CN117810320A - Reverse polarity light emitting diode and preparation method thereof - Google Patents

Abstract

The present disclosure provides a reverse polarity light emitting diode and a preparation method thereof, which belong to the technical field of photoelectron manufacturing. The light emitting diode includes: the device comprises a substrate, a transparent conductive layer, a dielectric layer and an epitaxial layer, wherein the transparent conductive layer, the dielectric layer and the epitaxial layer are sequentially laminated on the substrate; the dielectric layer is internally provided with a through hole, the through hole is filled with a conductive material, the conductive material is respectively and electrically connected with the transparent conductive layer and the epitaxial layer, and the aperture of one end of the through hole, which is close to the substrate, is smaller than that of one end of the through hole, which is far away from the substrate. The embodiment of the disclosure can reduce the voltage of the light emitting diode and improve the brightness of the light emitting diode.

Description

Reverse polarity light-emitting diode and preparation method thereof

Technical field

The present disclosure relates to the field of optoelectronic manufacturing technology, and in particular to a reverse polarity light-emitting diode and a preparation method thereof.

Background technique

Reverse Polarity Light Emitting Diodes (RPLED for short), also called "reverse LED". Its working principle is opposite to that of ordinary light-emitting diodes. When a reverse voltage is applied to RPLED, the carriers at its PN junction will recombine with the impurity ions contained in it, resulting in energy release, causing the RPLED to emit light.

Reverse polarity light-emitting diodes usually adopt a vertical structure. The reverse-polarity vertical light-emitting diodes include a substrate, a mirror layer, a transparent conductive layer, a dielectric film and an epitaxial layer that are stacked in sequence. A through hole exposing the transparent conductive layer is provided on the dielectric film, and an ohmic contact material is provided in the through hole, so that the transparent conductive layer can be electrically connected to the epitaxial layer through the through hole.

The size of the through hole determines the contact area between the epitaxial layer and the transparent conductive layer. Therefore, how to design the through hole has an important impact on the luminous effect of the epitaxial wafer.

Summary of the invention

Embodiments of the present disclosure provide a reverse polarity light-emitting diode and a preparation method thereof, which can reduce the voltage of the light-emitting diode and increase the brightness of the light-emitting diode. The technical solutions are as follows:

On the one hand, embodiments of the present disclosure provide a light-emitting diode. The light-emitting diode includes: a substrate, a transparent conductive layer, a dielectric layer and an epitaxial layer. The transparent conductive layer, the dielectric layer and the epitaxial layer are stacked in sequence. On the substrate; the dielectric layer has a through hole, the through hole is filled with a conductive material, the conductive material is electrically connected to the transparent conductive layer and the epitaxial layer respectively, the through hole A hole diameter at one end close to the substrate is smaller than a hole diameter at an end of the through hole away from the substrate.

Optionally, the through hole includes a first hole segment and a second hole segment that are connected, the first hole segment is close to the substrate, and a hole diameter of the first hole segment is smaller than a hole diameter of the second hole segment.

Optionally, the ratio of the radial cross-sectional area of the first hole segment to the radial cross-sectional area of the second hole segment is 1/2 to 2/3.

Optionally, the ratio of the sum of the radial cross-sectional areas of the first hole segments of all the through holes to the light-emitting area area of the light-emitting diode is 0.5% to 20%.

Optionally, the ratio of the sum of radial cross-sectional areas of the second hole segments of all the through holes to the light-emitting area of the light-emitting diode is 1% to 30%.

Optionally, the conductive material in the first hole section is different from the conductive material in the second hole section.

Optionally, the light-emitting diode further includes a first electrode located on a surface of the epitaxial layer away from the substrate; the dielectric layer has a plurality of through holes arranged in an array, and the The orthographic projection of the through hole on the substrate is located outside the orthographic projection of the first electrode on the substrate.

Optionally, the epitaxial layer includes an ohmic contact layer, a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer stacked in sequence, and the transparent conductive layer is connected to the ohmic contact layer through the through hole.

On the other hand, embodiments of the present disclosure also provide a method for preparing a light-emitting diode. The preparation method includes: providing a growth substrate; sequentially forming an epitaxial layer and a dielectric layer on the growth substrate. The dielectric layer There is a through hole away from the growth substrate that exposes the epitaxial layer. The through hole is filled with conductive material. The through hole is filled with conductive material. The through hole is close to the aperture of one end of the substrate. Smaller than the aperture of one end of the through hole away from the substrate; forming a transparent conductive layer on the dielectric layer, the transparent conductive layer being located on the surface of the dielectric layer away from the growth substrate and within the through hole on the conductive material; bond the substrate on the side of the transparent conductive layer away from the epitaxial layer, and remove the growth substrate.

Optionally, sequentially forming an epitaxial layer and a dielectric layer on the growth substrate includes: forming the epitaxial layer on the growth substrate; forming a conductive material on a surface of the epitaxial layer away from the growth substrate. block; the dielectric layer is formed on the surface of the epitaxial layer away from the growth substrate and the conductive material block, the dielectric layer has a recessed hole exposing the conductive material block, and the radial direction of the recessed hole The cross-sectional area is smaller than the radial cross-sectional area of the block of conductive material.

The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure include at least:

The light-emitting diode of the embodiment of the present disclosure includes a transparent conductive layer, a dielectric layer and an epitaxial layer sequentially stacked on a substrate. The dielectric layer has a through hole, and the through hole is filled with a conductive material. The transparent conductive layer and the dielectric layer are connected through the conductive material, so that the transparent conductive layer and the epitaxial layer are electrically connected. The diameter of the end of the through hole close to the substrate is smaller than the diameter of the end of the through hole away from the substrate. In this way, the through hole is set to have a large opening at one end and a small opening at the other end, so that the end with the larger opening of the through hole is connected to the epitaxial layer. , so that the contact area between the conductive material and the epitaxial layer is larger, and the smaller end of the through hole opening is connected to the transparent conductive layer, so that the contact area between the conductive material and the transparent conductive layer is smaller.

Since the contact area between the conductive material and the epitaxial layer determines the electrical properties of the light-emitting diode, a larger contact area between the conductive material and the epitaxial layer is equivalent to an increase in the ohmic contact area, and the corresponding parameter voltage will become smaller. Therefore, the larger the contact area between the conductive material and the epitaxial layer, the smaller the voltage of the light-emitting diode, and the smaller the contact area between the conductive material and the epitaxial layer, the greater the voltage of the light-emitting diode. Therefore, the larger end of the through hole has a larger contact area with the epitaxial layer, which can effectively reduce the forward voltage of the light-emitting diode.

Since the area of the dielectric film layer determines the brightness of the light-emitting diode, the larger the area of the dielectric film layer, the higher the brightness of the light-emitting diode. The smaller the area of the dielectric film layer, the lower the brightness of the light-emitting diode. Therefore, the smaller the area of the smaller end of the through hole, the larger the corresponding area of the dielectric film layer, which can effectively increase the brightness of the light-emitting diode.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can also be obtained based on these drawings without exerting creative efforts.

FIG1 is a schematic diagram of the structure of a light emitting diode provided by an embodiment of the present disclosure;

Figure 2 is an A-direction cross-sectional view provided in Figure 1;

Figure 3 is a flow chart of a method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure;

Figure 4 is a preparation state diagram of a light-emitting diode provided by an embodiment of the present disclosure;

FIG5 is a diagram showing a preparation state of a light emitting diode provided by an embodiment of the present disclosure;

FIG. 6 is a diagram showing a preparation state of a light emitting diode provided in an embodiment of the present disclosure.

Each mark in the figure is explained as follows:

10. Substrate;

20. Transparent conductive layer;

30, dielectric layer; 31, through hole; 311, first hole segment; 312, second hole segment;

32. Conductive material block; 33. concave hole;

40. Epitaxial layer; 42. Ohmic contact layer;

51. First electrode; 52. Second electrode;

60. Bonding layer;

70. Reflector layer.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present disclosure clearer, the embodiments of the present disclosure will be described in further detail below in conjunction with the accompanying drawings.

FIG. 1 is a schematic structural diagram of a light-emitting diode provided by an embodiment of the present disclosure. Figure 2 is a cross-sectional view along the direction A provided in Figure 1 . As shown in Figures 1 and 2, the light-emitting diode includes: a substrate 10, a transparent conductive layer 20, a dielectric layer 30 and an epitaxial layer 40. The transparent conductive layer 20, the dielectric layer 30 and the epitaxial layer 40 are sequentially stacked on the substrate 10.

As shown in FIG. 2 , the dielectric layer 30 has a through hole 31 , the through hole 31 is filled with conductive material, and the conductive material is electrically connected to the transparent conductive layer 20 and the epitaxial layer 40 respectively.

As shown in FIG. 2 , the aperture of the through hole 31 at one end close to the substrate 10 is smaller than the aperture of the through hole 31 at one end away from the substrate 10 .

The light-emitting diode of the embodiment of the present disclosure includes a transparent conductive layer 20, a dielectric layer 30 and an epitaxial layer 40 sequentially stacked on the substrate 10. The dielectric layer 30 has a through hole 31 penetrating the dielectric layer 30 , and the through hole 31 is also filled with a conductive material. The transparent conductive layer 20 and the dielectric layer 30 are connected through the conductive material, so that the transparent conductive layer 20 and the epitaxial layer 40 are electrically connected. sexual connection. The diameter of the end of the through hole 31 close to the substrate 10 is smaller than the diameter of the end of the through hole 31 away from the substrate 10. In this way, the through hole 31 is set to have a large opening at one end and a small opening at the other end, so that the opening of the through hole 31 is larger. One end of the through hole 31 is connected to the epitaxial layer 40, so that the contact area between the conductive material and the epitaxial layer 40 is larger, and the smaller end of the through hole 31 is connected to the transparent conductive layer 20, so that the contact area between the conductive material and the transparent conductive layer is smaller. .

Since the contact area between the conductive material and the epitaxial layer 40 determines the electrical properties of the light-emitting diode, a larger contact area between the conductive material and the epitaxial layer 40 is equivalent to an increase in the ohmic contact area, and the corresponding parameter voltage will become smaller. Therefore, the larger the contact area between the conductive material and the epitaxial layer 40 is, the smaller the voltage of the light-emitting diode is. The smaller the contact area between the conductive material and the epitaxial layer 40 is, the greater the voltage of the light-emitting diode is. Therefore, the larger end of the through hole 31 has a larger contact area with the epitaxial layer 40, which can effectively reduce the forward voltage of the light emitting diode.

Since the area of the dielectric film layer determines the brightness of the light-emitting diode, the larger the area of the dielectric film layer, the higher the brightness of the light-emitting diode. The smaller the area of the dielectric film layer, the lower the brightness of the light-emitting diode. Therefore, the smaller the area of the smaller end of the through hole, the larger the corresponding area of the dielectric film layer, which can effectively increase the brightness of the light-emitting diode.

In embodiments of the present disclosure, electrodes are provided on both sides of the epitaxial layer of the light-emitting diode away from the substrate and on the side of the substrate away from the epitaxial layer, so that current can be injected into the light-emitting diode through the electrodes. The light-emitting diode of this kind of structure is a vertical structure light-emitting diode.

Optionally, the substrate is a silicon substrate or a silicon carbide substrate. The substrate can be a flat substrate or a patterned substrate.

As an example, in the embodiment of the present disclosure, the substrate is a silicon substrate. The heat dissipation performance of the silicon substrate is better than that of GaAs, and the silicon substrate is a commonly used substrate with mature technology and low cost.

In the embodiment of the present disclosure, as shown in FIG. 1 , the epitaxial layer 40 includes an ohmic contact layer 42 , a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer sequentially stacked on the dielectric layer 30 . The transparent conductive layer 20 is connected to the ohmic contact layer 42 through the through hole 31 .

Exemplarily, the ohmic contact layer 42 may include a gold-zinc alloy layer or a gold-beryllium alloy layer.

As shown in Figures 1 and 2, the light-emitting diode also includes a first electrode 51 and a second electrode 52. The first electrode 51 is located on the surface of the epitaxial layer 40 away from the substrate 10, and the second electrode 52 is located on the surface of the substrate 10 away from the epitaxial layer 40. On the surface.

Wherein, one of the first semiconductor layer and the second semiconductor layer is a p-type layer, and the other of the first semiconductor layer and the second semiconductor layer is an n-type layer.

As an example, the first semiconductor layer is a p-type layer, and the second electrode is a p-type electrode. The second semiconductor layer is an n-type layer, and the first electrode is an n-type electrode.

Optionally, the first semiconductor layer is a p-type AlInP layer. The p-type AlInP layer may have a thickness of 0.5 μm to 3 μm.

Optionally, the multi-quantum well layer includes an AlGaInP quantum well layer and an AlGaInP quantum barrier layer that are grown alternately. The multi-quantum well layer may include 3 to 8 periods of AlGaInP quantum well layers and AlGaInP quantum barrier layers that are alternately stacked.

As an example, in the embodiment of the present disclosure, the multi-quantum well layer includes five periods of AlGaInP quantum well layers and AlGaInP quantum barrier layers that are alternately stacked.

Alternatively, the thickness of the multi-quantum well layer may be 150 nm to 200 nm.

Optionally, the second semiconductor layer is an n-type AlGaInP layer, and the thickness of the n-type AlGaInP layer may be 0.5 μm to 3 μm.

Optionally, as shown in FIG. 2 , the light-emitting diode further includes a mirror layer 70 , and the mirror layer 70 is located between the substrate 10 and the transparent conductive layer 20 .

By arranging the mirror layer 70 on the side of the epitaxial layer 40 away from the substrate 10 , the light emitted by the epitaxial layer 40 can be reflected at the position of the mirror layer 70 , so that more light can escape from the epitaxial layer 40 away from the surface of the substrate 10 Emission, enhance the luminous brightness.

Illustratively, mirror layer 70 includes a metal layer. For example, the metal layer may be a film layer made of metal materials with good reflective effects, such as Ag, Cu, or the like.

In the embodiment of the present disclosure, the second electrode 52 is disposed on the side of the silicon substrate 10 away from the epitaxial layer 40 . After the second electrode 52 is energized, the current will be transferred to the transparent conductive layer 20 through the silicon substrate 10 . Since the dielectric layer 30 is an insulating film layer, a through hole 31 is provided on the dielectric layer 30 and a conductive material is filled in the through hole 31 to allow the transparent conductive layer 20 to form ohmic contact with the conductive material, allowing current to pass through the transparent conductive layer 20 is transferred to the epitaxial layer 40.

Optionally, as shown in FIG. 1 , the surface of the dielectric layer 30 away from the substrate 10 has a plurality of through holes 31 arranged in an array, and the orthographic projection of the through holes 31 on the substrate 10 is located outside the orthographic projection of the first electrode 51 on the substrate 10 .

In the embodiment of the present disclosure, the surface of the epitaxial layer 40 away from the substrate 10 is the light-emitting surface, and the first electrode blocks the light. Therefore, arranging the through hole 31 at a position not opposite to the first electrode can conduct more current. The light is transferred to the region of the epitaxial layer 40 that is not opposed to the first electrode, so that the luminous intensity of the region of the epitaxial layer 40 that is not opposed to the first electrode is higher, thereby improving the luminous effect of the light-emitting diode.

For example, as shown in FIG. 1 , the through holes 31 are arranged in an array. Providing a plurality of spaced-apart through holes 31 allows current to be evenly transmitted to various areas of the epitaxial layer 40 through the conductive material in the through holes 31, thereby improving the light-emitting effect of the light-emitting diode.

Optionally, the transparent conductive layer 20 includes an indium tin oxide layer or an indium zinc oxide layer.

In the embodiment of the present disclosure, the dielectric layer 30 is usually a silicon oxide layer, a magnesium fluoride layer, and a titanium oxide layer. The adhesion between the dielectric layer 30 made of these materials and the epitaxial layer 40 is low, while the indium tin oxide layer and the indium oxide layer The adhesion between the zinc layer and the epitaxial layer 40 is higher than the adhesion between the dielectric layer 30 and the epitaxial layer 40. Therefore, using an indium tin oxide layer or an indium zinc oxide layer as the transparent conductive layer 20 can effectively improve the adhesion between the dielectric layer 30 and the epitaxial layer 40. Connection reliability of the epitaxial layer 40 .

Among them, the indium tin oxide layer and the indium zinc oxide layer both have good transmittance and low resistivity. Using the indium tin oxide layer or the indium zinc oxide layer as the transparent conductive layer 20 can allow more light to be transmitted from the transparent conductive layer 20 to The reflector layer 70 reduces the amount of light absorbed so that more light is reflected from the metal layer to the light emitting surface, thereby ensuring the light emitting effect.

Optionally, the thickness of the part of the transparent conductive layer 20 between the dielectric layer 30 and the substrate 10 is 10 nm to 500 nm.

Exemplarily, the thickness of the transparent conductive layer 20 may be 100 nm.

If the thickness of the transparent conductive layer 20 is too thin, it will affect the ohmic contact between the mirror layer 70 and the conductive material layer, and the adhesion between the mirror layer 70 and the dielectric film layer; if the thickness of the transparent conductive layer 20 is too thick, Then the absorption of light by the transparent conductive layer 20 will be increased, thereby reducing the luminous efficiency of the light-emitting diode.

Optionally, as shown in FIG. 2 , the through hole 31 includes a connected first hole section 311 and a second hole section 312 , and the first hole section 311 is close to the substrate 10 .

The hole diameter of the first hole section 311 is smaller than the hole diameter of the second hole section 312 .

By setting the through hole 31 as a stepped hole, the larger second hole section 312 in the through hole 31 is closer to the epitaxial layer 40, so that the contact area between the conductive material in the through hole 31 and the epitaxial layer 40 is larger, thereby It can effectively reduce the voltage of light-emitting diodes. Let the smaller first hole section 311 in the through hole 31 be close to the transparent conductive layer 20, so that the contact area between the conductive material in the through hole 31 and the transparent conductive layer 20 is smaller, thereby effectively improving the brightness of the light emitting diode.

For example, as shown in FIG. 1 , the first hole section 311 and the second hole section 312 are concentrically arranged circular holes. The diameters of the first hole section 311 and the second hole section 312 are both the diameters of circular holes.

Optionally, the ratio of the radial cross-sectional area of the first hole section 311 to the radial cross-sectional area of the second hole section 312 is 1/2 to 2/3.

The radial cross-sectional area refers to the area of the cross-section perpendicular to the axial direction of the through hole. For example, as shown in FIG. 1 , the radial cross-sectional area of the first hole segment may be a circular area parallel to the direction of the paper shown in FIG. 1 .

For example, the ratio of the radial cross-sectional area of the first hole section 311 to the radial cross-sectional area of the second hole section 312 is 1/2.

Since the aperture of the through hole 31 should not be set too large, by limiting the ratio of the radial cross-sectional areas of the first hole segment 311 and the second hole segment 312 within the above range, it is possible to avoid that the radial cross-sectional areas of the first hole segment 311 and the second hole segment 312 differ too much, thereby making the aperture of the second hole segment 312 too small and affecting the efficiency of current transmission.

Optionally, the ratio of the sum of the radial cross-sectional areas of the first hole segments 311 of all the through holes 31 to the light emitting area of the light emitting diode is 0.5% to 20%.

In the embodiment of the present disclosure, as shown in FIG. 1 , the light-emitting area area of the light-emitting diode refers to the area on the epitaxial layer 40 that is not blocked by the first electrode 51 .

As shown in FIG. 1 , the first hole segments 311 are arranged in an array, and the sum of the radial cross-sectional areas of all the first hole segments 311 is 0.5% to 20% of the light-emitting area of the light-emitting diode.

In this way, controlling the proportion of the first hole segments 311 in the area of the light-emitting area within this range can prevent the total radial cross-sectional area of all the first hole segments 311 from being too large without reducing the friction between the conductive material and the transparent conductive layer 20. Contact area purpose.

For example, the ratio of the sum of the radial cross-sectional areas of the first hole segments 311 of all through holes 31 to the area of the light-emitting area of the light-emitting diode is 5%.

Optionally, the ratio of the radial cross-sectional area of the second hole section 312 of all through holes 31 to the light-emitting area area of the light-emitting diode is 1% to 30%.

As shown in FIG. 1 , the second hole segments 312 are arranged in an array, and the sum of the radial cross-sectional areas of all the second hole segments 312 is 1% to 30% of the light-emitting area area of the light-emitting diode.

In this way, controlling the proportion of the second hole segments 312 in the area of the light-emitting area within this range can prevent the total radial cross-sectional area of all the second hole segments 312 from being too small and failing to improve the contact between the conductive material and the epitaxial layer 40 area purpose.

For example, the ratio of the radial cross-sectional area of the second hole segments 312 of all through holes 31 to the light-emitting area area of the light-emitting diode is 10%.

Optionally, the conductive material includes at least one of indium tin oxide, indium zinc oxide and metallic materials.

In one implementation, the conductive material in the first hole section may be different from the conductive material in the second hole section.

For example, the conductive material located in the first hole section 311 may be indium zinc oxide, and the conductive material located in the second hole section 312 may be a metal material.

In another implementation, the conductive material in the first hole segment and the second hole segment may be the same.

For example, the conductive material located in the first hole section 311 and the second hole section 312 may both be an indium tin oxide layer or an indium zinc oxide layer.

FIG. 3 is a flow chart of a method for manufacturing a light-emitting diode provided by an embodiment of the present disclosure. This method is used to prepare the light-emitting diode shown in Figures 1 to 2. As shown in Figure 3, the preparation method includes:

S11: providing a growth substrate.

Wherein, the growth substrate may be a GaAs sheet.

S12: Form the epitaxial layer 40 and the dielectric layer 30 sequentially on the growth substrate.

The dielectric layer 30 has a through hole 31 , and the through hole 31 is filled with conductive material. The diameter of the end of the through hole 31 close to the substrate 10 is smaller than the diameter of the end of the through hole 31 away from the substrate 10 .

S13 : forming a transparent conductive layer 20 on the dielectric layer 30 .

The transparent conductive layer 20 is located on the surface of the dielectric layer 30 away from the growth substrate and the conductive material in the through hole 31 .

S14: bonding the substrate 10 to the side of the transparent conductive layer 20 away from the epitaxial layer 40, and removing the growth substrate.

The light-emitting diode prepared by this preparation method includes a transparent conductive layer 20, a dielectric layer 30 and an epitaxial layer 40 that are sequentially stacked on the substrate 10. The dielectric layer 30 has a through hole 31 , and the through hole 31 is filled with a conductive material. The transparent conductive layer 20 and the dielectric layer 30 are connected through the conductive material, so that the transparent conductive layer 20 and the epitaxial layer 40 are electrically connected. The diameter of the end of the through hole 31 close to the substrate 10 is smaller than the diameter of the end of the through hole 31 away from the substrate 10. In this way, the through hole 31 is set to have a large opening at one end and a small opening at the other end, so that the opening of the through hole 31 is larger. One end of the through hole 31 is connected to the epitaxial layer 40, so that the contact area between the conductive material and the epitaxial layer 40 is larger, and the smaller end of the through hole 31 is connected to the transparent conductive layer 20, so that the contact area between the conductive material and the transparent conductive layer is smaller. .

Since the contact area between the conductive material and the epitaxial layer 40 determines the electrical properties of the light-emitting diode, the larger the contact area between the conductive material and the epitaxial layer 40, the smaller the voltage of the light-emitting diode, and the smaller the contact area between the conductive material and the epitaxial layer 40, the larger the voltage of the light-emitting diode. Therefore, the larger opening of the through hole 31 has a larger contact area with the epitaxial layer 40, which can effectively reduce the voltage of the light-emitting diode.

Since the contact area between the conductive material and the transparent conductive layer 20 determines the brightness of the light-emitting diode, the greater the contact area between the conductive material and the transparent conductive layer 20, the lower the brightness of the light-emitting diode, and the smaller the contact area between the conductive material and the transparent conductive layer 20. The brightness of the light-emitting diode is higher. Therefore, the smaller end of the through hole 31 has a smaller contact area with the transparent conductive layer 20 , which can effectively increase the brightness of the light emitting diode.

In the embodiment of the present disclosure, the epitaxial layer 40 may include: a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer.

Step S12 may include the following steps:

FIG. 4 is a diagram of the preparation state of a light-emitting diode provided by an embodiment of the present disclosure. As shown in Figure 4, in the first step, an epitaxial layer 40 is formed on the growth substrate.

Specifically, it includes: growing a second semiconductor layer, a multi-quantum well layer, a first semiconductor layer and an ohmic contact layer 42 on the GaAs wafer.

In the embodiment of the present disclosure, the first semiconductor layer is a p-type layer, and the second semiconductor layer is an n-type layer.

Optionally, the first semiconductor layer is a p-type AlInP layer, and the thickness of the p-type AlInP layer may be 0.5 μm to 3 μm.

Optionally, the multi-quantum well layer includes alternately grown AlGaInP quantum well layers and AlGaInP quantum barrier layers. Wherein, the multi-quantum well layer may include 3 to 8 periods of AlGaInP quantum well layers and AlGaInP quantum barrier layers alternately stacked.

As an example, in the embodiment of the present disclosure, the multi-quantum well layer includes five periods of AlGaInP quantum well layers and AlGaInP quantum barrier layers that are alternately stacked.

Alternatively, the thickness of the multi-quantum well layer may be 150 nm to 200 nm.

Optionally, the second semiconductor layer is an n-type AlGaInP layer, and the thickness of the n-type AlGaInP layer may be 0.5 μm to 3 μm.

Alternatively, the ohmic contact layer 42 may be a Mg-doped p-type GaP layer. Among them, the doping concentration of Mg is 1×10 ¹⁸ /cm ³ .

In the second step, the conductive material block 32 is formed on the surface of the epitaxial layer 40 away from the growth substrate.

As shown in Figure 4, the process specifically includes: spin-coating photoresist on the surface of the ohmic contact layer 42, exposing, developing, making a pattern with grooves on the photoresist, and then evaporating a conductive material to form a pattern in the groove. The conductive material is then stripped off the photoresist to obtain the conductive material block 32 formed of the conductive material.

Optionally, the conductive material includes at least one of indium tin oxide, indium zinc oxide and metallic materials.

For example, the conductive material may be indium tin oxide.

In the third step, the dielectric layer 30 is formed on the surface of the epitaxial layer 40 away from the growth substrate and the conductive material block 32 .

The dielectric layer 30 has a recessed hole 33 exposing the conductive material block 32 . The radial cross-sectional area of the recessed hole 33 is smaller than the radial cross-sectional area of the conductive material block 32 . The recessed hole 33 and the area of the dielectric layer 30 filled with the conductive material block 32 are Through holes 31 are formed.

As shown in FIG. 5 , the process specifically includes: depositing a dielectric layer 30 on the surface of the ohmic contact layer 42 , then spin-coating photoresist, exposing, and developing to form a through hole 31 exposing the ohmic contact layer 42 on the dielectric layer 30 .

Wherein, the dielectric layer 30 may be a silicon oxide layer.

Step S13 may include: forming a transparent conductive layer 20 on a surface of the dielectric film away from the growth substrate.

The transparent conductive layer 20 is located in the recessed hole 33 , and the transparent conductive layer 20 is electrically connected to the conductive material block 32 .

Exemplarily, the transparent conductive layer 20 includes an indium tin oxide layer or an indium zinc oxide layer.

As shown in FIG6 , step S13 may specifically include: forming a transparent conductive layer 20 on the surface of the dielectric layer 30 away from the growth substrate, in the recessed hole 33, and on the surface of the epitaxial layer 40 by sputtering the entire surface, so that the transparent conductive layer 20 is insulated from the epitaxial layer 40. The transparent conductive layer 20 cannot form an ohmic contact with the ohmic contact layer 42, but forms an ohmic contact with the conductive material layer.

Exemplarily, the thickness of the transparent conductive layer 20 may be 10 nm to 500 nm.

After step S13 , it may also include forming a mirror layer 70 on the surface of the transparent conductive layer 20 .

Making the mirror layer 70 may include forming a metal layer on the surface of the transparent conductive layer 20 .

When forming the metal layer, a metal layer can be formed on the surface of the transparent conductive layer 20 by deposition, and then annealed at a low temperature.

The metal layer may be a film layer made of metal materials such as Ag and Cu with good reflective effect.

Step S14 may include: first, bonding the mirror layer 70 to the silicon substrate 10 through the bonding layer 60, then removing the growth substrate, and forming the first electrode 51 on the surface of the second semiconductor layer; then, forming the first electrode 51 on the silicon substrate. The second electrode 52 is formed on the substrate 10; finally, a passivation layer is formed, and a cutting process is performed to form a single core particle.

The above are only optional embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection of the present disclosure. within the range.

Claims (10)

1. A light-emitting diode, characterized in that the light-emitting diode includes: a substrate (10), a transparent conductive layer (20), a dielectric layer (30) and an epitaxial layer (40), and the transparent conductive layer (20) , the dielectric layer (30) and the epitaxial layer (40) are sequentially stacked on the substrate (10); The dielectric layer (30) has a through hole (31), and the through hole (31) is filled with conductive material. The conductive material is connected to the transparent conductive layer (20) and the epitaxial layer (40) respectively. Electrically connected, the diameter of the end of the through hole (31) close to the substrate (10) is smaller than the diameter of the end of the through hole (31) away from the substrate (10). 2. The light-emitting diode according to claim 1, wherein the through hole (31) includes a connected first hole section (311) and a second hole section (312), and the first hole section (311) ) is close to the substrate (10), and the aperture of the first hole section (311) is smaller than the aperture of the second hole section (312). 3. The light emitting diode according to claim 2, characterized in that a ratio of a radial cross-sectional area of the first hole segment (311) to a radial cross-sectional area of the second hole segment (312) is 1/2 to 2/3. 4. The light-emitting diode according to claim 2, characterized in that the ratio of the sum of the radial cross-sectional areas of the first hole segments (311) of all the through holes (31) to the area of the light-emitting area of the light-emitting diode is 0.5% to 20%. 5. The light-emitting diode according to claim 2, characterized in that the ratio of the sum of the radial cross-sectional areas of the second hole segments (312) of all the through holes (31) to the area of the light-emitting area of the light-emitting diode 1% to 30%. 6. The light-emitting diode of claim 2, wherein the conductive material in the first hole section (311) is different from the conductive material in the second hole section (312). 7. The light-emitting diode according to any one of claims 1 to 6, characterized in that the light-emitting diode further includes a first electrode (51), the first electrode (51) is located on the epitaxial layer (40) A surface away from the substrate (10); The dielectric layer (30) has a plurality of through holes (31) arranged in an array, and the orthographic projection of the through holes (31) on the substrate (10) is located on the first electrode (51) outside the orthographic projection on the substrate (10). 8. The light-emitting diode according to any one of claims 1 to 6, characterized in that the epitaxial layer (40) includes an ohmic contact layer (42), a first semiconductor layer, a multi-quantum well layer and a third layer stacked in sequence. Two semiconductor layers, the transparent conductive layer (20) is connected to the ohmic contact layer (42) through the through hole (31). 9. A method for preparing a light-emitting diode, characterized in that the preparation method includes: providing a growth substrate; An epitaxial layer and a dielectric layer are sequentially formed on the growth substrate, wherein the dielectric layer is away from the growth substrate and has a through hole exposing the epitaxial layer, the through hole is filled with a conductive material, and the aperture of the through hole at one end close to the substrate is smaller than the aperture of the through hole at one end away from the substrate; forming a transparent conductive layer on the dielectric layer, the transparent conductive layer being located on the surface of the dielectric layer away from the growth substrate and the conductive material in the through hole; A substrate is bonded to a side of the transparent conductive layer away from the epitaxial layer, and the growth substrate is removed. 10. The preparation method according to claim 9, wherein sequentially forming an epitaxial layer and a dielectric layer on the growth substrate includes: forming the epitaxial layer on the growth substrate; forming a block of conductive material on a surface of the epitaxial layer away from the growth substrate; The dielectric layer is formed on the surface of the epitaxial layer away from the growth substrate and the conductive material block, the dielectric layer has a concave hole exposing the conductive material block, and the radial cross-sectional area of the concave hole is smaller than the radial cross-sectional area of the conductive material block.