Light emitting diode

Abstract

The invention relates to a light-emitting diode which comprises an epitaxial composite layer, a dielectric layer, a transparent conductive layer and a metal layer. Wherein the epitaxial composite layer is arranged on the dielectric layer, the dielectric layer is arranged on the transparent conductive layer, the transparent conductive layer is arranged on the metal layer, and the outer edge of the transparent conductive layer is coated by the metal layer.

Description

Technical Field

[0001] The present invention relates to a light emitting diode, in particular to a high brightness light emitting diode. Background Art

[0002] Light Emitting Diode (hereinafter referred to as LED) has the advantages of high brightness, small size, low power consumption and long life, and is widely used in lighting or display products. In the quaternary red light emitting diode products with a general emission wavelength of 590 to 1000 nanometers (nm), gallium arsenide (GaAs) epitaxial growth substrates are used, while in the short-wave infrared (SWIR) light emitting diode products with a wavelength of 1000 to 2000 nanometers, indium phosphide (InP) epitaxial growth substrates are used. In the latter part of the production process, in order to improve the photoelectric properties of the light emitting diode, a metal bonding process will be performed with another permanent bonding substrate. After the permanent substrate is bonded, the original epitaxial growth substrate will be removed. After the quaternary red light gallium arsenide substrate is bonded, an ammonia solution is used to remove the gallium arsenide substrate. On the other hand, when indium phosphide is used as the epitaxial growth substrate, a hydrochloric acid solution is used to remove it. However, when the InP epitaxial growth substrate is removed, the transparent conductive film in the LED structure is easily corroded and damaged by the hydrochloric acid solution at the outer edge, further reducing the process yield.

[0003] To overcome the above problems, the industry urgently needs an innovative structure and process of light-emitting diodes to improve the problem of the outer edge of the transparent conductive film being corroded and damaged by hydrochloric acid when removing the epitaxial growth substrate, thereby reducing the yield and thereby improving the brightness of the light-emitting diodes. Summary of the invention

[0004] The main purpose of the present invention is to provide a light emitting diode with an innovative transparent conductive layer structure, so as to improve the problem that the transparent conductive layer in the existing light emitting diode structure is easily corroded and damaged by hydrochloric acid solution, and thereby improve the brightness and process yield.

[0005] To achieve the above-mentioned purpose, the present invention provides a light-emitting diode, which comprises an epitaxial composite layer, a dielectric layer, a transparent conductive layer and a metal layer, wherein 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, and the outer edge of the transparent conductive layer is covered by the metal layer.

[0006] In one embodiment, the transparent conductive layer of the light emitting diode of the present invention further comprises a plurality of dot-shaped transparent electrodes, each of which is surrounded by a dielectric layer.

[0007] In one embodiment, the material of the transparent conductive layer of the light emitting diode of the present invention 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 one embodiment, the outer edge of the dielectric layer of the light emitting diode of the present invention is covered by a metal layer.

[0009] In one embodiment, the epitaxial composite layer of the light-emitting diode of the present invention further includes a first semiconductor layer, a light-emitting layer, a second semiconductor layer and a third semiconductor layer, wherein 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 one embodiment, the first semiconductor layer of the light emitting diode of the present invention is an N-type indium phosphide (InP) 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 (InGaAs) epitaxial layer.

[0011] In one embodiment, the light emitting wavelength band of the light emitting layer of the light emitting diode of the present invention is about 1000-2000 nanometers (nm).

[0012] In one embodiment, the light emitting diode of the present invention further comprises an upper electrode, which is disposed on the epitaxial composite layer and does not overlap with each of the dot-shaped transparent electrodes in a vertical position.

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

[0014] In one embodiment, the light emitting diode of the present invention further comprises a bonding substrate, and the bonding substrate is bonded to the metal layer.

[0015] After referring to the accompanying drawings and the specific embodiments described below, a person skilled in the art will be able to understand other objectives of the present invention, as well as the technical means and embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figures 1 to 8 A diagram showing the manufacturing steps and structure of a light emitting diode according to an embodiment of the present invention; and

[0017] Figure 5A , Fig. 8A FIG. 1 is a diagram showing the manufacturing steps and structure of a light emitting diode in another embodiment of the present invention.

[0018] Description of reference numerals:

[0019] 1.2 Light Emitting Diode

[0020] 100 Epitaxial growth substrate

[0021] 105 epitaxial composite layer

[0022] 110 first semiconductor layer

[0023] 120 Luminous Layer

[0024] 130 Second semiconductor layer

[0025] 140 Third semiconductor layer

[0026] 150 Dielectric layer

[0027] 160 Transparent conductive layer

[0028] 162 Dot-shaped transparent electrode

[0029] 170 Metal Layer

[0030] 180 bonding substrate

[0031] 190 Upper electrode. DETAILED DESCRIPTION

[0032] The present invention will be explained below through embodiments. The embodiments of the present invention are not intended to limit the present invention to any specific environment, application or special method as described in the embodiments. Therefore, the description of the embodiments is only for the purpose of explaining the present invention, and is not intended to limit the present invention. It should be noted that in the following embodiments and drawings, elements that are not directly related to the present invention have been omitted and not drawn, and the dimensional relationship between the elements in the drawings is only for easy understanding, and is not intended to limit the actual proportion.

[0033] Please refer to Figure 1, which discloses one embodiment of the present invention for making a light emitting diode, especially taking a short-wave infrared light emitting diode as an example, in which indium phosphide (InP) is used as an epitaxial growth substrate 100, but is not limited thereto. Subsequently, 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, and the third semiconductor layer 140 is disposed on the second semiconductor layer 130. Among them, the light emitting layer 120 is formed by a multiple quantum well (MQW) structure. In this embodiment, the light emitting wavelength band of the multiple quantum wells in the light emitting layer 120 can be 1000 to 2000 nanometers (nm). The first semiconductor layer 110 is an N-type indium phosphide (InP) epitaxial layer, the second semiconductor layer 130 is a P-type indium phosphide epitaxial layer, and the third semiconductor layer 140 is a P-type indium gallium arsenide (InGaAs) epitaxial layer. It should be noted that the material described in the above embodiment is only one embodiment, and the present invention is not limited thereto. In practical applications, the material and its composition can be adjusted according to the light emission wavelength. For example, the epitaxial layer can be aluminum gallium indium phosphide (AlGaInP), indium gallium phosphide (InGaP), aluminum gallium arsenide (AlGaAs), etc.

[0034] See also Figure 2 A dielectric layer 150 is formed by chemical vapor deposition to cover the entire epitaxial composite layer 105. The dielectric layer 150 is a low refractive index dielectric layer, and its material can be silicon oxide (SiO x ), silicon nitride (Si3N4), etc. Next, please refer to Figure 3 , and then remove part of the dielectric layer 150 by a yellow light etching process until the third semiconductor layer 140 on the surface of the epitaxial composite layer 105 is exposed, so as to form a patterned dielectric layer 150 for defining the distribution position and area of ​​the subsequent lower electrode. Figure 4 As shown, a transparent conductive material is deposited on the patterned dielectric layer 150 by evaporation to form a transparent conductive layer 160 covering the exposed epitaxial composite layer 105 and the dielectric layer 150. Figure 3 The patterned dielectric layer 150 exposes the recessed areas of the epitaxial composite layer 105. After the transparent conductive material is filled, a plurality of dot-shaped transparent electrodes 162 are formed in the recessed areas. 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. Figure 4In a preferred embodiment, the transparent conductive layer 160 and the dot-shaped transparent electrodes 162 are formed of materials such as 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.

[0035] See also Figure 5 , remove the outer edge of the transparent conductive layer 160 by a yellow light etching process, and then form a metal layer 170 by a vapor deposition process to cover the entire transparent conductive layer 160 and its outer edge. The material forming the metal layer 170 is gold (Au), silver (Ag), aluminum (Al), beryllium gold (BeAu), germanium gold (GeAu) or a combination thereof. Figure 6 The metal layer 170 is metal-bonded to a bonding substrate 180 , wherein the bonding substrate 180 may be, but is not limited to, a silicon substrate or a sapphire substrate.

[0036] See also Figure 7 , using hydrochloric acid solution to remove the indium phosphide epitaxial growth substrate 100 to expose the first semiconductor layer 110 of the epitaxial composite layer 105, and then flipping it so that the bonding substrate 180 is located at the bottom of the light-emitting diode structure. Figure 5 Since the outer edge of the transparent conductive layer 160 in the light-emitting diode structure of the present invention is covered by the metal layer 170, when the hydrochloric acid solution is used to remove the indium phosphide epitaxial growth substrate 100, the transparent conductive layer 160 can be completely protected by the metal layer 170 from being corroded by the hydrochloric acid solution, thereby improving the process yield.

[0037] Subsequently, the first semiconductor layer 110 is roughened, and the entire epitaxial composite layer 105 is subjected to a MESA process, and finally an upper electrode 190 is formed on the first semiconductor layer 110 to form the final structure of the light emitting diode 1 of the present invention. Figure 8 As shown. The material of the upper electrode 190 can be germanium gold (GeAu), germanium gold nickel (GeAuNi) or a combination thereof. Moreover, in order to achieve the effect of dispersing current and avoiding light shielding, the upper electrode 190 and the dot-shaped transparent electrode 162 do not overlap in the vertical position.

[0038] Another embodiment of the present invention will be described below. Figures 1 to 4 , Figure 5A It should be noted that the front-end process in this embodiment is the same as that in the previous embodiment and can be combined Figures 2 to 5 The above-mentioned corresponding contents are referred to and will not be described in detail. The difference between this embodiment and the above-mentioned embodiment is that Figure 5AAs shown, the yellow light etching process removes not only the outer edge of the transparent conductive layer 160, but also the outer edge of the dielectric layer 150. Then, the metal layer 170 is formed by the evaporation process to cover the entire transparent conductive layer 160, the dielectric layer 150 and their outer edges. Other subsequent processes of this embodiment, such as removing the epitaxial growth substrate 100, roughening the first semiconductor layer 110, MESA process, and forming the upper electrode 190, are the same as the above-mentioned embodiments. Therefore, please merge the above-mentioned related contents and drawings, and do not repeat them here.

[0039] See also Fig. 8A , which shows the final structure of another light-emitting diode 2 in this embodiment. Different from the previous embodiment, in this embodiment, not only the outer edge of the transparent conductive layer 160 is covered by the metal layer 170, but also the outer edge of the transparent conductive layer 160 and the outer edge of the dielectric layer 150 are covered by the metal layer 170. Therefore, when hydrochloric acid is used to remove the indium phosphide epitaxial growth substrate 100 in the subsequent process, the transparent conductive layer 160 and the dielectric layer 150 can be completely protected by the metal layer 170 from being corroded by the hydrochloric acid solution, thereby improving the process yield. In addition, in this embodiment, since the metal layer 170 presents a "U" shape and completely covers the transparent conductive layer 160 and the dielectric layer 150, compared with the previous embodiment, the "U"-shaped metal layer 170 in this embodiment can increase the chance of the light emitted by the light-emitting layer to be reflected upward, thereby improving the light extraction efficiency and brightness.

[0040] The above embodiments are only used to illustrate the embodiments of the present invention and explain the technical features of the present invention, and are not used to limit the protection scope of the present invention. Any changes or equivalent arrangements that can be easily completed by those skilled in the art belong to the scope claimed by the present invention, and the scope of protection of the present invention shall be based on the claims.

Claims

1. A light emitting diode comprising: an epitaxial composite layer; a dielectric layer, the epitaxial composite layer is disposed on the dielectric layer; a transparent conductive layer, the dielectric layer being disposed on the transparent conductive layer; and a metal layer; in, The transparent conductive layer is arranged on the metal layer, and the outer edge of the transparent conductive layer is covered by the metal layer. 2 . The light emitting diode as claimed in claim 1 , wherein the transparent conductive layer further comprises a plurality of dot-shaped transparent electrodes, each of which is surrounded by the dielectric layer. 3 . The light emitting diode as claimed in claim 1 , wherein a 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 . The light emitting diode as claimed in claim 1 , wherein an outer edge of the dielectric layer is covered by the metal layer.

5. The light emitting diode as claimed in claim 1, wherein the epitaxial composite layer further comprises a first semiconductor layer, a light emitting layer, a second semiconductor layer and a third semiconductor layer, wherein 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. 6 . The light emitting diode as claimed in claim 5 , wherein the first semiconductor layer 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. 7 . The light emitting diode as claimed in claim 5 , wherein the light emitting layer has a light emitting wavelength of about 1000-2000 nm. 8 . The light emitting diode as claimed in claim 2 , further comprising an upper electrode, wherein the upper electrode is disposed on the epitaxial composite layer and does not overlap with the dot-shaped transparent electrodes in a vertical position. 9 . The light emitting diode as claimed in claim 1 , wherein the material of the metal layer is gold, silver, aluminum, beryllium gold, germanium gold or a combination thereof. 10 . The light emitting diode as claimed in claim 1 , further comprising a bonding substrate, wherein the bonding substrate is bonded to the metal layer.

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