CN100481532C - Light-emitting diode element, flip chip type light-emitting diode packaging structure and light reflection structure - Google Patents

Abstract

The invention relates to a light-emitting diode element, a flip chip type light-emitting diode packaging structure and a light reflection structure. The light emitting diode element comprises an element substrate, a first type doping layer, a light emitting layer, a second type doping layer, a transparent conductive metal oxide layer, a reflecting layer and two electrodes. The first type doping layer is configured on the element substrate, the light emitting layer is configured on part of the first type doping layer, the second type doping layer is configured on the light emitting layer, and the second type doping layer and the first type doping layer are both made of III-V group compound semiconductor materials. The transparent conductive metal oxide layer is configured on the second type doping layer, and the reflecting layer is configured on the transparent conductive metal oxide layer. The two electrodes are respectively arranged on the reflecting layer and the first type doping layer.

Description

Light-emitting diode element, flip-chip light-emitting diode packaging structure and light reflection structure

technical field

The present invention relates to a structure of a semiconductor light emitting element, and in particular to a structure of a light emitting diode (Light Emitting Diode, LED) element, a package structure of a flip-chip light emitting diode, and a light reflection structure suitable for the light emitting diode.

Background technique

A light-emitting diode composed of III-V element compound semiconductor materials is a light-emitting element with a wide bandgap, which can emit light from infrared light to ultraviolet light, covering all visible light bands. In recent years, with the rapid development of high-brightness gallium nitride (GaN) blue/green LEDs, full-color LED displays, white LEDs, and LED traffic signs have been put into practical use, and the application of various other LEDs has also become more popular.

The basic structure of LED components includes P-type and N-type III-V group element compound epitaxial layers, and the light-emitting layer in between. The luminous efficiency of LED components depends on the quantum efficiency of the light-emitting layer and the light extraction efficiency of the component. The method to increase the quantum efficiency is mainly to improve the crystal growth quality and structural design of the light-emitting layer, and the key to increasing the light extraction efficiency is to reduce the energy loss caused by the reflection of the light emitted by the light-emitting layer inside the LED.

Since the positive and negative electrodes of GaN LED components are generally placed on the same surface, and the positive and negative electrodes will reflect light, most GaN LEDs are packaged in a flip-chip (flip-chip) package, so that the positive and negative electrodes face each other. An opaque substrate, and a reflective layer is formed on the epitaxial layer facing the substrate, so that most of the light is emitted toward the opposite side of the electrode. Another advantage of flip-chip packaging is that if it is matched with an appropriate surface mount (generally referred to as surmount) substrate, such as a silicon substrate, it will help the heat dissipation of the component, especially in a high-current operating environment. . In this way, not only the light extraction efficiency is improved, but also the quantum efficiency of the light-emitting layer will not be reduced due to overheating of the element.

In addition, in order to improve the electrical characteristics of LED components, a semi-transparent Ni/Au ohmic contact layer is generally formed on the surface of the epitaxial layer, and heat treatment is performed to form a good ohmic contact, and then a reflective layer is formed on it. However, because the Ni/Au layer itself has a high absorption rate of light (light transmittance is only ^60-70 %), and the interface between the epitaxial layer and the Ni/Au layer will be roughened by heat treatment and cannot reflect light, so The bottom reflection efficiency of flip-chip LED components will be reduced.

It can be seen that the above-mentioned existing LED elements, flip-chip LED packaging structures and light reflection structures still have many defects, and further improvements are urgently needed. In order to solve the defects of existing light-emitting diode elements, flip-chip light-emitting diode packaging structures, and light-reflecting structures, relevant manufacturers have tried their best to find solutions, but no suitable design has been developed for a long time. Obviously, it is a problem that relevant industry players are eager to solve.

In view of the defects in the above-mentioned existing light-emitting diode elements, flip-chip light-emitting diode packaging structures, and light-reflecting structures, the inventor actively researches and innovates based on his rich practical experience and professional knowledge in the design and manufacture of such products for many years, with a view to Creating a novel structure of light-emitting diode elements, flip-chip light-emitting diode packaging structures and light reflection structures can improve existing light-emitting diode elements, flip-chip light-emitting diode packaging structures and light reflection structures, making them more practical. Through continuous research, design, and after repeated trial samples and improvements, the present invention with practical value is finally created.

Contents of the invention

The purpose of the present invention is to overcome the defects of the existing light reflection structure and provide a novel light reflection structure. The technical problem to be solved is to make it applicable to light-emitting diode elements to improve the effect of light reflection. Therefore, it is more suitable for practical use.

Another object of the present invention is to overcome the defects of the existing light-emitting diode elements and provide a new type of light-emitting diode elements. The technical problem to be solved is to make it have the light reflection structure of the present invention, which can improve light reflection effect, which is more suitable for practical use.

Another purpose of the present invention is to overcome the defects of the existing flip-chip light-emitting diode packaging structure and provide a new flip-chip light-emitting diode packaging structure. The technical problem to be solved is to make it have the optical The reflective structure can enhance the effect of light reflection, so that it is more suitable for practical use.

The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions. A light-emitting diode element proposed according to the present invention, which includes: an element substrate; a first-type doped layer disposed on the element substrate; a light-emitting layer disposed on a part of the first-type doped layer; A second-type doped layer configured on the light-emitting layer, the second-type doped layer and the first-type doped layer are both composed of a III-V compound semiconductor material; a transparent conductive metal oxide a layer configured on the second type doped layer as an ohmic contact layer; a reflective layer configured on the transparent conductive metal oxide layer; and two electrodes respectively configured on the reflective layer and the first type on the doped layer.

The purpose of the invention and the solution to its technical problems can also be further realized by adopting the following technical measures.

The aforementioned light-emitting diode element, wherein the wavelength of light emitted by the light-emitting layer is λ, the refractive index of the transparent conductive metal oxide layer is n, and the thickness of the transparent conductive metal oxide layer is (2m+1)λ /4n (m is 0 or a positive integer).

In the aforementioned light-emitting diode element, the element substrate includes a sapphire substrate.

In the aforementioned light-emitting diode element, the III-V group compound semiconductor material includes gallium nitride, gallium phosphide or gallium arsenide phosphide.

In the aforementioned light-emitting diode device, the light-emitting layer includes a quantum well light-emitting layer.

The aforementioned light-emitting diode element, wherein the material of the transparent conductive metal oxide layer is selected from indium tin oxide (ITO), cerium tin oxide (CTO), antimony tin oxide (ATO), indium zinc oxide (IZO) or oxide Zinc (ZnO).

In the aforementioned light-emitting diode device, the first type doped layer is an n-type doped layer, and the second type doped layer is a p-type doped layer.

In the aforementioned light emitting diode device, wherein the first type doped layer is a p-type doped layer, and the second type doped layer is an n-type doped layer.

The purpose of the present invention and the solution to its technical problems are also achieved by the following technical solutions. A flip-chip light-emitting diode packaging structure proposed according to the present invention includes: a packaging substrate; and a light-emitting diode element, which is turned upside down on the packaging substrate and electrically connected to it, and the light-emitting diode element includes: an element substrate a first-type doped layer configured on the element substrate; a light-emitting layer configured on a part of the first-type doped layer; a second-type doped layer configured on the light-emitting layer, and the second Both the type doped layer and the first type doped layer are made of a III-V compound semiconductor material; a transparent conductive metal oxide layer is disposed on the second type doped layer as an ohmic contact layer; a reflective layer configured on the transparent conductive metal oxide layer; and two electrodes respectively configured on the reflective layer and the first type doped layer.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

In the aforementioned flip-chip light-emitting diode packaging structure, the wavelength of light emitted by the light-emitting layer is λ, the refractive index of the transparent conductive metal oxide layer is n, and the thickness of the transparent conductive metal oxide layer is (2m +1) λ/4n (m is 0 or a positive integer).

In the aforementioned flip-chip LED packaging structure, the element substrate includes a sapphire substrate.

In the aforementioned flip-chip LED packaging structure, the packaging substrate includes a silicon substrate.

In the foregoing flip-chip light emitting diode packaging structure, the III-V group compound semiconductor material includes gallium nitride, gallium phosphide or gallium arsenide phosphide.

In the aforementioned package structure of the flip-chip light-emitting diode, the light-emitting layer includes a quantum well light-emitting layer.

In the aforementioned flip-chip light emitting diode packaging structure, the material of the transparent conductive metal oxide layer is selected from indium tin oxide (ITO), cerium tin oxide (CTO), antimony tin oxide (ATO), indium zinc oxide ( IZO) or zinc oxide (ZnO).

In the aforementioned package structure of the flip-chip light emitting diode, the first type doped layer is an n-type doped layer, and the second type doped layer is a p-type doped layer.

In the aforementioned package structure of the flip-chip light emitting diode, the first type doped layer is a p-type doped layer, and the second type doped layer is an n-type doped layer.

In the aforementioned flip-chip LED packaging structure, the LED element is electrically connected to the packaging substrate through two bumps, and the two bumps are respectively located on the two electrodes.

The purpose of the present invention and the solution to its technical problems are also achieved by the following technical solutions. A light reflection structure for a light emitting diode according to the present invention, comprising: a transparent conductive metal oxide layer disposed on a doped III-V compound semiconductor layer as an ohmic contact layer; and A reflective layer is configured on the transparent conductive metal oxide layer.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

The aforementioned light reflection structure for light-emitting diodes, wherein the light-emitting wavelength of the light-emitting diodes is λ, the refractive index of the transparent conductive metal oxide layer is n, and the thickness of the transparent conductive metal oxide layer is (2m+ 1) λ/4n (m is 0 or a positive integer).

Compared with the prior art, the present invention has obvious advantages and beneficial effects. As can be seen from the above technical solutions, in order to achieve the aforementioned object of the invention, the main technical contents of the present invention are as follows:

The light reflection structure suitable for light-emitting diode elements of the present invention comprises: a transparent conductive metal oxide layer arranged on a doped III-V group compound semiconductor layer, and a reflective layer arranged on the transparent conductive metal oxide layer , wherein the transparent conductive metal oxide layer is an ohmic contact layer as a semiconductor layer. When the light-emitting wavelength of the light-emitting diode is λ, and the refractive index of the transparent conductive metal oxide layer is n, the thickness of the transparent conductive metal oxide layer is preferably (2m+1)λ/4n (m is 0 or a positive integers) to have the effect of constructive interference.

The light-emitting diode element of the present invention includes an element substrate, a first-type doped layer, a light-emitting layer, a second-type doped layer, a transparent conductive metal oxide layer, a reflective layer, and two electrodes. Wherein, the first-type doped layer is arranged on the element substrate, the light-emitting layer is arranged on part of the first-type doped layer, and the second-type doped layer is arranged on the light-emitting layer, and the second-type doped layer and the first-type doped layer are arranged on the light-emitting layer. The type I doped layers are all composed of III-V compound semiconductor materials. The transparent conductive metal oxide layer is configured on the second-type doped layer as an ohmic contact layer, and the reflective layer is configured on the transparent conductive metal oxide layer. The two electrodes are respectively arranged on the reflective layer and the first type doped layer.

The package structure of the flip-chip light emitting diode of the present invention includes a package substrate and a light emitting diode element, which are turned upside down on the package substrate and electrically connected with it. The light-emitting diode element includes an element substrate, a first-type doped layer, a light-emitting layer, a second-type doped layer, a transparent conductive metal oxide layer, a reflective layer, and two electrodes. Wherein, the first-type doped layer is arranged on the element substrate, the light-emitting layer is arranged on part of the first-type doped layer, and the second-type doped layer is arranged on the light-emitting layer, and the second-type doped layer and the first-type doped layer are arranged on the light-emitting layer. The type I doped layers are all composed of III-V compound semiconductor materials. The transparent conductive metal oxide layer is configured on the second-type doped layer as an ohmic contact layer, and the reflective layer is configured on the transparent conductive metal oxide layer. The two electrodes are respectively arranged on the reflective layer and the first type doped layer.

By means of the above technical solution, the present invention has at least the following advantages: Since the present invention uses transparent conductive metal oxide as the material of the ohmic contact layer, and the transparent conductive metal oxide does not need to be heat-treated to improve the ohmic contact effect, it is compatible with the second There can be a flat interface between the type doped layers, which can provide a good reflection effect; at the same time, the absorptivity of transparent conductive metal oxides to visible light can be as low as below 10% (such as indium tin oxide (ITO)), so its The influence on the reflection efficiency of the LED element is greatly reduced.

In summary, the light reflection structure of the present invention can be applied to light-emitting diode elements, and can enhance the effect of light reflection; the light-emitting diode element of the present invention has the light reflection structure of the present invention, and can enhance the effect of light reflection; The inventive flip-chip LED packaging structure has the light reflection structure of the invention, which can enhance the effect of light reflection. It has the above-mentioned many advantages and practical value, and there is no similar structural design publicly published or used in similar products, so it is indeed innovative. It has great improvements in product structure and function, and has a great technical advantage. Progress, and produced easy-to-use and practical effects, so that it is more suitable for practical use, and has wide application value in the industry. It is a novel, progressive and practical new design.

The above description is only an overview of the technical solutions of the present invention. In order to understand the technical means of the present invention more clearly and implement them according to the contents of the description, the preferred embodiments of the present invention and accompanying drawings are described in detail below.

Description of drawings

FIG. 1 is a cross-sectional view of the structure of a light-emitting diode device according to a preferred embodiment of the present invention, and an enlarged view of a portion adjacent to the interface of its transparent conductive metal oxide layer.

FIG. 2 is a schematic diagram of a flip-chip LED packaging structure obtained by flip-chip packaging the LED element in FIG. 1 .

100: Component substrate 110: N-type doped layer

120: Light-emitting layer 130: P-type doped layer

140: transparent conductive metal oxide layer 150: reflective layer

160: Anode 170: Cathode

180, 190: Bumps 200: Package substrate

Detailed ways

The specific structures, features and functions of the light-emitting diode element, the flip-chip light-emitting diode packaging structure and the light reflection structure according to the present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments.

Please refer to FIG. 1 , which is a structure of a light emitting diode device according to a preferred embodiment of the present invention, and an enlarged view of a portion adjacent to the interface of the transparent conductive metal oxide layer. The light emitting diode element of the preferred embodiment of the present invention, as shown in FIG. , reflective layer 150, and anode 160 and cathode 170. Wherein, the active layer composed of the N-type doped layer 110, the light-emitting layer 120 and the P-type doped layer 130 is sequentially fabricated on the element substrate 100 through a series of epitaxy processes, and the In the subsequent process, the N-type doped layer 110, the light-emitting layer 120, and the P-type doped layer 130 on some regions are removed by etching or other methods, so as to be singulated into multiple mutually independent island structure (MESA). It is worth noting that, in the above-mentioned island structure, the P-type doped layer 130, the light-emitting layer 120, and a part of the thickness of the N-type doped layer 110 on the area where the cathode 170 is to be formed will be removed, so that the cathode 170 It can be electrically connected with the N-type doped layer 110 smoothly.

Please refer to Fig. 1 again, the transparent conductive metal oxide layer 140 of the present embodiment is located on the P-type doped layer 130, the reflective layer 150 is located on the transparent conductive metal oxide layer 140, and the anode 160 is located on the reflective layer 150 on.

The above-mentioned element substrate 100 is, for example, a sapphire substrate. The material of the N-type doped layer 110, the light-emitting layer 120 and the P-type doped layer 130 is a III-V compound semiconductor material, such as gallium nitride, gallium phosphide or gallium arsenide phosphide, wherein the light-emitting layer 120 is for example It is a light-emitting layer with a single or multiple quantum well (Quantum Well) structure to increase the efficiency of light emission. The material of the transparent conductive metal oxide layer 140 is preferably indium tin oxide (ITO: indium tin oxide), but can also be cerium tin oxide (CTO: cerium tin oxide), antimony tin oxide (ATO: antimony tin oxide), oxide Indium zinc (IZO: indium zinc oxide), zinc oxide (ZnO: zinc oxide) or other similar transparent conductive metal oxide materials. The material of the reflective layer 150 is, for example, aluminum or silver, and the material of the anode 160 and the cathode 170 is, for example, chrome/gold.

As shown in the enlarged part in FIG. 1, since the transparent conductive metal oxide layer 140 does not need to be heat-treated to improve the ohmic contact effect, it can have a flat interface with the P-type doped layer 130, which can provide good reflection. Effect. In addition, from the theory of light interference, when the light emitting wavelength of the LED element is λ, and the refractive index of the transparent conductive metal oxide layer 140 is n, the thickness of the transparent conductive metal oxide layer 140 is preferably (2m+ 1) λ/4n (m is 0 or a positive integer, such as 1, 2, 3, ... etc.), so that the reflected light at the interface of the transparent conductive metal oxide layer 140/reflective layer 150 and the P-type doped layer 130/ The reflected light at the interface of the transparent conductive metal oxide layer 140 produces the effect of constructive interference.

Please refer to FIG. 2 , which is a flip-chip LED packaging structure obtained by flip-chip packaging the LED elements in FIG. 1 . As shown in FIG. 2, the light-emitting diode element in FIG. 1 is turned upside down on a package substrate 200, such as a silicon substrate, and is electrically connected to the package substrate 200 by bumps 180 and 190, wherein the bump 180 is electrically connected to the package substrate 200. The anode 160 is connected to the packaging substrate 200 , and the bump 190 is electrically connected to the cathode 170 and the packaging substrate 200 . Since the reflective layer 150 faces the package substrate 200 , the light emitted downward by the light emitting layer 120 is emitted from the component substrate 100 after reflection.

In addition, although this embodiment is an example of a light-emitting diode element with the above-mentioned structure and packaged in a flip-chip manner, the application of the present invention is not limited thereto, and can be applied to all forms of ohmic contact layers and reflective layers. In order to increase the efficiency of light reflection on the light-emitting diode components packaged in a way other than flip-chip. In addition, although the N-type doped layer is formed on the component substrate in this embodiment, and the P-type doped layer is formed on the light-emitting layer, the positions of the N-type and P-type doped layers can also be interchanged. , that is, the one formed on the component substrate is a P-type doped layer, and the one formed on the light-emitting layer is an N-type doped layer. However, at this time, the electrode formed on the reflective layer is used as a cathode, and the electrode on the P-type doped layer is used as an anode.

Since the present invention uses transparent conductive metal oxide as the material of the ohmic contact layer, and the transparent conductive metal oxide does not need to be heat-treated to improve the ohmic contact effect, it can have a flat interface with the second-type doped layer, and It can provide the effect of reflection; at the same time, the absorption rate of transparent conductive metal oxide to visible light can be as small as less than 10% (such as indium tin oxide (ITO)), so its influence on the reflection effect of LED components is greatly reduced.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes, but all the content that does not depart from the technical solution of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence still belong to the scope of the technical solutions of the present invention.

Claims (20)

1, a kind of light-emitting diode that is applicable to the crystal-coated light-emitting diodes encapsulating structure is characterized in that it comprises:

One element substrate;

One first type doped layer is disposed on this device substrate;

One luminescent layer is disposed on this first type doped layer of part;

One second type doped layer is disposed on this luminescent layer, and this second type doped layer and this first type doped layer are made of an III-V group iii v compound semiconductor material;

One transparent conductive metal oxide skin(coating) is disposed on this second type doped layer, with as an ohmic contact layer;

One reflector is disposed on this whole transparent conductive metal oxide skin(coating)s; And

Two electrodes are disposed at respectively on this reflector and this first type doped layer.

2, light-emitting diode according to claim 1, it is characterized in that the light wavelength that wherein said luminescent layer sends is λ, the refractive index of this transparent conductive metal oxide skin(coating) is n, and the thickness of this transparent conductive metal oxide skin(coating) is (2m+1) λ/4n, and m is 0 or one positive integer.

3, light-emitting diode according to claim 1 is characterized in that wherein said device substrate comprises a sapphire substrate.

4, light-emitting diode according to claim 1 is characterized in that wherein said III-V group iii v compound semiconductor material comprises gallium nitride, gallium phosphide or gallium arsenide phosphide.

5, light-emitting diode according to claim 1 is characterized in that wherein said luminescent layer comprises a quantum trap luminous layer.

6, light-emitting diode according to claim 1, the material that it is characterized in that wherein said transparent conductive metal oxide skin(coating) are to be selected from by tin indium oxide, cerium oxide tin, antimony tin, indium zinc oxide or zinc oxide.

7, light-emitting diode according to claim 1 is characterized in that the wherein said first type doped layer is to be a n type doped layer, and this second type doped layer is to be a p type doped layer.

8, light-emitting diode according to claim 1 is characterized in that the wherein said first type doped layer is to be a p type doped layer, and this second type doped layer is to be a n type doped layer.

9, a kind of crystal-coated light-emitting diodes encapsulating structure is characterized in that it comprises:

One base plate for packaging; And

One light-emitting diode, be overlying on this base plate for packaging and with its electric connection, this light-emitting diode comprises:

One element substrate;

One first type doped layer disposes on this device substrate;

One luminescent layer is disposed on this first type doped layer of part;

One second type doped layer is disposed on this luminescent layer, and this second type doped layer and this first type doped layer are made of an III-V group iii v compound semiconductor material;

One transparent conductive metal oxide skin(coating) is disposed on this second type doped layer, with as an ohmic contact layer;

One reflector is disposed on this whole transparent conductive metal oxide skin(coating)s; And

Two electrodes are disposed at respectively on this reflector and this first type doped layer.

10, crystal-coated light-emitting diodes encapsulating structure according to claim 9, it is characterized in that the light wavelength that wherein said luminescent layer sends is λ, the refractive index of this transparent conductive metal oxide skin(coating) is n, and the thickness of this transparent conductive metal oxide skin(coating) is (2m+1) λ/4n, and m is 0 or one positive integer.

11, crystal-coated light-emitting diodes encapsulating structure according to claim 9 is characterized in that wherein said device substrate comprises a sapphire substrate.

12, crystal-coated light-emitting diodes encapsulating structure according to claim 9 is characterized in that wherein said base plate for packaging comprises a silicon substrate.

13, crystal-coated light-emitting diodes encapsulating structure according to claim 9 is characterized in that wherein said III-V group iii v compound semiconductor material comprises gallium nitride, gallium phosphide or gallium arsenide phosphide.

14, crystal-coated light-emitting diodes encapsulating structure according to claim 9 is characterized in that wherein said luminescent layer comprises a quantum trap luminous layer.

15, crystal-coated light-emitting diodes encapsulating structure according to claim 9, the material that it is characterized in that wherein said transparent conductive metal oxide skin(coating) are to be selected from by tin indium oxide, cerium oxide tin, antimony tin, indium zinc oxide or zinc oxide.

16, crystal-coated light-emitting diodes encapsulating structure according to claim 9 is characterized in that the wherein said first type doped layer is to be a n type doped layer, and this second type doped layer is to be a p type doped layer.

17, crystal-coated light-emitting diodes encapsulating structure according to claim 9 is characterized in that the wherein said first type doped layer is to be a p type doped layer, and this second type doped layer is to be a n type doped layer.

18, crystal-coated light-emitting diodes encapsulating structure according to claim 9 is characterized in that wherein said light-emitting diode is to electrically connect by two projections and this base plate for packaging, and this two projection is to lay respectively on this two electrode.

19, a kind of light reflection structure that is used for light-emitting diode is characterized in that it comprises:

One transparent conductive metal oxide skin(coating) is disposed on the III-V compound semiconductor layer that mixes, with as an ohmic contact layer; And

One reflector is disposed on this whole transparent conductive metal oxide skin(coating)s.

20, the light reflection structure that is used for light-emitting diode according to claim 19, the emission wavelength that it is characterized in that wherein said light-emitting diode is λ, the refractive index of this transparent conductive metal oxide skin(coating) is n, and the thickness of this transparent conductive metal oxide skin(coating) is (2m+1) λ/4n, and m is 0 or one positive integer.

Images