Light-emitting diode

Abstract

To improve the conventional problem of a transparent conductive film of a light-emitting diode being easily corroded and damaged by hydrochloric acid solution and improve the luminance and product yield.SOLUTION: A light-emitting diode includes an epitaxial composite layer, a dielectric layer, a transparent conductive layer, and a metal layer. The epitaxial composite layer is disposed on the dielectric layer. The dielectric layer is disposed on the transparent conductive layer. The transparent conductive layer is disposed on the metal layer. The outer edge of the transparent conductive layer is covered with the metal layer.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a light emitting diode, and more particularly to a high brightness light emitting diode. [Background technology]

[0002] Light emitting diodes (hereinafter referred to as LEDs) have advantages such as high brightness, small size, low power consumption, and long life, and are widely used in lighting and display products. Generally, gallium arsenide (GaAs) epitaxial growth substrates are used for quaternary red light emitting diode products with an emission wavelength of 590 to 1000 nanometers (nm). Indium phosphide (InP) epitaxial growth substrates are used for short wavelength infrared (SWIR) light emitting diode products with an emission wavelength of 1000 to 2000 nanometers. In the latter stage of the manufacturing process, a permanent bonding substrate and metal bonding process are performed to improve the photoelectron properties of the light emitting diode. After bonding to the permanent substrate, the original epitaxial growth substrate is removed. Generally, after bonding of the quaternary red gallium arsenide substrate, the gallium arsenide substrate is removed using an ammonia solution. Meanwhile, when indium phosphide is used as the epitaxial growth substrate, the growth substrate is removed using a hydrochloric acid solution. However, when removing the indium phosphide growth substrate, the outer edge of the transparent conductive film of the light-emitting diode structure is easily corroded and damaged by the hydrochloric acid solution, resulting in a decrease in product yield.

[0003] In order to overcome the above-mentioned problems, it has become an urgent task for the industry to develop an innovative light-emitting diode structure and manufacturing process that improves the above-mentioned problem that the outer edge of the transparent conductive film is corroded and damaged by the hydrochloric acid solution when removing the epitaxial growth substrate, resulting in a decrease in product yield. Summary of the Invention

[0004] The main objective of the present invention is to provide a light emitting diode with an innovative transparent conductive layer structure, which can improve the traditional problem that the transparent conductive film of the light emitting diode is easily corroded and damaged by hydrochloric acid solution, and improve the brightness and product yield.

[0005] In order to achieve the above object, the present invention provides a light emitting diode including an epitaxial composite layer, a dielectric layer, a transparent conductive layer, and a metal layer, the epitaxial composite layer being disposed on the dielectric layer, the dielectric layer being disposed on the transparent conductive layer, the transparent conductive layer being disposed on the metal layer, and the outer edge of the transparent conductive layer being covered with the metal layer.

[0006] In an embodiment of the present invention, the transparent conductive layer of the light emitting diode includes a plurality of dot-shaped transparent electrodes surrounded by a dielectric layer.

[0007] In an embodiment of the present invention, the material of the transparent conductive layer of the light emitting diode is indium tin oxide, zinc aluminum oxide, zinc tin oxide, zinc oxide, nickel oxide, cadmium tin oxide, antimony tin oxide, or a combination thereof.

[0008] In an embodiment of the present invention, the outer edge of the dielectric layer of the light emitting diode is covered with a metal layer.

[0009] In an embodiment of the present invention, the epitaxial composite layer of the light-emitting diode includes a first semiconductor layer, a light-emitting layer, a second semiconductor layer, and a third semiconductor layer, the third semiconductor layer is disposed on the dielectric layer and electrically connected to the transparent conductive layer, the second semiconductor layer is disposed on the third semiconductor layer, the light-emitting layer is disposed on the second semiconductor layer, and the first semiconductor layer is disposed on the light-emitting layer.

[0010] In an embodiment of the present invention, the first semiconductor layer of the light emitting diode is an N-type indium phosphide epitaxial layer, the second semiconductor layer is a P-type indium phosphide epitaxial layer, and the third semiconductor layer is a P-type indium gallium arsenide epitaxial layer.

[0011] In an embodiment of the present invention, the light emitting layer of the light emitting diode has an emission wavelength of 1000 to 2000 nanometers (nm).

[0012] In an embodiment of the present invention, the light emitting diode further includes an upper electrode disposed on the epitaxial composite layer, and the upper electrode does not overlap with each dot-shaped transparent electrode when viewed in a vertical direction.

[0013] In an embodiment of the present invention, the material of the metal layer of the light emitting diode is gold (Au), silver (Ag), aluminum (Al), beryllium gold (BeAu), gold germanium (GeAu), or a combination thereof.

[0014] In an embodiment of the present invention, the light emitting diode further includes a bonding substrate bonded to the metal layer.

[0015] Those skilled in the art can understand other objects of the present invention, as well as the technical means and embodiments of the present invention, by referring to the drawings and the embodiments described below. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram showing a manufacturing process and structure of a light-emitting diode according to an embodiment of the present invention; [Diagram 2] 1 is a diagram showing a manufacturing process and structure of a light-emitting diode according to an embodiment of the present invention; [Diagram 3] 1 is a diagram showing a manufacturing process and structure of a light-emitting diode according to an embodiment of the present invention; [Figure 4] 1 is a diagram showing a manufacturing process and structure of a light-emitting diode according to an embodiment of the present invention; [Diagram 5] 1 is a diagram showing a manufacturing process and structure of a light-emitting diode according to an embodiment of the present invention; [Figure 5A] 1 is a diagram showing a manufacturing process and structure of a light emitting diode according to another embodiment of the present invention; [Figure 6] 1 is a diagram showing a manufacturing process and structure of a light-emitting diode according to an embodiment of the present invention; [Figure 7] 1 is a diagram showing a manufacturing process and structure of a light-emitting diode according to an embodiment of the present invention; [Figure 8] 1 is a diagram showing a manufacturing process and structure of a light-emitting diode according to an embodiment of the present invention; [Figure 8A] 1 is a diagram showing a manufacturing process and structure of a light emitting diode according to another embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The contents of the present invention will be described below through examples. The examples of the present invention are examples of embodiments, and are not intended to limit the present invention to the environments, applications, or specific aspects described in the examples. Therefore, the explanation of the examples is for explaining the present invention, but does not limit the present invention. In the embodiments and drawings, components that are not directly related to the present invention are omitted and not shown. The dimensional relationship between the components in the drawings is for ease of understanding, and does not limit the actual dimensions.

[0018] FIG. 1 is a diagram showing an embodiment of a light-emitting diode according to the present invention. The present invention takes as an example a short-wavelength infrared light-emitting diode using indium phosphide (InP) as an epitaxial growth substrate 100, but is not limited thereto. Next, an epitaxial composite layer 105 is formed on the indium phosphide substrate. Specifically, in this embodiment, the epitaxial composite layer 105 includes an N-type first semiconductor layer 110, a light-emitting layer 120, a second semiconductor layer 130, and a third semiconductor layer 140. The first semiconductor layer 110 is disposed on the epitaxial growth substrate 100. The light-emitting layer 120 is disposed on the first semiconductor layer 110. The second semiconductor layer 130 is disposed on the light-emitting layer 120. The third semiconductor layer 140 is disposed on the second semiconductor layer 130. The light-emitting layer 120 is formed in a multiple quantum well (MQW) structure. In this embodiment, the multiple quantum wells of the light emitting layer 120 have an emission wavelength of 1000 to 2000 nanometers (nm). The first semiconductor layer 110 is an epitaxial layer of N-type indium phosphide (InP). The second semiconductor layer 130 is an epitaxial layer of P-type indium phosphide. The third semiconductor layer 140 is an epitaxial layer of P-type indium gallium arsenide (InGaAs). Note that the materials described in the above embodiment are merely examples, and the present invention is not limited thereto. In practice, the materials and their compositions can be adjusted according to the emission wavelength. For example, the epitaxial layer may be aluminum gallium indium phosphide (AlGaInP), indium gallium phosphide (InGaP), aluminum gallium arsenide (AlGaAs), or the like.

[0019] As shown in FIG. 2, a dielectric layer 150 covering the entire epitaxial composite layer 105 is formed by chemical vapor deposition. This dielectric layer 150 is a low refractive index dielectric layer, and is made of silicon dioxide (SiO2), silicon nitride (Si3N4), or the like. Next, as shown in FIG. 3, a part of the dielectric layer 150 is removed by a yellow light etching process until the third semiconductor layer 140 on the surface of the epitaxial composite layer 105 is exposed. This forms a patterned dielectric layer 150 that defines the distribution position and area of ​​the subsequent lower electrode. As shown in FIG. 4, the patterned dielectric layer 150 is covered with a transparent conductive material by deposition, and a transparent conductive layer 160 that covers the exposed epitaxial composite layer 105 and the dielectric layer 150 is formed. As shown in FIG. 3, a patterning process is performed to form recessed areas where the epitaxial composite layer 105 is exposed from the dielectric layer 150. As shown in FIG. 4, these recessed areas are filled with a transparent conductive material to form dot-shaped transparent electrodes 162. Each dot-shaped transparent electrode 162 is surrounded by the dielectric layer 150 and is electrically connected to the third semiconductor layer 140 and the transparent conductive layer 160. In a preferred embodiment, the material of the transparent conductive layer 160 and these dot-shaped transparent electrodes 162 is indium tin oxide (ITO), aluminum zinc oxide (AZO), zinc tin oxide (IZO), zinc oxide (ZnO), nickel oxide, cadmium tin oxide, antimony tin oxide, or a combination thereof.

[0020] As shown in Fig. 5, the outer edge portion of the transparent conductive layer 160 is removed by a yellow light etching process, and then a metal layer 170 is formed by a deposition process to cover the entire transparent conductive layer 160 and its outer edge. The material of the metal layer 170 is gold (Au), silver (Ag), aluminum (Al), beryllium gold (BeAu), gold germanium (GeAu), or a combination thereof. As shown in Fig. 6, the metal layer 170 is metal-bonded to a bonding substrate 180. The bonding substrate 180 may be, but is not limited to, a silicon substrate or a sapphire substrate.

[0021] As shown in Fig. 7, the indium phosphide growth substrate 100 is removed using a hydrochloric acid solution to expose the first semiconductor layer 110 of the epitaxial composite layer 105. The whole is then turned over so that the bonding substrate 180 is at the bottom of the light-emitting diode structure. In particular, as shown in Fig. 5, the outer edge of the transparent conductive layer 160 in the light-emitting diode structure according to the present invention is covered with a metal layer 170, so that when the indium phosphide growth substrate 100 is removed using a hydrochloric acid solution, the transparent conductive layer 160 is completely protected from corrosion by the hydrochloric acid solution by the metal layer 170, thereby improving the product yield.

[0022] Next, the first semiconductor layer 110 is roughened and the entire epitaxial composite layer 105 is subjected to a MESA process, so that finally, as shown in Fig. 8, an upper electrode 190 is formed on the first semiconductor layer 110, thereby forming the final structure of the light-emitting diode 1 according to the present invention. The material of the upper electrode 190 is gold germanium (GeAu), germanium gold nickel (GeAuNi), or a combination thereof. Note that, in order to obtain the effect of dispersing the current and avoiding light blocking, the upper electrode 190 and the dot-shaped transparent electrodes 162 do not overlap when viewed in the vertical direction.

[0023] Hereinafter, another embodiment of the present invention will be described. As shown in FIG. 1 to FIG. 4 and FIG. 5A, the first half of the manufacturing process in this embodiment is the same as the previous embodiment, and the corresponding contents in FIG. 2 to FIG. 5 and the above can be referred to, so the description thereof will be omitted. This embodiment differs from the previous embodiment in that, as shown in FIG. 5A, not only the outer edge portion of the transparent conductive layer 160 is removed by the yellow light etching process, but also the outer edge portion of the dielectric layer 150 is etched and removed. Next, a metal layer 170 is formed to cover the entire transparent conductive layer 160, the dielectric layer 150 and its outer edge by a deposition process. Subsequent processes in this embodiment, such as the process of removing the epitaxial growth substrate 100, the process of roughening the first semiconductor layer 110, the MESA process, and the process of forming the upper electrode 190, are the same as the previous embodiment, and the above contents and drawings can be referred to, so the description thereof will be omitted.

[0024] FIG. 8A is a diagram showing the final structure of another light-emitting diode 2 in this embodiment. This embodiment differs from the above embodiment in that not only the outer edge of the transparent conductive layer 160 is covered with the metal layer 170, but both the outer edge of the transparent conductive layer 160 and the outer edge of the dielectric layer 150 are covered with the metal layer 170. Therefore, when the indium phosphide growth substrate 100 is removed using a hydrochloric acid solution, the transparent conductive layer 160 and the dielectric layer 150 are completely protected from corrosion by the hydrochloric acid solution by the metal layer 170, thereby improving the product yield. Note that in this embodiment, the metal layer 170 is U-shaped and completely covers the transparent conductive layer 160 and the dielectric layer 150. Compared with the above embodiment, the U-shaped metal layer 170 in this embodiment can increase the opportunity for upward reflection of the light emitted from the light-emitting layer, thereby improving the light extraction efficiency and brightness.

[0025] The above examples are for explaining the embodiments of the present invention and for explaining the characteristic configuration of the present invention. The present invention is not limited to the above examples. Modifications or equivalent arrangements that can be easily made by those skilled in the art are also within the scope of the present invention. The scope of protection of the rights of the present invention is based on the claims. [Explanation of symbols]

[0026] 1, 2 Light emitting diode 100 Epitaxial growth substrate 105 Epitaxial Composite Layer 110 First semiconductor layer 120 Light-emitting layer 130 Second semiconductor layer 140 Third semiconductor layer 150 Dielectric layer 160 Transparent conductive layer 162 Dot-shaped transparent electrode 170 Metal layer 180 Bonded substrate 190 Upper electrode

Claims

1. A light emitting diode, an epitaxial composite layer, a dielectric layer, a transparent conductive layer, and a metal layer; the epitaxial composite layer is disposed on the dielectric layer; the dielectric layer is disposed on the transparent conductive layer; A light emitting diode, wherein the transparent conductive layer is disposed on the metal layer, and an outer edge of the transparent conductive layer is covered with the metal layer.

2. 2. The light-emitting diode according to claim 1, wherein the transparent conductive layer includes a plurality of dot-shaped transparent electrodes surrounded by the dielectric layer.

3. 2. The light emitting diode of claim 1, wherein the material of the transparent conductive layer is indium tin oxide, zinc aluminum oxide, zinc tin oxide, zinc oxide, nickel oxide, cadmium tin oxide, antimony tin oxide, or a combination thereof.

4. 2. The light emitting diode according to claim 1, wherein an outer edge of the dielectric layer is covered with the metal layer.

5. 2. The light-emitting diode of claim 1, wherein the epitaxial composite layer includes a first semiconductor layer, a light-emitting layer, a second semiconductor layer, and a third semiconductor layer, the third semiconductor layer being disposed on the dielectric layer and electrically connected to the transparent conductive layer, the second semiconductor layer being disposed on the third semiconductor layer, the light-emitting layer being disposed on the second semiconductor layer, and the first semiconductor layer being disposed on the light-emitting layer.

6. 6. The light-emitting diode of claim 5, wherein the first semiconductor layer is an epitaxial layer of N-type indium phosphide (InP), the second semiconductor layer is an epitaxial layer of P-type indium phosphide (InP), and the third semiconductor layer is an epitaxial layer of P-type indium gallium arsenide (InGaAs).

7. 6. The light emitting diode according to claim 5, wherein the light emitting layer has an emission wavelength of 1000 to 2000 nanometers (nm).

8. The light emitting diode according to claim 2 , further comprising an upper electrode disposed on the epitaxial composite layer, the upper electrode not overlapping with each of the dot-shaped transparent electrodes when viewed in a vertical direction.

9. 2. The light emitting diode of claim 1, wherein the material of the metal layer is gold (Au), silver (Ag), aluminum (Al), beryllium gold (BeAu), gold germanium (GeAu), or a combination thereof.

10. The light emitting diode according to claim 1 , further comprising a bonding substrate bonded to the metal layer.

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