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 laminated layer, an insulating reflecting layer and an electrode structure, a first opening and a second opening are formed in the insulating reflecting layer, a second electrode in the electrode structure comprises a second contact electrode, the second contact electrode comprises an Ag material layer, and the Ag material layer is arranged between the first opening and the second opening. And a second semiconductor layer formed over the second semiconductor layer. For example, the second contact electrode can be an Ag electrode with relatively high reflectivity and can play a reflecting role, so that the reflectivity loss at the opening of the insulating reflecting layer is made up, and the light emitting effect of the light emitting diode is improved. Meanwhile, the second contact electrode can form good ohmic contact with the current diffusion layer, and the electrical performance 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), due to their high reliability, long lifespan, and low power consumption, are widely used in a variety of applications, including display devices, automotive lighting, and general lighting. GaN-based semiconductor flip-chip diodes, with their advantages of good heat dissipation, high luminous efficiency, and excellent stability, are increasingly favored by the market.

[0003] Traditional flip-chip LED chips include an N-type layer, an active layer, a P-type layer, and a metal electrode. In existing LEDs, the metal electrodes are usually stacked layers of Cr, Al, etc. In order to obtain good ohmic contact with the transparent conductive layer above the P-type layer, a thicker Cr layer is usually required. However, the reflectivity of the Cr layer in the visible light range is approximately 65%, which is obviously relatively low for the reflectivity required by LEDs. In addition, the thicker the Cr layer, the more obvious its light absorption phenomenon is, which in turn causes Al to reflect less light, affecting its reflectivity, which is extremely detrimental to the light output of the LED. Summary of the Invention

[0004] The present invention aims to provide a light-emitting diode and a light-emitting device. After an insulating reflective layer is covered on a semiconductor stack, a second contact electrode is first formed in an opening of the insulating reflective layer to increase light reflection at the opening of the insulating reflective layer and improve the light extraction effect of the light-emitting diode.

[0005] To achieve the above and other related purposes, the present invention provides a light emitting diode, comprising:

[0006] A semiconductor stack, comprising a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence;

[0007] an insulating reflective layer, located on one side of the second semiconductor layer and covering at least a surface of the semiconductor stack, wherein a first opening and a second opening are formed in the insulating reflective layer, the first opening being located above the first semiconductor layer, and the second opening being located above the second semiconductor layer;

[0008] a third insulating protective layer, located between the insulating reflective layer and the semiconductor stack;

[0009] An electrode structure is located above the insulating reflective layer, the electrode structure including 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 contact electrode, the second contact electrode is located above the second semiconductor layer, and the third insulating protection layer covers at least the surface and sidewalls of the second contact electrode, the second opening exposes the second contact electrode, and the second contact electrode includes an Ag material layer.

[0010] 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 this application.

[0011] As described above, the light-emitting diode and light-emitting device provided by the present invention have at least the following beneficial technical effects:

[0012] The light-emitting diode of the present invention includes a semiconductor stack, an insulating reflective layer, and an electrode structure. A first opening and a second opening are formed in the insulating reflective layer. The second electrode in the electrode structure includes a second contact electrode. The second contact electrode includes an Ag material layer and is formed above the second semiconductor layer. The second contact electrode can, for example, be an 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 second contact electrode can form a good ohmic contact with the current diffusion layer, thereby improving the electrical performance of the light-emitting diode. A second connecting electrode is formed above the second contact electrode. The second connecting electrode can, for example, be a multilayer structure formed of a metal material such as Cr or Al. The second connecting electrode 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.

[0013] On the other hand, the first electrode may include a first contact electrode and a first connecting electrode formed above the first semiconductor layer. The first connecting electrode fills the first opening in the insulating reflective layer to connect to the first contact electrode. The first contact electrode may serve as an etch 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 overetching. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Shown is a schematic structural diagram of a light-emitting diode provided in Example 1 of the present application.

[0015] Figure 2 Display as Figure 1 Schematic diagram of the local enlarged structure of the second connecting electrode.

[0016] Figure 3 Shown is a scanning electron microscope image of the second connecting electrode in the figure.

[0017] Figure 4 Show as Figure 1 The schematic diagram of the top view of the second connecting electrode toward the semiconductor stack is shown.

[0018] Figure 5 Shown is a schematic structural diagram of a light-emitting diode provided in Example 2 of the present application.

[0019] Figure 6 Shown is a schematic structural diagram of the light-emitting diode provided in Example 3 of the present application.

[0020] Figure 7 A schematic structural diagram of a light-emitting diode provided in Example 4 of the present application.

[0021] Figure 8 Shown is a schematic structural diagram of a light-emitting diode provided in Example 5 of the present application.

[0022] Figure 9 Shown is a schematic structural diagram of a light-emitting diode provided in Example 6 of the present application.

[0023] Figure 10 Shown is a schematic structural diagram of the light-emitting diode provided in Example 7 of the present application.

[0024] Figure 11 Display as Figure 10 A comparison chart of the reflectivity of the light-emitting diode in FIG. 1 and the light-emitting diode in the prior art.

[0025] Figure 12 A schematic structural diagram of a light-emitting device provided in Example 8 of the present application.

[0026] Reference numerals

[0027] 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 segment; 3022, second segment; 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, adhesive layer; 5014, reflective layer; 502, second contact electrode; 601, first insulating protection layer; 602, second insulating protection layer; 603, third insulating protection layer; 700, pad electrode; 701, first pad; 702, second pad;

[0028] 900, light-emitting device; 901, circuit substrate, 902, light-emitting unit; 903, circuit layer; 904, housing; 905, solder pad. DETAILED DESCRIPTION

[0029] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0030] 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 and are not 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.

[0031] Example 1

[0032] Example 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 alternative embodiment, the light-emitting diode further includes a substrate 100. The material of the substrate 100 may be sapphire, silicon carbide, silicon, or gallium nitride. In this embodiment, a sapphire substrate is used as an example.

[0034] Also refer to Figure 1 The 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, 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 is understood that the dopants of the first semiconductor layer 201 and the second semiconductor layer 203 may also be opposite to the above. 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 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 the exposed surface of the substrate 100 from the sidewalls of the semiconductor stack 200. 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 may 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, Al2O3 and SiON. In an optional embodiment, the thickness of the DBR structure is between 1 μm and 10 μm, further, between 0.3 μm and 5 μm, 1 μm and 2 μm, or between 4 μm and 5 μm, or between 2 μm and 6 μm.

[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. 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 1As shown, the first electrode 400 includes a first contact electrode 401 and a first connecting electrode 402. 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 performance 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 serve as an etching stop layer to ensure the etching accuracy of the first opening 301 and prevent 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 above-mentioned 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 above 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, which includes a contact layer 5011 and a connection layer 5012. The contact layer 5011 fills the second opening 302 and is electrically connected to the second semiconductor layer 203. 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 formed between the second semiconductor layer 203 and the insulating reflective layer 300. 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. In this case, the bottom of the second opening 302 exposes the current diffusion layer 204. The current diffusion layer 204 covers at least a portion of the surface of the second semiconductor layer 203 to diffuse the current as evenly as possible to the surface of the second semiconductor layer 203, thereby improving the luminescence effect.

[0039] At the same time, to prevent current concentration in 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 spreading layer 204. The current blocking layer 205 is an insulating material layer, such as a SiO2 and / or SiN material layer. To ensure electrical connection between the current spreading layer 204 and the second semiconductor layer 203 and the current spreading effect of the current spreading layer 204, the current blocking layer 205 is formed into a patterned structure, that is, it does not entirely cover the second semiconductor layer 203. 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 spreading 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, projected onto the plane of the surface of the semiconductor stack 200, is larger than the projected area of ​​the current blocking layer 205 below the second opening 302, and the projected area of ​​the current blocking layer 205 below the second opening 302 is located within the projected area of ​​the contact layer 5011. This facilitates the lateral diffusion of 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. Therefore, 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 into the current diffusion layer 204, the depth of the second opening 302 extending into the current diffusion layer 204 is less than or equal to Further, between 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 , thereby achieving electrical connection with the second semiconductor layer 203 .

[0041] In this embodiment, the contact layer 5011 of the second connection electrode 501 is formed into a multilayer structure including 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 fills the second opening 302. The Ni layer or Cr layer therein can enhance the adhesion between the contact layer 5011 and the current diffusion layer 204, forming a good ohmic contact with the current diffusion layer 204 and ensuring the electrical performance of the light-emitting diode. Furthermore, the Al layer in the contact layer 5011 has a reflective effect, which can increase the reflectivity of the contact layer 5011. This helps to compensate for the reflective effect of the insulating reflective layer 300 lost due to the formation of the second opening 302, thereby increasing the reflection effect of light radiated by the semiconductor stack 200 and improving the light extraction efficiency of the light-emitting diode.

[0042] Also refer to Figure 1 The connection layer 5012 is formed above the insulating reflective layer 300 and covers and connects to the contact layer 5011. The connection layer 5012 can be a single metal layer or multiple metal layers, for example, a stacked structure of Al, Ti, Ni, Cr, Pt, etc. The connection layer 5012 includes an Al layer, and the thickness of the Al layer is greater than the thickness of the Al in the contact layer 5011. Therefore, the connection electrode 5012 has a high reflectivity and can form a total reflection structure with the insulating reflective layer 300, thereby increasing the reflection efficiency of 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, 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 respective Al layer thicknesses enable the contact layer 5011 and the connection layer 5012 to have good adhesion, good reflective effect, and good electrical conductivity.

[0044] In another optional embodiment, the connecting layer 5012 has a multi-layer structure including a transparent conductive layer and an Ag layer. The transparent conductive layer and the current spreading layer 204 formed above the second semiconductor layer 203 may be made of the same or different materials, such as ITO. When projected onto the plane of the semiconductor stack 200, the projection of the transparent conductive layer in the connecting layer 5012 does not overlap or intersect with the projection of the contact layer 5011. In other words, the transparent conductive layer in the connecting layer 5012 is not formed above the contact layer 5011, thereby preventing the voltage of the light-emitting diode from being excessively 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 sidewalls of the second opening 302 include a first section 3021 and a second section 3022. The insulating reflective layer 300 surrounding the second opening 302 is formed into a platform structure 3023. The first section 3021 is formed as an inclined sidewall, for example, with the angle α between it and the plane of the current diffusion layer 204 at the bottom of the second opening 302 ranging from 40° to 70°, or further ranging from 40° to 50° or 50° to 60°. The second section 3022 connects the first section 3021 and the platform structure 3023 and forms a smooth transition section, for example, with rounded corners or an arc-shaped transition section. The contact layer 5011 covers the first and second sections 3021, 3022, and a portion 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, where R2 = (1.5-3)R1, R3 = (1-3)R1, and R3 ≥ R2. Specifically, R1 is between 2μm and 6μm, for example, approximately 4μm; R2 is between 3μm and 8μm, for example, approximately 6μm; and R3 is between 3μm and 10μm, for example, approximately 8μm. The above configuration of the contact layer 5011 can reduce the aperture of the second opening 302 to a certain extent while ensuring a good electrical connection between the contact layer 5011 and the second semiconductor layer 203. The contact layer 5011 not only covers the bottom of the second opening 302 and the first and second segments 3021 and 3022, but also forms a portion of the platform structure 3023, thereby increasing the reliability of the contact layer 5011 and its reflective 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 actual products, the contact layer 5011 can well fill the second opening 302 , ie, evenly cover the bottom and sidewalls of the second opening 302 , and 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 diagram schematically illustrates a projection from the second connection electrode 501 toward the semiconductor stack 200. It can be seen that the projected area of ​​the connection layer 5012 is larger than the projected area of ​​the contact layer 5011, and the projected area of ​​the contact layer 5011 is within the projected area of ​​the connection layer 5012, thereby ensuring good contact between the connection layer 5012 and the contact layer 5011. Specifically, the connection layer 5012 connects to the contact layer 5011 at the plurality of second openings 302, and the projected area of ​​each portion of the connection layer 5012 is larger than the projected area of ​​the contact layer 5011 it connects 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, the second connecting electrode 501, and the exposed surface of the insulating reflective layer 300, and further covers the sidewalls of the insulating reflective layer 300. The first insulating protective layer 601 can be formed of any one or more materials such as SiO2, SiN, Al2O3, etc., or can be formed of the same material 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 ensuring mutual insulation between the first connecting electrode 402 and the second connecting electrode 501, while preventing the light-emitting diode from being contaminated or damaged by external dust, moisture, etc.

[0049] The pad electrode 700 is located above the first insulating protective layer 601. The pad electrode 700 includes a first pad 701 and a second pad 702 that are spaced apart. The first pad 701 passes through the first insulating protective layer 601 and is connected to the first electrode 400, and the second pad 702 passes through 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 thereof.

[0050] Example 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 in the first embodiment will not be repeated here, and the differences are as follows:

[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. The first electrode 400 (or the first connecting electrode 402) is directly filled in the first opening 301 and is in direct contact with the first semiconductor layer 201. After omitting the first contact electrode 401, the first connecting electrode 402 and the second connecting electrode 501 can be prepared simultaneously in the same step, reducing the process complexity of the light-emitting diode and thus reducing costs.

[0053] Example 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 differences are as follows:

[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 above-mentioned 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. Furthermore, the transparent adhesion layer 5013 can be the same material layer as the current diffusion layer 204 above the second semiconductor layer 203 to further increase the adhesion and ohmic contact between the two. In an optional embodiment, the above-mentioned current diffusion layer 204 is ITO or GTO, with a thickness between Further, between The current diffusion layer 204 in this thickness range can reduce the absorption of visible light while ensuring good current diffusion effect and forming 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 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 on the reflective layer 5014 , for example, single-layer or multi-layer material layers such as Ti, Pt, Ni, and Au.

[0057] In an optional embodiment, the insulating reflective layer 300 is a DBR structure, and an ICP dry etching method is used to etch the insulating reflective layer 300 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 etching rate of the 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 the 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°. This etching angle 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. The thickness of the SiO2 layer is between In this embodiment, the DBR structure is formed by stacking TiO2 and SiO2, and has a thickness ranging from 2 μm to 6 μm. A DBR structure with this thickness has good reflectivity, especially at the sidewalls of the first opening 301. The DBR structure can reflect light radiated to the sidewalls as much as possible toward the light output surface, thereby reducing sidewall light leakage and other light losses.

[0059] The structure of the second connecting electrode 501 can simultaneously form a good ohmic contact with the current diffusion layer 204 above the second semiconductor layer 203, while also providing sufficiently high reflective properties for visible light. The second electrode 500 and insulating reflective layer 300 of this embodiment form a total reflection structure, achieving high reflectivity across the entire visible light band and a wide angle, thereby achieving higher quantum efficiency.

[0060] Example 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 similarities with the third embodiment are not repeated here, and the differences are as follows:

[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 connecting electrode 402 located above the insulating reflective layer 300. The first opening 301 exposes the first contact electrode 401, and the first connecting 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, Al, Cr / Al, Ni / Al, etc. In addition to forming 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, damage to the first semiconductor layer 201 (for example, N-type GaN) is avoided. 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 to be between 40° and 70°. This further ensures 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] Example 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 similarities with the third embodiment are not repeated here, and the differences are as follows:

[0065] like Figure 8 As shown, the light-emitting diode of this embodiment further includes a pad electrode 700, which 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 covers at least the surfaces and sidewalls of the first connecting electrode 402 and the second connecting electrode 501 to prevent Ag diffusion in the second connecting electrode 501, thereby ensuring the reflective effect of the second connecting electrode 501 and the optoelectronic properties of the semiconductor stack 200. Furthermore, the second insulating protective layer 602 covers the surfaces and sidewalls of the second connecting electrode 501 and the second connecting electrode 402, as well as the surface and sidewalls of the exposed insulating reflective layer 300. In the direction from the second connecting 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 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 to effectively prevent the migration of Ag in the second connection electrode 501, further protect the light-emitting diode from damage by external moisture or contaminants, and absorb as little light radiated by the semiconductor stack 200 as possible.

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

[0067] Example 6

[0068] This embodiment also provides a light emitting diode, such as Figure 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 similarities with the fifth embodiment are not repeated here, and the differences are as follows:

[0069] like Figure 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 connecting 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, damage to the first semiconductor layer 201 (for example, N-type GaN) is avoided. 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 to be between 40° and 70°. This further ensures 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] Example 7

[0071] This embodiment also provides a light emitting diode, such as Figure 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 similarities with the sixth embodiment are not repeated here, and the differences are as follows:

[0072] The second electrode of the light-emitting diode of this embodiment includes a second connecting 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 connecting electrode 501 fills the second opening 302 and connects to the second contact electrode 502. In alternative embodiments, the thickness of the second connecting 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. This third insulating protective layer 603 covers at least the surfaces and sidewalls of the first contact electrode 401 and the second contact electrode 502. Furthermore, it covers the surfaces and sidewalls of the first contact electrode 401 and the second contact electrode 502, as well as the surface and sidewalls of the semiconductor stack 200, and further extends to cover the exposed surface of the substrate 100. The insulating reflective layer 300 is formed above this 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 comprises a layer of Ag material.

[0074] In an optional embodiment, the third insulating protection layer 603 comprises at least 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 good reflection effect of the second contact electrode 502 and good photoelectric effect of the semiconductor epitaxial stack.

[0075] In order to increase the reflective 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 Figure 10 As shown, through holes are also formed in the third insulating reflective layer 603, connecting the first opening 301 and the second opening 302, respectively. 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, thereby connecting to 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, thereby connecting to the second contact electrode 502. The second connecting electrode 501 can be made of Al, a Cr / Al stack, or a Ni / Al stack, with a thickness ranging from 3μm to 8μm. This thickness setting can enhance the reflective 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. On the other hand, the connection reliability between the second connection electrode 501 and the first contact electrode 502 will 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 an optional embodiment, if Figure 10 As shown, the top opening radius of the second opening 302 is R2, defining the projection of the second contact electrode 502 as a circle, and the radius of the second contact electrode 502 is R4, where R4 = R2 to (R2 + 8 μm). 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. This ensures that when the DBR is dry-etched to form the second opening 300, the current diffusion layer 204 below the second contact electrode 502 is not etched, ensuring its integrity and current diffusion effect. At the same time, it ensures that as much light as possible is reflected by the insulating reflective layer 300, thereby improving the light extraction effect of the LED.

[0078] like Figure 11 As shown, compared to the prior art method of using Cr / Al materials as the 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 over 90%. In particular, the reflectivity reaches over 95% in the wavelength range between 420nm and 500nm and in the visible light range greater than 520nm. These features of the second electrode 500 reduce its absorption of light, improving the optical performance of the chip. Furthermore, the second contact electrode 502 (e.g., Ag) forms a good ohmic contact with the current diffusion layer 204 on the second semiconductor layer 203, resulting in a lower voltage for the light-emitting diode and improved light efficiency.

[0079] Example 8

[0080] This embodiment provides a semiconductor light emitting device, such as Figure 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. Figure 12As shown, the circuit substrate 910 has several 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. Figure 12 As shown, the light emitting device 900 may further include a housing 904 to protect the light emitting unit from external contamination or damage while not affecting the light emitting effect of the light emitting unit. The above-mentioned arrangement of the wiring layer and the solder pad area of ​​the light emitting diode of the present application increases the bonding force of the light emitting diode to the above-mentioned solder 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 skilled in 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 one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to 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; A third insulating protective layer, located between the insulating reflective layer and the semiconductor stack; An electrode structure is located above the insulating reflective layer, the electrode structure includes 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 contact electrode, the second contact electrode is located above the second semiconductor layer, and the third insulating protection layer at least covers the surface and sidewalls of the second contact electrode, the second opening exposes the second contact electrode, and the second contact electrode includes an Ag material layer.

2. The light emitting diode according to claim 1, characterized in that: The thickness of the insulating reflective layer is between 2 μm and 10 μm.

3. The light emitting diode according to claim 1, characterized in that: The third insulating protection layer includes at least an Al2O3 layer, or at least an Al2O3 layer and a SiO2 layer.

4. The light emitting diode according to claim 3, characterized in that: The thickness of the Al2O3 layer is between The thickness of the SiO2 layer is between 5. The light emitting diode according to claim 2, characterized in that: The first electrode includes a first contact electrode and a first connecting electrode. The first contact electrode is located above the first semiconductor layer. The first opening exposes the first contact electrode. The first connecting electrode fills the first opening and is connected to the first contact electrode.

6. 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. The top opening radius of the second opening is R2, and the radius of the second contact electrode is R4, wherein R4=R2~(R2+8μm).

7. The light emitting diode according to claim 1, characterized in that: It also includes a current diffusion layer and a current blocking layer. The current diffusion layer is located between the third insulating protection layer and the second semiconductor layer. The current blocking layer is located 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.

8. The light emitting diode according to claim 7, characterized in that: The thickness of the current diffusion layer is between 9. The light emitting diode according to claim 1 or 5, characterized in that: The second electrode further includes a second connecting electrode located above the insulating reflective layer and filled into the second opening to be connected to the second contact electrode.

10. The light emitting diode according to claim 9, characterized in that: The thickness of the second connecting electrode is between 3 μm and 8 μm.

11. The light emitting diode according to claim 9, characterized in that: The first connection electrode and the second connection electrode include Al or Cr / Al stacked layers or Ni / Al stacked layers.

12. 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 11.

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