TW202220238A - Light-emitting diode structure and flip-chip light emitting diode structure - Google Patents

Abstract

A light-emitting diode structure includes: a substrate, a light-emitting stack layer, a first electrode, a conductive first reflector and a second electrode. The light-emitting stack layer includes multiple layers sequentially stacked on the substrate, and outer layers of the light-emitting stack layer adjacent to and far away from the substrate are a bottom layer and a top layer, respectively. The first electrode is located on a surface of the bottom layer away from the substrate and is electrically connected to the bottom layer. The first reflector is located on a surface of the top layer away from the substrate and is electrically connected to the top layer. The second electrode is located on a surface of the first reflector away from the substrate and is electrically connected to the first reflector. The disclosure also provides flip-chip light emitting diode structure.

Description

Light-emitting diode structure and flip-chip light-emitting diode structure

The present invention relates to a light-emitting diode structure and a flip-chip light-emitting diode structure.

A conventional light-emitting diode structure includes a substrate, a first semiconductor layer located on a surface of the substrate, an active layer located on a surface of the first semiconductor away from the substrate, and an active layer located away from the first semiconductor layer. A second semiconductor layer on the surface of the semiconductor layer, a first electrode on the surface of the first semiconductor away from the substrate, a first reflector on the side of the second semiconductor layer away from the substrate, and a first reflector on the side of the second semiconductor layer away from the substrate The two semiconductor layers are on one side away from the substrate and partially cover the second electrode of the first reflector. The first electrode is in ohmic contact with the first semiconductor layer, the second electrode is in ohmic contact with the second semiconductor layer, and the first reflector is a distributed Bragg reflector. When a crack occurs in the first reflector near the second electrode due to external force, and the ohmic contact between the second electrode and the second semiconductor layer is destroyed, it is easy to cause the light-emitting diode to fail to emit light normally, so that the The product is abnormal.

In view of this, it is necessary to provide a light emitting diode structure with high durability.

One aspect of the present invention provides a light-emitting diode structure, comprising: substrate; The light-emitting stacked layer includes multiple layers stacked on the substrate in sequence, and the outer layers of the light-emitting stacked layer close to and away from the substrate are the bottom layer and the top layer, respectively; a first electrode, located on the surface of the bottom layer away from the substrate and electrically connected to the bottom layer; a conductive first reflector located on a surface of the top layer remote from the substrate and electrically connected to the top layer; and, The second electrode is located on the surface of the first reflector away from the substrate and is electrically connected to the first reflector.

In the embodiment of the present application, the first reflector includes a plurality of first dielectric layers and a plurality of second dielectric layers, the first dielectric layers and the second dielectric layers are alternately stacked and both are conductive, and the first dielectric layer and the second dielectric layer are alternately stacked. A first dielectric layer in a reflector is in contact with the light emitting stack layer, and the refractive index of the first dielectric layer is greater than the refractive index of the second dielectric layer.

，所述第二介質層的厚度均為

，其中

為所述發光二極體結構發射的光的波長，

為所述第一介質層的折射率；

為所述第二介質層的折射率。 In this embodiment of the present application, the thickness of the first dielectric layer is

, the thickness of the second dielectric layer is

,in

is the wavelength of light emitted by the light-emitting diode structure,

is the refractive index of the first dielectric layer;

is the refractive index of the second dielectric layer.

In the embodiment of the present application, the material of the first dielectric layer is titanium oxide doped with niobium, and the material of the second dielectric layer is indium tin oxide.

In the embodiment of the present application, the light emitting diode structure further includes a second reflector located on a surface of the substrate away from the light emitting stack layer.

In the embodiment of the present application, the second reflector includes a plurality of third dielectric layers and a plurality of fourth dielectric layers alternately stacked in sequence, the third dielectric layers and the fourth dielectric layers are alternately stacked, and the third dielectric layers and the fourth dielectric layers are alternately stacked. A third medium layer of the two reflectors is in contact with the substrate; the refractive index of the third medium layer is greater than the refractive index of the fourth medium layer.

，所述第四介質層的厚度均為

，其中

為所述發光二極體結構發射的光的波長，

為所述第三介質層的折射率，

為所述第四介質層的折射率；所述第三介質層與所述四層為電介質材料層。 In this embodiment of the present application, the thickness of the third dielectric layer is

, the thickness of the fourth dielectric layer is

,in

is the wavelength of light emitted by the light-emitting diode structure,

is the refractive index of the third dielectric layer,

is the refractive index of the fourth dielectric layer; the third dielectric layer and the fourth layer are dielectric material layers.

In the embodiment of the present application, the light-emitting stacked layer further includes an active layer, a semiconductor layer and a transparent conductive layer that are sequentially stacked between the bottom layer and the top layer, the bottom layer is a semiconductor material layer, and the top layer is a current diffusion layer; the light emitting stack layer further includes a current blocking layer on the semiconductor layer and sandwiched between the transparent conductive layers, the current blocking layer is disposed opposite to the second electrode.

In the embodiment of the present application, the light-emitting diode structure further includes an insulating layer, the insulating layer is located on the surface of the substrate with the light-emitting stack layer, and wraps the light-emitting stack layer disposed on the substrate; the The first electrode and the second electrode are exposed to the insulating layer.

Another aspect of the present invention also provides a flip-chip light-emitting diode structure, comprising: lining; and, The light emitting diode structure, and the first electrode and the second electrode face and connect to the same surface of the backing plate.

In the above light-emitting diode structure, even when the light-emitting diode structure is acted on by an external force, cracks appear between the part of the first reflector covered by the second electrode and other parts of the first reflector, And destroy the electrical connection relationship between the second electrode and the light emitting stack layer. Since the second electrode is located on the first reflector and the first reflector has conductive properties, it still does not affect the current conduction between the second electrode and the light emitting stack layer, that is, does not affect the The light emission of the light emitting diode structure is beneficial to improve the durability of the light emitting diode structure.

The drawings illustrate embodiments of the present invention, which may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

Referring to FIG. 1 , an embodiment of the present invention provides a light emitting diode structure 100 , which includes a substrate 10 , a light emitting stack layer 20 , a first electrode 30 , a second electrode 40 and a conductive first reflector 50 . The light-emitting stacked layer 20 is located on the substrate 10, and the light-emitting stacked layer 20 includes multiple layers stacked on the substrate 10 in sequence, wherein the outer layers of the light-emitting stacked layer 20 close to and away from the substrate 10 are the bottom layer 21 and the outer layer respectively. The top layer 26 , that is, other layers are stacked between the bottom layer 21 and the top layer 26 . The conductive first reflector 50 is located on the surface of the top layer 26 away from the substrate 10 and is electrically connected to the top layer 26 . The second electrode 40 is located on the surface of the first reflector 50 away from the substrate 10 and is electrically connected to the first reflector 50 . In this embodiment, the first reflector 50 is a distributed Bragg reflector, and the first reflector 50 is used to reflect the light generated by the light emitting stack layer 20 and transmitted to the first reflector 50 .

Usually, the first electrode 30 and the second electrode 40 are connected to opposite ends of the light emitting stack layer 20 and are applied with different voltages, so as to drive the light emitting diode structure 100 to emit light. In the prior art, the first reflector 50 is made of a non-conductive material. If there is a crack between the part of the first reflector 50 covered by the second electrode 40 and other parts of the first reflector 50, As a result, the electrical connection between the second electrode 40 and the light emitting stack layer 20 is damaged, as shown in FIG. 2 . In the present embodiment, since the second electrode 40 is located on the first reflector 50 and the first reflector 50 has conductive properties, even if the first reflector 50 is affected by the first reflector 50 due to an external force Cracks appear between the part covered by the second electrode 40 and other parts of the first reflector 50 , so that the electrical connection between the second electrode 40 and the light emitting stack layer 20 is destroyed, and the second electrode 40 is still not affected. The current conduction between the two electrodes 40 and the light emitting stacked layer 20 does not affect the light emission of the light emitting diode structure 100 .

In this embodiment, a semiconductor material may be grown on the surface of the substrate 10 , and the material of the substrate 10 may be an insulating material, a conductive material or a semiconductor material. The substrate 10 may be, but not limited to, sapphire, SiC, MgAl ₂ O ₄ , MgO, LiAlO ₂ , LiGaO ₂ or GaN. In this embodiment, a plurality of microstructures 104 can be formed on the surface of the substrate 10 close to the light-emitting stack layer 20 , the microstructures 104 face the light-emitting stack layer 20 , and the microstructures 104 can improve the formation of the light-emitting stack layer 20 . The luminous efficiency of the light-emitting diode structure 100 is described.

In this embodiment, the first electrode 30 and the second electrode 40 are both metal electrodes. The first electrode 30 and the second electrode 40 may include at least one of the following: gold (Au), silver (Ag), copper (Cu), zinc (Zn), aluminum (Al), indium (In) , Titanium (Ti), Silicon (Si), Germanium (Ge), Tin (Sn), Magnesium (Mg), Tantalum (Ta), Chromium (Cr), Tungsten (W), Ruthenium (Ru), Rhodium (Rh) , iridium (Ir), nickel (Ni), palladium (Pd), platinum (Pt) and their alloys. The first electrode 30 and the second electrode 40 may be formed of one or more layers of conductive materials. In some embodiments, the first electrode 30 and the second electrode 40 may be transparent electrodes, which may be but not limited to indium tin oxide (ITO), aluminum zinc oxide (AZO), indium zinc oxide ( IZO), zinc oxide (ZnO), indium trioxide (In ₂ O ₃ ), tin dioxide (SnO ₂ ), cadmium oxide (CdO), cadmium tin oxide (CdSnO ₄ ) or gallium trioxide (Ga _{2 )} O ₃ ) is formed.

Referring to FIG. 3 , the first reflector 50 includes a plurality of first dielectric layers 51 and a plurality of second dielectric layers 52 . The first dielectric layers 51 and the second dielectric layers 52 are alternately stacked and both are conductive. A first dielectric layer 51 of the first reflector 50 is in contact with the light emitting stack layer 20 . In the first reflector 50 , the refractive index of the first dielectric layer 51 is greater than the refractive index of the second dielectric layer 52 . In this embodiment, a first dielectric layer 51 and a second dielectric layer 52 in contact with each other form a first Bragg layer, the plurality of first Bragg layers form the first reflector 50, and each first Bragg layer The first dielectric layer 51 of the layers is closer to the light emitting stack layer 20 than the second dielectric layer 52 .

，所述第二介質層52的厚度均為

，其中

為所述發光二極體結構100發射的光的波長，

為所述第一介質層51的折射率，

為所述第二介質層52的折射率。 In an embodiment, the material of the first dielectric layer 51 is TiO ₂ :Nb, that is, the material of the first dielectric layer 51 is titanium oxide (TiO ₂ ) doped with niobium (Nb). The refractive index of the layer 51 is about 2.8; the material of the second dielectric layer 52 is indium tin oxide (In ₂ O ₃ :Sn), and its refractive index is about 2.2, satisfying that the refractive index of the first dielectric layer 51 is greater than the The refractive index of the second dielectric layer 52 is described. The thickness of the first dielectric layer 51 is

, the thickness of the second dielectric layer 52 is

,in

is the wavelength of the light emitted by the light-emitting diode structure 100,

is the refractive index of the first dielectric layer 51,

is the refractive index of the second dielectric layer 52 .

As shown in FIG. 1 , the light emitting diode structure 100 further includes a second reflector 60 on the surface of the substrate 10 away from the light emitting stack layer 20 . The second reflector 60 is a distributed Bragg reflector, and the second reflector 60 can be used to reflect the light generated by the light emitting stack 20 and transmitted to the second reflector 60 . In this embodiment, the second reflector 60 includes a plurality of third dielectric layers 61 and a plurality of fourth dielectric layers 62 that are alternately stacked in sequence, and a third dielectric layer 61 of the second reflector 60 is connected to the The substrate 10 is in contact and connected, and the refractive index of the third dielectric layer 61 is greater than the refractive index of the fourth dielectric layer 62 . The structures of the alternately stacked third dielectric layers 61 and the fourth dielectric layers 62 are similar to the structure of the first reflector 50 illustrated in FIG. 3 . In this embodiment, a third dielectric layer 61 and a fourth dielectric layer 62 in contact with each other form a second Bragg layer, the plurality of second Bragg layers form the second reflector 60, and each second Bragg layer The third dielectric layer 61 is closer to the substrate 10 than the fourth dielectric layer 62 is.

，所述第四介質層62的厚度均為

，其中

為所述發光二極體結構100發射的光的波長，

為所述第三介質層61的折射率，

為所述第四介質層62的折射率。所述第三介質層61與所述第四介質層62的厚度會受到所述發光二極體結構100發射的光的波長的影響。 In this embodiment, the thickness of the third dielectric layer 61 is

, the thickness of the fourth dielectric layer 62 is

,in

is the wavelength of the light emitted by the light-emitting diode structure 100,

is the refractive index of the third dielectric layer 61,

is the refractive index of the fourth dielectric layer 62 . The thicknesses of the third medium layer 61 and the fourth medium layer 62 are affected by the wavelength of the light emitted by the light emitting diode structure 100 .

In this embodiment, the third dielectric layer 61 and the fourth dielectric layer 62 are dielectric material layers. In one embodiment, the material of the third dielectric layer 61 is titanium oxide (TiO ₂ ) with a refractive index of about 2.8; the material of the fourth dielectric layer 62 is silicon oxide (SiO ₂ ) with a refractive index of about 2.8 is 1.4, which satisfies that the refractive index of the third dielectric layer 61 is greater than the refractive index of the fourth dielectric layer 62 .

As shown in FIG. 1 , the light-emitting stacked layer 20 further includes an active layer 22 , a semiconductor layer 23 and a transparent conductive layer 24 which are sequentially stacked and disposed between the bottom layer 21 and the top layer 26 . Specifically, the bottom layer 21 is located on the substrate 10 , the active layer 22 is located on the bottom layer 21 and a surface away from the substrate 10 , and the semiconductor layer 23 is located on the active layer 22 away from the bottom layer 21, the transparent conductive layer 24 is located on the surface of the semiconductor layer 23 away from the active layer 22, the top layer 26 is located on the transparent conductive layer 24 and covers the current blocking layer 25 and the transparent Conductive layer 24 . The first reflector 50 is located on the surface of the top layer 26 , which is a current spreading layer, away from the transparent conductive layer 24 . In this embodiment, the bottom layer 21 is a semiconductor material layer, and the top layer 26 is a current diffusion layer.

As shown in FIG. 1 , the light-emitting stack layer 20 further includes a current blocking layer 25 located on the semiconductor layer 23 and sandwiched between the transparent conductive layers 24 , that is, the second electrode 40 is located on the second electrode 40 . A reflector 50 is disposed away from the surface of the top layer 26 and facing the current blocking layer 25 .

In this embodiment, the top layer 26 serving as the current diffusion layer can distribute the current evenly to the area outside the second electrode 40 , and distribute the light-emitting area to the area outside the second electrode 40 . The current blocking layer 25 is formed directly on the semiconductor layer 23 and is in contact with the top layer 26 , and its position and shape correspond to the first electrode 30 , and the current blocking layer 25 can prevent current from flowing directly under the second electrode 40 . into the semiconductor layer 23 to reduce the probability of electron-hole recombination under the second electrode 40 , thereby improving the light extraction efficiency of the region other than the second electrode 40 .

In this embodiment, the first electrode 30 is in ohmic contact with the bottom layer 21 made of semiconductor material, and the second electrode 40 is in ohmic contact with the semiconductor layer 23 . The bottom layer 21 and the semiconductor layer 23 may be an n-type doped semiconductor layer and a p-type doped semiconductor layer, respectively. On the contrary, the bottom layer 21 and the semiconductor layer 23 may be a p-type doped semiconductor layer and an n-type doped semiconductor layer, respectively. Each of the bottom layer 21 and the semiconductor layer 23 may be formed of a single layer, or may include multiple layers having different doping concentrations and compositions. The active layer 22 may emit light having a predetermined energy level generated by electron-hole recombination, and the active layer 22 may be, but not limited to, a quantum well (SQW) structure.

In one embodiment, a buffer layer (not shown) may be disposed between the substrate 10 and the light-emitting stack layer 20 , and the buffer layer is used to improve the crystallinity of the semiconductor layer in the light-emitting stack layer 20 and The substrate 10 is protected when the light emitting stack layer 20 is formed on the substrate 10 . The buffer layer may be formed of undoped aluminum gallium nitride (AlxGa1-xN) grown at a low temperature.

Further referring to FIG. 1 , the light emitting diode structure 100 further includes an insulating layer 70 , and the insulating layer 70 is located on a surface of the substrate 10 having the light emitting stack layer 20 . The insulating layer 70 wraps the light-emitting stacked layer 20 disposed on the substrate 10 , and the first electrode 30 and the second electrode 40 are exposed relative to the insulating layer 70 . That is, the insulating layer 70 wraps the bottom layer 21 , the active layer 22 , the semiconductor layer 23 , the transparent conductive layer 24 , and the top layer 26 which are sequentially stacked on the substrate 10 . In this embodiment, the size of the bottom layer 21 is larger than that of the active layer 22 , the semiconductor layer 23 , the transparent conductive layer 24 , the top layer 26 , the first reflector 50 and the second electrode 40 , so that the active layer 22 , the semiconductor layer 23 , the transparent conductive layer 24 , the top layer 26 and the first reflector 50 are stacked in sequence on the side of the bottom layer 21 away from the substrate 10 to A laminated structure is formed, and the first electrode 30 is disposed on the bottom layer 21 with a distance from the laminated structure. An insulating layer 70 is filled between the first electrode 30 and the stacked structure.

In this embodiment, the insulating layer 70 is a transparent insulating layer or a non-transparent insulating layer. The current blocking layer 25 and the insulating layer are insulating materials, which may be, but not limited to, SiO ₂ , SiN _x , Al ₂ O ₃ , HfO, TiO ₂ and ZrO. The material of the top layer 26 may be, but not limited to, indium tin oxide (ITO), zinc aluminum oxide, tin oxide, cadmium tin oxide, antimony tin oxide, and nickel/gold (Ni/Au).

In this embodiment, the substrate 10 defines a first surface 101 , a second surface 102 opposite to the first surface 101 , and two surfaces connected between the first surface 101 and the second surface 102 Side 103. The second reflector 60 is located on the second surface 102; the light emitting stack layer 20 is located on the first surface 101; the first reflector 50 is located on the light emitting stack layer 20 away from the first one side of the surface 101 ; so that the light emitted by the light emitting diode structure 100 is emitted from the two side surfaces 103 of the substrate 10 .

Referring to FIG. 4 , an embodiment of the present invention further provides a flip-chip light emitting diode structure 200 , which includes a backing plate 80 and the light emitting diode structure 100 , the first electrode 30 and the second electrode 40 are oriented parallel to each other. The same surface of the backing plate 80 is attached. The backing plate 80 is provided with a plurality of conductive traces (not shown), the first electrode 30 and the second electrode 40 are electrically connected to the conductive traces on the backing plate 80 , and the light-emitting The diode structure 200 obtains the voltage or current signal required to emit light through the conductive traces.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. The up, down, left and right directions appearing in the figures are only for the convenience of understanding. Although the present invention has been described in detail with reference to the preferred embodiments, the Those of ordinary skill should understand that the technical solutions of the present invention may be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention.

100, 200: LED structure 10: Substrate 101: First Surface 102: Second Surface 103: Side 104: Microstructure 20: Light Emitting Stacked Layers 21: Ground Floor 22: Active layer 23: Semiconductor layer 24: Transparent conductive layer 25: Current blocking layer 26: Top Floor 30: The first electrode 40: Second electrode 50: First reflector 51: The first dielectric layer 52: Second dielectric layer 60: Second reflector 61: The third dielectric layer 62: Fourth dielectric layer 70: Insulation layer 80: Liner

FIG. 1 is a schematic diagram of a light emitting diode structure according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of cracks appearing in the first reflector of the light emitting diode structure according to an embodiment of the present invention.

3 is a schematic structural diagram of a plurality of first dielectric layers and a plurality of second dielectric layers of a first reflector of a light-emitting diode structure according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of a flip-chip light-emitting diode structure according to an embodiment of the present invention.

100: Light Emitting Diode Structure

10: Substrate

101: First Surface

102: Second Surface

103: Side

104: Microstructure

20: Light Emitting Stacked Layers

21: Ground Floor

22: Active layer

23: Semiconductor layer

24: Transparent conductive layer

25: Current blocking layer

26: Top Floor

30: The first electrode

40: Second electrode

50: First reflector

60: Second reflector

70: Insulation layer

Claims (10)

A light-emitting diode structure, which is improved by comprising: a substrate; a light-emitting stacked layer, comprising multiple layers stacked on the substrate in sequence, and the outer layers of the light-emitting stacked layer near and far from the substrate are a bottom layer and a top layer respectively; a first electrode located on the surface of the bottom layer away from the substrate and electrically connected to the bottom layer; a conductive first reflector located on a surface of the top layer away from the substrate and electrically connected to the top layer; and A second electrode is located on the surface of the first reflector away from the substrate and is electrically connected to the first reflector. The light emitting diode structure of claim 1, wherein the first reflector comprises a plurality of first dielectric layers and a plurality of second dielectric layers, and the first dielectric layers and the second dielectric layers in the first reflector alternate The layers are stacked and all are conductive, a first medium layer in the first reflector is in contact with the light-emitting stacked layer, and the refractive index of the first medium layer is greater than the refractive index of the second medium layer. The light emitting diode structure according to claim 2, wherein the thickness of the first dielectric layer is

, the thickness of the second dielectric layer is

,in

is the wavelength of light emitted by the light-emitting diode structure,

is the refractive index of the first dielectric layer;

is the refractive index of the second dielectric layer. The light emitting diode structure of claim 2, wherein the material of the first dielectric layer is titanium oxide doped with niobium, and the material of the second dielectric layer is indium tin oxide. The light emitting diode structure of claim 1, wherein the light emitting diode structure further comprises a second reflector located on a surface of the substrate away from the light emitting stack layer. The light-emitting diode structure of claim 5, wherein the second reflector comprises a plurality of third dielectric layers and a plurality of fourth dielectric layers alternately stacked in sequence, and the third dielectric layer of the second reflector and the Four dielectric layers are alternately stacked, and a third dielectric layer of the second reflector is in contact with the substrate; the refractive index of the third dielectric layer is greater than the refractive index of the fourth dielectric layer. The light emitting diode structure according to claim 6, wherein the thickness of the third dielectric layer is

, the thickness of the fourth dielectric layer is

,in

is the wavelength of light emitted by the light-emitting diode structure,

is the refractive index of the third dielectric layer,

is the refractive index of the fourth medium layer; the third medium layer and the four layers are dielectric material layers. The light emitting diode structure according to claim 1, wherein the light emitting stack layer further comprises an active layer, a semiconductor layer and a transparent conductive layer which are sequentially stacked between the bottom layer and the top layer, and the bottom layer is a semiconductor material layer, the top layer is a current diffusion layer; the light emitting stack layer further includes a current blocking layer on the semiconductor layer and sandwiched between the transparent conductive layers, the current blocking layer is disposed opposite to the second electrode . The light emitting diode structure according to claim 8, wherein the light emitting diode structure further comprises an insulating layer, the insulating layer is located on the surface of the substrate with the light emitting stack layer, and wraps the light emitting diode disposed on the substrate Light emitting stack layer; the first electrode and the second electrode are exposed relative to the insulating layer. A flip-chip light-emitting diode structure, the improvement of which includes: a liner; and The light emitting diode structure according to any one of claims 1 to 9, wherein the first electrode and the second electrode face and are connected to the same surface of the backing plate.

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