type semiconductor layer and a second conductive type semiconductor layer; a first electrode and a second electrode, which are respectively arranged on the first conductive type semiconductor layer and the second conductive type semiconductor layer and are located on the same side of the semiconductor light emitting element; at least one second electrode lead, which comprises a connecting section connected with the second electrode and an extending section extending from the connecting section to the first electrode; characterized in that the second electrode lead extending section has a first part extending from the second electrode lead connecting section to gradually approach the first electrode and a second part extending from the first part to gradually approach the first electrode, the width of the first part decreases from the extending direction, and the width of the second part is fixed. The width of the first part of the second electrode lead extending section decreases from the extending direction, so that the overvoltage impact performance (EOS performance) of the semiconductor light emitting element can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to a semiconductor light-emitting element, and belongs to the technical field of semiconductor optoelectronics. BACKGROUND

[0002] Light Emitting Diode (LED) has the advantages of high luminous intensity, high efficiency, small size, long service life, etc., and is considered as one of the most potential light sources. In recent years, LED has been widely used in daily life, such as lighting, signal display, backlight, car light and large screen display, etc. At the same time, these applications also put forward higher requirements on the brightness and luminous efficiency of LED.

[0003] In order to improve the luminous efficiency of LED, the design of LED chip will be optimized to small electrode and thin electrode lead in addition to gradually, so as to reduce the light blocking area and improve the luminous brightness. However, under a large current density, the thin electrode lead is easy to cause the current to be unable to realize effective expansion, which is concentrated at one end of the connection between the electrode lead and the electrode, the current expansion is uneven, the heat is locally concentrated, which leads to the fracture of the connection between the electrode and the electrode lead, and affects the reliability and anti-static ability of the LED chip.

[0004] Figure 1 A schematic diagram of an electrode structure of a conventional vertical light emitting diode, the first electrode and the second electrode of the vertical light emitting diode are located on the same side of the chip, the width of the connection section of the second electrode lead gradually narrows from the extension direction, the width of the end of the connection section is about 40%~50% of the initial width, and the width of the extension section is fixed. Since the vertical light emitting diode has poor heat dissipation, and the first electrode and the second electrode are both arranged on the front surface of the light emitting diode, the current can only diffuse through the electrode and the electrode lead on the front surface and the transparent conductive layer, and is easy to be crowded. The current is conducted through the electrode and the electrode lead, and is horizontally diffused through the surrounding transparent conductive layer, and the area through which the current flows will generate heat. The front end of the electrode lead is in a state where the load has not been completely diffused, and is easy to be affected by the concentrated load, and the surface is deposited with heat, so that the connection position of the connection section and the extension section of the electrode is easy to cause electrode blister burn, and loses the current conduction and diffusion ability. The end of the electrode lead is in the area after the current completes the flow of the electrode lead and the transparent conductive layer, and the load in this area has been further dispersed, so that the burn is not easy to occur. When the light emitting diode is just turned on, a transient high load current will be generated, which is more likely to aggravate the current crowding, and the connection position of the connection section and the extension section of the electrode lead is more likely to cause chip burn. SUMMARY

[0005] In order to solve the above problems, the application designs a semiconductor light emitting element, the first part of the second electrode lead extension section narrows gradually from the extension direction, the second part width is fixed. Through the second electrode lead extension section width from the extension direction is segmented or linearly narrowed, the front end of the electrode lead is wider, which helps to compensate for the weak point of the front end current diffusion, expand the current flux of the front end, let the load pass quickly, effectively disperse the heat, delay the occurrence of electrode blister burn caused by heat accumulation, can make the semiconductor light emitting element bear greater load, that is, the EOS performance is improved; At the same time, the overall widening design of the electrode lead can be avoided, the light blocking area is reduced, and the influence of light absorption or light blocking of the electrode lead on brightness is reduced.

[0006] In order to achieve the above object, the application provides a semiconductor light emitting element, comprising: a first conductive type semiconductor layer and a second conductive type semiconductor layer; a first electrode and a second electrode, respectively arranged on the first conductive type semiconductor layer and the second conductive type semiconductor layer, and located on the same side of the semiconductor light emitting element; at least one second electrode lead, comprising a connection section connected with the second electrode, and an extension section extending from the connection section to the first electrode; characterized in that: the second electrode lead extension section has a first part extending from the second electrode lead connection section to gradually approach the first electrode and a second part extending from the first part to gradually approach the first electrode, the width of the first part decreases in the extension direction, and the width of the second part is fixed.

[0007] Preferably, the width of the first part of the second electrode lead extension section linearly narrows from the extension direction at a fixed rate.

[0008] As another embodiment of the application, preferably, the width of the first part of the second electrode lead extension section narrows from the extension direction in segments, and the width of each segment is fixed or the width of each segment has different rates.

[0009] Preferably, the width of the first part of the second electrode lead extension section decreases from a horizontal extension direction.

[0010] Preferably, the second electrode lead connection section bends towards the first electrode or extends linearly towards the first electrode.

[0011] As an embodiment of the application, the second electrode lead is a plurality of leads, at least one of which bends towards the first electrode, and one of which extends linearly towards the first electrode.

[0012] Preferably, the width of the second electrode lead connecting section is fixed and ranges from 2um to 30um.

[0013] Preferably, the second electrode lead connecting section narrows from the direction of extension away from the second electrode, and the width of the end of the second electrode connecting section is 75% to 95% of the initial width.

[0014] Preferably, the width of the second part of the second electrode lead extension section ranges from 0.5um to 10um.

[0015] Preferably, the width of the second electrode lead connecting section is greater than the width of the second part of the second electrode lead extension section.

[0016] Preferably, the second part of the second electrode lead extension section extends linearly. More preferably, the second electrode lead extension section further comprises an end portion connected to the second part of the second electrode lead extension section, and the width of the end portion is fixed and curved towards the first electrode.

[0017] Preferably, the second part of the second electrode lead extension section is curved towards the first electrode.

[0018] Preferably, the distance from the end of the second electrode lead extension section to the first electrode is 20 to 300um.

[0019] Preferably, the length of the first part of the second electrode lead extension section accounts for 20% to 80% of the length of the entire second electrode lead extension section. More preferably, the length of the first part of the second electrode lead extension section accounts for 40% to 60% of the length of the entire second electrode lead extension section.

[0020] Preferably, the width of the second electrode lead connecting section is 1.5 to 3 times the width of the second part of the second electrode lead extension section.

[0021] As another embodiment of the present application, preferably, the first electrode has a plurality of leads, at least one of which comprises a connecting section connected to the first electrode and an extension section extending from the connecting section towards the second electrode, the first electrode lead extension section extending from the first electrode lead connecting section and gradually approaching the second electrode has a first part and a second part extending from the first part and gradually approaching the second electrode, the width of the first part of the first electrode lead extension section decreases along the direction of extension away from the first electrode, and the width of the second part is fixed.

[0022] Preferably, the width of the first part of the first electrode lead extension section narrows linearly at a fixed rate of change from the direction of extension.

[0023] Preferably, the width of the first part of the first electrode lead extension section narrows from the extension direction, and the width of each segment is fixed or the width of each segment has different variation rates.

[0024] Preferably, the width of the first electrode lead connection section is 1.5-3 times the width of the second part of the first electrode lead extension section.

[0025] Preferably, the length of the first part of the first electrode lead extension section accounts for 20%-80% of the entire length of the first electrode lead extension section. More preferably, the length of the first part of the first electrode lead extension section accounts for 40%-60% of the entire length of the first electrode lead extension section.

[0026] Preferably, a transparent conductive layer is further included, formed on the second conductive type semiconductor layer and forming ohmic contact with the second conductive type semiconductor layer.

[0027] Preferably, a current blocking layer is further included between the second conductive type semiconductor layer and the second electrode and the second electrode lead, and the current blocking layer includes a current blocking layer under the second electrode lead and a current blocking layer under the second electrode lead.

[0028] Preferably, the transparent conductive layer has an opening exposing the electrode current blocking layer.

[0029] More preferably, the width variation trend of the current blocking layer under the second electrode lead is consistent with the width variation trend of the second electrode lead.

[0030] As described above, the semiconductor light emitting element designed by the present application has the following beneficial effects:

[0031] By making the width of the electrode lead connection section greater than the width of the extension section, and making the width of the first part of the extension section narrow from the extension direction or linearly narrow, and making the width of the second part fixed, the weak point of the front end current diffusion can be compensated, the current flux of the front end can be expanded, the load can be quickly passed, the heat can be effectively dispersed, the occurrence of electrode blister burn caused by heat accumulation can be delayed, the semiconductor light emitting element can withstand greater load, that is, the EOS performance is improved; at the same time, the overall widening design of the electrode lead can be avoided, the light blocking area can be reduced, and the impact on brightness can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application together with the embodiments thereof, and explain the present application, but do not constitute a limitation of the present application. In addition, the drawing data is a description summary, not drawn to scale.

[0033] Figure 1 It is a schematic diagram of the electrode structure of the existing positive semiconductor light emitting element.

[0034] Figure 2 A cross-sectional view of the semiconductor light emitting element 1A mentioned in Embodiment 1 of the present application.

[0035] Figure 3 A schematic view of the width variation of the first portion of the second electrode lead extension of the present application.

[0036] Figure 4 A schematic view of the electrode structure of the semiconductor light emitting element 1A mentioned in Embodiment 1 of the present application.

[0037] Figure 5 A schematic view of the electrode structure of the modification example 1B mentioned in Embodiment 1 of the present application.

[0038] Figure 6 A schematic view of the electrode structure of the modification example 1C mentioned in Embodiment 1 of the present application.

[0039] Figure 7 A schematic view of the electrode structure of the comparative example 1D mentioned in Embodiment 1 of the present application.

[0040] Figure 8 A schematic view of the electrode structure of the reference example 1E mentioned in Embodiment 1 of the present application.

[0041] Figure 9 A schematic view of the electrode structure of the semiconductor light emitting element mentioned in Embodiment 2 of the present application.

[0042] Figure 10 A schematic view of the electrode structure of the semiconductor light emitting element mentioned in Embodiment 3 of the present application.

[0043] Figure 11 A schematic view of the electrode structure of the semiconductor light emitting element mentioned in Embodiment 4 of the present application.

[0044] Figure 12 A schematic view of the electrode structure of the semiconductor light emitting element mentioned in Embodiment 5 of the present application.

[0045] Explanation of element reference numerals in the drawings:

[0046] 1 substrate; 2 first conductive type semiconductor layer; 3 active layer; 4 second conductive type semiconductor layer; 5 current blocking layer; 6 transparent conductive layer; 7 first electrode; 71, 72 first electrode lead; 8 second electrode; 81, 82, 83 second electrode lead; 9 insulating protective layer. DETAILED DESCRIPTION

[0047] The present application now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the applications are shown. Indeed, these various embodiments can be practiced or carried out in various ways. Also, this application can be implemented in any of a number of ways, as will be apparent to those skilled in the art. It should be noted that the embodiments of the present application can vary as to the specific steps and sequences of steps illustrated without departing from the spirit of the underlying inventive concept. Additionally, it is to be understood that the specific elements and / or methods need not be limited to the precise descriptions set forth herein, and that the term "comprising" encompasses the other possibilities of "consisting essentially of and "consisting of.

[0048] It is to be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading the above description. The scope of the application should, therefore, be determined not with reference to the above description, but should instead be determined with reference to the appended claims, along with their full scope of equivalents.

[0049] Example 1

[0050] The present embodiment provides a semiconductor light emitting element, Figure 2 is a cross-sectional view of a semiconductor light emitting element, which includes: 1: a substrate; 2: a first conductive type semiconductor layer; 3: an active layer; 4: a second conductive type semiconductor layer; 5: a current blocking layer; 6: a transparent conductive layer; 7: a first electrode; 71, 72: a first electrode lead; 8: a second electrode; 81, 82, 83: a second electrode lead; and 9: an insulating protective layer.

[0051] The substrate 1 can be an insulating substrate or a conductive substrate. The substrate 1 is a growth substrate for epitaxial growth of a semiconductor stack, and includes an insulating substrate such as sapphire (Al2O3) or spinel (MgAl2O4); silicon carbide (SiC), ZnS, ZnO, Si, GaAs, diamond; and an oxide substrate such as lithium niobate, gallium niobate, and the like, which matches a lattice of a nitride semiconductor. The substrate 1 includes a first surface and a second surface, which are opposite to each other, and a side wall. The substrate 1 can include a plurality of protrusions formed in at least a portion of the first surface. The plurality of protrusions of the substrate 1 can be formed in a regular and / or irregular pattern. In the present embodiment, the substrate 1 is preferably a patterned sapphire substrate.

[0052] The thickness of the substrate 1 is between 40 and 300 um. In a case of a thicker substrate 1, the thickness of the substrate 1 is between 80 and 300 um. In a case of a thinner substrate 1, the thickness of the substrate 1 is, for example, 40 um or more, 80 um or less, or 40 um or more and 60 um or less.

[0053] The semiconductor stack includes a first conductive type semiconductor layer 2, an active layer 3, and a second conductive type semiconductor layer 4, which are sequentially stacked on the first surface of the substrate 1.

[0054] The first-conductivity-type semiconductor layer 2 can be composed of a III-V or II-VI compound semiconductor, and can be doped with a first dopant. The first-conductivity-type semiconductor layer 2 can be composed of a semiconductor material having a chemical formula of In X1 Al Y1 Ga 1-X1-Y1 N (0≤X1≤1, 0≤Y1≤1, 0≤X1+Y1≤1), such as GaN, AlGaN, InGaN, InAlGaN, and the like. In addition, the first dopant can be an n-type dopant, such as Si, Ge, Sn, Se, and Te. When the first dopant is an n-type dopant, the first-conductivity-type semiconductor layer doped with the first dopant is an n-type semiconductor layer. In the present embodiment, it is preferable that the first-conductivity-type semiconductor layer be an n-type semiconductor doped with an n-type dopant.

[0055] The active layer 3 is disposed between the first-conductivity-type semiconductor layer 2 and the second-conductivity-type semiconductor layer 4. The active layer 3 is a region that provides light radiation by recombination of electrons and holes, and different materials can be selected depending on the wavelength of the light to be emitted. The active layer 3 can be a single quantum well or a periodic structure of multiple quantum wells. The active layer 3 includes a well layer and a barrier layer, wherein the barrier layer has a larger band gap than the well layer. By adjusting the composition ratio of the semiconductor material in the active layer 3, it is possible to emit light of a desired wavelength.

[0056] The second-conductivity-type semiconductor layer 4 is formed on the active layer 3, and can be composed of a III-V or II-VI compound semiconductor. The second-conductivity-type semiconductor layer can be doped with a second dopant. The second-conductivity-type semiconductor layer 4 can be composed of a semiconductor material having a chemical formula of In X2 Al Y2 Ga 1-X2-Y2 N (0≤X2≤1, 0≤Y2≤1, 0≤X2+Y2≤1), or a material selected from the group consisting of AlInN, AlGaAs, GaP, GaAs, GaAsP, and AlGaInP. When the second dopant is a p-type dopant, such as Mg, Zn, Ca, Sr, and Ba, the second-conductivity-type semiconductor layer doped with the second dopant is a p-type semiconductor layer. In the present embodiment, it is preferable that the second-conductivity-type semiconductor layer be a p-type semiconductor doped with a p-type dopant.

[0057] In order to dispose the first electrode 7 and the second electrode 8, which will be described later, on the same side of the first-conductivity-type semiconductor layer 2 and the second-conductivity-type semiconductor layer 4, the second-conductivity-type semiconductor layer 4 can be laminated on the first-conductivity-type semiconductor layer 2 with a portion of the first-conductivity-type semiconductor layer 2 exposed, or the first-conductivity-type semiconductor layer 2 can be laminated on the second-conductivity-type semiconductor layer 4 with a portion of the second-conductivity-type semiconductor layer 4 exposed.

[0058] The semiconductor stack is formed by laminating the second-conductivity-type semiconductor layer 4 (p-type semiconductor layer) on the first-conductivity-type semiconductor layer 2 (n-type semiconductor layer) via the active layer 3. In terms of the p-type semiconductor layer and the active layer, it is preferable to remove a part of the n-type semiconductor layer in a part of the region in order to expose a part of the n-type semiconductor layer under these layers. The semiconductor stack can include at least one hole that exposes the first-conductivity-type semiconductor layer 2 at least partially through the active layer 3 and the second-conductivity-type semiconductor layer 4. The hole partially exposes the first-conductivity-type semiconductor layer 2, and the side surface of the hole can be surrounded by the light-emitting layer 3 and the second-conductivity-type semiconductor layer 4. Alternatively, the semiconductor stack can include one or a plurality of mesas including the active layer 3 and the second-conductivity-type semiconductor layer 4. The mesas are located on a part of the surface of the first-conductivity-type semiconductor layer 2. In the present embodiment, it is preferable that the semiconductor stack include one mesa including the active layer 3 and the second-conductivity-type semiconductor layer 4.

[0059] A transparent conductive layer 6 is located on the second-conductivity-type semiconductor layer 4. The transparent conductive layer 6 can form an ohmic contact with the second-conductivity-type semiconductor layer 4. Since it is disposed on the light-extraction surface side of the semiconductor light-emitting element, it is preferable that the conductive layer have transparency, and specifically, a conductive oxide layer. As such a conductive oxide, an oxide containing at least one selected from Zn, In, Sn, Mg, specifically, ZnO, In2O3, SnO2, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), GZO (Gallium-doped Zinc Oxide), and the like can be exemplified. Since the conductive oxide (particularly, ITO) has high light transmittance (for example, 60% or more, 70% or more, 75% or more, or 80% or more) in the visible light (visible region), and is also a material having a relatively high conductivity, it can be suitably used. The transparent conductive layer 6 can have an opening that exposes the current-blocking layer 5 below the second electrode described later.

[0060] The first electrode 7 and the second electrode 8 are directly or indirectly electrically connected to the first-conductivity-type semiconductor layer 2 and the second-conductivity-type semiconductor layer 4, respectively, in order to supply current to the first-conductivity-type semiconductor layer 2 and the second-conductivity-type semiconductor layer 4. In the case where the first-conductivity-type semiconductor layer is n-type, the first electrode refers to an n-side electrode, and in the case where the first-conductivity-type semiconductor layer is p-type, the first electrode refers to a p-side electrode. The same applies to the second electrode. In the present embodiment, it is preferable that the first electrode be an n-side electrode and the second electrode be a p-side electrode.

[0061] The second electrode 8 is in contact with the transparent conductive layer 6, and electrical connection between the second electrode and the second-conductivity-type semiconductor layer 4 is achieved.

[0062] In a plan view, the first electrode 7 or the second electrode 8 is preferably arranged inside the semiconductor light emitting element. In other words, it is preferable that the first electrode 7 is surrounded by the second conductive type semiconductor layer 4, or the second electrode 8 is surrounded by the first conductive type semiconductor layer 2. In this way, current can be diffused around the entire circumference of the first electrode 7 or the second electrode 8. In some embodiments, a portion of the first electrode 7 or the second electrode 8 can also not be surrounded by the second conductive type semiconductor layer 4 or the first conductive type semiconductor layer 2.

[0063] The first electrode 7 can also be surrounded by the second electrode 8 in part or in whole. In other words, it can be the case that the n-side electrode is surrounded by the p-side electrode in part or in whole, or the case that the p-side electrode is surrounded by the n-side electrode in part or in whole. Of these, the case that the n-side electrode is surrounded by the p-side electrode in part or in whole is preferable in terms of ensuring the area of the active layer 3.

[0064] The first electrode 7 and the second electrode 8 are pad electrodes that are electrically connected to external electrodes, external terminals, or the like, mainly for supplying current to the semiconductor light emitting element. The first electrode 7 and the second electrode 8 are respectively arranged so as to be biased toward opposite sides of the pair of edges of the semiconductor stack. The plan view shape of the pad electrodes can be appropriately adjusted according to the size of the semiconductor light emitting element, the arrangement of the electrodes, and the like, and can be, for example, a circular shape, a regular polygonal shape, or the like. Of these, a circular shape or a shape close to a circular shape is preferable in terms of the ease of wire bonding and the like. In addition, the size of the first electrode pad electrode and the second electrode pad electrode can be appropriately adjusted according to the size of the semiconductor light emitting element, the arrangement of the electrodes, and the like. For example, it can be a substantially circular shape with a diameter of approximately 70 to 150 μm. The shape and size of the first electrode pad electrode and the second electrode pad electrode can be the same or different.

[0065] The second electrode 8 has a plurality of electrode leads, at least one of which includes a connection section connected to the second electrode, and an extension section extending from the connection section toward the first electrode. The second electrode lead extension section has a first portion extending from the second electrode lead connection section toward the first electrode and gradually narrowing, and a second portion extending from the first portion toward the first electrode and gradually narrowing. The width of the first portion decreases in the extension direction, and the width of the second portion is constant. As one embodiment of the present application, the width of the first portion of the second electrode lead extension section can linearly decrease at a constant rate in the extension direction, as shown in FIG. a. As another embodiment of the present application, the width of the first portion of the second electrode lead extension section can decrease in segments, where the width of each segment is constant, as shown in FIG. b, or where the width of each segment decreases at a different rate, as shown in FIGS. c to e. Figure 3 a Figure 3 b Figure 3 c~3e

[0066] As an embodiment of the present application, the first electrode 7 has two electrode leads 71 and 72, which include a connecting section 71a, 72a connected to the first electrode 7 and an extending section 71b, 72b extending from the connecting section 71a, 72a to the first electrode 7. The width of the connecting section 71a, 72a and the extending section 71b, 72b is equal. Figure 4

[0067] The second electrode 8 has three electrode leads 81, 82 and 83. The second electrode leads 81 and 83 have the same shape, and the second electrode lead 81 will be taken as an example. The second electrode lead 81 includes a connecting section 81a connected to the second electrode 8 and an extending section 81b extending from the connecting section 81a to the first electrode 7. The extending section 81b of the second electrode lead 81 includes a first part 81b1 extending from the connecting section 81a to gradually approach the first electrode 7 and a second part 81b2 extending from the first part 81b1 to gradually approach the first electrode. The width of the first part 81b1 narrows step by step or linearly with a fixed change rate from the extending direction, and the width of the second part 81b2 is fixed. The connecting sections 81a and 83a of the second electrode are curved towards the first electrode. The second electrode lead 82 includes a connecting section 82a connected to the second electrode and an extending section 82b extending from the connecting section 82a to the first electrode. The extending section 82b includes a first part 82b1 extending linearly from the second electrode to gradually approach the first electrode and a second part 82b2 extending from the first part 82b1 to gradually approach the first electrode. In this embodiment, the extending section 81b of the second electrode lead 81 further includes an end part 81b3 curved towards the first electrode 7, and the width of the end part 81b3 is fixed and equal to the width of the second part 81b2. The addition of the end part 81b3 can make the second electrode lead 81 long enough, and the long enough second electrode lead 81 can reduce the working voltage of the device. Meanwhile, it is more preferable that the end part 81b3 of the electrode lead extending section ends the extension in a locally enlarged structure to prevent the current or charge from concentrating at the end of the electrode and prevent the end from being burnt.

[0068] ​The width of the second electrode lead connecting section is greater than the width of the second electrode lead extension section. The width of the second electrode lead connecting section is fixed, and the width is 2-30 um. For example, 4-15 um. Alternatively, the width of the second electrode lead connecting section gradually narrows from the extension direction, and the width of the end of the connecting section is 75-95% of the width of the starting connecting section. Preferably, the width of the second electrode lead connecting section is 1.5-3 times the width of the second part of the second electrode lead extension section, for example, the width of the second part of the second electrode lead extension section is 2-5 um. The length of the first part of the second electrode lead extension section accounts for 20-80% of the entire extension section length, and more preferably, the length of the first part of the second electrode lead extension section accounts for 40-60% of the entire extension section length.

[0069] Due to the poor heat dissipation of the positive light emitting diode, and the first electrode and the second electrode are arranged on the front surface of the light emitting diode, the current can only diffuse through the electrodes and electrode leads on the front surface and the transparent conductive layer, and current congestion is prone to occur. The front end of the electrode lead is in a state where the load has not been diffused, and is easily affected by the concentrated load, surface thermal deposition, and the connection position between the connecting section and the extension section is prone to electrode blister burn, and loses the ability to diffuse. The end of the lead is in an area where the current has completed the flow of the electrode lead and the transparent conductive layer, and the load has been further dispersed in this area, and is not prone to burn. Therefore, the width of the second electrode connecting section is designed to be greater than the width of the second electrode extension section, wherein the width of the end of the second electrode connecting section is more than 75% of the starting width, or more preferably, the width of the connecting section is constant, and the width of the first part of the second electrode extension section decreases from the extension direction of the second electrode to the first electrode, and the width of the second part is fixed. The method can compensate for the weakness of the front end current diffusion, enlarge the current flow of the front end, make the load pass quickly, effectively disperse the heat, delay the occurrence of electrode blister burn caused by heat accumulation, and enable the semiconductor light emitting element to withstand greater load, i.e. improve the EOS performance. At the same time, the overall widening design of the electrode lead can be avoided, the light blocking area is reduced, and the influence on brightness is reduced.

[0070] In the semiconductor light emitting element, since the carrier mobility of the p-electrode is low, current congestion is often caused at the bottom of the p-electrode and the p-electrode lead. Therefore, a current blocking layer 5 is often added at the bottom of the electrode and the electrode lead to suppress the over-injection of current and increase the current diffusion. The current blocking layer 5 is disposed at least on a part of the second conductive type semiconductor layer 4. The current blocking layer 5 can be disposed on the second conductive type semiconductor layer 5 corresponding to the portions where the second electrode 8 and the electrode leads 81, 82, 83 are located. The current blocking layer 5 can include an electrode current blocking layer and an electrode lead current blocking layer. The electrode current blocking layer and the electrode lead current blocking layer can be disposed corresponding to the positions of the second electrode and the second electrode lead, respectively. Preferably, the current blocking layer under the second electrode lead has the same shape as the second electrode lead and has a width dimension slightly larger than the size of the electrode lead. The width cannot be too large, otherwise light loss will be caused.

[0071] The current blocking layer 5 can prevent the current supplied to the second electrode 8 from being directly transmitted to the semiconductor layer to cause current concentration and promote current diffusion. Therefore, the current blocking layer 5 can have insulating property and can include an insulating substance and can be formed as a single layer or a multi-layer structure. For example, the current blocking layer 5 can include SiO x , SiON x and SiN x . Since it is disposed on the light extraction surface side of the semiconductor light emitting element, the current blocking layer 5 is preferably light transmissive.

[0072] In this embodiment 1A, as Figure 4As shown, the width of the first part of the extension segment of the second electrode lead narrows segmentally from the extension direction, with each segment having a different rate of width change. The first part 81b1 of the second electrode lead extension segment 81b is divided into three segments L1, L2, and L3. The lengths of L1, L2, and L3 are the same, each being 20% ​​of the total length of the extension segment 81b. The width of the second electrode lead connecting segment 81a is d0. The end widths of the three segments L1, L2, and L3 of the first part are d1, d2, and d3, respectively, where d1 is 90% of d0, d2 is 60% of d0, and d3 is 30% of d0. The width d3 of the end of the third segment is the same as the width d4 of the second part 81b2 of the second electrode lead extension segment. The width change rate of the first segment L1 is lower than that of the second and third segments L2 and L3. This is because the load is concentrated at the very front end of the electrode lead and has not yet fully diffused. Therefore, the width change rate of the first segment L1 of the electrode lead extension is set to be the smallest. As the load gradually diffuses along the electrode lead, the width of the electrode lead extension along the extension direction can be set to gradually increase the width change rate. This ensures that the overvoltage impact performance of the semiconductor light-emitting element is not affected, while reducing the width of the rear end of the electrode lead extension, reducing the light-blocking or light-absorbing area of ​​the electrode lead, thereby improving the luminous brightness. Similarly, the width change method of the second electrode leads 82 and 83 is the same as that of the second electrode lead 81. For example, the width of the connecting segment d0 is 4~12um, and the width of the second part d4 is 2~5um.

[0073] As a variation of Example 1A, in Example 1B, as... Figure 5 As shown, the first part of the second electrode lead extension 81b is a single-segment gradient, designated L1'. The width d0' of the second electrode connection segment is the same as the width d0 in Embodiment 1A. The width at the end of L1' is d1', which is 30% of the width d0' of the connection segment. That is, the width of the second part of the second electrode lead extension in Embodiment 1B is the same as the width of the second part of the second electrode lead in Embodiment 1A. The width design of the second electrode leads 82 and 83 is the same as that of the second electrode lead 81.

[0074] As another implementation of Example 1A, in Example 1C, such as Figure 6 As shown, the first part of the second electrode lead extension 81b is a two-segment gradient, designated L1'' and L2'', with widths d1'' and d2'' respectively. The width of the connecting segment is d0'', the same as the width d0 of the connecting segment in Embodiment 1, where d1'' is 80% of d0'' and d2'' is 30% of d0''. The rate of change of the width of the first segment of the first part of the second electrode lead extension is smaller than the rate of change of the width of the second segment. The width design of the second electrode leads 82 and 83 is the same as that of the second electrode lead 81.

[0075] As a comparative example 1D, such as Figure 7As shown, the width of the second electrode lead connecting section 82a in the comparative example is the same as the width of the second electrode lead extending section 82b, and is widened relative to the conventional second electrode structure, and is equal to the width d0 of the connecting section in Example 1A.

[0076] As a reference example 1E, as shown, the width of the connecting section of the electrode structure of the conventional positive light emitting diode is equal to the width d0 of the connecting section in Example 1A, and the width of the connecting section gradually narrows to 30% of the initial width, and the width of the extending section remains unchanged. Figure 8

[0077] In all of Examples 1A-1E, the end portion is allowed to be locally enlarged, so as to prevent the current or charge from being concentrated at the end of the electrode, and to prevent the end from being burned.

[0078] The samples of Examples 1A, 1B, 1C and Comparative Example 1D, Reference Example 1E above were tested, a forward current of 120 mA was passed, and the luminous intensity was tested; at the same time, an overvoltage impact (EOS performance) test was performed, a source test variable voltage source was used, the voltage was stepped by 1 V, 3 times were struck at each voltage, and the interval was 3 s; after each test, the Vf data was tested by using the LED-800. If the data is normal, the next voltage is struck, and the above operation is repeated until the chip Vf fails, and the high and low of the failure voltage Vf reflects the size of the overvoltage impact capability of the semiconductor light emitting element. The results are shown in the following table:

[0079]

[0080] ​As shown in the above table data, based on the data of the EOS performance tested by Reference Example 1E, the EOS performance of the electrode lead using one-stage, two-stage, three-stage segmented gradual change and continuous fixed widening is improved by 50%, 52%, 53% and 55% respectively compared with that of Reference Example. Since the width of the second electrode lead connecting section and the width of the second part of the second electrode lead extension section in Example 1A, 1B and 1C are the same, and the width of the second electrode lead connecting section in Comparative Example 1D is the same as that in Example 1A, 1B and 1C, when one-stage, two-stage, three-stage segmented gradual change and continuous fixed widening are used, the distance corresponding to the change from the width of the second electrode lead connecting section to the width of the second part of the second electrode lead is lengthened, and the diffusion capacity of the current flux at the front end of the electrode lead is also enhanced one by one, so that the load at the front end of the electrode lead can pass quickly and cannot cause the load to be crowded, which can effectively disperse heat and delay the occurrence of electrode blister burn caused by heat accumulation, so that the semiconductor light emitting element can bear greater load, i.e. the EOS performance is improved. As can be seen from the data in Table 1, the EOS performance of one-stage segmented gradual change in Example 1A is improved by 50%, and when two-stage segmented gradual change and three-stage segmented gradual change are used, the EOS performance is slightly improved compared with one-stage segmented gradual change; when overall widening design is used, the EOS performance is slightly improved compared with three-stage segmented gradual change. Since when one-stage, two-stage, three-stage segmented gradual change and continuous fixed widening are used, the distance corresponding to the change from the width of the second electrode lead connecting section to the width of the second part of the second electrode lead is lengthened, and the light blocking area of the electrode lead is also gradually increased, as shown in the above table data, the luminance is decreased and shows a gradually decreasing trend. Considering the influence of the segmented gradual change mode of the electrode lead on the EOS performance and the luminous brightness, two-stage segmented design is preferred, which can ensure that the light emitting diode has better EOS performance and luminous brightness.

[0081] When the failure voltage Vf of Example 1A, 1B, 1C and Comparative Example 1D, Reference Example 1F is implemented, burn occurs at different positions of the electrode. As shown in the above table data, the burn of the electrode lead in Example 1A is at the front end of the electrode lead, the burn of the electrode lead in Example 1B is at the front end of the electrode lead, the burn of the electrode lead in Example 1C is at the front end of the electrode lead, and the burn of the electrode lead in Comparative Example 1D is at the front end of the electrode lead. Figures 4 to 8The electrode burn locations are shown by the dashed boxes. In the reference example 1F, the burn location is at the junction of the second electrode lead connecting segment and the extending segment. In the one-segment gradual change design of example 1B, the burn location is at the junction of the first part and the second part of the second electrode lead extending segment, i.e. the end of the first segment gradual change of the second electrode lead extending segment, and the junction of the first electrode connecting segment and the extending segment also burns. In the two-segment gradual change design of example 1C, the three-segment gradual change design of example 1A, and the overall widening design of reference example 1E, the electrode burn locations are at the junction of the first electrode connecting segment and the extending segment. The current is injected from the first electrode and the second electrode and spreads to the first electrode lead and the second electrode lead. Because the electron mobility on the first electrode side is greater than the hole mobility on the second electrode side, the charge is usually concentrated in the direction of the second electrode lead extending segment, which can cause current congestion. Therefore, in the reference example 1E, the electrode burn location is at the junction of the second electrode connecting segment and the extending segment. In the one-segment gradual change design of example 1B, the width of the electrode lead connecting segment is widened compared to the reference example 1E, and the width of the first part of the second electrode lead extending segment is narrowed in the direction of the extension. This can compensate for the weakness of the current spread at the front end, expand the current flow at the front end, quickly pass the load, effectively disperse the heat, delay the occurrence of electrode blistering caused by heat accumulation, increase the overvoltage impact capacity of the semiconductor element, enhance the EOS performance of the one-segment gradual change design, and shift the burn location from the junction of the second electrode connecting segment and the extending segment to the end of the first part of the second electrode lead extending segment. Under the action of a higher voltage, the load of the N electrode cannot be effectively expanded, and thus the burn also occurs at the junction of the first electrode connecting segment and the extending segment. In the two-segment, three-segment gradual change design, and the overall widening design, the gradual change length of the first part of the second electrode lead extending segment is lengthened, the current expansion capacity of the second electrode lead is greatly enhanced, and the corresponding overvoltage impact capacity is also enhanced. Under the action of a higher voltage, the current of the second electrode lead can be effectively expanded, and the current of the first electrode lead cannot be effectively expanded, and thus the burn occurs at the junction of the first electrode connecting segment and the extending segment.

[0082] In the embodiment of the present application, an insulating protective layer 9 is provided on the surface of the semiconductor wafer stack, the first electrode, and the second electrode. The insulating protective layer includes an opening that exposes part of the upper surface of the first electrode and the second electrode, respectively. The insulating protective layer can be made of SiNx, SiOx, and Al2O3. The insulating protective layer can be a single-layer structure or a multi-layer structure.

[0083] Example 2

[0084] In this embodiment, as shown in Figure 9 The difference between this embodiment and example 1 is that the two leads 81 and 83 of the p electrode in this embodiment do not have end portions as in example 1, and the other parts are the same.

[0085] Example 3

[0086] As shown in FIG. 3, the difference between this example and Example 1 is that in this example, the second electrode has only two electrode leads, and the first electrode has only one electrode lead extending linearly from the first electrode to the second electrode. Figure 10

[0087] Example 4

[0088] As shown in FIG. 4, the difference between this example and Example 1 is that in this example, the second electrode has only one electrode lead, and the first electrode has only one electrode lead extending linearly from the first electrode to the second electrode. Figure 11

[0089] Example 5

[0090] As shown in FIG. 5, the difference between this example and Example 1 is that in this example, the first electrode has multiple electrode leads, and at least one first electrode lead includes a connecting segment connected to the first electrode and an extending segment extending from the connecting segment to the second electrode, the first electrode extending segment includes a first portion extending from the first electrode connecting segment gradually closer to the second electrode and a second portion extending from the first portion gradually closer to the second electrode, the width of the first portion is gradually narrowed from the extending direction, and the width of the second portion is fixed. Figure 12

[0091] The above examples are only illustrative of the principles and effects of the present application, and are not intended to limit the present application. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought of the present application fall within the scope of the present application defined by the appended claims.​​​

Claims

1. A vertical semiconductor light emitting device, comprising: a first conductive type semiconductor layer and a second conductive type semiconductor layer; a transparent conductive layer on the second conductive type semiconductor layer; a first electrode and a second electrode on the first conductive type semiconductor layer and the transparent conductive layer respectively, and on the same side of the semiconductor light emitting device, the second electrode being a p-type electrode; at least one second electrode lead including a connecting segment connected to the second electrode and an extending segment extending toward the first electrode, the extending segment including a first part extending from the connecting segment toward the first electrode, the first part extending linearly toward the first electrode; characterized in that: the extending segment further includes a second part extending from the first part of the extending segment toward the first electrode, the second part extending linearly toward the first electrode; the first part of the extending segment is divided into N segments in the extending direction, where 1 < N ≤ 3, the width of the first part of the extending segment decreases gradually in the extending direction, and the rate of change of the width gradually increases; the width of the second part is fixed; the length of the first part of the extending segment accounts for 20% to 80% of the length of the second electrode lead extending linearly.

2. The flip-chip semiconductor light emitting element according to claim 1, wherein the first semiconductor layer is a p-type semiconductor layer, and the second semiconductor layer is an n-type semiconductor layer. N is 2 or 3, the width of each segment of the first part of the extending segment decreases gradually, and the rate of change of the width in the extending direction gradually increases.

3. The flip-chip semiconductor light emitting element according to claim 1, wherein the connecting segment of the second electrode lead bends toward the first electrode, and the width at the joint of the extending segment and the connecting segment of the second electrode lead is more than 75% of the initial width of the connecting segment of the second electrode lead.

4. The flip-chip semiconductor light emitting element according to claim 3, wherein there are multiple second electrode leads, at least one of which has a connecting segment that bends toward the first electrode, and one of which extends linearly toward the first electrode.

5. The flip-chip semiconductor light emitting element according to claim 1, wherein the width of the connecting segment of the second electrode lead ranges from 2 um to 30 um.

6. A flip-chip semiconductor light emitting element according to claim 3, wherein the width of the connecting segment of the second electrode lead narrows along the extending direction away from the second electrode, and the width at the joint of the connecting segment and the extending segment of the second electrode lead is 75% to 95% of the initial width of the connecting segment.

7. A flip-chip semiconductor light emitting element according to claim 1, wherein the width of the second part of the extending segment of the second electrode lead ranges from 0.5 um to 10 um.

8. The flip-chip semiconductor light emitting element according to claim 1, wherein the second electrode lead further includes an end part, the end part of the second electrode lead being connected to the second part of the extending segment of the second electrode lead, having a fixed width, and bending toward the first electrode.

9. The flip-chip semiconductor light emitting element according to claim 1, wherein the distance from the end of the extending segment of the second electrode lead to the first electrode is 20 to 300 um.

10. The flip-chip semiconductor light emitting element according to claim 1, wherein the length of the first part of the extending segment of the second electrode lead accounts for 20% to 60% of the length of the second electrode lead extending linearly.

11. The flip-chip semiconductor light emitting element according to claim 1, wherein the length of the first part of the extending segment of the second electrode lead accounts for 40% to 80% of the length of the second electrode lead extending linearly.

12. A flip-chip semiconductor light emitting element according to claim 1, wherein the width of the connecting segment of the second electrode lead is 1.5 to 3 times the width of the second part of the extending segment of the second electrode lead.

Images