CN115332423A - Light-emitting diode and method of making the same - Google Patents

Abstract

The invention provides a light emitting diode and a preparation method thereof. The light emitting diode may at least include: an epitaxial structure with opposite first surfaces and second surfaces, from the first surface to the second surface, including a first semiconductor layer, a light emitting layer and a second semiconductor layer stacked in sequence; a number of transparent conductive units , is arranged at intervals on the surface of the first semiconductor layer away from the light-emitting layer; the protective layer is formed on each transparent conductive unit and covers each transparent conductive unit; the insulating layer is formed on the protective layer and exposes part of the protective layer surface. This setup can improve the stability and uniformity of forward voltage (VF) in light-emitting diodes with excellent optoelectronic performance.

Description

Light-emitting diode and its preparation method

technical field

The invention relates to the technical field of semiconductor light emitting devices, in particular to a light emitting diode and a preparation method thereof.

Background technique

With the development of LED (light-emitting diode) chips and the technological change of related products, LED chips have attracted attention because of their advantages in small size, high integration, fast response, good thermal stability and low energy consumption, and have been used in It is popularized and applied in the field of daily life, and products involving chips in different fields have higher and higher requirements for the overall photoelectric performance of the chip.

In the existing light-emitting diode manufacturing process, when forming the ohmic contact pattern of the transparent conductive layer on the epitaxial structure, it needs to go through multiple times of dry etching and wet etching, and the process is complex and time-consuming. During this process, if the transparent conductive layer is exposed or exposed for too long, the light-emitting diode is likely to generate an excessively high forward voltage, thereby affecting the overall performance of the LED chip.

Therefore, in the light-emitting diode manufacturing process, how to reduce the exposure time of the transparent conductive layer and ensure the uniformity of the forward voltage of the light-emitting diode, improve the reliability of the light-emitting diode to ensure that the chip has stable photoelectric performance has become a technology in the art One of the technical problems urgently needed to be solved by personnel.

Contents of the invention

An embodiment of the present invention provides a light-emitting diode, which may at least include: an epitaxial structure, having a first surface and a second surface opposite to each other, and from the first surface to the second surface, a first semiconductor layer, a light-emitting layer, and The second semiconductor layer; several transparent conductive units are arranged at intervals on the surface of the first semiconductor layer away from the light-emitting layer; the protective layer is formed on each transparent conductive unit and covers each transparent conductive unit; the insulating layer is formed on the on the protective layer and expose part of the surface of the protective layer.

In some embodiments, among the transparent conductive units, the distance between two adjacent transparent conductive units is 10 μm to 40 μm.

In some embodiments, the graphic shape of the cross-section of the transparent conductive unit is arbitrary, and may be a regular graphic or an irregular graphic. When the cross section of the transparent conductive unit is a circle, the diameter of the circle is 10 μm to 20 μm.

In some embodiments, the transparent conductive unit may be made of an oxide material with high transparency, high conductivity, and low contact resistance, and may serve as an ohmic contact layer of the first semiconductor layer. The thickness of the transparent conductive unit is 0 angstroms to 500 angstroms, which can make good current conduction with the first semiconductor layer.

In some embodiments, the protective layer is at least one of Au, Cr, Ni, and Pt. The protective layer has a thickness of 100 angstroms to 200 angstroms. In this way, the protective layer can effectively cover the transparent conductive unit, and at the same time ensure that the transparent conductive unit has better current conduction performance.

In some embodiments, there is an inclination angle between the protection layer and the surface of the first semiconductor layer away from the light-emitting layer, and the inclination angle is 30° to 60°, so as to completely and well cover the transparent conductive unit.

In some embodiments, the projection of the transparent conductive unit on the first semiconductor layer is located within the projection range of the protective layer on the first semiconductor layer, and on the surface of the first semiconductor layer away from the light-emitting layer along the horizontal direction, the terminal point of the transparent conductive unit and the The spacing between the ends of the protective layer is 1 μm to 5 μm.

In some embodiments, the total area of the several transparent conductive units is greater than 5% of the total area of the first semiconductor layer away from the light emitting layer.

In some embodiments, the insulating layer is provided with openings, which can expose part of the surface of the protective layer. The projection of the opening on the first semiconductor layer is located within the projection range of the transparent conductive unit on the first semiconductor layer.

In some embodiments, the light emitting diode may further include a substrate, and the first semiconductor layer in the epitaxial structure may be bonded to the substrate through a bonding layer.

In some embodiments, a specular reflective layer may also be provided between the insulating layer and the bonding layer.

In some embodiments, the light emitting diode may further include: a first electrode disposed on the side of the substrate away from the bonding layer and electrically connected to the first semiconductor layer; a second electrode disposed on the second semiconductor layer away from the light emitting layer one side of the second semiconductor layer and is electrically connected to the second semiconductor layer; the passivation layer is disposed on the second semiconductor layer, covering the area of the second semiconductor layer on the surface of the side away from the light-emitting layer that is not covered by the second electrode, and the second A semiconductor layer, a light emitting layer and a side wall region of the second semiconductor layer.

A method for manufacturing a light-emitting diode provided by an embodiment of the present invention can be used to manufacture a light-emitting diode with the aforementioned structure. The method for preparing a light-emitting diode may at least include the following steps: growing an epitaxial structure, sequentially growing a second semiconductor layer, a light-emitting layer, and a first semiconductor layer on a growth substrate to form an epitaxial structure; making a transparent conductive layer, and forming a transparent conductive layer on the first semiconductor layer. Form several transparent conductive units arranged at intervals on the surface of the layer far away from the light-emitting layer, and form a protective layer on each transparent conductive unit; make an insulating layer, form an insulating layer on the protective layer, and expose part of the surface of the protective layer; transfer epitaxial structure In the epitaxial structure, one side of the first semiconductor layer is bonded to a substrate through a bonding layer, and the growth substrate is removed.

In some embodiments, before implementing the step of transferring the epitaxial structure, the following steps may also be included: opening holes in the insulating layer, and setting an opening in the insulating layer above the protective layer, and part of the protective layer may be exposed at the opening surface; and setting a specular reflection layer, forming a specular reflection layer on the insulating layer, the specular reflection layer covering the opening and the surface of the insulating layer away from the first semiconductor layer.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. Those skilled in the art can also obtain other drawings based on these drawings without creative work.

1 is a schematic cross-sectional view of an embodiment of a light-emitting diode in the present invention;

Figure 2 is a partially enlarged schematic diagram of area A in Figure 1;

FIG. 3 is a schematic flowchart of a manufacturing method of an embodiment of a light emitting diode in the present invention; and FIGS. 4 to 8 are schematic diagrams of a manufacturing process of an embodiment of a light emitting diode in the present invention.

Reference signs:

1-light-emitting diode; 10-substrate; 11-bonding layer; 12-mirror reflection layer; 20-epitaxial structure; 20a-first surface; 20b-second surface; 21-first semiconductor layer; 22-luminescent layer; 23-second semiconductor layer; 30-transparent conductive unit; 40-protective layer; 50-insulating layer; 51-opening hole; 60-first electrode; 70-second electrode; 80-passivation layer; 100-growth lining Bottom; D1, D2, D3-distance; α-tilt angle.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The technical features designed in different embodiments of the present invention described below can be combined with each other as long as they do not constitute conflicts with each other.

Please refer to FIG. 1 . FIG. 1 is a schematic cross-sectional view of an embodiment of a light emitting diode 1 in the present invention. In order to achieve at least one of the above advantages or other advantages, an embodiment of the present invention proposes a light emitting diode 1, which may at least include: an epitaxial structure 20, a transparent conductive unit 30 formed on the epitaxial structure 20, and a protective layer 40 and insulating layer 50.

The epitaxial structure 20 can be formed on a substrate by metal organic chemical vapor deposition (MOCVD), molecular beam epitaxy (MBE), hydride vapor deposition (HVPE), physical vapor deposition (PVD) or ion plating. . According to the different functions and uses of the light-emitting diode 1 to be prepared, the substrate can be a temporary growth substrate. After the epitaxial structure 20 is grown and formed, the epitaxial structure 20 is transferred to other substrates or mounting substrates for subsequent process.

The epitaxial structure 20 can provide light of a specific central emission wavelength, such as blue, green or red light or violet or ultraviolet light. The epitaxial structure 20 may have a first surface 20a and a second surface 20b opposite to each other. From the first surface 20a to the second surface 20b, the first semiconductor layer 21 and the light emitting layer 22 (or active layer 22, active layer) are sequentially stacked. 22) and the second semiconductor layer 23, the electrical properties of the first semiconductor layer 21 and the second semiconductor layer 23 are opposite.

In the illustrated embodiment, only the first semiconductor layer 21 is a P-type semiconductor layer and the second semiconductor layer 23 is an N-type semiconductor layer as an example for illustration. The present invention is not limited thereto. In other embodiments, the first semiconductor layer 21 may be an N-type semiconductor layer, and the second semiconductor layer 23 may be a P-type semiconductor layer.

In the illustrated embodiment, the first semiconductor layer 21 in the epitaxial structure 20 is a P-type semiconductor layer, which can provide holes to the light emitting layer 22 under the action of a power supply. In some embodiments, the P-type semiconductor layer in the first semiconductor layer 21 includes a P-type doped nitride layer, phosphide layer (such as GaP) or arsenide layer. The P-type doped nitride layer, phosphide layer or arsenide layer may include one or more P-type impurities of group II elements. The P-type impurity may be one of Mg, Zn, Be or a combination thereof. The first semiconductor layer 21 may be a single-layer structure or a multi-layer structure with different compositions.

The light emitting layer 22 may be a quantum well structure (Quantum Well, QW for short). In some embodiments, the light-emitting layer 22 (or active layer 22 , active layer 22 ) may be a multiple quantum wells (MQWs for short) structure in which quantum well layers and quantum barrier layers are alternately stacked. The light-emitting layer 22 can be a single quantum well structure, or a multi-quantum well structure. In some embodiments, the light emitting layer 22 may include a GaN/AlGaN, InAlGaN/InAlGaN, InGaN/AlGaN, GaInP/AlGaInP, GaInP/AlInP or InGaAs/AlInGaAs multi-quantum well structure. In order to improve the luminous efficiency of the light-emitting layer 22 , it can be realized by changing the depth of the quantum wells, the number of pairs of quantum wells and quantum barriers, the thickness and/or other characteristics in the light-emitting layer 22 .

The second semiconductor layer 23 in the epitaxial structure 20 is an N-type semiconductor layer, which can provide electrons to the light-emitting layer 22 under the action of a power supply. In some embodiments, the N-type semiconductor layer in the second semiconductor layer 23 includes an N-type doped nitride layer, a phosphide layer (such as AlGaInP) or an arsenide layer. The N-type doped nitride layer may include one or more N-type impurities of Group IV elements. The N-type impurity may be one of Si, Ge, Sn or a combination thereof. The second surface 20 b of the epitaxial structure 20 is the same surface as the surface of the second semiconductor layer 23 on the side away from the light-emitting layer 22 . The arrangement of the epitaxial structure 20 is not limited thereto, and other arrangements can be selected according to actual needs.

The first surface 20 a of the epitaxial structure 20 is the same surface as the surface of the first semiconductor layer 21 away from the light emitting layer 22 . A transparent conductive layer is provided on the surface of the first semiconductor layer 21 away from the light-emitting layer 22 . In the illustrated embodiment, the transparent conductive layer is located on the first surface 20 a of the epitaxial structure 20 . The transparent conductive layer is composed of several transparent conductive units 30 , and these transparent conductive units 30 are arranged at intervals on the surface of the first semiconductor layer 21 (P layer in the figure) away from the light-emitting layer 22 .

Among these transparent conductive units 30 , there is a certain distance D1 between two adjacent transparent conductive units 30 , as shown in FIG. 2 . Depending on the products or application scenarios involved in the light emitting diode 1 , the design requirements for optical parameters are different. The distance D1 between two adjacent transparent conductive units 30 is 10 μm to 40 μm. In a preferred embodiment, the distance D1 between two adjacent transparent conductive units 30 is 20 μm to 30 μm. At this time, these transparent conductive units 30 can not only form a good current conduction with the first semiconductor layer 21 , but also make the surface of the first semiconductor layer 21 away from the light-emitting layer 22 have better optical properties. The light emitting diode 1 provided with this transparent conductive layer structure can be used in different types of products, such as high-current chips, high-voltage chips, automotive products, lighting products and other scenarios.

The transparent conductive unit 30 (transparent conductive layer) may be made of an oxide material with high transparency, high electrical conductivity, and low contact resistance. For example, the transparent conductive unit can be indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZNO), cadmium tin oxide (CTO), indium oxide (InO), indium (In) doped zinc oxide (ZNO ), aluminum (Al) doped zinc oxide (ZNO), gallium (Ga) doped zinc oxide (ZNO), or any combination of the foregoing. The transparent conductive unit 30 can be used as an ohmic contact layer of the first semiconductor layer 21 to ensure that the light emitting diode 1 has good electrical characteristics. The transparent conductive unit 30 has a thickness of 0 angstroms to 500 angstroms, which can make it have good current conduction and current spreading performance with the first semiconductor layer 21 . In a preferred embodiment, the thickness of the transparent conductive unit 30 is 200 angstroms. At this time, there is an ohmic contact layer with sufficient thickness on the first semiconductor layer 21, and the light emitting diode 1 has good electrical characteristics. At the same time, the transparent conductive unit 30 The influence on light absorption is small, and the light-emitting diode 1 has good light-emitting characteristics. The light emitting diode 1 can be widely used in chip products or light emitting devices using the transparent conductive unit 30 as an ohmic contact.

When the transparent conductive unit 30 assumes the function of an ohmic contact layer, the transparent conductive unit 30 may have a periodic pattern structure. The cross-section of the transparent conductive unit 30 can have different shapes, so as to increase the cross-sectional area of the transparent conductive unit 30 , facilitate the diffusion of current to achieve uniform distribution, and reduce the forward voltage of the light emitting diode 1 . The cross-section of the transparent conductive unit 30 can be a regular pattern, such as a circle, a square, a rectangle, or an irregular pattern, so that the optical characteristics that meet the overall design requirements of the light emitting diode 1 are formed in the first semiconductor layer 21 region. In some embodiments, when the cross section of the transparent conductive unit 30 is a circle, the diameter of the circle is 10 μm to 20 μm. In some preferred embodiments, when the cross section of the transparent conductive unit 30 is a circle, the diameter of the circle is 10 μm to 15 μm.

In order to enable the several transparent conductive units 30 to achieve continuous and stable photoelectric performance in the region of the first semiconductor layer 21 , a protective layer 40 is formed on each transparent conductive unit 30 to cover and protect the transparent conductive units 30 . As shown in FIG. 1 , the protective layer 40 covers the sidewall region of the transparent conductive unit 30 and the surface of the transparent conductive unit 30 away from the first semiconductor layer 21 .

The material of the protective layer 40 may be one of Au, Cr, Ni, Pt or any combination thereof. As shown in the figure, in some embodiments, the sidewall of the protection layer 40 has a reflective function, which can reflect the light emitted by the first semiconductor layer 21 and enhance the overall optical properties of the light emitting diode 1 . The protective layer 40 has a thickness of 100 angstroms to 200 angstroms. The setting method of the protective layer 40 can not only cover and protect the surface of the transparent conductive unit 30 away from the first semiconductor layer 21, but also ensure that the sidewall area of the transparent conductive unit 30 is covered with a protective layer 40 of sufficient thickness, so that The exposed part of the transparent conductive unit 30 in the region of the first semiconductor layer 21 can be completely covered by the protective layer 40 .

The effective covering of the transparent conductive unit 30 by the protective layer 40 can ensure that the transparent conductive unit 30 has better current conduction performance, so that the current spreads uniformly or uniformly on the first surface 20a of the first semiconductor layer 21 located on the epitaxial structure 20 distributed. In addition, the complete coverage of the transparent conductive unit 30 by the protective layer 40 can keep the thickness of the transparent conductive unit 30 stable, so that the photoelectric characteristics of the light emitting diode 1 in the region of the first semiconductor layer 21 can be continuously and stably output.

In some embodiments, as shown in FIG. 2 , there is an inclination angle α between the protective layer 40 and the surface of the first semiconductor layer 21 away from the light-emitting layer 22 , and the inclination angle α is 30 degrees to 60 degrees to ensure the transparent conductive unit. The sidewall area of 30 is covered with a protective layer of sufficient thickness. In the illustrated example, it can be understood that there is an inclination angle α between the protective layer 40 and the first surface 20 a of the epitaxial structure 20 , and the inclination angle α is 30 degrees to 60 degrees. In order to make the protective layer 40 better cover the sidewall area of the transparent conductive unit 30 , preferably, the sidewall of the protective layer 40 is parallel to the sidewall of the transparent conductive unit 30 . In the illustrated example, the inclination angle formed between the surfaces of the first semiconductor layer 21 of the transparent conductive unit 30 away from the light-emitting layer 22 is also 30 degrees to 60 degrees.

The projection of the transparent conductive unit 30 on the first semiconductor layer 21 is located within the projection range of the protective layer 40 on the first semiconductor layer 21. It can be understood that the exposed area of the transparent conductive unit 30 on one side of the first semiconductor layer 21 is completely covered by the protective layer. 40 covered or clad. As shown in FIG. 2 , on the surface of the first semiconductor layer 21 away from the light-emitting layer 22 (the first surface 20a of the epitaxial structure 20 in the example shown in the figure) along the horizontal direction, the terminal of the transparent conductive unit 30 and the terminal of the protective layer 40 thereon The distance D2 between them is 1 μm to 5 μm, so that the sidewall area of the transparent conductive unit 30 is covered with a protective layer 40 of sufficient thickness. The coated state prevents the sidewall of the transparent conductive unit 30 from being etched. In a preferred embodiment, the distance D2 between the end of the transparent conductive unit 30 and the end of the protective layer 40 may be 2 μm to 3 μm.

In some embodiments, the total area of several transparent conductive units 30 is greater than 5% of the total area of the first semiconductor layer 21 away from the light-emitting layer 22, ensuring that the first semiconductor layer 21 can be formed on the first surface 20a of the epitaxial structure 20 Good current distribution effect. In a preferred embodiment, the total area of several transparent conductive units 30 is 10% to 40% of the total area of the first semiconductor layer 21 away from the light-emitting layer 22, especially in high-current light-emitting diode 1 products, the current The uniform spreading effect of the light-emitting diode 1 is better, and the forward voltage and overall brightness of the light-emitting diode 1 are more uniform.

In order to further ensure the stability of the functional properties of these transparent conductive units 30 and the protective layer 40 , an insulating layer 50 is formed on the protective layer 40 to cover and protect the protective layer 40 . The insulating layer 50 covers part of the surface of the protection layer 40 and fills the gaps between the plurality of transparent conductive units 30 . The insulating layer 50 can completely protect the transparent conductive unit 30 , prevent the transparent conductive unit 30 from being over-etched, and ensure the stability of the forward voltage (VF) in the LED 1 .

The insulating layer 50 can also take on the function of an electric current blocking layer (EBL), preventing the current from congesting in the area of the first semiconductor layer 21 away from the light-emitting layer 22 and forming a uniform distribution. The insulating layer 50 can also serve as a light reflecting surface to increase the light output of the first semiconductor layer 21 and improve the light emitting performance of the light emitting diode 1 .

In the illustrated example, the first semiconductor layer 21 in the epitaxial structure 20 can be bonded to a substrate 10 through the bonding layer 11 . The substrate 10 may contain a conductive material. In some embodiments, a specular reflective layer 12 may also be provided between the insulating layer 50 and the bonding layer 11 to increase the light intensity of the LED 1 and improve the brightness. An opening 51 may be provided on the insulating layer 50 to expose part of the surface of the protective layer 40 . The specular reflection layer 12 fills the opening 51 on the insulating layer 50 and covers the surface of the insulating layer 50 away from the first semiconductor layer 21 .

When the light-emitting diode 1 has a higher requirement on brightness, if the cross section of the transparent conductive unit 30 is circular, the opening 51 is also circular, and the diameter of the opening 51 is smaller than that of the transparent conductive unit 30 . The distance D3 between the end of the opening 51 and the end of the transparent conductive unit 30 is 3 μm to 8 μm. The projection of the opening 51 on the first semiconductor layer 21 is located within the projection range of the transparent conductive unit 30 on the first semiconductor layer 21 . In this way, the contact surface between the transparent conductive unit 30 and the protective layer 40 and the specular reflection layer 12 can be enlarged to form an ODR system and improve the brightness of the LED 1 . When the light-emitting diode 1 does not require high brightness, if the cross section of the transparent conductive unit 30 is circular, the opening 51 is also circular, and the diameter of the opening 51 can be larger than the diameter of the transparent conductive unit 30, reducing the number of transparent conductive units 30 and The contact surface of the protective layer 40 and the specular reflection layer 12 .

The light emitting diode 1 can also include a first electrode 60 and a second electrode 70, and the two are separated from each other. The first electrode 60 is disposed on a side of the substrate 10 away from the bonding layer 11 and is electrically connected to the first semiconductor layer 21 . The second electrode 70 is disposed on a side of the second semiconductor layer 23 away from the light emitting layer 22 , and is electrically connected to the second semiconductor layer 23 . The first electrode 60 and the second electrode 70 may be made of metal materials such as chromium (Cr), titanium (Ti), tungsten (W), gold (Au), aluminum (Al), indium (In), tin (Sn), Nickel (Ni), rhodium (Rh), platinum (Pt), germanium (Ge), beryllium (Be), gold germanium (AuGe), gold germanium nickel (AuGeNi), beryllium gold (BeAu), gold zinc (AuZn), etc. one or a combination of more. The first electrode 60 and the second electrode 70 can be a single-layer structure or a laminated structure, for example, can be Ti/Au, Ti/Pt/Au, Cr/Au, Cr/Pt/Au, Ni/Au, Ni/Pt /Au, Cr/Al/Cr/Ni/Au, Au/AuGeNi/Au or Au/BeAu/Au, etc. In the illustrated example, the first electrode 60 is a P electrode, and the second electrode 70 is an N electrode.

The light emitting diode 1 may further include a passivation layer 80 to insulate and protect the epitaxial structure 20, the second electrode 70, etc., so as to ensure that the light emitting diode 1 as a whole has good photoelectric performance. The passivation layer 80 is disposed on the second semiconductor layer 23 . The passivation layer 80 covers the area of the surface of the second semiconductor layer 23 away from the light-emitting layer 22 not covered by the second electrode 70 , and the sidewall areas of the first semiconductor layer 21 , the light-emitting layer 22 and the second semiconductor layer 23 .

A method for manufacturing a light-emitting diode 1 provided by an embodiment of the present invention can be used to manufacture a light-emitting diode 1 with the aforementioned structure.

Referring to FIG. 3 in conjunction with FIG. 1 , FIG. 3 is a schematic flowchart of a manufacturing method of an embodiment of the light-emitting diode 1 in the present invention, but the manufacturing method and process of the light-emitting diode 1 in the present invention are not limited to those shown in FIG. 3 . The flow chart of the preparation method for obtaining the light emitting diode 1 shown in FIG. 1 by using the preparation method of the light emitting diode 1 shown in FIG. 1 is described as follows.

The manufacturing method of the light emitting diode 1 may at least include the following steps: growing the epitaxial structure 20 , making a transparent conductive layer, making an insulating layer 50 , and transferring the epitaxial structure 20 . Here, the light-emitting diode 1 with the structure shown in the figure is taken as an example to illustrate the specific implementation process of each step of the manufacturing method of the light-emitting diode 1 in the present invention.

Step S11: growing the epitaxial structure 20

As shown in FIG. 4, a growth substrate 100 is provided, and a second semiconductor layer 23, a light-emitting layer 22, and a first semiconductor layer 21 are sequentially grown on the upper surface of the growth substrate 100, so that Epitaxial structure 20.

In the illustrated embodiment, the growth substrate 100 is a GaAs substrate. The epitaxial structure 20 grown on the GaAs substrate 100 may have opposing first and second surfaces 20a, 20b. The epitaxial structure 20 includes a second semiconductor layer 23, a light emitting layer 22 (or active layer 22, active layer 22) and a first semiconductor layer 21, a second semiconductor layer 23 stacked in sequence from the second surface 20b to the first surface 20a. is an N-type semiconductor layer, and the first semiconductor layer 21 is a P-type semiconductor layer. The first surface 20 a is the surface of the first semiconductor layer 21 away from the light emitting layer 22 , and the second surface 20 b is the surface of the second semiconductor layer 23 away from the light emitting layer 22 . The first semiconductor layer 21 may be doped with GaP, and the GaP may be disposed in a region of the first semiconductor layer 21 adjacent to the first surface 20 a of the epitaxial structure 20 .

Step S12: Making a transparent conductive layer

As shown in FIG. 5 , in the epitaxial structure 20 prepared in step S11, the surface of the first semiconductor layer 21 far away from the light-emitting layer 22 (the first surface 20a in the epitaxial structure 20 in the example shown in the figure) forms several intervals. transparent conductive units 30 , and a protective layer 40 is formed on each transparent conductive unit 30 . The protection layer 40 can completely cover the area of the transparent conductive unit 30 exposed on the first surface 20 a to form a coating protection.

In the illustrated example, the first semiconductor layer 21 is a P-type semiconductor layer, and several transparent conductive units 30 arranged at intervals can be used as transparent conductive layers in the P-type semiconductor layer region to laterally expand the current in the P-type semiconductor layer region, so that The current in the LED 1 can be evenly distributed. The transparent conductive unit 30 can assume the function of an ohmic contact layer, which facilitates the smooth conduction of the current in the region of the first semiconductor layer 21 (P layer).

Step S13: Making the insulating layer 50

As shown in FIG. 6 , after the process of the transparent conductive layer is completed, an insulating layer 50 is formed on the first surface 20 a of the epitaxial structure 20 . The insulating layer 50 covers the exposed area of the protective layer 40 on the first surface 20 a and the area of the first semiconductor layer 21 (P layer) on the first surface 20 a not covered by the transparent conductive unit 30 and the protective layer 40 . The insulating layer 50 can cover and protect the first semiconductor layer 21 (P layer) and the protective layer 40 , and can also undertake the function of lateral expansion of the current in the region of the first semiconductor layer 21 (P layer).

As shown in FIG. 7 , in some embodiments, after the insulating layer 50 is manufactured, the following steps may be further included: setting an opening 51 on the insulating layer 50 and setting a specular reflection layer 12 . Etching the corresponding area of the insulating layer 50 above the passivation layer 40 to form an opening 51 to expose part of the surface of the passivation layer 40 , and then forming the specular reflection layer 12 on the insulating layer 50 . The specular reflection layer 12 fills the region of the opening 51 and covers the surface of the insulating layer 50 on a side away from the first semiconductor layer 21 . The specular reflection layer 12 is in contact with the protection layer 40 to increase the light output of the LED 1 .

During the process of etching and forming the opening 51 on the insulating layer 50 , the transparent conductive unit 30 will not be etched because it is completely covered by the protection layer 40 , thereby ensuring the stability of the forward voltage (VF) of the LED 1 .

Step S14: Transferring the epitaxial structure 20

In some embodiments, the bonding layer 11 is deposited on the surface of the insulating layer 50 in the epitaxial structure 20 prepared in step S13 , and the bonding layer 11 is planarized. The bonding layer 11 can be formed by depositing a transparent material, and then the surface of the formed transparent bonding layer 11 is flattened by polishing to ensure that the epitaxial structure 20 has a flat or flat contact surface when transferred to other substrates, and then The overall photoelectric performance of the light emitting diode 1 is not affected when the epitaxial structure 20 is transferred.

The epitaxial structure 20 is bonded on a substrate 10 through the bonding layer 11, and the growth substrate 100 is removed. The substrate 10 can be a conductive substrate, a metal substrate, etc., and its material can be selected and determined according to the actual requirements of the light emitting diode 1 . In the illustrated example, one side of the first semiconductor layer 21 in the epitaxial structure 20 is bonded to a substrate 10 through the bonding layer 11 .

As shown in FIG. 8 , in some other embodiments, a specular reflection layer 12 is provided on the surface of the insulating layer 50, and then a bonding layer 11 is deposited and formed on the specular reflection layer 12, and the bonding layer 11 is planarized. deal with. The epitaxial structure 20 is bonded to the substrate 10 via the bonding layer 11, and the growth substrate 100 is removed. Whether the specular reflection layer 12 is provided or not and its thickness can be determined according to the actual demand of the light emitting diode 1 .

After the process step of transferring the epitaxial structure 20 , the manufacturing method of the light emitting diode 1 may further include a step of: disposing the electrodes 60 / 70 . The first electrode 60 is disposed on a side of the substrate 10 away from the bonding layer 11 and is electrically connected to the first semiconductor layer 21 . The second electrode 70 is disposed on a side of the second semiconductor layer 23 away from the light emitting layer 22 , and is electrically connected to the second semiconductor layer 23 . A passivation layer 80 may also be disposed on the second semiconductor layer 23 . The passivation layer 80 covers the area of the surface of the second semiconductor layer 23 away from the light-emitting layer 22 not covered by the second electrode 70 , and the sidewall areas of the first semiconductor layer 21 , the light-emitting layer 22 and the second semiconductor layer 23 . The passivation layer 80 can insulate and protect the epitaxial structure 20, the second electrode 70, etc., so as to ensure that the light-emitting diode 1 as a whole has good photoelectric performance.

In a light-emitting diode 1 provided by the present invention, the arrangement of several transparent conductive units 30 distributed at intervals, the protective layer 40 and the insulating layer 50 can prevent the transparent conductive unit 30 from being etched during the manufacturing process and have a sufficient thickness , which is conducive to the current conduction and uniform distribution of the current in the first semiconductor layer 21 (P layer) region, thereby ensuring the stability and uniformity of the forward voltage (VF) in the light emitting diode 1 and reducing the manufacturing cost of the light emitting diode 1 . In addition, in the light-emitting diode 1 , the specular reflection layer 12 disposed between the insulating layer 50 and the bonding layer 11 can increase the light output of the light-emitting diode 1 and improve the overall light-emitting performance of the light-emitting diode 1 . The overall arrangement of the light emitting diode 1 provided by the present invention can improve the reliability of the light emitting diode to ensure that the chip has the photoelectric performance close to the design requirement.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present invention. scope.

Claims (15)

1. A light-emitting diode, characterized in that: at least comprising: an epitaxial structure having opposite first and second surfaces, comprising a first semiconductor layer, a light emitting layer and a second semiconductor layer stacked in sequence from the first surface to the second surface; Several transparent conductive units are arranged at intervals on the surface of the first semiconductor layer away from the light-emitting layer; a protective layer formed on each of the transparent conductive units and covering each of the transparent conductive units; The insulating layer is formed on the protection layer and exposes part of the surface of the protection layer. 2 . The light emitting diode according to claim 1 , wherein the distance between two adjacent transparent conductive units is 10 μm to 40 μm. 3. The light emitting diode according to claim 1, characterized in that: the cross-section of the transparent conductive unit is one of a regular pattern and an irregular pattern. 4 . The light emitting diode according to claim 3 , wherein the cross section of the transparent conductive unit is a circle, and the diameter of the circle is 10 μm to 20 μm. 5. The light emitting diode according to claim 1, characterized in that: the thickness of the transparent conductive unit is 0 angstroms to 500 angstroms, and the transparent conductive unit is an oxide with high transparency, high conductivity and low contact resistance Material. 6 . The light emitting diode according to claim 1 , wherein the protective layer has a thickness of 100 angstroms to 200 angstroms, and the protective layer is at least one of Au, Cr, Ni, and Pt. 7. The light-emitting diode according to claim 1, wherein there is an inclination angle between the protective layer and the surface of the first semiconductor layer away from the light-emitting layer, and the inclination angle is 30° to 60° Spend. 8. The light emitting diode according to claim 1, characterized in that: the projection of the transparent conductive unit on the first semiconductor layer is located within the projection range of the protective layer on the first semiconductor layer, in the The surface of the first semiconductor layer away from the light-emitting layer is along the horizontal direction, and the distance between the end of the transparent conductive unit and the end of the protection layer thereon is 1 μm to 5 μm. 9. The light emitting diode according to claim 1, wherein the total area of the plurality of transparent conductive units is greater than 5% of the total area of the first semiconductor layer away from the light emitting layer. 10. The light emitting diode according to claim 1, characterized in that: the insulating layer is provided with an opening, and the projection of the opening on the first semiconductor layer is located at the position of the transparent conductive unit on the first semiconductor layer. Within the projection range of the semiconductor layer. 11. The light emitting diode according to any one of claims 1 to 10, wherein the light emitting diode further comprises a substrate, and the first semiconductor layer in the epitaxial structure is in contact with the substrate through a bonding layer. Bond. 12 . The light emitting diode according to claim 11 , wherein a specular reflective layer is disposed between the insulating layer and the bonding layer. 13 . 13. The light emitting diode according to claim 11, characterized in that: said light emitting diode further comprises: a first electrode, disposed on a side of the substrate away from the bonding layer, and electrically connected to the first semiconductor layer; a second electrode, disposed on a side of the second semiconductor layer away from the light-emitting layer, and electrically connected to the second semiconductor layer; a passivation layer, disposed on the second semiconductor layer, covering the area of the second semiconductor layer not covered by the second electrode on the surface of the second semiconductor layer away from the light-emitting layer, and the first semiconductor layer, The light-emitting layer and the sidewall regions of the second semiconductor layer. 14. A method for preparing a light-emitting diode, characterized in that the method at least comprises: growing an epitaxial structure, sequentially growing a second semiconductor layer, a light emitting layer and a first semiconductor layer on a growth substrate to form an epitaxial structure; Making a transparent conductive layer, forming several transparent conductive units arranged at intervals on the surface of the first semiconductor layer away from the light-emitting layer, and forming a protective layer on each of the transparent conductive units; making an insulating layer, forming an insulating layer on the protective layer, and exposing part of the surface of the protective layer; transferring an epitaxial structure, in which one side of the first semiconductor layer is bonded to a substrate through a bonding layer, and removing the growth substrate. 15. The method for manufacturing a light-emitting diode according to claim 14, characterized in that: before implementing the step of transferring the epitaxial structure, the following steps are further included: an opening in the insulating layer, an opening is provided in the insulating layer above the protective layer, and the opening exposes a part of the surface of the protective layer; and A specular reflection layer is provided to form a specular reflection layer on the insulating layer, and the specular reflection layer covers the opening and the surface of the insulating layer on a side away from the first semiconductor layer.

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