Semiconductor epitaxial structure, light emitting diode, preparation method and display device
By designing an etch cut-off layer with a thickness greater than or equal to the epitaxial layer in a semiconductor LED chip and forming a step structure, the dry etching accuracy problem is solved, side etching damage is avoided, and the chip manufacturing and transfer yield is improved.
Patent Information
- Application Number
- CN202411566064.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-05
- Publication Date
- 2025-03-25
AI Technical Summary
In the prior art, during the dry etching process of semiconductor LED chips, it is difficult to accurately stop the etching cut-off layer, resulting in too deep or too shallow etching, affecting the manufacturing yield and transfer yield of the chip.
A semiconductor epitaxial structure is adopted, including a substrate, an etch cutoff layer and an epitaxial layer. The thickness of the etch cutoff layer is greater than or equal to the epitaxial layer, forming a step structure to avoid side etching, and a wet etching liquid is used to protect the epitaxial layer when the substrate is subsequently removed.
It effectively avoids side corrosion damage caused by dry etching errors, ensuring the improvement of chip manufacturing yield and transfer yield.
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Figure CN119698139A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a semiconductor epitaxial structure, a light emitting diode and a preparation method thereof, and a display device. Background Art
[0002] Micro-LED is a new generation of display technology. Compared with traditional LED, it has the same light-emitting principle, but the size of a single LED is less than 20μm, which greatly increases the difficulty of its preparation. Among them, mass transfer technology is the key. In order to adapt to large-area display, a large number of LEDs need to be transferred from the sapphire substrate to the glass plate.
[0003] In the process of forming existing LED chips, dry etching of the epitaxial layer is generally used to form the Mesa table. In order to avoid over-etching, an etching stop layer is generally added between the substrate and the epitaxial layer. However, due to the problem of dry etching depth accuracy, it is impossible to accurately stop at the etching stop layer. Etching too deep or too shallow will affect the subsequent process, thereby affecting the chip production yield or transfer yield. Summary of the invention
[0004] In view of the above shortcomings of the prior art, an object of the present invention is to provide a semiconductor epitaxial structure, a light emitting diode and a manufacturing method, and a display device, so as to improve the manufacturing yield and transfer yield of the light emitting diode.
[0005] In order to achieve the above-mentioned object and other related objects, the present invention provides a semiconductor epitaxial structure, comprising:
[0006] substrate;
[0007] The etching stop layer is arranged above the substrate, and the thickness of the etching stop layer is greater than or equal to
[0008] The epitaxial layer is arranged above the etching stop layer, and the epitaxial layer sequentially stacks the first semiconductor layer, the active layer and the second semiconductor layer above the etching stop layer.
[0009] The present invention also provides a light emitting diode, comprising:
[0010] substrate;
[0011] The etching stop layer is arranged above the substrate. In a direction parallel to the substrate, the etching stop layer includes a first part and a second part. The thickness of the first part is greater than the thickness of the second part, so that the etching stop layer forms a step structure on a side away from the substrate. The thickness of the second part is greater than or equal to
[0012] The epitaxial structure is arranged above the first part of the etching stop layer, and the epitaxial structure sequentially stacks a first semiconductor layer, an active layer and a second semiconductor layer above the first part.
[0013] The present invention also provides a method for preparing a light emitting diode, comprising:
[0014] Provide a light emitting diode, which is the light emitting diode mentioned above;
[0015] The substrate of the light emitting diode is removed by wet etching.
[0016] The present invention also provides a display device, comprising a packaging substrate and at least one light-emitting diode arranged on the packaging substrate, the light-emitting diode is the above-mentioned light-emitting diode or is formed by the above-mentioned light-emitting diode preparation method, and one side of the light-emitting diode having an electrode is bonded to the packaging substrate.
[0017] Compared with the prior art, the semiconductor epitaxial structure, light-emitting diode, preparation method, and display device of the present invention have at least the following beneficial effects:
[0018] The semiconductor epitaxial structure of the present invention comprises a substrate, an etching stop layer and an epitaxial layer. The etching stop layer is arranged above the substrate, and the thickness of the etching stop layer is greater than or equal to The epitaxial layer is arranged above the etching stop layer, and the first semiconductor layer, the active layer and the second semiconductor layer are sequentially stacked on the epitaxial layer above the etching stop layer. Since the overall thickness of the etching stop layer is relatively thick, even if there is an error in the dry etching and the etching depth is too deep, the etching stop layer located at the isolation groove position will not be etched through, and there is still enough thickness of the etching stop layer remaining to protect the epitaxial layer at the edge position, thereby avoiding the wet etching solution from causing side etching damage to the epitaxial layer when the substrate is subsequently removed. In addition, since the etching stop layer is not etched through, after the substrate is subsequently removed, a raised surface will not be formed on the transfer surface of the light-emitting diode, thereby avoiding affecting the transfer yield of the chip.
[0019] The light emitting diode of the present invention is formed by etching the semiconductor epitaxial structure. The etching stop layer after etching forms a second part at the isolation groove position. The unetched part forms a first part. The thickness of the first part is greater than the thickness of the second part so that a step structure is formed near the light emitting diode isolation groove. The thickness of the second part near the isolation groove is greater than or equal to The side etching of the epitaxial structure by the etching liquid can be avoided when the substrate is subsequently removed. In addition, since the etching stop layer is not etched through, a raised surface will not be formed on the transfer surface of the light-emitting diode after the substrate is subsequently removed, which will affect the transfer yield.
[0020] The method for manufacturing a light emitting diode and the display device of the present invention include the light emitting diode mentioned above, and also have the above technical effects. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 A schematic structural diagram of an epitaxial layer is provided in an embodiment of the present invention;
[0022] Figure 2 Etching for an example Figure 1 Schematic diagram of the structure from the epitaxial layer to the etching stop layer;
[0023] Figure 3 For Figure 2 A schematic diagram of a structure after an electrode layer and an insulating protective layer are formed on the basis of the electrode layer;
[0024] Figure 4 To remove Figure 3 A schematic diagram of the structure after the substrate in FIG.
[0025] Figure 5 Overetching in another example Figure 1 Schematic diagram of the structure from epitaxial layer to substrate;
[0026] Figure 6 For Figure 5 A schematic diagram of a structure after an electrode layer and an insulating protective layer are formed on the basis of the electrode layer;
[0027] Figure 7 To remove Figure 6 Schematic diagram of the structure after the middle substrate;
[0028] Figure 8 Schematic diagram of the structure of a light emitting diode in an embodiment of the present invention.
[0029] List of reference numerals:
[0030] 100 Substrate
[0031] 200 Etching stop layer
[0032] 201 Part 1
[0033] 202 Part 2
[0034] 300 ohm contact layer
[0035] 400 epitaxial layer
[0036] 410 epitaxial structure
[0037] 420 First table structure
[0038] 430 Second table structure
[0039] 401 First semiconductor layer
[0040] 402 Active Layer
[0041] 403 Second semiconductor layer
[0042] 500 Insulation protection layer
[0043] 601 First Electrode
[0044] 602 second electrode
[0045] 700 Transfer substrate
[0046] 001 Depression
[0047] 002 Bump DETAILED DESCRIPTION
[0048] The following specific embodiments illustrate the embodiments of the present invention, and those familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.
[0049] It should be noted that the diagrams provided in the embodiments of the present invention are only used to illustrate the basic concept of the present invention in a schematic manner. Although the diagrams only show the components related to the present invention rather than being drawn according to the number, shape and size of the components in actual implementation, the form, quantity and proportion of each component can be changed at will during actual implementation, and the layout of the components may also be more complex. The structures, proportions, sizes, etc. illustrated in the drawings of the specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions that can be implemented in this application, so they have no technical substantive significance. Any structural modification, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed in this application without affecting the effects and purposes that can be achieved by the present invention.
[0050] When preparing light-emitting diodes, refer to Figure 1 First, a substrate 100 is provided, and an etching stop layer 200 and an epitaxial layer 400 are formed on the substrate 100. The inventors found during the preparation process that when the epitaxial layer 400 is etched by dry etching to form a Mesa pattern, the depth accuracy of the dry etching cannot be accurately stopped at the etching stop layer 200. For example, referring to Figure 2When the etching depth is too shallow, the etching depth will stop in the etching stop layer 200. At this time, a relatively thin portion of the etching stop layer 200 remains. Figure 3 After forming the insulating protective layer 500 and the electrode on the epitaxial structure 410, the substrate 100 of the light emitting diode needs to be removed. Figure 4 Since only a thin portion of the etching stop layer 200 remains at the etching position, the etching liquid will quickly etch away the position when removing the substrate 100, causing side corrosion, and the corrosion extends to the internal epitaxial layer 400, causing damage to the epitaxial structure 410, which is not conducive to the manufacturing yield of the chip. Figure 5 When the etching depth is too deep, the etching stop layer 200 will be completely etched away, and the etching will extend into the substrate 100. Since the etching rate near the epitaxial layer 400 is relatively large, a recess 001 will be formed on the substrate 100. Figure 6 When the insulating protective layer 500 is subsequently formed on the etched structure, the insulating protective layer 500 forms a depression 001 identical to the substrate 100 at a position corresponding to the depression 001 structure on the substrate 100. Before the light-emitting diode is transferred, the substrate 100 of the light-emitting diode is generally removed by etching liquid. At this time, the insulating protective layer 500 is exposed on the transfer surface of the light-emitting diode. The original depression 001 is inverted to form a protrusion 002. Due to the existence of the protrusion 002 structure, the transfer surface of the light-emitting diode cannot be well adsorbed and matched with the transfer head, and the light-emitting diode is transferred to the transfer substrate 700, thereby affecting the subsequent transfer process.
[0051] In order to solve the background technology and the above-mentioned technical problems, the present embodiment provides a semiconductor epitaxial structure, a light-emitting diode and a preparation method, and a display device, which can avoid the impact on the subsequent manufacturing yield and transfer yield of the light-emitting diode due to the inability to stop at the etching stop layer due to the depth accuracy problem of dry etching, thereby improving the manufacturing yield and transfer yield of the chip.
[0052] Specifically, this embodiment provides a semiconductor epitaxial structure, including:
[0053] substrate;
[0054] The etching stop layer is arranged above the substrate, and the thickness of the etching stop layer is greater than or equal to
[0055] The epitaxial layer is arranged above the etching stop layer, and the first semiconductor layer, the active layer and the second semiconductor layer are sequentially stacked on the epitaxial layer above the etching stop layer. Since the overall thickness of the etching stop layer is relatively thick, even if there is an error in the dry etching and the etching depth is too deep, the etching stop layer located at the isolation groove position will not be etched through, and there is still enough thickness of the etching stop layer remaining to protect the epitaxial layer at the edge position, so as to avoid the wet etching solution causing side etching damage to the epitaxial layer when the substrate is subsequently removed. In addition, since the etching stop layer is not etched through, a raised surface will not be formed on the transfer surface of the light-emitting diode after the substrate is subsequently removed, which will affect the transfer yield.
[0056] Optionally, the material of the etching stop layer is one of InGaP and InGaAs.
[0057] Optionally, the semiconductor epitaxial structure further includes:
[0058] The ohmic contact layer is arranged between the etching stop layer and the epitaxial layer.
[0059] This embodiment also provides a light emitting diode, including:
[0060] substrate;
[0061] The etching stop layer is arranged above the substrate. In a direction parallel to the substrate, the etching stop layer includes a first part and a second part. The thickness of the first part is greater than the thickness of the second part, so that the etching stop layer forms a step structure on a side away from the substrate. The thickness of the second part is greater than or equal to
[0062] The epitaxial structure is arranged above the first part of the etching stop layer, and the first semiconductor layer, the active layer and the second semiconductor layer are sequentially stacked above the first part of the epitaxial structure. The second part, even if the ICP etching is at the maximum floating limit of 0.1 to 0.15 μm, that is, the etching depth is too deep, the etching stop layer will not be etched through, and no raised surface will be formed on the transfer surface of the light-emitting diode after the subsequent removal of the substrate, affecting the transfer yield.
[0063] Optionally, the total thickness of the first portion is greater than or equal to
[0064] Optionally, the material of the etching stop layer is one of InGaP and InGaAs.
[0065] Optionally, the epitaxial structure comprises:
[0066] A first mesa structure is formed by sequentially etching the second semiconductor layer and the active layer downward from a portion of the surface of the second semiconductor layer, or etching the second semiconductor layer, the active layer and a portion of the first semiconductor layer downward, and the remaining portion of the first semiconductor layer corresponding to the etching position forms a first mesa structure;
[0067] The second mesa structure is formed by the second semiconductor layer, the active layer and the first semiconductor layer corresponding to the surface of the second semiconductor layer that has not been etched.
[0068] Optionally, the light emitting diode further comprises:
[0069] A first electrode is disposed on the first mesa structure and is electrically connected to the first semiconductor layer exposed on the mesa of the first mesa structure;
[0070] The second electrode is disposed on the second mesa structure and is electrically connected to the second semiconductor layer of the second mesa structure.
[0071] Optionally, the light emitting diode further comprises:
[0072] The insulating protective layer covers the sidewalls and surfaces of the first mesa structure and the second mesa structure, and the insulating protective layer forms a first opening on the mesa of the first mesa structure, and the first electrode is formed in the first opening; the insulating protective layer forms a second opening on the second mesa structure, and the second electrode is formed in the second opening. The provision of the insulating protective layer can prevent the epitaxial structure from directly contacting the air to produce oxidation or corrosion reactions, thereby affecting chip performance.
[0073] Optionally, the thickness of the insulating protective layer is at least As described above, the epitaxial structure of the light emitting diode is effectively protected when the substrate is removed.
[0074] Optionally, the material of the insulating protection layer is one of SiO2, Si3N4 or Al2O3.
[0075] Optionally, the material of the insulating protection layer is Si3N4, which does not react with most wet etching solutions, so as to effectively block the corrosion of the etching solution when etching the substrate and protect the integrity of the chip structure.
[0076] Optionally, an angle between a side wall of the first mesa structure or the second mesa structure and a plane where the first semiconductor layer is located is greater than 80 degrees.
[0077] This embodiment also provides a method for preparing a light emitting diode, comprising:
[0078] Provide a light emitting diode, which is the light emitting diode mentioned above;
[0079] The substrate of the light emitting diode is removed by wet etching.
[0080] This embodiment also provides a display device, which includes a packaging substrate and at least one light-emitting diode arranged on the packaging substrate. The light-emitting diode is the above-mentioned light-emitting diode or is formed by the above-mentioned light-emitting diode preparation method. One side of the light-emitting diode has an electrode bonded to the packaging substrate.
[0081] The present invention is described in detail below with reference to specific embodiments.
[0082] Example 1
[0083] This embodiment provides a semiconductor epitaxial structure, referring to Figure 1 The semiconductor epitaxial structure includes a substrate 100 , an etching stop layer 200 and an epitaxial layer 400 .
[0084] The substrate 100 includes, but is not limited to, one of InP, GaAs, and GaP. This embodiment is described by taking the substrate 100 as GaAs as an example.
[0085] The etching stop layer 200 is disposed above the substrate 100. Optionally, a buffer layer (not shown in the figure) can also be formed between the substrate 100 and the etching stop layer 200. Since the lattice quality of the buffer layer is better than the lattice quality of the growth substrate 100, growing the buffer layer on the substrate 100 is beneficial to eliminating the influence of the lattice defects of the substrate 100 on the semiconductor epitaxial layer 400. The etching stop layer 200 is used as an etching stop layer 200 for dry etching or wet etching. Optionally, an ohmic contact layer 300 is also formed on the etching stop layer 200, and the material of the ohmic contact layer 300 is GaAs.
[0086] In order to prevent the thickness of the etching stop layer 200 near the isolation groove from being too thin or being etched through when etching the epitaxial structure, thereby failing to protect the epitaxial structure in the subsequent substrate etching process or affecting chip transfer, in this embodiment, the thickness of the etching stop layer 200 is greater than or equal to Therefore, even if there is an error in the uniformity of subsequent dry etching, the minimum thickness of the etching stop layer 200 after etching will be greater than or equal to The remaining thickness of the etching stop layer 200 can protect the epitaxial layer 400 in the subsequent process of removing the substrate without damaging the epitaxial layer 400. At the same time, it will not produce an uneven surface in the transfer process, affecting the transfer yield. Optionally, the material of the etching stop layer 200 is one of InGaP and InGaAs.
[0087] The epitaxial layer 400 is disposed above the etching stop layer 200, and the epitaxial layer is sequentially stacked with a first semiconductor layer 401, an active layer 402 and a second semiconductor layer 403 above the etching stop layer 200. In the present embodiment, the epitaxial layer 400 is formed on the ohmic contact layer 300. The first semiconductor layer 401 of the epitaxial structure 410 may be an N-type semiconductor layer, and the second semiconductor layer 403 may be a P-type semiconductor layer. Of course, it is also possible that the first semiconductor layer 401 is a P-type semiconductor layer and the second semiconductor layer 403 is an N-type semiconductor layer. The N-type semiconductor layer provides electrons for composite luminescence, for example, electrons may be provided by doping N-type impurities. The active layer 402 is a region that provides light radiation for the recombination of electrons and holes. Different materials may be selected according to different luminescence wavelengths, and the active layer may be a periodic structure of a single quantum well or a multiple quantum well. The active layer 402 includes a well layer and a barrier layer, wherein the barrier layer has a larger band gap than the well layer. By adjusting the composition ratio of the semiconductor material in the active layer 402, it is expected to radiate light of different wavelengths. The P-type semiconductor layer can provide holes for compound luminescence, for example, holes can be provided by P-type impurities. In this embodiment, the material of the N-type semiconductor layer is AlInP, the material of the active layer 402 is AlGaInP, and the material of the P-type semiconductor layer is AlInP. The light-emitting diode epitaxial structure 410 in this embodiment can radiate red light. Of course, in other embodiments, the epitaxial layer can also be composed of other materials.
[0088] Example 2
[0089] This embodiment provides a light emitting diode, referring to Figure 8 The light emitting diode includes a substrate 100 , an etching stop layer 200 and an epitaxial structure 410 .
[0090] Among them, refer to Figure 8 The etching stop layer 200 is disposed above the substrate 100. Along the direction parallel to the substrate 100, the etching stop layer 200 includes a first portion 201 and a second portion 202. The thickness of the first portion 201 is greater than the thickness of the second portion 202, so that the etching stop layer forms a step structure on the side away from the substrate. The second portion 202 is formed near the isolation groove at the edge of the light-emitting diode after etching the epitaxial layer 400 and the etching stop layer 200 in sequence. It is the remaining portion of the etching stop layer 200 near the isolation groove after etching. The thickness of the second portion 202 is greater than or equal to Since the thickness of the remaining second portion 202 of the etching stop layer 200 is relatively thick, when the substrate 100 is subsequently removed, the second portion 202 at the edge can effectively block the etching solution to avoid side etching. Since the etching stop layer 200 after etching has the second portion 202, even if the ICP etching is at the maximum floating limit of 0.1 to 0.15 μm, that is, the etching depth is too deep, the etching stop layer 200 will not be etched through, and no raised surface will be formed on the transfer surface of the light-emitting diode after the substrate 100 is subsequently removed, which affects the transfer yield. Optionally, the total thickness of the etching stop layer 200 is greater than or equal to Since the etching stop layer 200 is thick as a whole, even if the etching depth is too deep, the etching stop layer 200 will not be etched through, and thus a raised surface will not be formed on the transfer surface of the light-emitting diode after the substrate 100 is subsequently removed, thereby affecting the transfer yield. Optionally, an ohmic contact layer 300 is also formed on the etching stop layer 200, and the material of the ohmic contact layer 300 is GaAs.
[0091] Reference Figure 8 , the epitaxial structure 410 is disposed above the etching stop layer 200, and the epitaxial structure 410 is sequentially stacked with the first semiconductor layer 401, the active layer 402 and the second semiconductor layer 403 above the etching stop layer 200. In the present embodiment, the epitaxial structure 410 is formed on the ohmic contact layer 300. The epitaxial structure 410 is formed with a first mesa structure 420 and a second mesa structure 430. The second semiconductor layer 403, the active layer 402 or the second semiconductor layer 403, the active layer 402 and a part of the first semiconductor layer 401 are sequentially etched downward from a part of the surface of the second semiconductor layer 403, and the remaining first semiconductor layer 401 after etching is formed as the first mesa structure 420. The second semiconductor layer 403, the active layer 402 and the first semiconductor layer 401 corresponding to the remaining unetched surface of the second semiconductor layer 403 are formed as the second mesa structure 430. Optionally, an angle α between a sidewall of the first mesa structure 420 or the second mesa structure 430 and a plane where the first semiconductor layer 401 is located is greater than 80 degrees, for example, 85 degrees to 90 degrees.
[0092] The first semiconductor layer 401 of the epitaxial structure 410 may be an N-type semiconductor layer, and the second semiconductor layer 403 may be a P-type semiconductor layer. Of course, the first semiconductor layer 401 may be a P-type semiconductor layer, and the second semiconductor layer 403 may be an N-type semiconductor layer. The N-type semiconductor layer provides electrons for composite luminescence, for example, electrons may be provided by doping N-type impurities. The active layer 402 is a region for providing light radiation for the recombination of electrons and holes. Different materials may be selected according to different luminescence wavelengths, and the active layer may be a periodic structure of a single quantum well or multiple quantum wells. The active layer 402 includes a well layer and a barrier layer, wherein the barrier layer has a larger band gap than the well layer. By adjusting the composition ratio of the semiconductor material in the active layer 402, it is expected to radiate light of different wavelengths. The P-type semiconductor layer can provide holes for composite luminescence, for example, holes may be provided by P-type impurities, so as to. In this embodiment, the material of the N-type semiconductor layer is AlInP, the material of the active layer 402 is AlGaInP, and the material of the P-type semiconductor layer is AlInP. The light emitting diode epitaxial structure 410 in this embodiment can radiate red light. Of course, in other embodiments, the epitaxial layer can also be composed of other materials.
[0093] Reference Figure 8 , the light emitting diode further includes a first electrode 601 and a second electrode 602, the first electrode 601 is disposed on the first mesa structure 420, and is electrically connected to the first semiconductor layer 401 exposed on the mesa of the first mesa structure 420. The second electrode 602 is disposed on the second mesa structure 430, and is electrically connected to the second semiconductor layer 403 of the second mesa structure 430. In this embodiment, the light emitting diode further includes an insulating protective layer 500, which covers the sidewalls and surfaces of the first mesa structure 420 and the second mesa structure 430 to prevent the epitaxial structure from directly contacting the air to produce oxidation or corrosion reactions, thereby affecting the chip performance. The insulating protective layer 500 forms a first opening (not shown in the figure) on the mesa of the first mesa structure 420, and the first electrode 601 is formed in the first opening. The insulating protective layer 500 forms a second opening (not shown in the figure) on the second mesa structure 430, and the second electrode 602 is formed in the second opening. Furthermore, the second electrode 602 is further extended from the second opening to a portion of the mesa of the first mesa structure 420 to facilitate subsequent bonding with the substrate.
[0094] In this embodiment, in order to effectively protect the epitaxial structure of the light-emitting diode when the substrate 100 is subsequently removed, the thickness of the insulating protection layer 500 is at least In the above, the material of the insulating protection layer 500 is one of SiO2, Si3N4 or Al2O3. In order to effectively block the corrosion of the etching solution when etching the substrate 100 and protect the epitaxial structure 410 of the light-emitting diode, the material of the insulating protection layer 500 is Si3N4, which does not react with most of the wet etching solutions, thereby protecting the integrity of the chip structure.
[0095] Example 3
[0096] This embodiment provides a method for preparing a light emitting diode, and the method for preparing a light emitting diode includes:
[0097] S1: providing a substrate, and sequentially forming an etching stop layer and an epitaxial layer on the substrate;
[0098] Specifically, refer to Figure 1 , the substrate 100 may be a GaAs substrate 100. The etching stop layer 200 and the epitaxial layer 400 may be formed on the substrate 100 by physical vapor deposition (PVD), chemical vapor deposition (CVD), epitaxial growth or atomic beam deposition (ALD). In this embodiment, an ohmic contact layer 300 is formed between the etching stop layer 200 and the epitaxial layer 400, and the material thereof is GaAs. The total thickness of the etching stop layer 200 is greater than or equal to 100 Å.
[0099] S2: etching the epitaxial layer and etching the stop layer to form a first mesa structure and a second mesa structure;
[0100] Specifically, refer to Figure 1 and 8 , the etching stop layer 200 and the epitaxial layer 400 are dry-etched by plasma vapor phase etching (ICP). The second semiconductor layer 403, the active layer 402 or the second semiconductor layer 403, the active layer 402 and a part of the first semiconductor layer 401 are sequentially etched downward from a part of the surface of the second semiconductor layer 403, and the remaining part of the first semiconductor layer 401 corresponding to the etching position forms a first mesa structure 420. The second semiconductor layer 403, the active layer 402 and the first semiconductor layer 401 corresponding to the surface of the unetched second semiconductor layer 403 form a second mesa structure 430. At the position of the side wall of the first mesa structure 420 and the substrate 100, the etching stop layer 200 is etched to form a first part 201 and a second part 202, and the thickness of the first part 201 is greater than the thickness of the second part 202, so that the etching stop layer 200 forms a step structure at a position close to the isolation groove. At this time, since the thickness of the etching stop layer 200 is greater than or equal to Even if there is an error in the dry etching precision, the minimum thickness of the second portion 202 is greater than or equal to The thickness of the remaining second portion 202 can block the wet etching solution when the substrate 100 is subsequently removed, thereby protecting the epitaxial structure from damage.
[0101] S3: forming an insulating protection layer on the first mesa structure, the second mesa structure and the substrate, forming a first opening on the insulating protection layer of the first mesa structure, forming a second opening on the insulating protection layer of the second mesa structure, forming a first electrode in the first opening, and forming a second electrode in the second opening;
[0102] Specifically, refer to Figure 8 An insulating protective layer 500 is formed on the surfaces of the first mesa structure 420, the second mesa structure 430 and the substrate 100. The insulating protective layer 500 can be formed by chemical vapor deposition. A first opening and a second opening are formed by photolithography, and a metal material layer is deposited in the first opening and the second opening to form a first electrode 601 and a second electrode 602, respectively. In this embodiment, the first electrode 601 and the second electrode 602 can be formed by evaporation or sputtering.
[0103] S4: removing the substrate by wet etching, and leaving at least a part of the thickness of the etching cut-off layer of the light-emitting diode.
[0104] Specifically, refer to Figure 8 When removing the substrate 100, the substrate 100 is removed by etching with hydrogen peroxide to obtain the light-emitting diode to be transferred. Since the remaining thickness of the etching stop layer 200 at the edge of the light-emitting diode is relatively thick, it is greater than or equal to Furthermore, the epitaxial structure 410 will not be etched away by hydrogen peroxide, and the epitaxial structure 410 can be effectively protected from damage. In addition, since the etching stop layer 200 is not completely etched away, the uneven transfer surface due to over-etching will not occur, thereby ensuring the transfer yield of the chip.
[0105] Example 4
[0106] This embodiment provides a display device, which includes a packaging substrate and at least one light emitting diode disposed on the packaging substrate. The light emitting diode is the light emitting diode in embodiment 1 or embodiment 2, and the light emitting diode is bonded to the packaging substrate through one side of the electrode.
[0107] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.
Claims
1. A semiconductor epitaxial structure, characterized in that: include: substrate; An etching stop layer is disposed above the substrate, and the thickness of the etching stop layer is greater than or equal to The epitaxial layer is arranged above the etching stop layer, and the epitaxial layer sequentially stacks a first semiconductor layer, an active layer and a second semiconductor layer above the etching stop layer.
2. The semiconductor epitaxial structure according to claim 1, characterized in that: The material of the etching stop layer is one of InGaP and InGaAs.
3. The semiconductor epitaxial structure according to claim 1, characterized in that: The semiconductor epitaxial structure further comprises: The ohmic contact layer is arranged between the etching stop layer and the epitaxial layer.
4. A light emitting diode, characterized in that: include: substrate; An etching stop layer is arranged above the substrate. In a direction parallel to the substrate, the etching stop layer includes a first portion and a second portion. The thickness of the first portion is greater than the thickness of the second portion, so that the etching stop layer forms a step structure on a side away from the substrate. The thickness of the second portion is greater than or equal to The epitaxial structure is arranged above the first part of the etching stop layer, and the epitaxial structure sequentially stacks a first semiconductor layer, an active layer and a second semiconductor layer above the first part.
5. The light emitting diode according to claim 4, characterized in that: The total thickness of the first portion is greater than or equal to 6. The light emitting diode according to claim 4, characterized in that: The material of the etching stop layer is one of InGaP and InGaAs.
7. The light emitting diode according to claim 4, characterized in that: The epitaxial structure comprises: A first mesa structure, wherein the second semiconductor layer and the active layer are sequentially etched downward from a portion of the surface of the second semiconductor layer, or the second semiconductor layer, the active layer and a portion of the first semiconductor layer are etched downward, and the remaining portion of the first semiconductor layer corresponding to the etching position forms the first mesa structure; The second mesa structure is formed by the second semiconductor layer, the active layer and the first semiconductor layer corresponding to the unetched surface of the second semiconductor layer.
8. The light emitting diode according to claim 7, characterized in that: The light emitting diode further comprises: A first electrode is disposed on the first mesa structure and is electrically connected to the first semiconductor layer exposed on the mesa of the first mesa structure; The second electrode is disposed on the second mesa structure and is electrically connected to the second semiconductor layer of the second mesa structure.
9. The light emitting diode according to claim 8, characterized in that: The light emitting diode further comprises: An insulating protective layer covers the side walls and surfaces of the first mesa structure and the second mesa structure, and the insulating protective layer forms a first opening on the mesa of the first mesa structure, and the first electrode is formed in the first opening; the insulating protective layer forms a second opening on the second mesa structure, and the second electrode is formed in the second opening.
10. The light emitting diode according to claim 9, characterized in that: The thickness of the insulating protective layer is at least above.
11. The light emitting diode according to claim 9, characterized in that: The material of the insulating protection layer is one of SiO2, Si3N4 or Al2O3.
12. The light emitting diode according to claim 9, characterized in that: The material of the insulating protection layer is Si3N4.
13. The light emitting diode according to claim 7, characterized in that: An angle between a side wall of the first mesa structure or the second mesa structure and a plane where the first semiconductor layer is located is greater than 80 degrees.
14. A method for preparing a light emitting diode, characterized in that: include: Provide a light emitting diode, wherein the light emitting diode is the light emitting diode according to any one of claims 4 to 13; The substrate of the light emitting diode is removed by wet etching.
15. A display device, characterized in that: The display device includes a packaging substrate and at least one light-emitting diode arranged on the packaging substrate, the light-emitting diode is the light-emitting diode described in any one of claims 4 to 13 or is formed by the light-emitting diode preparation method in claim 14, and one side of the light-emitting diode having an electrode is bonded to the packaging substrate.