Reversed polarity light emitting diode and preparation method thereof

Abstract

The invention provides a reversed polarity light emitting diode and a preparation method thereof, and belongs to the technical field of photoelectron manufacturing. The light-emitting diode comprises a substrate, a silver mirror reflecting layer, an epitaxial structure and a wrapping structure, wherein the substrate, the silver mirror reflecting layer and the epitaxial structure are stacked in sequence; the wrapping structure and the silver mirror reflecting layer are both located on the same surface of the epitaxial structure, and the wrapping structure surrounds the silver mirror reflecting layer. According to the embodiment of the invention, the problem of metal migration in the silver mirror reflecting layer can be improved, and the reversed-polarity light-emitting diode is prevented from electric leakage.

Description

Technical Field

[0001] 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 Art

[0002] The reverse polarity light emitting diode generally adopts a vertical structure, and the reverse polarity vertical light emitting diode includes a substrate, a silver mirror reflection layer, a transparent conductive layer, a dielectric layer and an epitaxial layer stacked in sequence. A through hole is provided on the dielectric layer to expose the transparent conductive layer, and the transparent conductive layer can be electrically connected to the epitaxial layer through the through hole.

[0003] Since the silver mirror reflective layer is usually spread all over the surface of the transparent conductive layer, after the reverse polarity LED is split, the metal Ag on the side wall of the silver mirror reflective layer is exposed to the air. When the reverse polarity LED is lit for a long time, the metal Ag is easily oxidized and easily migrates to the epitaxial layer at the cutting path position, causing leakage of the reverse polarity LED. Summary of the invention

[0004] The embodiment of the present disclosure provides a reverse polarity light emitting diode and a method for manufacturing the same, which can improve the problem of metal migration in the silver mirror reflection layer and prevent the reverse polarity light emitting diode from leaking electricity. The technical solution is as follows:

[0005] On the one hand, an embodiment of the present disclosure provides a reverse polarity light emitting diode, which includes: a substrate, a silver mirror reflection layer, an epitaxial structure and a wrapping structure, wherein the substrate, the silver mirror reflection layer and the epitaxial structure are stacked in sequence; the wrapping structure and the silver mirror reflection layer are both located on the same surface of the epitaxial structure, and the wrapping structure surrounds the silver mirror reflection layer.

[0006] Optionally, the wrapping structure includes a bonding layer, the bonding layer is located on the surface of the substrate close to the epitaxial structure, the surface of the bonding layer away from the substrate has a wrapping groove, the silver mirror reflecting layer is located in the wrapping groove, and the surface of the silver mirror reflecting layer away from the substrate and the surface of the bonding layer away from the substrate are both connected to the same surface of the epitaxial structure.

[0007] Optionally, the groove depth of the wrapping groove is greater than or equal to the thickness of the silver mirror reflection layer.

[0008] Optionally, the reverse polarity light emitting diode further includes a bonding layer, which is located on the surface of the substrate close to the epitaxial structure; the encapsulating structure includes a metal protective layer, the metal protective layer and the silver mirror reflecting layer are both located on the surface of the bonding layer away from the substrate, and the metal protective layer surrounds the silver mirror reflecting layer.

[0009] Optionally, the metal protection layer includes an Au layer.

[0010] Optionally, the bonding layer includes at least one of a Ti layer, a Pt layer, an Au layer, and an In layer.

[0011] Optionally, the thickness of the silver mirror reflection layer is 200 nm to 1000 nm.

[0012] Optionally, a ratio of an area of ​​an orthographic projection of the silver mirror reflection layer on the substrate to an area of ​​an orthographic projection of the epitaxial structure on the substrate is 0.6 to 0.95.

[0013] Optionally, the epitaxial structure includes: 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 stacked on a surface of the silver mirror reflective layer away from the substrate; the dielectric layer has a through hole connecting the epitaxial layer and the transparent conductive layer, the through hole is filled with a conductive material block, and the conductive material block is electrically connected to the transparent conductive layer and the epitaxial layer respectively.

[0014] On the other hand, an embodiment of the present disclosure also provides a method for preparing a reverse polarity light-emitting diode, the preparation method comprising: preparing an epitaxial structure; forming a silver mirror reflection layer and a wrapping structure on the same surface of the epitaxial structure, the wrapping structure surrounding the silver mirror reflection layer; bonding a side of the silver mirror reflection layer away from the epitaxial structure to a substrate.

[0015] The beneficial effects brought by the technical solution provided by the embodiments of the present disclosure include at least:

[0016] The reverse polarity light emitting diode of the disclosed embodiment has a silver mirror reflection layer and a wrapping structure formed on the same surface of the epitaxial structure, and the wrapping structure surrounds and wraps the silver mirror reflection layer. In this way, the wrapping structure can be used to surround the side wall of the silver mirror reflection layer to prevent the metal Ag at the location of the side wall of the silver mirror reflection layer from migrating to the area where the epitaxial structure is located, thereby causing the film layer on the epitaxial structure to short-circuit and cause the reverse polarity light emitting diode to leak electricity, thereby improving the reliability of the reverse polarity light emitting diode. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] Figure 1 is a schematic structural diagram of a reverse polarity light emitting diode provided by an embodiment of the present disclosure;

[0019] Figure 2is a schematic structural diagram of a reverse polarity light emitting diode provided by an embodiment of the present disclosure;

[0020] Figure 3 is a flow chart of a method for preparing a reverse polarity light emitting diode provided by an embodiment of the present disclosure;

[0021] Figure 4 is a diagram of a preparation state of a light emitting diode provided by an embodiment of the present disclosure;

[0022] Figure 5 is a diagram of a preparation state of a light emitting diode provided by an embodiment of the present disclosure;

[0023] Figure 6 is a diagram of a preparation state of a light emitting diode provided by an embodiment of the present disclosure;

[0024] Figure 7 is a diagram of a preparation state of a light emitting diode provided by an embodiment of the present disclosure;

[0025] Figure 8 This is a diagram of the preparation state of a light emitting diode provided in an embodiment of the present disclosure.

[0026] The descriptions of the marks in the figure are as follows:

[0027] 10. Substrate;

[0028] 20. Silver mirror reflection layer;

[0029] 30. Epitaxial structure;

[0030] 31. Transparent conductive layer; 32. Dielectric layer; 33. Epitaxial layer; 34. Conductive material block;

[0031] 40. Package structure;

[0032] 41, bonding layer; 410, wrapping groove;

[0033] 42. Metal protective layer;

[0034] 61. First electrode; 62. Second electrode. DETAILED DESCRIPTION

[0035] 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.

[0036] 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.

[0037] Figure 1 Schematic diagram of a reverse polarity light emitting diode provided by an embodiment of the present disclosure. Figure 1 As shown, the reverse polarity light emitting diode comprises: a substrate 10, a silver mirror reflection layer 20, an epitaxial structure 30 and a packaging structure 40, wherein the substrate 10, the silver mirror reflection layer 20 and the epitaxial structure 30 are stacked in sequence.

[0038] like Figure 1 As shown, the encapsulating structure 40 and the silver mirror reflecting layer 20 are both located on the same surface of the epitaxial structure 30 , and the encapsulating structure 40 surrounds the silver mirror reflecting layer 20 .

[0039] The reverse polarity light emitting diode of the disclosed embodiment has a silver mirror reflection layer 20 and a wrapping structure 40 formed on the same surface of the epitaxial structure 30, and the wrapping structure 40 surrounds and wraps the silver mirror reflection layer 20. In this way, the wrapping structure 40 can be used to surround the side wall of the silver mirror reflection layer 20 to prevent the metal Ag at the location of the side wall of the silver mirror reflection layer 20 from migrating to the area where the epitaxial structure 30 is located, thereby causing the film layer on the epitaxial structure 30 to short-circuit and cause the reverse polarity light emitting diode to leak electricity, thereby improving the reliability of the reverse polarity light emitting diode.

[0040] In one implementation of the present disclosure, Figure 1 As shown, the encapsulation structure 40 includes a bonding layer 41, which is located on the surface of the substrate close to the epitaxial structure 30, and the surface of the bonding layer 41 away from the substrate has a encapsulation groove 410, the silver mirror reflection layer 20 is located in the encapsulation groove 410, and the surface of the silver mirror reflection layer 20 away from the substrate and the surface of the bonding layer 41 away from the substrate are both connected to the same surface of the epitaxial structure 30.

[0041] The silver mirror reflection layer 20 is wrapped in the wrapping groove 410 by digging a groove in the bonding layer 41, so that the side wall of the silver mirror reflection layer 20 can be completely covered, thereby preventing the metal Ag of the silver mirror reflection layer 20 from migrating to the epitaxial layer 33 and affecting the stability of the reverse polarity light emitting diode.

[0042] At the same time, by using the bonding layer 41 to wrap the silver mirror reflection layer 20, there is no need to add other film layers, which can reduce the difficulty and cost of preparation.

[0043] Optionally, the groove depth of the wrapping groove 410 is greater than or equal to the thickness of the silver mirror reflection layer 20 .

[0044] By making the depth of the wrapping groove 410 not less than the thickness of the silver mirror reflection layer 20, it is ensured that the bonding layer 41 can completely wrap the side wall of the silver mirror reflection layer 20, thereby avoiding the problem of metal Ag migration to the greatest extent.

[0045] For example, Figure 1 As shown, the groove depth of the wrapping groove 410 is equal to the thickness of the silver mirror reflection layer 20.

[0046] Optionally, the thickness of the silver mirror reflection layer 20 is 200 nm to 1000 nm.

[0047] As an example, the thickness of the silver mirror reflection layer 20 is 350 nm, and accordingly, the groove depth of the wrapping groove 410 is greater than or equal to 350 nm. For example, the groove depth of the wrapping groove 410 may be 350 nm.

[0048] Optionally, the bonding layer 41 includes at least one of a Ti layer, a Pt layer, an Au layer, and an In layer.

[0049] Illustratively, the bonding layer 41 may be a Ti layer and an In layer stacked sequentially.

[0050] In the embodiment of the present disclosure, the In layer in the bonding layer 41 can utilize the good bonding performance of In to improve the bonding stability between the silver mirror reflection layer 20 and the substrate.

[0051] In another implementation of the present disclosure, Figure 2 Schematic diagram of a reverse polarity light emitting diode provided by an embodiment of the present disclosure. Figure 2 As shown, the reverse polarity light emitting diode further includes a bonding layer 41 , and the bonding layer 41 is located on the surface of the substrate close to the epitaxial structure 30 .

[0052] like Figure 2As shown, the encapsulation structure 40 includes a metal protection layer 42, and the metal protection layer 42 and the silver mirror reflection layer 20 are both located on the surface of the bonding layer 41 away from the substrate, and the metal protection layer 42 surrounds the silver mirror reflection layer 20. That is, the metal protection layer 42 and the silver mirror reflection layer 20 are sandwiched between the epitaxial structure 30 and the bonding layer 41.

[0053] By wrapping the edge of the silver mirror reflection layer 20 with a metal protective layer 42, the metal protective layer 42 isolates the metal Ag and prevents the metal Ag from being exposed to the air. At the same time, the metal protective layer 42 is used to replace the peripheral edge of the silver mirror reflection layer 20 that has been removed, so that the metal protective layer 42 plays a mirror reflection role, which not only improves the reliability of the reverse polarity light-emitting diode, but also reduces the brightness loss caused by reducing the area of ​​the silver mirror reflection layer 20.

[0054] Exemplarily, the metal protection layer 42 includes an Au layer. Metal Au has good stability, and the use of metal Au to wrap the sidewall of the silver mirror reflection layer 20 can effectively prevent the problem of metal Ag migration.

[0055] Furthermore, metal Au has a good reflective effect on light, which can reduce the brightness loss caused by reducing the area of ​​the silver mirror reflective layer 20 .

[0056] Optionally, the bonding layer 41 includes at least one of a Ti layer, a Pt layer, an Au layer, and an In layer.

[0057] Illustratively, the bonding layer 41 may be a Ti layer and an In layer stacked sequentially.

[0058] In the embodiment of the present disclosure, the In layer in the bonding layer 41 can utilize the good bonding performance of In to improve the bonding stability between the silver mirror reflection layer 20 and the substrate.

[0059] Optionally, the thickness of the silver mirror reflection layer 20 is 200 nm to 1000 nm. Exemplarily, the thickness of the silver mirror reflection layer 20 is 350 nm.

[0060] Optionally, a ratio of an area of ​​an orthographic projection of the silver mirror reflection layer 20 on the substrate to an area of ​​an orthographic projection of the epitaxial structure 30 on the substrate is 0.6 to 0.95.

[0061] By setting the ratio of the area of ​​the silver mirror reflection layer 20 to the area of ​​the epitaxial structure 30 within the above range, it is possible to avoid the area of ​​the silver mirror reflection layer 20 being too large, resulting in the length of the wrapping structure 40 being too small in the horizontal direction, and failing to achieve the effect of tightly wrapping the side wall of the silver mirror reflection layer 20; it is also possible to avoid the area of ​​the silver mirror reflection layer 20 being too small, resulting in the length of the wrapping structure 40 being too large in the horizontal direction, and greatly reducing the area of ​​the silver mirror reflection layer 20, so that the reflective surface of the silver mirror reflection layer 20 is reduced, thereby weakening the brightness of the reverse polarity light emitting diode.

[0062] Exemplarily, the ratio of the area of ​​the orthographic projection of the silver mirror reflection layer 20 on the substrate to the area of ​​the orthographic projection of the epitaxial structure 30 on the substrate is 0.85.

[0063] Alternatively, if Figure 1 , 2 As shown, the epitaxial structure 30 includes: a transparent conductive layer 31, a dielectric layer 32 and an epitaxial layer 33, which are sequentially stacked on the surface of the silver mirror reflective layer 20 away from the substrate.

[0064] like Figure 1 , 2 As shown, the dielectric layer 32 has a through hole connecting the epitaxial layer 33 and the transparent conductive layer 31 , and the through hole is filled with a conductive material block 34 , which is electrically connected to the transparent conductive layer 31 and the epitaxial layer 33 , respectively.

[0065] In the embodiment of the present disclosure, electrodes are provided on both the side of the epitaxial layer 33 of the light emitting diode away from the substrate and the side of the substrate away from the epitaxial layer 33, so that current can be injected into the light emitting diode through the electrodes. The light emitting diode of this structure is a vertical structure light emitting diode.

[0066] Optionally, the substrate is a silicon substrate or a silicon carbide substrate. The substrate can be a flat substrate or a patterned substrate.

[0067] 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.

[0068] In the present disclosure, Figure 1 , 2 As shown, the epitaxial layer 33 includes an ohmic contact layer, a first semiconductor layer, a multi-quantum well layer and a second semiconductor layer sequentially stacked on the dielectric layer 32. The transparent conductive layer 31 is connected to the ohmic contact layer through a conductive material block 34 in the through hole.

[0069] Exemplarily, the ohmic contact layer may include a gold-zinc alloy layer or a gold-beryllium alloy layer.

[0070] Exemplarily, the ohmic contact layer may also be an indium tin oxide layer or an indium zinc oxide layer.

[0071] like Figure 1 , 2 As shown, the light emitting diode further includes a first electrode 61 and a second electrode 62 . The first electrode 61 is located on a surface of the epitaxial layer 33 away from the substrate, and the second electrode 62 is located on a surface of the substrate away from the epitaxial layer 33 .

[0072] 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.

[0073] As an example, the first semiconductor layer is a p-type layer, and the second electrode 62 is a p-type electrode. The second semiconductor layer is an n-type layer, and the first electrode 61 is an n-type electrode.

[0074] 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.

[0075] 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.

[0076] As an example, in the embodiment of the present disclosure, the multi-quantum well layer includes five periods of alternately stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers.

[0077] Optionally, the thickness of the multi-quantum well layer may be 150 nm to 200 nm.

[0078] 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.

[0079] Exemplarily, the silver mirror reflection layer 20 may include a film layer made of a metal material having a good reflection effect, such as an Ag layer and a Cu layer.

[0080] In the disclosed embodiment, the second electrode 62 is disposed on the side of the silicon substrate away from the epitaxial layer 33. When the second electrode 62 is energized, the current is transferred to the transparent conductive layer 31 through the silicon substrate. Since the dielectric layer 32 is an insulating film layer, a through hole is disposed on the dielectric layer 32, and a conductive material block 34 is filled in the through hole, so that the transparent conductive layer 31 forms an ohmic contact with the conductive material block 34, so that the current can be transferred to the epitaxial layer 33 through the transparent conductive layer 31.

[0081] Alternatively, if Figure 1 As shown, the surface of the dielectric layer 32 away from the substrate has a plurality of through holes arranged in an array, and the orthographic projections of the through holes on the substrate are located outside the orthographic projections of the first electrode 61 on the substrate.

[0082] In the embodiment of the present disclosure, the surface of the epitaxial layer 33 away from the substrate is the light emitting surface, and the first electrode 61 will block the light. Therefore, setting the through hole at a position not opposite to the first electrode 61 can transfer more current to the area of ​​the epitaxial layer 33 that is not opposite to the first electrode 61. In this way, the luminous intensity of the area of ​​the epitaxial layer 33 that is not opposite to the first electrode 61 is higher, thereby improving the luminous effect of the light-emitting diode.

[0083] For example, Figure 1 As shown, the through holes are arranged in an array. Arranging a plurality of through holes distributed at intervals allows the current to be uniformly transferred to various regions of the epitaxial layer 33 through the conductive material blocks 34 in the through holes, thereby improving the light-emitting effect of the light-emitting diode.

[0084] Optionally, the transparent conductive layer 31 includes an indium tin oxide layer or an indium zinc oxide layer.

[0085] In the disclosed embodiment, the dielectric layer 32 is generally a silicon oxide layer, a magnesium fluoride layer, and a titanium oxide layer. The dielectric layer 32 made of these materials has low adhesion to the silver mirror reflection layer 20, while the adhesion of the indium tin oxide layer and the indium zinc oxide layer to the silver mirror reflection layer 20 is higher than the adhesion of the dielectric layer 32 to the silver mirror reflection layer 20. Therefore, using an indium tin oxide layer or an indium zinc oxide layer as the transparent conductive layer 31 can effectively improve the connection reliability between the dielectric layer 32 and the silver mirror reflection layer 20.

[0086] Among them, 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 31 can allow more light to be transmitted from the transparent conductive layer 31 to the reflector layer, reduce the amount of light absorbed, and allow more light to be reflected from the metal layer to the light emitting surface, thereby ensuring the light emitting effect.

[0087] Optionally, the thickness of a portion of the transparent conductive layer 31 located between the dielectric layer 32 and the substrate is 10 nm to 500 nm.

[0088] Exemplarily, the thickness of the transparent conductive layer 31 may be 100 nm.

[0089] If the transparent conductive layer 31 is too thin, the adhesion between the reflector layer and the dielectric layer 32 will be affected; if the transparent conductive layer 31 is too thick, the transparent conductive layer 31 will increase its absorption of light, thereby reducing the luminous efficiency of the light-emitting diode.

[0090] Optionally, the conductive material block 34 includes at least one of indium tin oxide, indium zinc oxide and a metal material.

[0091] By way of example, the conductive material block 34 located in the through hole may be indium zinc oxide.

[0092] Figure 3The flowchart of the method for preparing a reverse polarity light emitting diode provided by the embodiment of the present disclosure is as follows. Figures 1 to 2 The reverse polarity LED shown. Figure 3 As shown, the preparation method comprises:

[0093] S11: preparing an epitaxial structure.

[0094] S12 : forming a silver mirror reflection layer 20 and a packaging structure 40 on the same surface of the epitaxial structure 30 .

[0095] The wrapping structure 40 surrounds the silver mirror reflection layer 20.

[0096] S13: bonding the side of the silver mirror reflection layer 20 away from the epitaxial structure 30 to the substrate.

[0097] The reverse polarity light emitting diode prepared by the preparation method has a silver mirror reflection layer 20 and a wrapping structure 40 formed on the same surface of the epitaxial structure 30, and the wrapping structure 40 surrounds and wraps the silver mirror reflection layer 20. In this way, the wrapping structure 40 can be used to surround the side wall of the silver mirror reflection layer 20 to prevent the metal Ag at the location of the side wall of the silver mirror reflection layer 20 from migrating to the area where the epitaxial structure 30 is located, thereby causing the film layer on the epitaxial structure 30 to short-circuit, causing the reverse polarity light emitting diode to leak electricity, and improving the reliability of the reverse polarity light emitting diode.

[0098] The preparation of the epitaxial structure 30 in step S11 may include the following steps:

[0099] The first step is to provide a growth substrate.

[0100] The growth substrate may be a GaAs wafer.

[0101] In the second step, an epitaxial layer 33 is formed on the growth substrate.

[0102] In the embodiment of the present disclosure, the epitaxial layer 33 may include: a first semiconductor layer, a multi-quantum well layer, and a second semiconductor layer.

[0103] Exemplarily, the first semiconductor layer is a p-type layer, and the second semiconductor layer is an n-type layer.

[0104] As an example, the n-type layer may include: an n-type roughening layer, an n-type current spreading layer, and an n-type confinement layer.

[0105] As an example, the p-type layer may include: a p-type confinement layer, a p-type current spreading layer, a transition layer, and a p-type ohmic contact layer.

[0106] Exemplarily, the p-type confinement layer, the p-type current spreading layer and the transition layer may all be AlInP layers.

[0107] Illustratively, the p-type ohmic contact layer may be a p-type GaP layer.

[0108] The p-type GaP layer can be doped with Mg, and the doping concentration of Mg is 1×10 18 / cm 3 .

[0109] Exemplarily, the thickness of the p-type layer is 0.5 μm to 3 μm.

[0110] Optionally, the multi-quantum well layer includes an AlGaInP quantum well layer and an AlGaInP quantum barrier layer that are grown alternately.

[0111] The multi-quantum well layer may include 3 to 8 periods of alternately stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers.

[0112] As an example, in the embodiment of the present disclosure, the multi-quantum well layer includes five periods of alternately stacked AlGaInP quantum well layers and AlGaInP quantum barrier layers.

[0113] Exemplarily, the thickness of the multi-quantum well layer may be 150 nm to 200 nm.

[0114] Optionally, the n-type roughening layer, the n-type current spreading layer and the n-type confinement layer may all be n-type AlGaInP layers.

[0115] Exemplarily, the thickness of the n-type AlGaInP layer may be 0.5 μm to 3 μm.

[0116] Specifically, it may include: using MOCVD method to grow n-type roughening layer, n-type current spreading layer, n-type confinement layer, multi-quantum well layer, p-type confinement layer, p-type current spreading layer, transition layer and p-type ohmic contact layer

[0117] The third step is Figure 4 As shown, a conductive material block 34 is formed on a surface of the epitaxial layer 33 away from the growth substrate.

[0118] Specifically, it includes: evaporating a conductive material on the p-type ohmic contact layer, then spin-coating a photoresist on the surface, exposing, developing, making a pattern with grooves on the photoresist, corroding the conductive material, removing the resist, making the required pattern, that is, forming a conductive material block 34 in the groove.

[0119] Optionally, the conductive material block 34 includes at least one of indium tin oxide, indium zinc oxide and a metal material.

[0120] For example, the conductive material block 34 may be indium tin oxide.

[0121] Exemplarily, the thickness of the conductive material block 34 is 5 nm to 300 nm.

[0122] The fourth step is Figure 5 As shown, a dielectric layer 32 is formed on a surface of the epitaxial layer 33 away from the growth substrate and on a conductive material block 34 .

[0123] The dielectric layer 32 has a through hole exposing the conductive material block 34 .

[0124] Specifically, the process includes: depositing a dielectric layer 32 on the surface of the p-type ohmic contact layer, and then spin-coating photoresist, exposing, and developing to form a through hole on the dielectric layer 32 that exposes the p-type ohmic contact layer.

[0125] The dielectric layer 32 may be at least one of a silicon oxide layer and a titanium oxide layer.

[0126] Step 5: Figure 6 As shown, a transparent conductive layer 31 is formed on a surface of the dielectric layer 32 away from the growth substrate.

[0127] The transparent conductive layer 31 is electrically connected to the conductive material block 34 .

[0128] Exemplarily, the transparent conductive layer 31 includes an indium tin oxide layer or an indium zinc oxide layer.

[0129] Specifically, it may include: forming a transparent conductive layer 31 on a surface of the dielectric layer 32 away from the growth substrate by full-surface sputtering, so that the transparent conductive layer 31 forms an ohmic contact with the conductive material block 34 .

[0130] Exemplarily, the thickness of the transparent conductive layer 31 may be 10 nm to 500 nm.

[0131] To prepare Figure 1 For the reverse polarity light emitting diode shown, steps S12 to S13 may include the following steps:

[0132] First, if Figure 7 As shown, a silver mirror reflection layer 20 is formed on the surface of the transparent conductive layer 31 .

[0133] When forming the silver mirror reflection layer 20 , a metal layer may be formed on the surface of the transparent conductive layer 31 by evaporation, and then annealed at a low temperature.

[0134] The metal layer may be a film layer made of metal materials such as Ag and Cu with good reflective effect.

[0135] Then, the photoresist is spin-coated, exposed, and developed, and the peripheral edge of the silver mirror reflection layer 20 is removed by a stripping or etching process.

[0136] Exemplarily, the thickness of the silver mirror reflection layer 20 is 200 nm to 1000 nm.

[0137] Then, if Figure 1As shown, the silver mirror reflection layer 20 is bonded to the silicon substrate through the bonding layer 41, and the bonding layer 41 wraps the side wall of the silver mirror reflection layer 20 and the surface of the silver mirror reflection layer 20 close to the silicon substrate.

[0138] Then, the growth substrate is removed, and a first electrode 61 is formed on the surface of the second semiconductor layer; and a second electrode 62 is formed on the silicon substrate.

[0139] Finally, a cutting process is performed to produce individual core particles.

[0140] To prepare Figure 2 For the reverse polarity light emitting diode shown, steps S12 to S13 may include the following steps:

[0141] First, if Figure 8 As shown, a silver mirror reflection layer 20 is formed on the surface of the transparent conductive layer 31 .

[0142] When forming the silver mirror reflection layer 20 , a metal layer may be formed on the surface of the transparent conductive layer 31 by evaporation, and then annealed at a low temperature.

[0143] The metal layer may be a film layer made of metal materials such as Ag and Cu with good reflective effect.

[0144] Then, the photoresist is spin-coated, exposed, and developed, and the peripheral edge of the silver mirror reflection layer 20 is removed by a stripping or etching process.

[0145] Exemplarily, the thickness of the silver mirror reflection layer 20 is 200 nm to 1000 nm.

[0146] Then, if Figure 8 As shown, a metal protection layer 42 is evaporated on the transparent conductive layer 31 exposed at the peripheral edge of the silver mirror reflection layer 20 , so that the metal protection layer 42 wraps the side wall of the silver mirror reflection layer 20 .

[0147] The metal protection layer 42 may be an Au layer.

[0148] Then, if Figure 2 As shown, the silver mirror reflection layer 20 and the metal protection layer 42 are bonded to the silicon substrate via the bonding layer 41 .

[0149] Next, the growth substrate is removed, and a first electrode 61 is formed on the surface of the second semiconductor layer; and a second electrode 62 is formed on the silicon substrate.

[0150] Finally, a cutting process is performed to produce individual core particles.

[0151] Tables 1 to 3 below give data descriptions of leakage current of light emitting diodes. Table 1 shows leakage current of light emitting diodes provided by related art, where the silver mirror reflection layer of the light emitting diode is spread over the surface of the transparent conductive layer. Table 2 shows Figure 1 Table 3 shows the leakage current of the LED. Figure 2 Schematic diagram of the leakage of the light-emitting diode.

[0152] Table 1

[0153]

[0154] Table 2

[0155]

[0156] Table 3

[0157]

[0158] According to Table 1, some of the light-emitting diodes in the related art detected a leakage voltage of 5V when the working time reached 96 hours, indicating that the light-emitting diodes began to leak. However, in Tables 2 and 3, the light-emitting diodes provided by the embodiments of the present disclosure did not leak when the working time reached 500 hours. It can be seen that the light-emitting diodes provided by the embodiments of the present disclosure can improve the leakage problem and enhance the reliability of the light-emitting diodes.

[0159] 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 reverse polarity light emitting diode, characterized in that: The reverse polarity light emitting diode comprises: a substrate (10), a silver mirror reflection layer (20), an epitaxial structure (30) and a wrapping structure (40), wherein the substrate (10), the silver mirror reflection layer (20) and the epitaxial structure (30) are stacked in sequence; The encapsulating structure (40) and the silver mirror reflecting layer (20) are both located on the same surface of the epitaxial structure (30), and the encapsulating structure (40) surrounds the silver mirror reflecting layer (20).

2. The reverse polarity light emitting diode according to claim 1, characterized in that: The encapsulation structure (40) comprises a bonding layer (41), the bonding layer (41) being located on a surface of the substrate (10) close to the epitaxial structure (30), the surface of the bonding layer (41) away from the substrate (10) having an encapsulation groove (410), the silver mirror reflection layer (20) being located in the encapsulation groove (410), and the surface of the silver mirror reflection layer (20) away from the substrate (10) and the surface of the bonding layer (41) away from the substrate (10) being connected to the same surface of the epitaxial structure (30).

3. The reverse polarity light emitting diode according to claim 2, characterized in that: The groove depth of the wrapping groove (410) is greater than or equal to the thickness of the silver mirror reflection layer (20).

4. The reverse polarity light emitting diode according to claim 1, characterized in that: The reverse polarity light emitting diode further comprises a bonding layer (41), wherein the bonding layer (41) is located on a surface of the substrate (10) close to the epitaxial structure (30); The encapsulating structure (40) comprises a metal protective layer (42), wherein the metal protective layer (42) and the silver mirror reflecting layer (20) are both located on a surface of the bonding layer (41) away from the substrate (10), and the metal protective layer (42) surrounds the silver mirror reflecting layer (20).

5. The reverse polarity light emitting diode according to claim 4, characterized in that: The metal protection layer (42) comprises an Au layer.

6. The reverse polarity light emitting diode according to any one of claims 2 to 5, characterized in that: The bonding layer (41) includes at least one of a Ti layer, a Pt layer, an Au layer, and an In layer.

7. The reverse polarity light emitting diode according to any one of claims 1 to 5, characterized in that: The thickness of the silver mirror reflection layer (20) is 200nm to 1000nm.

8. The reverse polarity light emitting diode according to any one of claims 1 to 5, characterized in that: The ratio of the area of ​​the orthographic projection of the silver mirror reflection layer (20) on the substrate (10) to the area of ​​the orthographic projection of the epitaxial structure (30) on the substrate (10) is 0.6 to 0.

95.

9. The reverse polarity light emitting diode according to any one of claims 1 to 5, characterized in that: The epitaxial structure (30) comprises: a transparent conductive layer (31), a dielectric layer (32) and an epitaxial layer (33), wherein the transparent conductive layer (31), the dielectric layer (32) and the epitaxial layer (33) are sequentially stacked on a surface of the silver mirror reflection layer (20) away from the substrate (10); The dielectric layer (32) has a through hole connecting the epitaxial layer (33) and the transparent conductive layer (31); the through hole is filled with a conductive material block (34); and the conductive material block (34) is electrically connected to the transparent conductive layer (31) and the epitaxial layer (33), respectively.

10. A method for preparing a reverse polarity light emitting diode, characterized in that: The preparation method comprises: preparing an epitaxial structure; forming a silver mirror reflection layer and a wrapping structure on the same surface of the epitaxial structure, wherein the wrapping structure surrounds the silver mirror reflection layer; The side of the silver mirror reflection layer away from the epitaxial structure is bonded to a substrate.

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