Light emitting diode and light emitting device

Abstract

The invention provides a light emitting diode and a light emitting device, the light emitting diode comprises a semiconductor lamination layer, an insulation reflection layer and an electrode structure, a first opening and a second opening are formed in the insulation reflection layer, a second electrode in the electrode structure comprises a second connection electrode, the second connection electrode comprises a contact layer and a connection layer, the contact layer is filled into the second opening of the insulating reflecting layer and is electrically connected with the second semiconductor layer of the semiconductor lamination layer; and the connecting layer is formed above the contact layer and is connected with the contact layer. For example, the contact layer can be an Ag electrode with relatively high reflectivity and can play a role in reflection, so that the loss of reflectivity at the opening of the insulating reflecting layer is made up, and the light emitting effect of the light emitting diode is improved. And meanwhile, the contact layer can form good ohmic contact with the current diffusion layer, so that the electrical property of the light emitting diode is improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor devices, and in particular to a light emitting diode and a light emitting device. Background Art

[0002] Light-emitting diodes (LEDs) are widely used in display devices, vehicle lamps, general lighting, etc. due to their high reliability, long life, and low power consumption. GaN-based semiconductor flip-chip diodes have the advantages of good heat dissipation, high luminous efficiency, and good stability, and are increasingly favored by the market.

[0003] When preparing a chip, a contact electrode (PAD1) is usually formed after evaporating ITO to form a good ohmic contact with ITO. This process increases the complexity of the process and increases the cost. In order to reduce the cost of the chip, simple flip chip has become a further research direction.

[0004] To prepare a simple flip chip, usually after evaporating ITO, the DBR layer is directly covered, which can not only increase the effective reflection of the DBR, but also omit the preparation of PAD1 and reduce costs. After evaporating the DBR, further holes are punched to connect the electrodes. The electrode can be made of a metal material with high reflectivity combined with the DBR to form an ODR structure with better reflection effect; or a metal material with good adhesion can be used to form a good ohmic contact with ITO. However, no electrode can meet these two requirements: 1. It can form a good ohmic contact with ITO; 2. It can be combined with the DBR to form a good ODR structure to increase light reflection. Therefore, the electrode structure of the existing light-emitting diode affects the brightness and voltage of the chip. Summary of the invention

[0005] In view of the defects and shortcomings of the flip-chip diode in the prior art, the purpose of the present invention is to provide a light-emitting diode and a light-emitting device. After the insulating reflective layer is covered on the semiconductor stack, a contact layer is first formed in the opening of the insulating reflective layer to increase the adhesion with one side of the second semiconductor layer, and at the same time compensate for the light reflection at the opening of the insulating reflective layer, thereby improving the light emitting effect of the light-emitting diode.

[0006] To achieve the above-mentioned object and other related objects, the present invention provides a light emitting diode, which includes:

[0007] A semiconductor stack, comprising a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence;

[0008] an insulating reflective layer, located on one side of the second semiconductor layer and at least covering a surface of the semiconductor stack, wherein a first opening and a second opening are formed in the insulating reflective layer, wherein the first opening is located above the first semiconductor layer, and the second opening is located above the second semiconductor layer;

[0009] An electrode structure is located above the insulating reflective layer, the electrode structure comprising a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer, wherein

[0010] The second electrode includes a second connecting electrode, which includes a contact layer and a connecting layer. The contact layer fills the second opening and extends onto the insulating reflective layer outside the second opening to be electrically connected to the second semiconductor layer. The connecting layer is formed above the contact layer and connected to the contact layer.

[0011] A second aspect of the present invention provides a light-emitting device, which includes a substrate and a plurality of light-emitting units located on the substrate, wherein the light-emitting units include the light-emitting diodes provided in the present application.

[0012] As described above, the light emitting diode and the light emitting device provided by the present invention have at least the following beneficial technical effects:

[0013] The light-emitting diode of the present invention includes a semiconductor stack, an insulating reflective layer and an electrode structure, wherein a first opening and a second opening are formed in the insulating reflective layer, and the second electrode in the electrode structure includes a second connecting electrode, wherein the second electrode includes a contact layer and a connecting layer, wherein the contact layer is filled into the second opening of the insulating reflective layer and is electrically connected to the second semiconductor layer of the semiconductor stack, and the connecting layer is formed above the contact layer and connected to the contact layer. The contact layer may be, for example, an Al or Ag electrode with a high reflectivity, which can play a reflective role and compensate for the reflectivity loss at the opening of the insulating reflective layer, thereby increasing the light-emitting effect of the light-emitting diode. At the same time, the contact layer can form a good ohmic contact with the current diffusion layer, thereby improving the electrical performance of the light-emitting diode. The connecting layer is formed above the contact layer, and the connecting layer may be, for example, a multilayer structure formed by any of a plurality of metal materials such as Cr, Al, Ti, Pt, etc. The connecting layer can form a good ODR structure with the insulating reflective layer, thereby increasing the reflection effect and improving the optical performance of the light-emitting diode.

[0014] On the other hand, the first electrode may include a first contact electrode and a first connection electrode formed above the first semiconductor layer, the first connection electrode filling the first opening in the insulating reflective layer to be connected to the first contact electrode. The first contact electrode may serve as an etching stop layer when etching the insulating reflective layer to form the first opening, thereby ensuring etching accuracy and preventing damage to the first semiconductor layer due to over-etching. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Shown is a schematic diagram of the structure of a light emitting diode provided in Example 1 of the present application.

[0016] Figure 2 Display as Figure 1 Schematic diagram of the local enlarged structure of the second connecting electrode.

[0017] Figure 3 The scanning electron microscope image of the second connecting electrode is shown in the figure.

[0018] Figure 4 Display as Figure 1 The schematic diagram of the top view of the second connecting electrode toward the semiconductor stack is shown.

[0019] Figure 5 Shown is a schematic diagram of the structure of a light emitting diode provided in Example 2 of the present application.

[0020] Figure 6 Shown is a schematic diagram of the structure of the light-emitting diode provided in Example 3 of the present application.

[0021] Figure 7 A schematic diagram of the structure of a light emitting diode provided in Example 4 of the present application.

[0022] Figure 8 Shown is a schematic diagram of the structure of a light-emitting diode provided in Example 5 of the present application.

[0023] Fig. 9 Shown is a schematic diagram of the structure of the light-emitting diode provided in Example 6 of the present application.

[0024] Fig.10 Shown is a schematic diagram of the structure of the light-emitting diode provided in Example 7 of the present application.

[0025] Fig.11 Display as Fig.10 A comparison chart of the reflectivity of the light-emitting diode in FIG. 1 and the light-emitting diode in the prior art.

[0026] Fig.12 Shown is a schematic diagram of the structure of the light-emitting device provided in Example 8 of the present application.

[0027] Reference numerals

[0028] 100, substrate; 200, semiconductor stack; 201, first semiconductor layer, 202, active layer, 203, second semiconductor layer; 204, current diffusion layer; 205, current blocking layer; 300, insulating reflective layer; 301, first opening; 302, second opening; 3021, first section; 3022, second section; 3023, platform structure; 400, first electrode; 401, first contact electrode; 402, first connecting electrode; 500, second electrode; 501, second connecting electrode; 5011, contact layer; 5012, connecting layer; 5013, transparent adhesive layer; 5014, reflecting layer; 502, second contact electrode; 601, first insulating protective layer; 602, second insulating protective layer; 603, third insulating protective layer; 700, pad electrode; 701, first pad; 702, second pad;

[0029] 900, light-emitting device; 901, circuit substrate, 902, light-emitting unit; 903, circuit layer; 904, housing; 905, solder pad. DETAILED DESCRIPTION

[0030] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0031] It should be noted that the illustrations provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Although the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation, the form, quantity, positional relationship and proportion of each component in actual implementation can be changed at will under the premise of realizing the technical solution of this party, and the component layout form may also be more complicated.

[0032] Embodiment 1

[0033] This embodiment provides a light emitting diode, such as Figure 1 As shown, the light emitting diode of this embodiment includes a semiconductor stack 200, an insulating reflective layer 300 located above the semiconductor stack 200, and an electrode structure located above the insulating reflective layer 300. In an optional embodiment, the light emitting diode further includes a substrate 100, and the material of the substrate 100 can be sapphire, silicon carbide, silicon or gallium nitride. In this embodiment, the substrate 100 is taken as a sapphire substrate as an example.

[0034] Also refer to Figure 1The semiconductor stack 200 is located above the substrate 100 and includes a first semiconductor layer 201, an active layer 202 and a second semiconductor layer 203 stacked in sequence from bottom to top. The first semiconductor layer 201, the active layer 202 and the second semiconductor layer 203 may include Ш-V nitride semiconductors, for example, they may include nitride semiconductors such as (Al, Ga, In). The first semiconductor layer 201 may include n-type impurities (for example, Si, Ge, Sn), and the second semiconductor layer 203 may include p-type impurities (for example, Mg, Sr, Ba). It can be understood that the dopants of the first semiconductor layer 201 and the second semiconductor layer 203 may also be opposite to the above content. The active layer 202 may include a multi-quantum well structure (MQW), and the active layer 202 may emit a desired wavelength by adjusting the composition ratio of the nitride semiconductor.

[0035] The semiconductor stack 200 is formed with a mesa structure to expose a portion of the surface of the first semiconductor layer 201, so as to facilitate the subsequent formation of an electrode structure. The shape of the portion of the surface of the first semiconductor layer 201 exposed by the mesa structure of the semiconductor stack 200 can be arbitrary, and the mesa structure can be an open mesa structure or a closed mesa structure with a hole structure.

[0036] Also refer to Figure 1 , the insulating reflective layer 300 is located above the semiconductor stack 200, that is, on the side of the second semiconductor layer 203 of the semiconductor stack 200, and at least covers the surface of the semiconductor stack 200. In this embodiment, the insulating reflective layer 300 covers the surface and sidewalls of the semiconductor stack 200, and further covers from the sidewalls of the semiconductor stack 200 to the exposed surface of the substrate 100. The insulating reflective layer 300 protects the semiconductor stack 200 from damage by external moisture or pollutants to ensure good optical and electrical properties of the light-emitting diode. Optionally, the insulating reflective layer 300 can be a single-layer structure, whose refractive index is lower than the refractive index of the semiconductor stack 200, and can reflect the light emitted from the semiconductor stack 200, for example, it can be a SiO2 layer, or a SiN x or the insulating layer reflective layer 300 is a multilayer structure, such as SiO2 layer and SiN x The two layers formed by the layer combination can also be a DBR structure formed by alternating two material layers with different refractive indices, such as any one of TiO2, Nb2O5, Ta2O5, HfO2, ZrO2 and ZnO, and any one of SiO2, MgF2, A12O3 and SiON. In an optional embodiment, the thickness of the DBR structure is between 1μm and 10μm, further, between 0.3μm and 5μm, 1μm to 2μm, or between 4μm and 5μm, or between 2μm and 6μm.

[0037] like Figure 1 As shown, a first opening 301 and a second opening 302 are formed in the insulating reflective layer 300. The first opening 301 is located above the first semiconductor layer 201 exposed in the semiconductor stack 200, and the second opening 302 is located above the second semiconductor layer 203. The electrode structure of the light emitting diode is located above the insulating reflective layer 300, and the electrode structure includes a first electrode 400 connected to the first semiconductor layer 201 and a second electrode 500 connected to the second semiconductor layer 203. In this embodiment, as shown in FIG. Figure 1 As shown, the first electrode 400 includes a first contact electrode 401 and a first connecting electrode 402, and the first contact electrode 401 is formed above the first semiconductor layer 201 exposed by the mesa structure. The first contact electrode 401 can be a single-layer metal material layer or a multi-layer metal material layer, for example, one or any combination of nickel, gold, chromium, titanium, platinum, palladium, chromium, iridium, aluminum, tin, indium, tin, copper, cobalt, iron, rhodium, zirconium, tungsten, and molybdenum. In an optional embodiment, it can be an Al, Cr / Al or Ni / Al structure. The first contact electrode 401 forms a good ohmic contact with the first semiconductor layer 201, thereby ensuring good electrical properties of the light-emitting diode. In addition, in the process of etching the insulating reflective layer 300 to form the above-mentioned first opening, the first contact electrode 401 can be used as an etching stop layer to ensure the etching accuracy of the first opening 301, while preventing damage to the first semiconductor layer 201 due to over-etching. As shown Figure 1 As shown, the first opening 301 is formed above the first semiconductor layer 201 and its bottom exposes the first contact electrode 401 . The first connecting electrode 402 fills the first opening 301 and is connected to the first contact electrode 401 at the bottom of the first opening 301 , and extends to the insulating reflective layer 300 outside the first opening 301 .

[0038] Also refer to Figure 1 The second electrode 500 includes a second connection electrode 501, and the second connection electrode 501 includes a contact layer 5011 and a connection layer 5012, wherein the contact layer 5011 is filled into the second opening 302 and is electrically connected to the second semiconductor layer 203, and the connection layer 5012 is formed above the contact layer 5011 and is connected to the contact layer 5011. Optionally, a current diffusion layer 204 is further formed between the second semiconductor layer 203 and the insulating reflective layer 300, and the current diffusion layer 204 is a transparent conductive material layer, such as indium tin oxide (ITO), indium zinc oxide (IZO), aluminum-doped zinc oxide transparent conductive glass (AZO), etc. At this time, the bottom of the second opening 302 exposes the current diffusion layer 204. The current diffusion layer 204 covers at least part of the surface of the second semiconductor layer 203 to diffuse the current to the surface of the second semiconductor layer 203 as evenly as possible to improve the light-emitting effect.

[0039] At the same time, in order to prevent the current from being concentrated at the second semiconductor layer 203 below the second opening 302, a current blocking layer 205 is provided between the second semiconductor layer 203 and the current diffusion layer 204. The current blocking layer 205 is an insulating material layer, such as a SiO2 and / or SiN material layer. In order to ensure the electrical connection between the current diffusion layer 204 and the second semiconductor layer 203 and the current diffusion effect of the current diffusion layer 204, the current blocking layer 205 is formed into a patterned structure, that is, the second semiconductor layer 203 is not entirely covered by the current blocking layer 205. For example, the current blocking layer 205 is located below the second opening 302 and is formed into an island or block structure, and the current diffusion layer 204 covers the surface and sidewalls of the current blocking layer 205. When the current blocking layer 205 is located below the second opening 302 and is formed into an island or block structure, the projected area of ​​the contact layer 5011 is larger than the projected area of ​​the current blocking layer 205 below the second opening 302 when projected on the plane where the surface of the semiconductor stack 200 is located, and the projection of the current blocking layer 205 below the second opening 302 is located within the projection range of the contact layer 5011. This facilitates the lateral diffusion of the current from the contact layer 5011 along the current diffusion layer.

[0040] As described above, the current diffusion layer 204 is formed between the second semiconductor layer 203 and the insulating reflective layer 300, so the bottom of the second opening 302 includes the current diffusion layer 204, that is, the bottom of the second opening 302 is located on the surface of the current diffusion layer 204, or the bottom of the second opening 302 is located inside the current diffusion layer 204, but does not penetrate the current diffusion layer 204. In an optional embodiment, the thickness of the current diffusion layer 204 is between Further, between or between When the bottom of the second opening 302 is located inside the current diffusion layer 204, that is, when the second opening 302 extends to the inside of the current diffusion layer 204, the depth of the second opening 302 extending in the current diffusion layer 204 is less than or equal to Further, between And it is ensured that the current diffusion layer 204 is not penetrated. The contact layer 5011 fills the second opening 302 and is connected to the current diffusion layer 204 exposed at the bottom of the second opening 302 to achieve electrical connection with the second semiconductor layer 203 .

[0041] In this embodiment, the contact layer 5011 of the second connection electrode 501 is formed as a multilayer structure containing an Al layer, such as a Ni / Al / Ti / Pt stacked structure or a Cr / Al / Ti / Pt stacked structure. As described above, the contact layer 5011 is filled in the second opening 302, and the Ni layer or Cr layer therein can increase the adhesion between the contact layer 5011 and the current diffusion layer 204, and form a good ohmic contact with the current diffusion layer 204, thereby ensuring the electrical performance of the light-emitting diode. At the same time, the Al layer in the contact layer 5011 has a reflective effect, which can increase the reflectivity of the contact layer 5011, which is conducive to compensating for the reflection effect lost by the insulating reflective layer 300 due to the formation of the second opening 302, thereby increasing the reflection effect of the light radiated by the semiconductor stack 200, and improving the light emitting effect of the light-emitting diode.

[0042] Also refer to Figure 1 , the connection layer 5012 is formed on the insulating reflective layer 300, and covers and connects the contact layer 5011. The connection layer 5012 can be a single metal material layer or a multi-layer metal material layer, for example, a stacked structure of Al, Ti, Ni, Cr, Pt, etc. The above-mentioned connection layer 5012 contains an Al layer, and the thickness of the Al layer is greater than the thickness of Al in the contact layer 5011, so the connection electrode 5012 has a higher reflectivity, and can form a total reflection structure with the insulating reflective layer 300, thereby increasing the reflection efficiency of the light radiated by the semiconductor stack 200 and improving the light extraction effect.

[0043] As described above, both the contact layer 5011 and the connection layer 5012 can form a multilayer structure and can include an Al layer. In an optional embodiment, it is defined that: the thickness of the contact layer 5011 is T1, the thickness of the Al layer in the contact layer 5011 is T1a, the thickness of the connection layer 5012 is T2, and the thickness of the Al layer in the connection layer 5012 is T2a, wherein 200nm≤T1≤500nm, 1500nm≤T2≤5000nm, T1a=(0.1~0.6)*T1, T2a=(0.2~0.8)*T2, and T1a=(0.1~0.5)*T2a. The configuration of the contact layer 5011 and the connection layer 5012 containing the Al layer and the configuration of the thickness of each Al layer make the contact layer 5011 and the connection layer 5012 have good adhesion, good reflection effect, and good conductive effect.

[0044] In another optional embodiment, the connection layer 5012 is a multi-layer structure, including a transparent conductive layer and an Ag layer. The transparent conductive layer and the current diffusion layer 204 formed on the second semiconductor layer 203 are the same or different material layers, for example, both can be ITO material layers. When projected on the plane where the surface of the semiconductor stack 200 is located, the projection of the transparent conductive layer in the connection layer 5012 does not overlap or intersect with the projection of the contact layer 5011. That is, the transparent conductive layer in the connection layer 5012 will not be formed on the contact layer 5011, thereby avoiding causing the voltage of the light-emitting diode to be too high.

[0045] In an optional embodiment of this embodiment, if Figure 2 and Figure 3 As shown, the contact layer 5011 fills the second opening 302 and also extends to the insulating reflective layer 300 outside the second opening 302. Figure 3 The sidewall of the second opening 302 includes a first section 3021 and a second section 3022. The insulating reflective layer 300 outside the second opening 302 is formed as a platform structure 3023. The first section 3021 is formed as an inclined sidewall. For example, the angle α between the first section 3021 and the plane where the current diffusion layer 204 at the bottom of the second opening 302 is located is between 40° and 70°, and further, between 40° and 50° and 50° and 60°. The second section 3022 is a connecting section between the first section 3021 and the platform structure 3023, and is formed as a smooth transition section, for example, a rounded or arc-shaped transition section. The contact layer 5011 covers the first section 3021, the second section 3022 and part of the platform structure 3023, forming a "T"-shaped structure.

[0046] In an optional embodiment, the second opening 302 is formed as a circular hole with a circular cross-section, and the bottom radius of the second opening 302 is defined as R1, and the top opening radius is defined as R2. Figure 4As shown, the projection of the contact layer 5011 is a circular structure, and the radius of the contact layer 5011 is defined as R3, wherein R2 = (1.5-3) R1, R3 = (1-3) R1, and R3 ≥ R2. Specifically, the above R1 is between 2 μm and 6 μm, for example, about 4 μm; R2 is between 3 μm and 8 μm, for example, about 6 μm; and R3 is between 3 μm and 10 μm, for example, about 8 μm. The above arrangement of the contact layer 5011 can make the aperture of the second opening 302 smaller to a certain extent, and at the same time, ensure that the contact layer 5011 forms a good electrical connection with the second semiconductor layer 203. The contact layer 5011 not only covers the bottom of the second opening 302 and the above first section 3021 and second section 3022, but is also formed on part of the platform structure 3023 to increase the reliability of the contact layer 5011 and increase its reflection area. The connection layer 5012 covers the contact layer 3011 and also covers a portion of the insulating reflective layer 300 around the contact layer 5011, which is beneficial to improving the adhesion between the contact layer 5011 and the connection layer 5012. Figure 3 As shown, in an actual product, the contact layer 5011 can well fill the second opening 302 , that is, evenly cover the bottom and sidewalls of the second opening 302 , and can evenly extend to the portion of the insulating reflective layer 300 outside the second opening 302 .

[0047] In the light emitting diode, there may be multiple second openings 302, and the connection layer 5012 of the second connection electrode 501 may be formed into a structure that connects the contact layers 5011 at multiple second openings 302 as needed. Since the first opening 301 is formed above the first semiconductor layer 201 exposed by the mesa structure, in order to ensure sufficient light emitting area of ​​the light emitting diode, the surface area of ​​the mesa structure is usually small, so one first opening 301 is usually formed at one mesa structure. Figure 4 The projection from the second connection electrode 501 to the semiconductor stack 200 is schematically shown, and it can be seen that the projection area of ​​the connection layer 5012 is larger than the projection area of ​​the contact layer 5011, and the projection of the contact layer 5011 is located within the projection range of the connection layer 5012, thereby ensuring good contact between the connection layer 5012 and the contact layer 5011. Specifically, the connection layer 5012 is connected to the contact layer 5011 at the plurality of second openings 302, and the projection area of ​​each part of the connection layer 5012 is larger than the projection area of ​​the contact layer 5011 it is connected to.

[0048] Refer again Figure 1The light emitting diode of this embodiment further includes a first insulating protective layer 601 and a pad electrode 700. The first insulating protective layer 601 is located above the electrode structure and the insulating reflective layer 300. Specifically, the first insulating protective layer 601 covers the first connecting electrode 402 and the second connecting electrode 501, as well as the surface of the exposed insulating reflective layer 300, and further covers the side wall of the insulating reflective layer 300. The first insulating protective layer 601 can be a material layer formed by any one or more of SiO2, SiN, Al2O3, etc., or can be a material layer that is the same as the insulating reflective layer 300. The first insulating protective layer 601 further insulates the light emitting diode and protects it from impurities and dust, further ensures the mutual insulation between the first connecting electrode 402 and the second connecting electrode 501, and prevents the light emitting diode from being polluted or damaged by external dust, water vapor, etc.

[0049] The pad electrode 700 is located above the first insulating protective layer 601, and the pad electrode 700 includes a first pad 701 and a second pad 702 arranged at intervals. The first pad 701 penetrates the first insulating protective layer 601 and is connected to the first electrode 400, and the second pad 702 penetrates the first insulating protective layer 601 and is connected to the second electrode. Specifically, the first pad 701 is connected to the first connection electrode 402, and the second pad 702 is connected to the second connection electrode 501. The shape and number of the first pad 701 and the second pad 702 can be selected according to actual needs. The pad electrode 700 can be one of gold, titanium, platinum, palladium, chromium, aluminum, tin, indium, and copper, or any combination of multiple thereof.

[0050] Embodiment 2

[0051] This embodiment also provides a light emitting diode, such as Figure 5 As shown, the light emitting diode of this embodiment includes a semiconductor stack 200, an insulating reflective layer 300 located above the semiconductor stack 200, and an electrode structure located above the insulating reflective layer 300. The same points as those of the first embodiment are not repeated here, and the difference is that:

[0052] like Figure 5 As shown, the light emitting diode of this embodiment omits the first contact electrode 401 above the first semiconductor layer 201, and the first electrode 400 (or the first connecting electrode 402) is directly filled in the first opening 301 and directly contacts the first semiconductor layer 201. After omitting the first contact electrode 401, the preparation of the first connecting electrode 402 and the second connecting electrode 501 can be completed in the same step, which reduces the process complexity of the light emitting diode and is conducive to reducing costs.

[0053] Embodiment 3

[0054] This embodiment also provides a light emitting diode, such as Figure 6 As shown, the light emitting diode of this embodiment includes a semiconductor stack 200, an insulating reflective layer 300 located above the semiconductor stack 200, and an electrode structure located above the insulating reflective layer 300. The same points as those of the first or second embodiment are not repeated here, and the difference is that:

[0055] In the present application, the second connection electrode 501 of the second electrode 500 is formed into a multi-layer structure, and the second connection electrode 501 is filled in the second opening 302 and electrically connected to the second semiconductor layer 203. In the direction gradually away from the insulating reflective layer 300, the second connection electrode 501 at least includes a transparent adhesion layer 5013 and a reflective layer 5014 located above the transparent adhesion layer 5013. The transparent adhesion layer 5013 is a material layer that can form a good contact with the current diffusion layer 204 above the second semiconductor layer 203, preferably a transparent material layer, for example, it can be a transparent material layer such as ITO or GTO. Further, the transparent adhesion layer 5013 can be the same material layer as the current diffusion layer 204 above the second semiconductor layer 203, so as to further increase the adhesion and ohmic contact between the two. In an optional embodiment, the current diffusion layer 204 is ITO or GTO, and the thickness is between Further, between The current diffusion layer 204 within this thickness range can reduce the absorption of visible light while ensuring a good current diffusion effect and forming a good contact with the transparent adhesive layer 5013, which is beneficial to improving the light extraction efficiency of the light emitting diode. Figure 6 Although not shown in detail, it should be understood that the current blocking layer 205 described in the first embodiment is also formed between the current diffusion layer 204 and the second semiconductor layer 203 .

[0056] The reflective layer 5014 of the second connecting electrode 501 is a metal material layer with high reflectivity, such as an Ag layer or an Al layer. Optionally, the reflective layer 5014 is an Ag layer. On the one hand, the Ag layer has a higher reflectivity, which can increase the reflection of light and improve the light emitting effect of the light emitting diode; on the other hand, the Ag layer can have better adhesion with the transparent adhesive layer 5013, increase the connection reliability between the two, and improve the stability of the light emitting diode. In an optional embodiment, the thickness of the transparent adhesive layer 5013 is between 1000 and 2000. Further In addition to the transparent adhesive layer 5013 and the reflective layer 5014 , the second connection electrode 501 may further include other metal layers formed above the reflective layer 5014 , for example, a single layer or multiple layers of materials such as Ti, Pt, Ni, and Au.

[0057] In an optional embodiment, the insulating reflective layer 300 is a DBR structure, and the insulating reflective layer 300 is etched by an ICP dry etching method to form a first opening 301 and a second opening 302. In this process, in order to avoid excessive loss of ITO due to over-etching, the dry etching adopts a combination of fast etching and slow etching. The ratio of the etching rate of the DBR to the rate of ITO in the last stage is 300:1 to 50:1. The above etching process can ensure that the current diffusion layer 204 is not affected by etching or accidentally damaged. Therefore, the current diffusion layer 204 can be made thinner while ensuring good ohmic contact. For example, its thickness can be controlled to be within The etching angle of the DBR is between 40° and 70°, which can ensure good opening characteristics of the first opening 301 and the second opening 302 in the DBR structure, especially the first opening 301, which is conducive to the subsequent repair of the first semiconductor layer 201 exposed by the first opening 301 after etching through the first opening 301, thereby ensuring its good photoelectric performance.

[0058] In an optional embodiment, in order to ensure good adhesion between the DBR structure and the current diffusion layer 204 and the reflection efficiency of the DBR, before forming the above-mentioned DBR structure, a SiO2 layer is first deposited on the surface of the semiconductor stack 200, and the thickness of the SiO2 layer is between In this embodiment, the DBR structure is formed by stacking TiO2 and SiO2, and the thickness of the DBR structure is between 2 μm and 6 μm. The DBR structure with this thickness has good reflectivity, especially at the side wall of the first opening 301, the DBR structure can reflect the light radiated to the side wall as much as possible to the light output surface, reducing the side wall leakage and other light losses.

[0059] The above structure of the second connection electrode 501 can simultaneously satisfy the requirements of forming a good ohmic contact with the current diffusion layer 204 above the second semiconductor layer 203 and having a sufficiently high reflection effect on visible light. The above second electrode 500 and the insulating reflective layer 300 of this embodiment form a total reflection structure, which can achieve high reflection of the entire visible light band and wide angle, and achieve higher quantum efficiency.

[0060] Embodiment 4

[0061] This embodiment also provides a light emitting diode, such as Figure 7 As shown, the light emitting diode of this embodiment includes a semiconductor stack 200, an insulating reflective layer 300 located above the semiconductor stack 200, and an electrode structure located above the insulating reflective layer 300. The same points as those of the third embodiment are not repeated here, and the difference is that:

[0062] like Figure 7As shown, in this embodiment, the first electrode 400 includes a first contact electrode 401 formed above the first semiconductor layer 201 exposed by the mesa structure and a first connection electrode 402 located above the insulating reflective layer 300. The first opening 301 exposes the first contact electrode 401, and the first connection electrode 402 fills the first opening 301 and is connected to the first contact electrode 401. Optionally, the first contact electrode 401 is a metal that can form a good ohmic contact with the first semiconductor layer 201, for example, it can be Al, Cr / Al, Ni / Al, etc. In addition to being able to form a good ohmic contact with the first semiconductor layer 201, the first contact electrode 401 can also serve as an etching stop layer. When etching the insulating reflective layer 300 to form the first opening 301, it is prevented from damaging the first semiconductor layer 201 (for example, N-type GaN) by etching. Furthermore, the opening length of the first opening 301 is smaller than the bottom length of the first contact electrode 401, and the etching angle of the insulating reflective layer 300 is set between 40° and 70°, thereby further ensuring that when the insulating reflective layer 300 is etched to form the first opening 301, the bottom of the first opening 301 will not be formed outside the first contact electrode 401, thereby preventing the first semiconductor layer 201 from being damaged by etching.

[0063] Embodiment 5

[0064] This embodiment also provides a light emitting diode, such as Figure 8 As shown, the light emitting diode of this embodiment includes a semiconductor stack 200, an insulating reflective layer 300 located above the semiconductor stack 200, and an electrode structure located above the insulating reflective layer 300. The same points as those of the third embodiment are not repeated here, and the difference is that:

[0065] like Figure 8 As shown, the light emitting diode of this embodiment also includes a pad electrode 700, and the pad electrode 700 includes a first pad 701 electrically connected to the first electrode 400 of the electrode structure and a second pad 702 electrically connected to the second electrode 500 of the electrode structure. A second insulating protective layer 602 is also formed between the pad electrode 700 and the electrode structure. Specifically, the second insulating protective layer 602 at least covers the surface and side walls of the first connection electrode 402 and the second connection electrode 501 to block the diffusion of Ag in the second connection electrode 501, ensure the reflection effect of the second connection electrode 501, and the photoelectric characteristics of the semiconductor stack 200. Further, the second insulating protective layer 602 covers the surface and side walls of the second connection electrode 501 and the second connection electrode 402, as well as the surface and side walls of the exposed insulating reflective layer 300. In the direction from the second connection electrode 501 to the second pad 702, the second insulating protective layer 602 includes at least an Al2O3 layer and a SiO2 layer formed by atomic layer deposition stacked in sequence. The thickness of Al2O3 formed by atomic layer deposition is between Further, between The thickness of the SiO2 layer is between 1 μm and 3 μm, and further between 1 μm and 2 μm and 3 μm. The thickness of the second insulating protective layer 602 is set so that it can well prevent the migration of Ag in the second connecting electrode 501, and further protect the light-emitting diode from damage by external water vapor or pollutants. In addition, it can also absorb as little light radiated by the semiconductor stack 200 as possible.

[0066] The second insulating protective layer 602 is formed with through holes above the first semiconductor layer 201 and the second semiconductor layer 203 to expose the first connection electrode 402 and the second connection electrode 501. The through hole above the first semiconductor layer 201 penetrates the second insulating protective layer 602 to expose the first connection electrode 402; the through hole above the second semiconductor layer 203 penetrates the second insulating protective layer 602 to expose the second connection electrode 501. The first pad 701 and the second pad 702 fill the through holes to connect with the first connection electrode 402 and the second connection electrode 501 respectively. The first pad 701 and the second pad 702 are spaced apart above the second insulating protective layer 602, and the two can have the same material composition, so the two can be formed by the same deposition step. Optionally, the first pad 701 and the second pad 702 can be Al, Cr / Al or Ni / Al structural layers.

[0067] Embodiment 6

[0068] This embodiment also provides a light emitting diode, such as Fig. 9 As shown, the light emitting diode of this embodiment includes a semiconductor stack 200, an insulating reflective layer 300 located above the semiconductor stack 200, and an electrode structure located above the insulating reflective layer 300. The same points as those of the fifth embodiment are not repeated here, and the difference is that:

[0069] like Fig. 9As shown, the first electrode 400 of the light-emitting diode of this embodiment also includes a first contact electrode 401 formed above the first semiconductor layer 201 exposed by the mesa structure. The first opening 301 exposes the first contact electrode 401, and the first connection electrode 402 fills the first opening 301 and is connected to the first contact electrode 401. Optionally, the first contact electrode 401 is a metal that can form a good ohmic contact with the first semiconductor layer 201, for example, it can be Al, Cr / Al, Ni / Al, etc. In addition to being able to form a good ohmic contact with the first semiconductor layer 201, the first contact electrode 401 can also serve as an etching stop layer. When etching the insulating reflective layer 300 to form the first opening 301, it is prevented from damaging the first semiconductor layer 201 (for example, N-type GaN) by etching. Furthermore, the opening length of the first opening 301 is smaller than the bottom length of the first contact electrode 401, and the etching angle of the insulating reflective layer 300 is set between 40° and 70°, thereby further ensuring that when the insulating reflective layer 300 is etched to form the first opening 301, the bottom of the first opening 301 will not be formed outside the first contact electrode 401, thereby preventing the first semiconductor layer 201 from being damaged by etching.

[0070] Embodiment 7

[0071] This embodiment also provides a light emitting diode, such as Fig.10 As shown, the light emitting diode of this embodiment includes a semiconductor stack 200, an insulating reflective layer 300 located above the semiconductor stack 200, and an electrode structure located above the insulating reflective layer 300. The same points as those of the sixth embodiment are not repeated here, and the difference is that:

[0072] The second electrode of the light emitting diode of this embodiment includes a second connection electrode 501 and a second contact electrode 502. The second contact electrode 502 is located above the second semiconductor layer 203. The second opening 302 in the insulating reflective layer 300 exposes the second contact electrode 502. The second connection electrode 501 fills the second opening 302 and is connected to the second contact electrode 502. In an optional embodiment, the thickness of the second connection electrode 501 is between 3 μm and 8 μm, and further, between 4 μm and 7 μm or between 4 μm and 6 μm.

[0073] In addition, in this embodiment, a third insulating protective layer 603 is formed between the insulating reflective layer 300 and the semiconductor stack 200, and the third insulating protective layer 603 at least covers the surface and sidewalls of the first contact electrode 401 and the second contact electrode 502. Further, the surface and sidewalls of the first contact electrode 401 and the second contact electrode 502 and the surface and sidewalls of the semiconductor stack 200 are covered, and further, the surface and sidewalls of the semiconductor stack 200 are extended to cover the exposed surface of the substrate 100. The insulating reflective layer 300 is formed on the third insulating protective layer 603. In this embodiment, the thickness of the insulating reflective layer 300 is between 4 μm and 10 μm. The second contact electrode 502 includes an Ag material layer.

[0074] In an optional embodiment, the third insulating protection layer 603 at least comprises an Al2O3 layer and / or a SiO2 layer formed by atomic layer deposition stacked in sequence. The thickness of the Al2O3 layer is between The thickness of the SiO2 layer is between Further, between The material selection and thickness setting of the third insulating protection layer 603 enable it to effectively block the diffusion and migration of Ag in the second contact electrode 502 , thereby ensuring a good reflection effect of the second contact electrode 502 and a good photoelectric effect of the semiconductor epitaxial stack.

[0075] In order to increase the reflection effect of the insulating reflective layer 300, in this embodiment, the thickness of the insulating reflective layer 300 is between 1 μm and 10 μm, and further, between 2 μm and 6 μm. At the same time, the thickness of the current diffusion layer 204 is between While ensuring a good current diffusion effect, the light absorption phenomenon is reduced as much as possible, so that more light can be reflected by the second electrode 500 and the insulating reflective layer 300 to become the output light of the light emitting diode.

[0076] Likewise Fig.10 As shown, through holes respectively connected to the first opening 301 and the second opening 302 are also formed in the third insulating reflective layer 603. The first connecting electrode 402 of the first electrode 400 is located above the insulating reflective layer 300, filling the through holes in the first opening 301 and the third insulating protective layer 603 to connect with the first contact electrode 401. The second connecting electrode 501 of the second electrode 500 is located above the insulating reflective layer 300, filling the through holes in the second opening 302 and the third insulating protective layer 603 to connect with the second contact electrode 502. The second connecting electrode 501 can be Al or a Cr / Al stack or a Ni / Al stack, and its thickness is between 3μm and 8μm. This thickness setting can increase the reflection effect.

[0077] The second contact electrode 502 should not be too small. If it is too small, the overlay error in the manufacturing process may cause the second contact electrode 502 to not correspond well with the second opening 302. Therefore, on the one hand, the current diffusion layer 204 may be damaged due to over-etching, and on the other hand, the connection reliability between the second connection electrode 501 and the first contact electrode 502 may be reduced, affecting the electrical performance of the light-emitting diode. Similarly, the area of ​​the second contact electrode 502 should not be too large. Since the DBR reflectivity is greater than the reflectivity of the second contact electrode 502, if the area of ​​the second contact electrode 502 is too large, it will reduce the light that can be reflected by the insulating reflective layer 300, thereby affecting the luminous efficiency of the light-emitting diode. Therefore, in the optional embodiment, if Fig.10 As shown, the top opening radius of the second opening 302 is R2, and the projection of the second contact electrode 502 is defined as a circle, and the radius of the second contact electrode 502 is R4, where R4=R2~(R2+8μm). As described above, the area of ​​the second contact electrode 502 is controlled to be slightly larger than or equal to the opening size of the second opening 302, thereby ensuring that when the DBR is dry-etched to form the second opening 300, the current diffusion layer 204 under the second contact electrode 502 is protected from being etched, thereby ensuring its integrity and current diffusion effect; at the same time, ensuring that as much light as possible can be reflected by the insulating reflective layer 300, thereby improving the light emitting effect of the light emitting diode.

[0078] like Fig.11 As shown, compared with the prior art in which Cr / Al material is used as a metal layer directly in contact with the current diffusion layer 204, the formation of the second contact electrode 502 increases the reflectivity at the second electrode 500 from less than 75% to more than 90%, especially in the wavelength band between 420nm and 500nm, in the visible light range greater than 520nm, the reflectivity reaches more than 95%. The above characteristics of the second electrode 500 reduce its absorption of light and improve the optical properties of the chip. At the same time, the second contact electrode 502 (such as Ag) can form a good ohmic contact with the current diffusion layer 204 on the second semiconductor layer 203, so that the voltage of the light-emitting diode is low and the light efficiency is improved.

[0079] Embodiment 8

[0080] This embodiment provides a semiconductor light emitting device, such as Fig.12 As shown, the light emitting device 900 includes a circuit substrate 201 and a plurality of light emitting units 902 electrically connected to the circuit substrate 901. In this embodiment, the light emitting units 902 are semiconductor light emitting elements provided in the first embodiment. Fig.12As shown, the circuit substrate 910 has a plurality of groups of pads 905. The pad electrode 700 of each light emitting unit 902 is electrically connected to a group of pads 905. In addition, a circuit layer 903 is provided in the circuit substrate 901, and the light emitting unit 902 is electrically connected to the circuit layer 903 via the pads 905. Fig.12 As shown, the light emitting device 900 may also include a housing 904 to protect the light emitting unit from external pollution or damage, while not affecting the light emitting effect of the light emitting unit. The above-mentioned arrangement of the wiring layer and the pad area of ​​the light emitting diode of the present application increases the bonding force of the light emitting diode fixed to the above-mentioned pad, thereby improving the reliability of the device.

[0081] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A light emitting diode, characterized in that: include: A semiconductor stack, comprising a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence; an insulating reflective layer, located on one side of the second semiconductor layer and at least covering a surface of the semiconductor stack, wherein a first opening and a second opening are formed in the insulating reflective layer, wherein the first opening is located above the first semiconductor layer, and the second opening is located above the second semiconductor layer; An electrode structure is located above the insulating reflective layer, the electrode structure comprising a first electrode electrically connected to the first semiconductor layer and a second electrode electrically connected to the second semiconductor layer, wherein The second electrode includes a second connecting electrode, which includes a connecting layer and a contact layer. The contact layer fills the second opening and extends to a portion of the insulating reflective layer outside the second opening to be electrically connected to the second semiconductor layer. The connecting layer is formed above the contact layer and connected to the contact layer.

2. The light emitting diode according to claim 1, characterized in that: The connection layer covers the contact layer and is formed on a portion of the insulating reflective layer around the contact layer.

3. The light emitting diode according to claim 1, characterized in that: The side wall of the second opening has a first section and a second section extending from the bottom of the second opening, the insulating reflective layer outside the second opening is formed as a platform structure, the first section is an inclined side wall, the second section is formed as a smooth transition side wall connecting the first section and the platform, and the contact layer covers the first section, the second section and part of the platform structure.

4. The light emitting diode according to claim 1, characterized in that: The second opening is formed as a circular hole with a circular cross-section, and the bottom radius R1 of the second opening, the top opening radius R2 and the radius R3 of the second connecting electrode satisfy: R2 = (1.5 ~ 3) * R1, R3 = (1 ~ 3) * R1, and R3 ≥ R2.

5. The light emitting diode according to claim 1, characterized in that: When projected onto the plane where the surface of the semiconductor stack is located, the projection area of ​​the contact layer is smaller than the projection area of ​​the connection layer, and the projection of the contact layer is located within the projection range of the connection layer.

6. The light emitting diode according to claim 1, characterized in that: The contact layer includes an Ag layer and / or an Al layer.

7. The light emitting diode according to claim 6, characterized in that: The connecting layer is a multilayer structure including an Al layer, and the thickness of the contact layer T1, the thickness of the Al layer of the contact layer T1a, the thickness of the connecting layer T2, and the thickness of the Al layer of the connecting layer T2a satisfy: 200nm≤T1≤500nm, 1500nm≤T2≤5000nm, T1a= (0.1~0.6)*T1, T2a=(0.2~0.8)*T2, and T1a=(0.1~0.5)*T2a.

8. The light emitting diode according to claim 6, characterized in that: The connecting layer is a multi-layer structure, including a transparent conductive layer and an Ag layer. When projected on the plane where the surface of the semiconductor stack is located, the projection of the transparent conductive layer does not overlap or intersect with the projection of the contact layer.

9. The light emitting diode according to claim 1, characterized in that: It also includes a current diffusion layer located between the second semiconductor layer and the insulating reflective layer, the contact layer is connected to the current diffusion layer, and the bottom of the second opening is formed on the surface of the current diffusion layer or extends to the inside of the current diffusion layer.

10. The light emitting diode according to claim 9, characterized in that: The depth of the second opening in the current diffusion layer is less than or equal to 11. The light emitting diode according to claim 9, characterized in that: A current blocking layer is also included, which is between the current diffusion layer and the second semiconductor layer, covers a portion of the second semiconductor layer, and is at least located below the second opening.

12. The light emitting diode according to claim 11, characterized in that: When projected on the plane where the surface of the semiconductor stack is located, the projection area of ​​the contact layer is larger than the projection area of ​​the current blocking layer below the second opening, and the projection of the current blocking layer below the second opening is within the projection range of the contact layer.

13. The light emitting diode according to claim 1, characterized in that: The first electrode fills the first opening to be electrically connected to the first semiconductor layer.

14. The light emitting diode according to claim 1, characterized in that: The first electrode includes a first contact electrode and a first connecting electrode. The first contact electrode is formed above the first semiconductor layer and is located below the first opening. The first connecting electrode fills the first opening and is connected to the first contact electrode.

15. The light emitting diode according to claim 1 or 14, characterized in that: Also includes: A first insulating protective layer, located above the electrode structure and the insulating reflective layer; A pad electrode is located above the first insulating protective layer, and includes a first pad and a second pad that are spaced apart from each other. The first pad penetrates the first insulating protective layer and is connected to the first electrode, and the second pad penetrates the first insulating protective layer and is connected to the second electrode.

16. A light emitting device, characterized in that: The invention comprises a substrate and a plurality of light-emitting units located on the substrate, wherein the light-emitting units comprise the light-emitting diodes according to any one of claims 1 to 15.

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