Reversed-polarity LED chip, preparation method thereof and lighting equipment
By processing the reverse polarity LED chip etching surface, removing hanging bonds and reducing roughness, the efficiency and reliability problems after ICP dry etching are solved, and higher external quantum efficiency and reliability are achieved.
Patent Information
- Application Number
- CN202411890600.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-03-21
AI Technical Summary
After the ICP dry etching of the existing reverse polarity LED chip, the hanging bonds on the etching surface lead to a decrease in external quantum efficiency and a poor reliability.
After dry etching, the etching surface is processed, hanging bonds are removed and roughness is reduced, the method includes a high temperature annealing process or a wet solution treatment.
The external quantum efficiency and reliability of the reverse polarity LED chip are improved, making the etching surface smoother and forming a micro-reflector.
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Figure CN119677249A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of LED technology, and in particular to a reverse polarity LED chip, a preparation method thereof, and a lighting device. Background Art
[0002] With the gradual development of LED (Light Emitting Diode), LED lighting has completely replaced traditional lighting sources. Keeping up with the pace of technological innovation, the continuous innovation of intelligent manufacturing scale, automation and digitization, the current LED market competition is particularly fierce, and each LED chip factory is pursuing LED chips with higher light efficiency.
[0003] In the prior art, the reverse polarity LED chip will be patterned with relatively high precision in the Mesa process or on the epitaxial wafer, and the process used is the ICP (full name: Inductively Coupled Plasma) dry etching process. Some of the high-brightness reverse polarity LED chips use the ICP dry etching process to etch the P-type window layer to reduce the absorption of light by the P-type window layer, further improving the brightness of the reverse polarity LED chip.
[0004] However, after the P-type window layer is subjected to ICP dry etching, a large number of dangling bonds will be present on the etched surface, resulting in a decrease in the external quantum efficiency of the reverse polarity LED chip and a decrease in reliability. Summary of the invention
[0005] In view of the above problems, the present application provides a reverse polarity LED chip and a preparation method thereof, and a lighting device to improve the brightness and reliability of the reverse polarity LED chip. The specific solution is as follows:
[0006] The first aspect of the present application provides a method for preparing a reverse polarity LED chip, the method for preparing a reverse polarity LED chip comprising:
[0007] providing a temporary substrate;
[0008] forming an epitaxial wafer on one side of the temporary substrate, wherein the epitaxial wafer includes a P-type window layer;
[0009] Etching the P-type window layer based on a dry etching process;
[0010] The etched surface is processed to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
[0011] Preferably, in the above-mentioned method for preparing the reverse polarity LED chip, the step of treating the etched surface to remove dangling bonds on the etched surface and reduce the roughness of the etched surface comprises:
[0012] The etched surface is processed based on a high temperature annealing process to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
[0013] Preferably, in the above-mentioned method for preparing the reverse polarity LED chip, the step of treating the etched surface based on a high temperature annealing process to remove dangling bonds on the etched surface and reduce the roughness of the etched surface comprises:
[0014] Under the conditions of an inert gas atmosphere, an annealing temperature range of 410° C.-430° C., and an annealing time range of 10s-20s, the etched surface is treated to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
[0015] Preferably, in the method for preparing the reverse polarity LED chip, the flow rate of the inert gas is in the range of 40 slpm-60 slpm.
[0016] Preferably, in the above-mentioned method for preparing the reverse polarity LED chip, the step of treating the etched surface to remove dangling bonds on the etched surface and reduce the roughness of the etched surface comprises:
[0017] The etching surface is treated by soaking in a wet solution to remove dangling bonds on the etching surface and reduce the roughness of the etching surface.
[0018] Preferably, in the above-mentioned method for preparing the reverse polarity LED chip, the etching surface is treated by soaking in a wet solution to remove dangling bonds on the etching surface and reduce the roughness of the etching surface, comprising:
[0019] The epitaxial wafer after etching the P-type window layer is immersed in a mixed solution composed of H3PO4, H2O2 and H2O. Under the conditions that the temperature range of the mixed solution is 20℃-30℃ and the immersion time range is 15s-25s, the etched surface is treated to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
[0020] Preferably, in the above-mentioned method for preparing the reverse polarity LED chip, the ratio of H3PO4:H2O2:H2O in the mixed solution is 2:1:1.
[0021] Preferably, in the above-mentioned method for preparing the reverse polarity LED chip, the method for preparing the reverse polarity LED chip further comprises:
[0022] providing a target substrate;
[0023] A substrate transfer process is performed based on the target substrate to remove the temporary substrate.
[0024] A second aspect of the present application provides a reverse polarity LED chip, wherein the reverse polarity LED chip is obtained by any of the methods for preparing the reverse polarity LED chip described above.
[0025] A third aspect of the present application provides a lighting device, which includes the reverse polarity LED chip described above.
[0026] By means of the above technical scheme, the present application provides a reverse polarity LED chip and its preparation method and lighting equipment. After dry etching the P-type window layer, the etched surface is further processed to remove dangling bonds on the etched surface, reduce the roughness of the etched surface, make the etched surface smoother, form a micro-mirror, and thus improve the external quantum efficiency and reliability of the reverse polarity LED chip. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The above and other features, advantages and aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings. Throughout the accompanying drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic and the originals and elements are not necessarily drawn to scale.
[0028] Figure 1 A schematic flow chart of a method for preparing a reverse polarity LED chip provided by an embodiment of the present invention;
[0029] Figure 2-Figure 3 for Figure 1 A schematic diagram of a part of the structure corresponding to the preparation method shown;
[0030] Figure 4 A schematic diagram for comparing an etching surface without treatment and an etching surface with treatment provided by an embodiment of the present invention;
[0031] Figure 5 A schematic flow chart of another method for preparing a reverse polarity LED chip provided by an embodiment of the present invention;
[0032] Figure 6 A schematic flow chart of another method for preparing a reverse polarity LED chip provided by an embodiment of the present invention;
[0033] Figure 7 A schematic flow chart of another method for preparing a reverse polarity LED chip provided by an embodiment of the present invention;
[0034] Figure 8-Figure 14 for Figure 7 Schematic diagram of the partial structure corresponding to the preparation method shown. DETAILED DESCRIPTION
[0035] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application. The terms used in the implementation mode of the present application are only used to explain the specific embodiments of the present application, and are not intended to limit the present application. It is known to those skilled in the art that with the development of technology and the emergence of new scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.
[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0037] It should be noted that the directional words appearing in the present invention are based on the relative position relationship shown in the drawings and cannot be used as an absolute limitation to the present application.
[0038] refer to Figure 1 , Figure 1 A schematic flow chart of a method for preparing a reverse polarity LED chip provided in an embodiment of the present invention. The method for preparing a reverse polarity LED chip provided in an embodiment of the present invention comprises:
[0039] S101: Figure 2 As shown, a temporary substrate 11 is provided.
[0040] Specifically, in the embodiment of the present invention, the temporary substrate 11 includes but is not limited to a GaAs substrate.
[0041] S102: Figure 3 As shown, an epitaxial wafer is formed on one side of the temporary substrate 11 , and the epitaxial wafer includes a P-type window layer 19 .
[0042] Specifically, in the embodiment of the present invention, the epitaxial wafer includes a buffer layer 12, an etching stop layer 13, an ohmic contact layer 14, an N-type roughening layer 15, an N-type confinement layer 16, an MQW layer 17, a P-type confinement layer 18 and a P-type window layer 19 which are sequentially stacked on the temporary substrate 11.
[0043] The buffer layer 12 includes but is not limited to a GaAs buffer layer.
[0044] The ohmic contact layer 14 includes but is not limited to a GaAs ohmic contact layer.
[0045] The N-type roughening layer 15 includes but is not limited to an N-type AlGaInP roughening layer.
[0046] The N-type confinement layer 16 includes but is not limited to an N-type AlGaInP confinement layer.
[0047] The P-type confinement layer 18 includes but is not limited to a P-type AlGaInP confinement layer.
[0048] The P-type window layer 19 includes but is not limited to a P-type GaP window layer.
[0049] The surface doping concentration of the P-type window layer 19 is about 2×10 18 cm -3 about.
[0050] S103: etching the P-type window layer 19 based on a dry etching process.
[0051] Specifically, in the embodiment of the present invention, it includes but is not limited to using acetone, isopropyl alcohol, deionized water, etc. to clean the epitaxial wafer prepared in step S102, and then performing photolithography patterning on the surface of the P-type window layer 19, including but not limited to using an ICP dry etching process to etch the P-type window layer 19.
[0052] It should be noted that the functional layer of the AlGaInP material is also etched during the etching process of the P-type window layer 19. At this time, the etched surface is relatively rough, with a roughness of about Ra130, and there are a large number of dangling bonds on the etched surface, which leads to a decrease in the external quantum efficiency of the reverse polarity LED chip and a poor reliability.
[0053] S104: Processing the etched surface to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
[0054] Specifically, in the embodiment of the present invention, after the P-type window layer 19 is dry-etched, the etched surface is further processed to remove dangling bonds on the etched surface and reduce the roughness of the etched surface (for example, the roughness of the etched surface is reduced from about Ra130 to about Ra80), so that the etched surface becomes smoother and a micro-mirror is formed, thereby improving the external quantum efficiency and reliability of the reverse polarity LED chip.
[0055] refer to Figure 4 , Figure 4 A comparison diagram of not processing the etched surface and processing the etched surface provided by an embodiment of the present invention. Figure 4 As shown in a, it is a schematic diagram of the prior art in which the P-type window layer is dry-etched without any treatment. The etched surface is relatively rough, and there are a large number of dangling bonds on the etched surface, which leads to a decrease in the external quantum efficiency of the reverse polarity LED chip and a deterioration in reliability. Figure 4 As shown in b, it is a schematic diagram of the technical solution of the present application for continuing processing after dry etching the P-type window layer 19. After dry etching the P-type window layer 19, the etched surface is further processed to remove dangling bonds on the etched surface, reduce the roughness of the etched surface, make the etched surface smoother, form a micro-mirror, and thus improve the external quantum efficiency and reliability of the reverse polarity LED chip.
[0056] In an optional embodiment of the present invention, reference Figure 5 , Figure 5 A schematic flow chart of another method for preparing a reverse polarity LED chip provided by an embodiment of the present invention. One possible implementation method of "treating the etched surface to remove dangling bonds on the etched surface and reduce the roughness of the etched surface" in step S104 is:
[0057] S104A: Processing the etched surface based on a high temperature annealing process to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
[0058] Specifically, in an embodiment of the present invention, under an inert gas atmosphere, an annealing temperature range is 410°C-430°C, and an annealing time range is 10s-20s, the etched surface is processed to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
[0059] The flow rate of the inert gas is in the range of 40 slpm to 60 slpm. For example, the flow rate of the inert gas is 50 slpm.
[0060] In one possible implementation, under the conditions of N2 atmosphere, N2 flow rate of 50slpm, annealing temperature of 420°C, and annealing time of 15s, the etched surface is processed to remove dangling bonds on the etched surface, reduce the roughness of the etched surface, make the etched surface smoother, form a micro-mirror, and thereby improve the external quantum efficiency and reliability of the reverse polarity LED chip.
[0061] In an optional embodiment of the present invention, reference Figure 6 , Figure 6 A schematic flow chart of another method for preparing a reverse polarity LED chip provided by an embodiment of the present invention. Another possible implementation method of "treating the etched surface to remove dangling bonds on the etched surface and reduce the roughness of the etched surface" in step S104 is:
[0062] S104B: treating the etched surface by immersing it in a wet solution to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
[0063] Specifically, in an embodiment of the present invention, the epitaxial wafer after etching the P-type window layer 19 is immersed in a mixed solution composed of H3PO4, H2O2 and H2O. Under the conditions that the temperature range of the mixed solution is 20°C-30°C and the immersion time range is 15s-25s, the etched surface is treated to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
[0064] Wherein, the ratio of H3PO4:H2O2:H2O in the mixed solution is 2:1:1.
[0065] In a possible implementation, the epitaxial wafer after etching the P-type window layer is immersed in a mixed solution composed of H3PO4:H2O2:H2O in a ratio of 2:1:1. Under the conditions that the temperature of the mixed solution is 25°C and the immersion time is 20s, the etched surface is treated to remove dangling bonds on the etched surface, reduce the roughness of the etched surface, make the etched surface smoother, form a micro-mirror, and thereby improve the external quantum efficiency and reliability of the reverse polarity LED chip.
[0066] From the above description, it can be seen that the technical solution of the present application processes the etched surface by a high-temperature annealing process or immersion in a wet solution to remove dangling bonds on the etched surface, reduce the roughness of the etched surface, make the etched surface smoother, form a micro-mirror, and thereby improve the external quantum efficiency and reliability of the reverse polarity LED chip.
[0067] In an optional embodiment of the present invention, reference Figure 7 , Figure 7 A schematic flow chart of another method for preparing a reverse polarity LED chip provided in an embodiment of the present invention. The method for preparing a reverse polarity LED chip provided in an embodiment of the present invention further includes:
[0068] S105: Figure 8 As shown, an ODR layer 20 is formed on a side of the P-type window layer 19 facing away from the temporary substrate 11 .
[0069] Specifically, in the embodiments of the present invention, Figure 8 As shown, the ODR (Omni-Directional Reflector) layer 20 is composed of a dielectric layer 21 and a high-reflection layer 22, wherein the dielectric layer 21 includes but is not limited to a SiO2 layer, and the high-reflection layer 22 includes but is not limited to a stack of Al2O3 / ITO / IZO and other film layers.
[0070] S106: Fig. 9 As shown, the ODR layer 20 is etched to form dielectric holes 23 .
[0071] S107: Fig.10 As shown, a P-type ohmic contact layer 24 is formed in the dielectric hole 23 .
[0072] Specifically, in the embodiment of the present invention, the P-type ohmic contact layer 24 includes but is not limited to a stack of AuZnAu / AuBe / Au.
[0073] S108: Fig.11 As shown, a metal mirror layer 25 is formed.
[0074] Specifically, in the embodiment of the present invention, the metal mirror layer 25 includes but is not limited to a stacked structure of Ag-TiW-Ti-Pt-Au.
[0075] S109: Fig.12 As shown, a target substrate 26 is provided.
[0076] Specifically, in the embodiment of the present invention, the target substrate 26 includes but is not limited to a Si substrate.
[0077] S110: Fig.13 As shown, a substrate transfer process is performed based on the target substrate 26 to remove the temporary substrate 11.
[0078] Specifically, in the embodiment of the present invention, the target substrate 26 is bonded to the epitaxial wafer prepared in step S109 in combination with the bonding layer 27, and the etching stop layer 13 is etched away to remove the temporary substrate 11, thereby completing the substrate transfer process.
[0079] S111: Fig.14 As shown, an N-side electrode 28 is prepared.
[0080] After the N-side electrode 28 is prepared, a cutting path is formed by, but not limited to, ICP etching. After the cutting path is prepared, the P-type window layer 19 is processed, and the etched surface after the cutting path is prepared is also processed in the same way. Exemplarily, the etched surface after the cutting path is prepared is processed by soaking in a wet solution to repair etching damage. Then, roughening, surface passivation, grinding, back gold, back cutting and splitting are performed to form the required reverse polarity LED chip.
[0081] Based on the above embodiment of the present invention, another embodiment of the present invention further provides a reverse polarity LED chip, and the reverse polarity LED chip is obtained by the preparation method of the reverse polarity LED chip described in the above embodiment.
[0082] Based on the above embodiment of the present invention, another embodiment of the present invention further provides a lighting device, wherein the lighting device comprises the reverse polarity LED chip described in the above embodiment.
[0083] The above is a detailed introduction to a reverse polarity LED chip and its preparation method and lighting equipment provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for general technicians in this field, according to the idea of the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.
[0084] It should be noted that each embodiment in this specification is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.
[0085] It should also be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device that includes a series of elements is inherent to the elements, or also includes elements inherent to these processes, methods, articles or devices. In the absence of further restrictions, the elements defined by the sentence "including a..." do not exclude the presence of other identical elements in the process, method, article or device that includes the elements.
[0086] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A method for preparing a reverse polarity LED chip, characterized in that: The method for preparing the reverse polarity LED chip comprises: providing a temporary substrate; forming an epitaxial wafer on one side of the temporary substrate, wherein the epitaxial wafer includes a P-type window layer; Etching the P-type window layer based on a dry etching process; The etched surface is processed to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
2. The method for preparing a reverse polarity LED chip according to claim 1, characterized in that: The step of processing the etched surface to remove dangling bonds on the etched surface and reduce the roughness of the etched surface comprises: The etched surface is processed based on a high temperature annealing process to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
3. The method for preparing a reverse polarity LED chip according to claim 2, characterized in that: The step of processing the etched surface based on a high temperature annealing process to remove dangling bonds on the etched surface and reduce the roughness of the etched surface comprises: Under the conditions of an inert gas atmosphere, an annealing temperature range of 410° C.-430° C., and an annealing time range of 10s-20s, the etched surface is treated to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
4. The method for preparing a reverse polarity LED chip according to claim 3, characterized in that: The flow rate of the inert gas is in the range of 40 slpm to 60 slpm.
5. The method for preparing a reverse polarity LED chip according to claim 1, characterized in that: The step of processing the etched surface to remove dangling bonds on the etched surface and reduce the roughness of the etched surface comprises: The etching surface is treated by soaking in a wet solution to remove dangling bonds on the etching surface and reduce the roughness of the etching surface.
6. The method for preparing a reverse polarity LED chip according to claim 5, characterized in that: The step of treating the etched surface by soaking in a wet solution to remove dangling bonds on the etched surface and reduce the roughness of the etched surface comprises: The epitaxial wafer after etching the P-type window layer is immersed in a mixed solution composed of H3PO4, H2O2 and H2O. Under the conditions that the temperature range of the mixed solution is 20℃-30℃ and the immersion time range is 15s-25s, the etched surface is treated to remove dangling bonds on the etched surface and reduce the roughness of the etched surface.
7. The method for preparing a reverse polarity LED chip according to claim 6, characterized in that: The ratio of H3PO4:H2O2:H2O in the mixed solution is 2:1:
1.
8. The method for preparing a reverse polarity LED chip according to claim 1, characterized in that: The method for preparing the reverse polarity LED chip further includes: providing a target substrate; A substrate transfer process is performed based on the target substrate to remove the temporary substrate.
9. A reverse polarity LED chip, characterized in that: The reverse polarity LED chip is obtained by the method for preparing the reverse polarity LED chip according to any one of claims 1 to 8.
10. A lighting device, characterized in that: The lighting device comprises the reverse polarity LED chip according to claim 9.