Light emitting diode for improving etching damage and preparation method thereof

Abstract

The invention provides a light emitting diode for improving etching damage and a preparation method thereof, and belongs to the technical field of photoelectron manufacturing. The preparation method comprises the following steps: forming an epitaxial layer; and irradiating the local area of the epitaxial layer by using laser to decompose the local area of the epitaxial layer and form a groove. According to the embodiment of the invention, the damage to the side wall of the epitaxial layer can be improved in the process of forming the groove in the epitaxial layer, and the light-emitting effect of the light-emitting diode is ensured.

Description

Technical Field

[0001] The present disclosure relates to the field of optoelectronic manufacturing technology, and in particular to a light emitting diode with improved etching damage and a preparation method thereof. Background Art

[0002] Light Emitting Diode (LED) is a very influential new product in the optoelectronics industry. It has the characteristics of small size, long service life, rich colors and low energy consumption. It is widely used in lighting, display screens, signal lights, backlight sources, toys and other fields.

[0003] In the related art, a light emitting diode includes a substrate and an epitaxial layer, wherein the epitaxial layer is stacked on the substrate. In the process of preparing a light emitting diode, a groove is usually formed by etching the surface of the epitaxial layer by wet etching or dry etching.

[0004] Wet etching has isotropic process characteristics and cannot meet the needs of high-precision etching. When the material to be etched is difficult to react with the etching solution, wet etching is difficult to form grooves. Dry etching, because the plasma it uses has high energy, will cause microscopic damage to the side walls of the etched film layer. The smaller the size of the light-emitting diode, the greater the impact of this sidewall damage on the light efficiency of the light-emitting diode. Summary of the invention

[0005] The embodiment of the present disclosure provides a light-emitting diode with improved etching damage and a method for manufacturing the same, which can improve the damage to the side wall of the epitaxial layer during the process of forming a groove on the epitaxial layer, thereby ensuring the light-emitting effect of the light-emitting diode. The technical solution is as follows:

[0006] On the one hand, an embodiment of the present disclosure provides a method for preparing a light emitting diode, the method comprising: forming an epitaxial layer; and irradiating a local area of ​​the epitaxial layer with a laser to decompose the local area of ​​the epitaxial layer and form a groove.

[0007] In one implementation of the present disclosure, using laser to irradiate a local area of ​​the epitaxial layer includes: forming a light-shielding layer on the surface of the epitaxial layer, the light-shielding layer having an etching opening exposing the local area of ​​the epitaxial layer; using laser to irradiate the etching opening to form the groove on the surface of the epitaxial layer.

[0008] In another implementation of the present disclosure, the light shielding layer includes a photoresist layer and / or a metal layer.

[0009] In another implementation of the present disclosure, the thickness of the light shielding layer is 0.1 μm to 10 μm.

[0010] In another implementation of the present disclosure, irradiating the local area of ​​the epitaxial layer with laser includes: irradiating the local area of ​​the epitaxial layer with a patterned laser spot to form the groove on the surface of the epitaxial layer.

[0011] In another implementation of the present disclosure, using laser to irradiate a local area of ​​the epitaxial layer includes: when the preparation material of the epitaxial layer includes GaN, using a laser with a wavelength of 248nm or 266nm to irradiate the epitaxial layer; when the preparation material of the epitaxial layer includes AlN, using a laser with a wavelength of 198.3nm to irradiate the epitaxial layer.

[0012] Optionally, irradiating a local area of ​​the epitaxial layer with a laser comprises: when the preparation material of the epitaxial layer comprises GaN, using an energy greater than or equal to 100 MJ / cm 2 The epitaxial layer is irradiated with laser.

[0013] Optionally, using laser to irradiate a local area of ​​the epitaxial layer includes: determining the number of times N that the laser irradiates the epitaxial layer based on the target etching depth of the epitaxial layer and the single etching depth of the laser, where N is a positive integer; after completing the Nth laser irradiation and before performing the N+1th laser irradiation, cleaning the surface of the epitaxial layer.

[0014] An embodiment of the present disclosure provides a light emitting diode, which is prepared by the preparation method as described above. The light emitting diode includes an epitaxial layer, and a surface of the epitaxial layer has grooves.

[0015] Optionally, the light-emitting diode also includes a transparent conductive layer, a passivation layer, a first electrode and a second electrode; the epitaxial layer includes a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer stacked in sequence, the surface of the second semiconductor layer has the groove, the transparent conductive layer is located on the surface of the second semiconductor layer, the passivation layer is located on the surface of the second semiconductor layer and in the groove and covers the transparent conductive layer, and the passivation layer has through holes respectively exposing the transparent conductive layer and the groove; the first electrode is located in the groove and on the surface of the passivation layer and is connected to the first semiconductor layer through the through hole, and the second electrode is located on the surface of the passivation layer and is connected to the transparent conductive layer through the through hole.

[0016] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure include at least:

[0017] The method for preparing a light-emitting diode provided by the embodiment of the present disclosure uses laser irradiation of a local area of ​​an epitaxial layer, and uses the laser to decompose the irradiated area of ​​the epitaxial layer, thereby achieving the purpose of making a groove on the epitaxial layer. Compared with the method of dry etching the epitaxial layer in the related art, laser decomposition will not cause damage to the epitaxial material due to plasma etching bombarding and injection of the side wall of the epitaxial material, and can effectively reduce the decrease in the light efficiency of the light-emitting diode caused by dry etching.

[0018] Compared with wet etching, laser decomposition can increase the speed of laser decomposition of epitaxial materials by adjusting the laser wavelength, energy and number of laser irradiations, thereby meeting the purpose of digging grooves on the surfaces of various epitaxial materials and effectively improving the efficiency of digging grooves on the epitaxial layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 is a flow chart of a method for preparing a light emitting diode provided by an embodiment of the present disclosure;

[0021] Figure 2 is a flow chart of another method for preparing a light emitting diode provided by an embodiment of the present disclosure;

[0022] Figure 3 is a diagram of a preparation state of a light emitting diode provided by an embodiment of the present disclosure;

[0023] Figure 4 is a diagram of a preparation state of a light emitting diode provided by an embodiment of the present disclosure;

[0024] Figure 5 It is a schematic diagram of a light emitting diode provided in an embodiment of the present disclosure.

[0025] The descriptions of the marks in the figure are as follows:

[0026] 10. Substrate;

[0027] 20. epitaxial layer; 21. first semiconductor layer; 22. multi-quantum well layer; 23. second semiconductor layer; 24. groove;

[0028] 30. light shielding layer; 31. etching opening;

[0029] 40. Passivation layer;

[0030] 50. Transparent conductive layer;

[0031] 61. First electrode; 62. Second electrode. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0033] Unless otherwise defined, the technical terms or scientific terms used herein shall have the usual meanings understood by persons with ordinary skills in the field to which the present disclosure belongs. The words "first", "second", "third" and similar words used in the patent application specification and claims of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "one" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "include" or "comprise" and similar words mean that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, and do not exclude other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", "top", "bottom" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0034] Figure 1 FIG. 1 is a flow chart of a method for preparing a light emitting diode provided by an embodiment of the present disclosure. Figure 1 As shown, the preparation method comprises:

[0035] Step 101 : forming an epitaxial layer 20 .

[0036] Specifically, it may include: preparing an epitaxial layer 20 on the surface of the substrate.

[0037] Exemplarily, the epitaxial layer 20 includes a first semiconductor layer 21, a multi-quantum well layer 22, and a second semiconductor layer 23. The first semiconductor layer 21, the multi-quantum well layer 22, and the second semiconductor layer 23 are sequentially stacked on the substrate.

[0038] Step 102 : using laser to irradiate a local area of ​​the epitaxial layer 20 , so that the local area of ​​the epitaxial layer 20 is decomposed and a groove 24 is formed.

[0039] Exemplarily, the groove 24 on the epitaxial layer 20 may be a concave hole on the second semiconductor layer 23 that exposes the first semiconductor layer 21 , and the concave hole is used for subsequent preparation of electrodes.

[0040] Exemplarily, the groove 24 on the epitaxial layer 20 may be an isolation groove penetrating the epitaxial layer 20 , and the isolation groove is used to split the product from the isolation groove during the subsequent splitting operation to obtain a plurality of light emitting diodes.

[0041] The method for preparing a light-emitting diode provided in the embodiment of the present disclosure uses laser irradiation to a local area of ​​the epitaxial layer 20, and uses the laser to decompose the irradiated area of ​​the epitaxial layer 20, thereby achieving the purpose of making a groove 24 on the epitaxial layer 20. Compared with the related art, in which the epitaxial layer 20 is dry-etched, the laser decomposition will not cause damage to the epitaxial material due to the bombardment and injection of the side wall of the epitaxial material by plasma etching, and can effectively reduce the decrease in the light efficiency of the light-emitting diode caused by dry etching.

[0042] Compared with wet etching, laser decomposition can increase the speed of laser decomposition of epitaxial materials by adjusting the laser wavelength, energy and number of laser irradiations, thereby meeting the purpose of digging grooves on the surfaces of various epitaxial materials and effectively improving the efficiency of digging grooves on the epitaxial layer 20.

[0043] Figure 2 FIG. 1 is a flow chart of another method for preparing a light emitting diode provided by an embodiment of the present disclosure. Figure 2 As shown, the preparation method comprises:

[0044] Step 201 : forming an epitaxial layer 20 .

[0045] Specifically, the method may include: preparing an epitaxial layer 20 on the surface of the substrate 10 .

[0046] For example, Figure 3 As shown, the epitaxial layer 20 includes a first semiconductor layer 21, a multi-quantum well layer 22 and a second semiconductor layer 23. The first semiconductor layer 21, the multi-quantum well layer 22 and the second semiconductor layer 23 are sequentially stacked on the substrate 10.

[0047] The substrate is a sapphire substrate, a silicon substrate or a silicon carbide substrate. The substrate can be a flat substrate or a patterned substrate.

[0048] As an example, in the embodiment of the present disclosure, the substrate is a sapphire substrate. The sapphire substrate is a commonly used substrate with mature technology and low cost. Specifically, it can be a patterned sapphire substrate or a sapphire flat sheet substrate.

[0049] The sapphire substrate may be pre-treated, placed in a MOCVD (Metal-organic Chemical Vapor Deposition) reaction chamber, and baked for 12 to 18 minutes. As an example, in the embodiment of the present disclosure, the sapphire substrate is baked for 15 minutes.

[0050] Specifically, the baking temperature may be 1000° C. to 1200° C., and the pressure in the MOCVD reaction chamber during baking may be 100 mbar to 200 mbar.

[0051] Growing the epitaxial layer 20 on the substrate 10 may include: sequentially forming a first semiconductor layer 21 , a multi-quantum well layer 22 , and a second semiconductor layer 23 on the sapphire substrate by using MOCVD technology.

[0052] The first semiconductor layer 21 is an n-type layer, and the second semiconductor layer 23 is a p-type layer.

[0053] Optionally, the first semiconductor layer 21 is a silicon-doped n-type GaN layer, and the thickness of the n-type GaN layer may be 0.5 μm to 3 μm.

[0054] The growth temperature of the n-type GaN layer may be 1000° C. to 1100° C., and the growth pressure of the n-type GaN layer may be 100 torr to 300 torr.

[0055] Optionally, the multi-quantum well layer 22 includes alternately grown InGaN quantum well layers and GaN quantum barrier layers. The multi-quantum well layer 22 may include 3 to 8 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0056] When growing the multi-quantum well layer 22, the pressure of the MOCVD reaction chamber is controlled at 200 torr. When growing the InGaN quantum well layer, the temperature of the reaction chamber is 760° C. to 780° C. When growing the GaN quantum barrier layer, the temperature of the reaction chamber is 860° C. to 890° C.

[0057] As an example, in the embodiment of the present disclosure, the multi-quantum well layer 22 includes five periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0058] Optionally, the thickness of the multi-quantum well layer 22 may be 150 nm to 200 nm.

[0059] Optionally, the second semiconductor layer 23 is a magnesium-doped p-type GaN layer. The thickness of the p-type GaN layer may be 0.5 μm to 3 μm.

[0060] When growing the p-type GaN layer, the growth pressure of the p-type GaN layer may be 200 Torr to 600 Torr, and the growth temperature of the p-type GaN layer may be 800° C. to 1000° C.

[0061] Step 202 : forming a light shielding layer 30 on the surface of the epitaxial layer 20 , wherein the light shielding layer 30 has an etching opening 31 exposing a local area of ​​the epitaxial layer 20 .

[0062] like Figure 4As shown, a light shielding layer 30 is formed on the surface of the epitaxial layer 20 , and an etching opening 31 is formed on the surface of the light shielding layer 30 .

[0063] Optionally, the light shielding layer 30 includes a photoresist layer and / or a metal layer.

[0064] Using photoresist or metal as a mask to block the laser can prevent the laser from irradiating the area on the epitaxial layer 20 where the grooves 24 are not required, thereby achieving the purpose of irradiating the local area of ​​the epitaxial layer 20.

[0065] Exemplarily, the light shielding layer 30 is a metal layer, and the metal layer includes at least one of a Cr layer, a Pt layer, and an Au layer.

[0066] Optionally, the thickness of the light shielding layer 30 is 0.1 μm to 10 μm. By setting the thickness of the light shielding layer 30 within the above range, it is possible to avoid the light shielding layer 30 being too thin to completely shield the laser projection, so that the position of the epitaxial layer 20 that does not need to be grooved is decomposed; it is also possible to avoid the light shielding layer 30 being too thick to increase the preparation cost of the light shielding layer 30.

[0067] Exemplarily, the thickness of the light shielding layer 30 is 2 μm.

[0068] Step 203 : using laser to irradiate the etching opening 31 , so as to form a groove 24 on the surface of the epitaxial layer 20 .

[0069] like Figure 4 As shown, it may specifically include: using laser to irradiate the light shielding layer 30 so that the laser passes through the etching opening 31 to decompose the epitaxial layer 20 exposed by the etching opening 31 ; then, cleaning away the residue after decomposition, so as to form a groove 24 on the epitaxial layer 20 .

[0070] Exemplarily, there may be a plurality of etching openings 31, at least some of which are opposite to the region of the concave hole for preparing the electrode on the epitaxial layer 20, and at least some of which are opposite to the region of the isolation groove for forming the epitaxial layer 20. In this way, after the etching openings 31 are irradiated with laser, the concave hole for preparing the electrode and the isolation groove for splitting the product can be formed on the epitaxial layer 20, respectively.

[0071] Alternatively, the shorter the laser wavelength, the greater the chemical bond energy of the epitaxial material that can be decomposed.

[0072] Exemplarily, when the preparation material of the epitaxial layer 20 includes GaN, the epitaxial layer 20 is irradiated with a laser having a wavelength of 248 nm or 266 nm.

[0073] For example, when the epitaxial layer 20 is a GaN material layer, a laser with a wavelength of 248 nm is used to irradiate the epitaxial layer 20. The GaN material will decompose into metal Ga and N2 under laser irradiation, and the groove 24 is formed on the epitaxial layer 20 after the generated metal Ga and the light shielding layer 30 are cleaned.

[0074] As an example, when the material of the epitaxial layer 20 includes GaN, the energy used is greater than or equal to 100 MJ / cm 2 The epitaxial layer 20 is irradiated with laser.

[0075] When the laser energy exceeds 100MJ / cm 2 When the GaN material layer is decomposed by laser, the energy of the laser can be controlled to exceed 100MJ / cm 2 , so as to quickly decompose the GaN material and form the groove 24.

[0076] Exemplarily, when the preparation material of the epitaxial layer 20 includes AlN, a laser with a wavelength of 198.3 nm is used to irradiate the epitaxial layer 20. The AlN material will decompose into metal Al and N2 under laser irradiation, and the groove 24 is formed on the epitaxial layer 20 after cleaning the generated metal Al and the light shielding layer 30.

[0077] In the embodiment of the present disclosure, when the thickness of the epitaxial layer 20 to be etched is relatively large, for example, when the thickness to be etched reaches 0.5 μm to 7 μm, multiple laser irradiations may be used to achieve the etching.

[0078] Specifically, it may include: determining the number N of times the laser irradiates the epitaxial layer 20 based on the target etching depth of the epitaxial layer 20 and the single etching depth of the laser, where N is a positive integer.

[0079] Exemplarily, the single laser etching depth is usually below 1000 nm. For example, when the single laser etching depth is 500 nm and the target etching depth is 1 μm, the number of laser irradiations can be determined to be 2.

[0080] After the Nth laser irradiation is completed and before the N+1th laser irradiation is performed, the surface of the epitaxial layer 20 is cleaned.

[0081] Since metal will remain on the surface of the epitaxial layer 20 when the laser decomposes the epitaxial material, before laser etching again, the residual metal needs to be cleaned with a solution such as HCL / ammonia+hydrogen peroxide / phosphoric acid to facilitate the laser to continue irradiating and decomposing the epitaxial layer 20.

[0082] Step 204 : using a patterned laser spot to irradiate a local area of ​​the epitaxial layer 20 to form a groove 24 on the surface of the epitaxial layer 20 .

[0083] In the disclosed embodiment, a laser instrument can be directly used to focus the laser light into an image, so that a laser spot with a pattern is emitted from the laser instrument. In this way, there is no need to make a light shielding layer 30 on the surface of the epitaxial layer 20, but a patterned laser spot is used to directly laser-etch the required pattern on the surface of the epitaxial layer 20, thereby making the groove 24 more efficiently.

[0084] It should be noted that step 204 and steps 202 to 203 are steps of laser decomposing the epitaxial layer 20 . Therefore, when performing the laser decomposing operation of the epitaxial layer 20 , any one of step 204 or steps 202 to 203 may be selected.

[0085] After step 204 or step 203, the preparation method further comprises the following steps:

[0086] In the first step, a current blocking layer is formed on the surface of the second semiconductor layer 23 , and a transparent conductive layer 50 is formed on the surface of the second semiconductor layer 23 and the surface of the current blocking layer.

[0087] Exemplarily, the current blocking layer is a silicon oxide layer. Silicon oxide has good insulation properties and can effectively block the current in the electrode from being transferred vertically downward to the epitaxial layer 20 .

[0088] Exemplarily, the transparent conductive layer 50 is an indium tin oxide layer or an indium zinc oxide layer.

[0089] Exemplarily, the thickness of the transparent conductive layer 50 may be 1000 angstroms to 5000 angstroms. For example, the thickness of the transparent conductive layer 50 is 2000 angstroms.

[0090] In the second step, a first electrode 61 is formed in the concave hole, and the first electrode 61 is connected to the first semiconductor layer 21 . A second electrode 62 is formed on the surface of the transparent conductive layer 50 , and the second electrode 62 is connected to the transparent conductive layer 50 .

[0091] In a third step, a passivation layer 40 is formed on the surface of the second semiconductor layer 23 , the surface of the transparent conductive layer 50 , the surface of the first electrode 61 , the surface of the second electrode 62 and in the groove 24 .

[0092] The passivation layer 40 may be a distributed Bragg reflector (DBR) layer, and the DBR layer includes a plurality of periodically alternately stacked SiO2 layers and TiO2 layers. The number of periods of the DBR layer may be between 20 and 50. For example, the number of periods of the DBR layer is 32.

[0093] The thickness of the SiO2 layer in the DBR layer may be 800 angstroms to 1200 angstroms, and the thickness of the TiO2 layer may be 500 angstroms to 900 angstroms.

[0094] After the passivation layer 40 is formed, two through holes need to be formed by etching on the surface of the passivation layer 40 .

[0095] One of the through holes exposes the first electrode 61 , and the other through hole exposes the second electrode 62 .

[0096] In the fourth step, a first pad and a second pad are formed on the surface of the passivation layer 40 .

[0097] The first pad is connected to the first electrode 61 through a through hole, and the second pad is connected to the second electrode 62 through another through hole.

[0098] Exemplarily, the first pad and the second pad may each be a first Al layer, a first Ti layer, a second Al layer, a second Ti layer, and an Au layer stacked in sequence.

[0099] In the embodiment of the present disclosure, after the pad is manufactured, the preparation method may further include: manufacturing a protective layer on the surface of the passivation layer 40 .

[0100] Illustratively, in the embodiment of the present disclosure, the protective layer may be a silicon oxide layer, and the thickness of the silicon oxide layer is 2000 angstroms.

[0101] It should be noted that after the protective layer is grown on the surface of the passivation layer 40 , a through hole exposing the pad can be etched on the surface of the protective layer using photolithography technology to facilitate electrical connection.

[0102] Finally, the sapphire substrate can be subjected to operations such as splitting, AOI backside inspection, and film inversion and expansion to obtain light-emitting diodes.

[0103] Figure 5 Schematic diagram of a light emitting diode provided by an embodiment of the present disclosure. Figure 5 As shown, the light emitting diode comprises an epitaxial layer 20, and a surface of the epitaxial layer 20 has a groove 24. The sidewall of the groove 24 of the light emitting diode described above is less damaged, so the light emitting effect of the light emitting diode is also better.

[0104] like Figure 5 As shown, the light emitting diode further includes a transparent conductive layer 50 , a passivation layer 40 , a first electrode 61 and a second electrode 62 .

[0105] like Figure 5 As shown, the epitaxial layer 20 includes a first semiconductor layer 21 , a multi-quantum well layer 22 , and a second semiconductor layer 23 stacked in sequence, and a surface of the second semiconductor layer 23 has a groove 24 .

[0106] Optionally, one of the first semiconductor layer 21 and the second semiconductor layer 23 is a p-type layer, and the other of the first semiconductor layer 21 and the second semiconductor layer 23 is an n-type layer.

[0107] Exemplarily, the first semiconductor layer 21 is an n-type layer, and the second semiconductor layer 23 is a p-type layer.

[0108] Optionally, the first semiconductor layer 21 is a silicon-doped n-type GaN layer, and the thickness of the n-type GaN layer may be 0.5 μm to 3 μm.

[0109] Optionally, the multi-quantum well layer 22 includes alternately grown InGaN quantum well layers and GaN quantum barrier layers, wherein the multi-quantum well layer 22 may include 3 to 8 periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0110] As an example, in the embodiment of the present disclosure, the multi-quantum well layer 22 includes five periods of alternately stacked InGaN quantum well layers and GaN quantum barrier layers.

[0111] Optionally, the thickness of the multi-quantum well layer 22 may be 150 nm to 200 nm.

[0112] Optionally, the second semiconductor layer 23 is a magnesium-doped p-type GaN layer. The thickness of the p-type GaN layer may be 0.5 μm to 3 μm.

[0113] like Figure 5 As shown, the transparent conductive layer 50 is located on the surface of the second semiconductor layer 23, the passivation layer 40 is located on the surface of the second semiconductor layer 23 and in the groove 24, and the passivation layer 40 covers the transparent conductive layer 50, and the passivation layer 40 has through holes that expose the transparent conductive layer 50 and the groove 24 respectively.

[0114] Exemplarily, the transparent conductive layer 50 is an indium tin oxide layer or an indium zinc oxide layer.

[0115] Exemplarily, the thickness of the transparent conductive layer 50 may be 1000 angstroms to 5000 angstroms. For example, the thickness of the transparent conductive layer 50 is 2000 angstroms.

[0116] Both the indium tin oxide layer and the indium zinc oxide layer have good transmittance and low resistivity. Using the indium tin oxide layer or the indium zinc oxide layer as the transparent conductive layer 50 can allow more light to be transmitted from the transparent conductive layer 50, thereby ensuring the light output effect; at the same time, due to the low resistivity, it is also convenient for carrier conduction and improves the injection efficiency.

[0117] Exemplarily, the passivation layer 40 may be a DBR layer, which includes a plurality of SiO2 layers and TiO2 layers that are periodically and alternately stacked, and the number of periods of the DBR layer may be between 20 and 50. For example, the number of periods of the DBR layer is 32.

[0118] The thickness of the SiO2 layer in the DBR layer may be 800 angstroms to 1200 angstroms, and the thickness of the TiO2 layer may be 500 angstroms to 900 angstroms.

[0119] In addition to the passivation effect, the DBR layer is also used to reflect the light emitted from the multi-quantum well layer 22 to the DBR layer to the sapphire substrate, thereby improving the light extraction effect.

[0120] like Figure 5 As shown, the first electrode 61 is located in the groove 24 and on the surface of the passivation layer 40, and is connected to the first semiconductor layer 21 through a through hole. The second electrode 62 is located on the surface of the passivation layer 40, and is connected to the transparent conductive layer 50 through a through hole.

[0121] Exemplarily, each of the first electrode 61 and the second electrode 62 may include a plurality of metal layers stacked in sequence, and the metal layers include a Ti layer, an Al layer, a Pt layer, a Ni layer, and an Au layer.

[0122] Among them, setting metal Ti in the electrode can improve the strength of the electrode; setting metal Al and Pt in the electrode can improve the corrosion resistance of the electrode; setting metal Ni in the electrode can increase the melting point of the electrode; setting metal Au in the electrode can make the electrode more resistant to corrosion.

[0123] Illustratively, the electrode includes a Ti layer, an Al layer, a Pt layer, a Ni layer, and an Au layer stacked in sequence.

[0124] Optionally, the thickness of the electrode is 0.1 μm to 3 μm.

[0125] Exemplarily, the thickness of the Ti layer is 2 μm; the thickness of the Al layer is 1 μm; the thickness of the Pt layer is 0.5 μm; the thickness of the Ni layer is 1.2 μm; and the thickness of the Au layer is 1.5 μm.

[0126] The above description is only an optional embodiment of the present disclosure and is 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 scope of the present disclosure.

Claims

1. A method for preparing a light emitting diode, characterized in that: The preparation method comprises: forming an epitaxial layer (20); Laser is used to irradiate a local area of ​​the epitaxial layer (20), so that the local area of ​​the epitaxial layer (20) is decomposed and a groove (24) is formed.

2. The preparation method according to claim 1, characterized in that: Using laser to irradiate a local area of ​​the epitaxial layer (20) comprises: A light shielding layer (30) is formed on the surface of the epitaxial layer (20), wherein the light shielding layer (30) has an etching opening (31) exposing a local area of ​​the epitaxial layer (20); The etching opening (31) is irradiated with laser light to form the groove (24) on the surface of the epitaxial layer (20).

3. The preparation method according to claim 2, characterized in that: The light shielding layer (30) comprises a photoresist layer and / or a metal layer.

4. The preparation method according to claim 2, characterized in that: The thickness of the light shielding layer (30) is 0.1 μm to 10 μm.

5. The preparation method according to claim 1, characterized in that: Using laser to irradiate a local area of ​​the epitaxial layer (20) comprises: A patterned laser spot is used to irradiate a local area of ​​the epitaxial layer (20), thereby forming the groove (24) on the surface of the epitaxial layer (20).

6. The preparation method according to any one of claims 1 to 5, characterized in that: Using laser to irradiate a local area of ​​the epitaxial layer (20) comprises: When the preparation material of the epitaxial layer (20) includes GaN, a laser with a wavelength of 248 nm or 266 nm is used to irradiate the epitaxial layer (20); When the preparation material of the epitaxial layer (20) includes AlN, a laser with a wavelength of 198.3 nm is used to irradiate the epitaxial layer (20).

7. The preparation method according to any one of claims 1 to 5, characterized in that: Using laser to irradiate a local area of ​​the epitaxial layer (20) comprises: When the preparation material of the epitaxial layer (20) includes GaN, the energy used is greater than or equal to 100 MJ / cm 2 The epitaxial layer (20) is irradiated with laser.

8. The preparation method according to any one of claims 1 to 5, characterized in that: Using laser to irradiate a local area of ​​the epitaxial layer (20) comprises: Based on the target etching depth of the epitaxial layer (20) and the single etching depth of the laser, determining the number of times N that the laser irradiates the epitaxial layer (20), where N is a positive integer; After the Nth laser irradiation is completed and before the N+1th laser irradiation is performed, the surface of the epitaxial layer (20) is cleaned.

9. A light emitting diode, characterized in that: The light emitting diode is manufactured by the manufacturing method according to any one of claims 1 to 8, and comprises an epitaxial layer (20), wherein a surface of the epitaxial layer (20) has a groove (24).

10. The light emitting diode according to claim 9, characterized in that: The light-emitting diode further comprises a transparent conductive layer (50), a passivation layer (40), a first electrode (61) and a second electrode (62); The epitaxial layer (20) comprises a first semiconductor layer (21), a multi-quantum well layer (22), and a second semiconductor layer (23) which are stacked in sequence; the surface of the second semiconductor layer (23) has the groove (24); the transparent conductive layer (50) is located on the surface of the second semiconductor layer (23); the passivation layer (40) is located on the surface of the second semiconductor layer (23) and in the groove (24), and covers the transparent conductive layer (50); the passivation layer (40) has through holes respectively exposing the transparent conductive layer (50) and the groove (24); The first electrode (61) is located in the groove (24) and on the surface of the passivation layer (40), and is connected to the first semiconductor layer (21) through a through hole; the second electrode (62) is located on the surface of the passivation layer (40), and is connected to the transparent conductive layer (50) through a through hole.

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