Epitaxial structure and fabrication method, light emitting element and fabrication method

Abstract

The application provides an epitaxial structure with simple process and low cost and a manufacturing method, which comprises the following steps: depositing an N-type material layer on a first substrate, etching the N-type material layer to form a first protrusion, at least part of the surface of the first protrusion being curved, sequentially depositing a first active layer and a first P-type layer on the first protrusion, removing the first substrate, etching the side of the N-type material layer away from the first protrusion to form a second protrusion corresponding to the first protrusion, at least part of the surface of the second protrusion being curved, and sequentially depositing a second active layer and a second P-type layer on the second protrusion. The first protrusion and the second protrusion constitute the N-type layer, the first active layer and the second active layer constitute the active layer, and the first P-type layer and the second P-type layer constitute the P-type layer. The application further provides a method for manufacturing a light-emitting element by using the epitaxial structure and the light-emitting element.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display, in particular to an epitaxial structure and a manufacturing method thereof, a light-emitting element and a manufacturing method thereof. BACKGROUND

[0002] In the field of display, micro light-emitting diodes (Micro-LED) are usually assembled on a driving panel to form a high-density LED array for display. As the pursuit of smaller Micro-LED chips continues, it is urgent to ensure the light-emitting area and light-emitting efficiency of the chips. At this time, by making the Micro-LED chip into a spherical shape, the light-emitting area and light-emitting efficiency of the chip can be improved. However, special equipment is needed to form a spherical epitaxial layer structure in the process of the Micro-LED chip, and the use of special equipment will inevitably increase the complexity and cost of the Micro-LED chip. SUMMARY

[0003] To solve the above problems, the present application provides an epitaxial structure and a manufacturing method thereof, a light-emitting element manufactured based on the epitaxial structure, and a manufacturing method of the light-emitting element.

[0004] An embodiment of the present application provides a manufacturing method of an epitaxial structure, comprising:

[0005] depositing an N-type material layer on a first substrate, etching the N-type material layer to form a first protrusion, at least part of the surface of the first protrusion being a curved surface;

[0006] forming a first active layer and a first P-type layer on the first protrusion in sequence;

[0007] removing the first substrate, etching the side of the N-type material layer away from the first protrusion to form a second protrusion corresponding to the first protrusion, at least part of the surface of the second protrusion being a curved surface;

[0008] forming a second active layer and a second P-type layer on the second protrusion in sequence; wherein the first protrusion and the second protrusion constitute an N-type layer, the first active layer and the second active layer constitute an active layer, and the first P-type layer and the second P-type layer constitute a P-type layer.

[0009] Compared with the prior art, the aforementioned epitaxial structure can completely use existing equipment to manufacture a spherical N-type layer, an active layer, a P-type layer, and an insulating layer, and completely does not need to use special equipment to form a spherical epitaxial structure, thereby reducing the complexity and cost of manufacturing the spherical epitaxial structure.

[0010] Optionally, the first protrusion and the second protrusion are mirror-symmetric.

[0011] Optionally, the surface of the first protrusion is hemispherical, and the surface of the second protrusion is hemispherical; the first protrusion with the hemispherical surface and the second protrusion with the hemispherical surface combine to form a spherical shape.

[0012] Optionally, the forming of the first protrusion comprises:

[0013] forming a first spherical particle on the N-type material layer;

[0014] etching the N-type material layer to form the first protrusion by taking the first spherical particle as a mask.

[0015] Optionally, before the first substrate is removed, the method further comprises:

[0016] forming an etching stop layer on the first P-type layer; wherein the surface of the etching stop layer away from the first P-type layer is planarized.

[0017] Optionally, the forming of the second protrusion comprises:

[0018] forming a second spherical particle on the N-type material layer away from the etching stop layer;

[0019] etching the N-type material layer, the first active layer and the first P-type layer to form the second protrusion by taking the second spherical particle as a mask; wherein the end surface of the first active layer and the first P-type layer formed after etching is flush with the etching stop layer.

[0020] Optionally, before the second spherical particle is formed, the method further comprises:

[0021] forming a first photoresist layer on the N-type material layer away from the etching stop layer;

[0022] performing a patterning process on the first photoresist layer;

[0023] etching the N-type material layer, the first active layer and the first P-type layer by taking the first photoresist layer after the patterning process as a mask to form an island-shaped structure corresponding to the first protrusion; wherein the length of the island-shaped structure along the extension direction of the etching stop layer is at least greater than the length of the first protrusion along the extension direction of the etching stop layer.

[0024] forming the second spherical particle on the island-shaped structure to form the second spherical particle on the island-shaped structure.

[0025] Optionally, the forming of the second active layer comprises:

[0026] disposing a second photoresist layer on one side of the second protrusion; wherein the second photoresist layer covers the end surface of the first active layer and the end surface of the first P-type layer.

[0027] The second photoresist layer is patterned to expose the end surface of the first active layer and at least part of the second protrusion;

[0028] An active material layer is deposited on the exposed end surface of the first active layer and at least part of the second protrusion to form a second active layer.

[0029] Optionally, the forming of the second P-type layer comprises:

[0030] The second photoresist layer is removed, and a third photoresist layer is arranged on one side of the second protrusion; wherein the third photoresist layer covers the exposed surface of the second protrusion, the second active layer and the end surface of the first P-type layer;

[0031] The third photoresist layer is patterned to expose the end surface of the first P-type layer and the second active layer;

[0032] A P-type material layer is deposited on the exposed end surface of the first P-type layer and the second active layer to form a second P-type layer.

[0033] Optionally, the forming of the first insulating layer comprises:

[0034] The third photoresist layer is removed, and an insulating material layer is deposited on one side of the second protrusion to form a first insulating layer.

[0035] Optionally, the forming of the second insulating layer comprises:

[0036] A second substrate is arranged on the surface of the first insulating layer;

[0037] The etching stop layer and part of the first insulating layer are removed to expose the end surface of the first P-type layer and the first insulating layer;

[0038] An insulating material layer is deposited on the surface of the first P-type layer and the end surface of the first insulating layer to form a second insulating layer.

[0039] An embodiment of the present application provides an epitaxial structure, which is manufactured by the method of any of the above embodiments.

[0040] An embodiment of the present application further provides a manufacturing method of a light emitting element, comprising:

[0041] Providing an epitaxial structure as described above;

[0042] Manufacturing an N electrode and a P electrode on the epitaxial structure respectively; wherein the N electrode is electrically connected to the N-type layer, and the P electrode is electrically connected to the P-type layer.

[0043] The present application provides a light emitting element, which is manufactured by the manufacturing method of the light emitting element. BRIEF DESCRIPTION OF DRAWINGS

[0044] To more clearly illustrate the structural features and effects of this application, a detailed description is provided below in conjunction with the accompanying drawings and specific embodiments.

[0045] Figure 1 This is a three-dimensional structural diagram of the extensional structure in one embodiment of this application;

[0046] Figure 2 for Figure 1 A schematic diagram of the cross-sectional structure of the extensional structure shown along any central axis.

[0047] Figures 3-20 for Figure 2 A schematic diagram of the cross-sectional structure corresponding to each step in the fabrication method of the shown epitaxial structure;

[0048] Figure 21 This is a schematic cross-sectional view of the light-emitting element along any central axis in the first embodiment of this application;

[0049] Figure 22 As described in the first embodiment of this application Figure 21 A schematic diagram of the cross-sectional structure of the N-electrode used in the fabrication of the light-emitting element shown;

[0050] Figures 23-34 As described in the second embodiment of this application Figure 21 A schematic diagram of the cross-sectional structure corresponding to each step in the fabrication method of the light-emitting element shown;

[0051] Figure 35 This is a cross-sectional structural diagram of the light-emitting element in the third embodiment of this application;

[0052] Figure 36 A cross-sectional view of the light-emitting element in the fourth embodiment of this application;

[0053] Figure 37 This is a cross-sectional structural diagram of the light-emitting element in the fifth embodiment of this application.

[0054] Explanation of reference numerals in the attached figures:

[0055] 100 - Epitaxial structure, O - Center, 110 - N-type layer, 111 - First protrusion, 112 - Second protrusion, 120 - Active layer, 121 - First active layer, 122 - Second active layer, 123 - First notch, 130 - P-type layer, 131 - First P-type layer, 132 - Second P-type layer, 133 - Second notch, 140 - Insulating layer, 141 - First insulating layer, 142 - Second insulating layer, 150 - N-electrode, 160 - P-electrode, 170-current diffusion layer, 180-electron blocking layer, 10-N-type material layer, 20-first substrate, 30-first spherical particle, 40-etch blocking layer, 60-second spherical particle, 001-symmetry line, 70-second photoresist layer, 80-third photoresist layer, 90-second substrate, 200-light-emitting element, H1-first opening, end face F1 of the first active layer, end face F2 of the first P-type layer, end face F3 of the first insulating layer. Detailed Implementation

[0056] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort should fall within the scope of protection of this application.

[0057] This application provides an epitaxial structure 100, please refer to... Figure 1 , Figure 1 This is a three-dimensional structural diagram of the extensional structure 100 of this application. (See diagram below.) Figure 1 As shown, the epitaxial structure 100 is spherical with a center O, which is the intersection of all the central axes of the epitaxial structure 100 in this application.

[0058] Please see Figure 2 , Figure 2 for Figure 1 A schematic cross-sectional view of the extensional structure 100 along any central axis. Figure 2 In the embodiment shown, the epitaxial structure 100 from the center O to the outer surface (i.e. the outline of the epitaxial structure 100) includes an N-type layer 110, an active layer 120, a P-type layer 130, and an insulating layer 140 stacked sequentially.

[0059] like Figure 2As shown, the N-type layer 110 is a solid spherical structure, including a center O. It can be understood that the center O of the N-type layer 110 is the same as the center O of the epitaxial structure 100. The active layer 120 is a spherical layer located between the N-type layer 110 and the P-type layer 130. In this embodiment, the active layer 120 completely covers the N-type layer 110 and is also completely covered by the P-type layer 130. The insulating layer 140 is a spherical layer that completely covers the P-type layer 130. The insulating layer 140 can be made of SiO2 or Si3N4 material; this embodiment does not specify a particular material. The insulating layer 140 protects the insulation between multiple epitaxial structures 100, between the epitaxial structure 100 and the external environment, and between the internal structure of the epitaxial structure 100.

[0060] This application also provides a method such as Figure 1 For the fabrication method of the epitaxial structure 100 shown, please refer to [link / reference needed]. Figures 3-20 This is the first embodiment of this application. Figure 2 The diagram shows a cross-sectional view of each step in the fabrication of the shown epitaxial structure 100. (See attached diagram.) Figures 3-20 As shown, the fabrication of the epitaxial structure 100 includes the following steps:

[0061] Step 100: Deposit an N-type material layer on the first substrate, and etch the N-type material layer to form a first protrusion, wherein at least a portion of the surface of the first protrusion is curved.

[0062] Step 100 specifically includes:

[0063] Step S001, please refer to Figure 3 , Figure 3 This is a schematic cross-sectional view of the structure after an N-type material layer has been grown on the substrate. (Example:) Figure 3 As shown, a first substrate 20 is provided, on which an N-type material layer 10 is grown by metal-organic chemical vapor deposition (MOCVD). The N-type material layer 10 can be made of aluminum gallium indium phosphide (AlGaInP) or other materials; this application does not impose specific limitations. The material of the first substrate 20 can be sapphire, quartz, or ceramic, etc. Figure 3 In the embodiment shown, the first substrate 20 is made of sapphire material.

[0064] Step S002, please refer to Figure 4 , Figure 4 This is a schematic diagram of the cross-sectional structure of the first protrusion 111. Figure 4As shown, the first spherical particles 30 are made away from the surface of the first substrate 20, and the N-type material layer 10 is etched by taking the first spherical particles 30 as a mask to obtain the first protrusion 111, at least part of the surface of the first protrusion 111 is curved. Wherein, the etching can be wet etching, dry etching, etc., in the embodiment, the N-type material layer 10 can be etched by dry etching.

[0065] The first spherical particles 30 can be made by spin coating method, and can also be made by other ways, which are not limited in the embodiment. In Figure 4 In the embodiment, the first spherical particles 30 are made by spin coating method. In addition, the curved surface shape of the first protrusion 111 can be an elliptical surface, a spherical surface, etc., in the embodiment, the first protrusion 111 is a hemisphere with a spherical surface.

[0066] Step 200, sequentially depositing the first active layer and the first P-type layer on the first protrusion 111.

[0067] Wherein, the step 200 specifically includes:

[0068] Step S003, please refer to Figure 5 , Figure 5 The cross-sectional structure of the first active layer 121 and the first P-type layer 131 is shown. As Figure 5 shown, after removing the first spherical particles 30, a layer of active material layer and a layer of P-type material layer are sequentially and orderly grown on the surface of the first protrusion 111 and the N-type material layer 10 by MOCVD method to form the first active layer 121 and the first P-type layer 131, wherein the deposition thickness of the first active layer 121 and the first P-type layer 131 can be the same, or can be adjusted according to the needs, which are not limited in the application. In Figure 5 In the embodiment, the deposition thickness of the first active layer 121 and the first P-type layer 131 is basically the same. The first active layer 121 covers the planarized surface of the first protrusion 111 and the N-type material layer 10, and corresponds to the spherical layer structure of the first active layer 121, which has a spherical surface covering the spherical surface of the first protrusion 111.

[0069] The first P-type layer 131 covers the first active layer 121, so the first P-type layer 131 has a spherical surface corresponding to the spherical layer structure of the first active layer 121, that is, has a spherical layer structure. Wherein, the material of the active material layer can be aluminum gallium indium phosphide series, aluminum gallium indium nitride series, zinc oxide series, and its structure can be single heterostructure, double heterostructure, double side heterostructure, multi-layer quantum well, etc., the material of the P-type material layer can be gallium phosphide, and the material and structure of the active material layer and the P-type material layer are not limited in the embodiment.

[0070] Step S004, please refer toFigure 6 , Figure 6 This is a schematic diagram of the cross-sectional structure after fabrication of the Etch Stop Layer (ESL) 40. (See diagram below.) Figure 6 As shown, an etch barrier layer 40 is deposited on the surface of the first P-type layer 131 facing away from the first substrate 20. The surface of the etch barrier layer 40 facing away from the first P-type layer 131 is a planarized surface. The etch barrier layer 40 can be made of SiC or other silicon-containing materials. This application embodiment does not impose specific limitations on the material of the etch barrier layer 40.

[0071] Step 300: Remove the first substrate 20 and etch the side of the N-type material layer 10 away from the first protrusion 111 to form a second protrusion corresponding to the first protrusion 111, wherein at least a portion of the surface of the second protrusion is curved.

[0072] Step 300 specifically includes:

[0073] Step S005, please refer to Figure 7 , Figure 7 This is a schematic cross-sectional view of the structure after removing the first substrate 20. Figure 7 In the illustrated embodiment, the positions of the first substrate 20 and the etch barrier layer 40 are swapped in three-dimensional space, and the first substrate 20 is peeled off. That is, the N-type material layer 10 is exposed away from the surface of the first protrusion 111 to facilitate subsequent processes.

[0074] Step S006, please refer to Figure 8 , Figure 8 A cross-sectional structural diagram showing the island-shaped structure corresponding to the first protrusion 111. (See diagram below.) Figure 8 As shown, a first photoresist layer (not shown in the figure) is formed on the surface of the N-type material layer 10 away from the etch barrier layer 40, and the first photoresist layer is patterned so that the first photoresist layer contains a first preset pattern (not shown in the figure).

[0075] Using a first photoresist layer containing a first preset pattern as a mask, the N-type material layer 10, the first active layer 121, and the first P-type layer 131 are etched to form an island-shaped structure corresponding to the first protrusion 111. The length of the island-shaped structure along the extension direction of the etch stop layer 40 is at least greater than the length of the first protrusion 111 along the extension direction of the etch stop layer 40. In this embodiment, the island-shaped structure corresponding to the first protrusion 111 is the structure formed by the first protrusion 111 extending from a hemispherical structure to a spherical structure, and the first active layer 121 and the first P-type layer 131 extending from a hemispherical layer to a spherical layer structure.

[0076] After the island-shaped structure corresponding to the first protrusion 111 is formed, the first photoresist layer is peeled off.

[0077] Step S007, please refer toFigure 9 , Figure 9 is a schematic view of a cross-sectional structure for forming the second protrusion 112. As shown, etching is continued on the N-type material layer 10, the first active layer 121, and the first P-type layer 131. Specifically, the second spherical particles 60 are formed on the island-shaped structure, i.e., the second spherical particles 60 are formed on the surface of the N-type material layer 10 away from the etching stop layer 40. The forming method of the second spherical particles 60 is not specifically limited in the embodiment. Figure 9

[0078] The N-type material layer 10, the first active layer 121, and the first P-type layer 131 are etched with the second spherical particles 60 as a mask to form the second protrusion 112 having a curved surface shape. The curved surface shape of the second protrusion 112 can be an elliptical curved surface, a spherical curved surface, etc. In the embodiment, the second protrusion 112 is a hemisphere with a spherical curved surface.

[0079] Further, as shown in Figure 9 , the second protrusion 112 is mirror-symmetrical to the first protrusion 111 about the symmetry line 001, and the second protrusion 112 and the first protrusion 111 combine to form the N-type layer 110. The N-type layer 110 has a spherical structure as a whole, and the surface profile thereof is a spherical surface shape. The symmetry line 001 is the symmetry central axis of the first protrusion 111 and the second protrusion 112.

[0080] In addition, the end faces of the first active layer 121 and the first P-type layer 131 formed after etching are flush with the etching stop layer 40, i.e., the end face F1 of the first active layer 121 and the end face F2 of the first P-type layer 131 are flush with the etching stop layer 40.

[0081] Step 400, a second active layer and a second P-type layer are sequentially deposited on the second protrusion. The first protrusion 111 and the second protrusion 112 constitute the N-type layer 110, the first active layer 121 and the second active layer constitute the active layer, and the first P-type layer 131 and the second P-type layer constitute the P-type layer.

[0082] Step 400 specifically includes:

[0083] Step S008, please refer to Figure 10 , Figure 10 is a schematic view of a cross-sectional structure after the second photoresist layer 70 is patterned.

[0084] As shown in Figure 10 , after the second spherical particles 60 shown in Figure 9 are removed, the second photoresist layer 70 is arranged on the surface of the N-type layer 110 exposed, the surface of the first active layer 121 exposed, the surface of the first P-type layer 131 exposed, and the surface of the etching stop layer 40.

[0085] ​The second photoresist layer 70 is patterned, i.e. the second photoresist layer 70 is exposed and developed. After the exposure and development, the second photoresist layer 70 covers the surface of the etch stop layer 40 and the end surface F2 of the first P-type layer 131, and exposes part of the surface of the N-type layer 110 and the first active layer 121, i.e. part of the spherical surface of the second protrusion 112 and the end surface F1 of the first active layer 121. Figure 10 In the embodiment shown, the second photoresist layer 70 exposes the entire spherical surface of the second protrusion 112 and the end surface F1 of the first active layer 121 after the exposure and development.

[0086] Step S009, please refer to Figure 11 , Figure 11 is a schematic view of the cross-sectional structure of the second active layer 122. An active layer material layer can be deposited on the exposed spherical surface of the second protrusion 112, the end surface F1 of the first active layer 121, and the surface of the second photoresist layer 70 by the MOCVD method to obtain the second active layer 122. The deposition thickness of the second active layer 122 can be the same as the deposition thickness of the first active layer 121.

[0087] As shown in Figure 11 , the second active layer 122 covers the end surface F1 of the first active layer 121, the spherical surface of the second protrusion 112, and the surface of the second photoresist layer 70. Therefore, the second active layer 122 forms a spherical layer on the spherical surface of the second protrusion 112, which has substantially the same structure and size as the end surface F1 of the first active layer 121.

[0088] In this embodiment, the second active layer 122 is a hemispherical layer of the spherical surface, and the second active layer 122 is mirror-symmetrical to the first active layer 121 about the symmetry line 001. Further, the second active layer 122 and the first active layer 121 combine to form the active layer 120, which is a spherical layer covering the N-type layer 110.

[0089] Step S010, please refer to Figure 12 , Figure 12 is a schematic view of the cross-sectional structure after the second photoresist layer 70 is peeled off. As shown in Figure 12 , the second photoresist layer 70 and the active layer material layer covering the surface of the second photoresist layer 70 are peeled off. The surface of the etch stop layer 40, the surface of the second active layer 122, and the end surface F2 of the first P-type layer 131 are exposed.

[0090] Step S011, please refer to Figure 13 , Figure 13 is a schematic view of the cross-sectional structure after the third photoresist layer 80 is patterned. As shown in Figure 13As shown, a third photoresist layer 80 is coated on the surface of the etch barrier layer 40, the surface of the second active layer 122, and the end face F2 of the first P-type layer 131, and the third photoresist layer 80 is patterned. Figure 13 In the embodiment shown, the third photoresist layer 80 is exposed and developed so that the third photoresist layer 80 covers the surface of the etch barrier layer 40 and exposes the spherical surface of the second active layer 122 and the end face F2 of the first P-type layer 131.

[0091] Step S012, please refer to Figure 14 , Figure 14 A schematic cross-sectional view of the structure used to fabricate the second P-type layer 132. Figure 14 In the embodiment shown, a P-type material layer can be deposited on the spherical surface of the exposed second active layer 122, the end face F2 of the first P-type layer 131, and the surface of the third photoresist layer 80 using the MOCVD method.

[0092] like Figure 14 As shown, a P-type material layer covering the spherical surface of the second active layer 122 and the end face F2 of the first P-type layer 131 forms the second P-type layer 132. That is, the second P-type layer 132 is a spherical layer with a spherical surface, and the end face size of the spherical layer is basically the same as the shape and size of the end face F2 of the first P-type layer 131. In this embodiment, the first P-type layer 131 and the second P-type layer 132 are mirror-symmetrical about the symmetry line 001, and the first P-type layer 131 and the second P-type layer 132 are combined to form a P-type layer 130, which is a spherical layer covering the active layer 120.

[0093] Step S013, please refer to Figure 15 , Figure 15 This is a schematic diagram of the cross-sectional structure after the third photoresist layer 80 has been peeled off. Figure 15 As shown, peeling is as follows Figure 14 The third photoresist layer 80 and the P-type material layer deposited on the surface of the third photoresist layer 80 are shown to expose part of the surface of the P-type layer 130 and the surface of the etch barrier layer 40, that is, to expose the spherical surface of the second P-type layer 132 and the flat surface of the etch barrier layer 40.

[0094] Step S014, please refer to Figure 16 , Figure 16 This is a cross-sectional structural diagram illustrating the fabrication of the first insulating layer 141. Insulating material layers are deposited on the surface of the second P-type layer 132 and the surface of the etch barrier layer 40. (Example...) Figure 16 As shown, the insulating material layer covering the spherical surface of the second P-type layer 132 forms a spherical surface with the same shape as the second P-type layer 132, which is the first insulating layer 141.

[0095] In this embodiment, the first insulating layer 141 is a spherical layer with a spherical surface, and the size of the end surface F3 (see Figure 18 ) of the first insulating layer 141 can be substantially the same as the end surface shape and size of the P-type layer 130, which is not limited in this embodiment.

[0096] Step S015, please refer to Figure 17 , Figure 17 is a schematic diagram of the cross-sectional structure after the second substrate 90 is disposed. The spherical surface formed by the first insulating layer 141 and the surface of the insulating material layer deposited on the etching stop layer 40 are disposed with the second substrate 90. As shown in Figure 17 , the surface of the second substrate 90 away from the etching stop layer 40 can be a planarized surface.

[0097] Step S016, please refer to Figure 18 , Figure 18 is a schematic diagram of the cross-sectional structure after the etching stop layer 40 is peeled off.

[0098] The etching stop layer 40 and the second substrate 90 are exchanged in three-dimensional space, and the etching stop layer 40 and the insulating material layer deposited on the etching stop layer 40 are peeled off. As shown in Figure 18 , the surface of the second substrate 90, the end surface F3 of the first insulating layer 141, and the surface of the first P-type layer 131 are exposed to facilitate the subsequent process.

[0099] Step S017, please refer to Figure 19 , Figure 19 is a schematic diagram of the cross-sectional structure after the second insulating layer 142 is made. The insulating material layer is deposited on the surface of the second substrate 90, the surface of the first P-type layer 131, and the end surface F3 of the first insulating layer 141, and the insulating material layer deposited on the surface of the second substrate 90 is peeled off.

[0100] As shown in Figure 19 , the insulating material layer deposited on the surface of the first P-type layer 131 forms the second insulating layer 142 covering the first P-type layer 131, i.e. the second insulating layer 142 is a spherical layer with a spherical surface, and the end surface shape and size of the spherical layer of the second insulating layer 142 are substantially the same as the shape and size of the end surface F3 of the first insulating layer 141. In this embodiment, the first insulating layer 141 and the second insulating layer 142 cooperate to form the insulating layer 140, and the insulating layer 140 covers the P-type layer 130 in a spherical layer structure.

[0101] Step S018, please refer to Figure 20 , Figure 20 is a schematic diagram of the cross-sectional structure after the second substrate 90 is peeled off. As shown in Figure 20 , the second substrate 90 is peeled off from the surface of the first insulating layer 141 as shown in Figure 19 to obtain a structure as shown inFigure 2 The epitaxial structure 100 is shown.

[0102] The epitaxial structure 100 can be made by using existing equipment to form the N-type layer 110, the active layer 120, the P-type layer 130 and the insulating layer 140, and no special equipment is needed to form the epitaxial structure 100, thereby reducing the complexity and cost of the epitaxial structure 100.

[0103] The application also provides a light emitting element 200. In this embodiment, the light emitting element 200 is formed by forming an N electrode and a P electrode on the epitaxial structure 100 shown in Figure 2 The N electrode is electrically connected to the N-type layer, and the P electrode is electrically connected to the P-type layer. The N electrode and the P electrode receive a driving signal from the outside to drive the N-type layer and the P-type layer to emit light from the active layer.

[0104] Specifically, as shown in Figure 21 The N electrode 150 is electrically connected to the N-type layer 110, and the P electrode 160 is electrically connected to the P-type layer 130. Figure 21 is a cross-sectional structure diagram of the light emitting element 200 along any central axis. The light emitting element 200 is obtained by forming the N electrode 150 and the P electrode 160 on the basis of the epitaxial structure 100.

[0105] The application also provides a method for manufacturing the light emitting element 200 shown in Figure 21 Specifically, the method comprises the steps of manufacturing the N electrode 150 and the P electrode 160 on the basis of the epitaxial structure 100 to obtain the light emitting element 200.

[0106] As shown in Figure 22 is a cross-sectional structure diagram corresponding to each step in the method for manufacturing the light emitting element shown in Figure 21 In this embodiment, the steps of manufacturing the N electrode 150 and the P electrode 160 on the basis of the epitaxial structure 100 to obtain the light emitting element 200 comprise:

[0107] The N-type layer 110, the active layer 120, the P-type layer 130 and the insulating layer 140 of the light emitting element 200 can be manufactured by the steps S001-S017 for manufacturing the epitaxial structure 100.

[0108] Step S019, please refer to Figure 22 , Figure 22A cross-sectional structure of the N electrode 150 is shown in the figure. A first opening H1 is formed on the insulating layer 140, and the N electrode 150 is arranged in the first opening H1. The inner wall of the first opening H1 is coated with an insulating material to insulate the N electrode 150 from other structures. The material of the insulating material is not limited in the embodiment, and in the embodiment shown in the figure, the material of the insulating material is the same as that of the insulating layer 140. Specifically, a Si3N4 cover film is used as a mask to etch the insulating layer 140 by plasma etching with chlorine gas until the surface of the N-type layer 110 is exposed. The N electrode 150 is formed by a Ni / Au evaporation film. The method of forming the N electrode 150 is not limited in the embodiment. The structure, position, and material of the N electrode 150 are not limited in the embodiment. It can be understood that the first opening H1 and the N electrode 150 can be an elongated strip or a square structure, and are arranged along an arbitrary central axis of the spherical profile of the light emitting element 200. The N electrode 150 allows the current to uniformly spread on the N-type layer 110 and does not block the light. Figure 22

[0109] When the N electrode 150 is formed, the Si3N4 cover film is removed.

[0110] Step S020, please refer to Figure 21 Figure 21 A cross-sectional structure of the P electrode 160 is shown in the figure. As shown in the figure, the P electrode 160 is formed on the insulating layer 140 to be in ohmic contact with the P-type layer 130 at a distance from the N electrode 150. Figure 21 Figure 21 In the embodiment shown in the figure, the P electrode 160 is formed on the surface of the insulating layer 140 opposite to the N electrode 150 by a Ti / Au evaporation film to be in contact with the surface of the P-type layer 130. The structure and position of the P electrode are not limited in the embodiment. In the embodiment shown in the figure, the orthogonal projection of the P electrode 160 on the vertical plane of the central axis of the N electrode 150 is linear. Figure 21

[0111] The N electrode 150 and the P electrode 160 form a conductive path between the N-type layer 110 and the P-type layer 130, i.e., the N-type layer 110, the active layer 120, and the P-type layer 130 cooperate to emit light under the driving of the current in the power supply.

[0112] ​​​​The light emitting element 200 made on the basis of the epitaxial structure 100 has a large light emitting area of the active layer 120 of the spherical layer, so that the light emitting efficiency of the light emitting element 200 is effectively improved.

[0113] Referring to Figures 23-34 , FIG. 8 is a cross-sectional view of a light emitting element according to a second embodiment of the present application, and Figure 21 FIG. 9 is a cross-sectional view of a light emitting element according to a second embodiment of the present application, and

[0114] The N-type layer 110, the first active layer 121, and the first P-type layer 131 of the light emitting element 200 according to the present application can be made through the steps S001-S007 of making the epitaxial structure 100.

[0115] Referring to Figure 23 , Figure 23 , FIG. 6 is a cross-sectional view of a light emitting element according to a second embodiment of the present application, and Figure 23 The second photoresist layer 70 is disposed on the exposed surface of the N-type layer 110, the exposed surface of the first active layer 121, the exposed surface of the first P-type layer 131, and the surface of the etching stop layer 40, and is patterned, i.e., exposed and developed, so that the second photoresist layer 70 covers the surface of the etching stop layer 40 and the end surface of the first P-type layer 131, and exposes part of the surface of the N-type layer 110 and the first active layer 121, i.e., part of the spherical surface of the second protrusion 112 and the end surface of the first active layer 121. Figure 23 In the embodiment shown in FIG. 6, the second photoresist layer 70 exposes part of the surface of the second protrusion 112 and the end surface of the first active layer 121 after being exposed and developed.

[0116] Referring to Figure 24 , Figure 24 , FIG. 7 is a cross-sectional view of a light emitting element according to a second embodiment of the present application, and

[0117] The second active layer 122 can be made by depositing an active layer material layer on the spherical surface of the partially exposed second protrusion 112, the end surface of the first active layer 121, and the surface of the second photoresist layer 70 by the MOCVD method, so that the second active layer 122 has the same thickness as the first active layer 121. Figure 24As shown, the second active layer 122 covers the end face of the first active layer 121, the exposed spherical surface of the second protrusion 112, and the planarized surface of the second photoresist layer 70. Therefore, the second active layer 122 forms a spherical layer with the same dimensions as the end face of the first active layer 121 on the spherical surface corresponding to the second protrusion 112. Since the surface of the second protrusion 112 is provided with a portion of the second photoresist layer 70, the second active layer 122 has a first notch 123, exposing a portion of the N-type layer 110 surface. This embodiment does not specifically limit the position, shape, or structure of the first notch 123. It can be understood that the second active layer 122 is a hemispherical layer with a spherical surface, and the second active layer 122 is mirror-symmetrical to the first active layer 121 about the symmetry line 001. Furthermore, the second active layer 122 combines with the first active layer 121 to form an active layer 120, which is a spherical layer covering the N-type layer 110. Understandably, the active layer 120 has a first notch 123.

[0118] Step S023, please refer to Figure 25 , Figure 25 This is a schematic cross-sectional view of the structure after partial removal of the second photoresist layer 70. (See diagram below.) Figure 25 As shown, the second photoresist layer 70 and the active layer material layer covering the surface of the second photoresist layer 70 are peeled off, so that the surface of the etch barrier layer 40, the surface of the second active layer 122, the end face of the first P-type layer 131 are exposed, and part of the surface of the N-type layer 110 is exposed from the first notch 123.

[0119] Step S024, please refer to Figure 26 , Figure 26 This is a schematic cross-sectional view of the patterned third photoresist layer 80. Figure 26 As shown, a third photoresist layer 80 is coated on the surface of the etch barrier layer 40, the surface of the second active layer 122, the end face of the first P-type layer 131, and the surface of the portion of the N-type layer 110 exposed from the first notch 123, and the third photoresist layer 80 is patterned. Figure 13 In the embodiment shown, the third photoresist layer 80 is exposed and developed so that the third photoresist layer 80 covers the etch barrier layer 40 and the surface of the N-type layer 110 exposed at the first notch 123, and exposes the surface of the second active layer 122 and the end face of the first P-type layer 131.

[0120] Step S025, please refer to Figure 27 , Figure 27 A schematic cross-sectional view of the structure used to fabricate the second P-type layer 132. Figure 27 In the illustrated embodiment, a P-type material layer can be deposited on the spherical surface exposing the second active layer 122, the end face of the first P-type layer 131, and the surface of the third photoresist layer 80 using the MOCVD method. For example... Figure 27As shown, the P-type material layer covering the spherical surface of the second active layer 122 and the end surface of the first P-type layer 131 forms the second P-type layer 132, i.e. the second P-type layer 132 is a spherical layer with a spherical surface, and the end surface size of the spherical layer is the same as that of the first P-type layer 131. Further, since the part of the third photoresist layer 80 is arranged on the surface of the part of the N-type layer 110 exposed from the first gap 123, the second P-type layer 132 has a second gap 133. As shown, Figure 27 the shape size and position of the second gap 133 correspond to those of the first gap 123.

[0121] It can be understood that the first P-type layer 131 and the second P-type layer 132 are mirror symmetrical about the symmetry line 001, and the first P-type layer 131 and the second P-type layer 132 combine to form the P-type layer 130, which is a spherical layer covering the active layer 120, and the P-type layer 130 has the second gap 133, and the second gap 133 and the first gap 123 combine to form the first opening H1.

[0122] Step S026, please refer to Figure 28 , Figure 28 is a cross-sectional structure diagram after the third photoresist layer 80 is stripped. As shown, Figure 28 the third photoresist layer 80 and the P-type material layer deposited on the surface of the third photoresist layer 80 are stripped to expose the surface of the second P-type layer 132, the surface of the etching stop layer 40, and part of the surface of the N-type layer 110. Among them, part of the surface of the N-type layer 110 is exposed from the first opening H1.

[0123] Step S027, please refer to Figure 29 , Figure 29 is a cross-sectional structure diagram for manufacturing the first insulating layer 141. An insulating material layer is deposited on the surface of the second P-type layer 132, the part of the surface of the N-type layer 110 exposed, and the surface of the etching stop layer 40. As shown, Figure 29 the insulating material layer covering the spherical surface of the second P-type layer 132 will form a spherical surface with the same shape as the second P-type layer 132, i.e. the first insulating layer 141. It can be understood that the first insulating layer 141 is a spherical layer with a spherical surface, and the end surface size thereof can be the same as that of the P-type layer 130, or can be adjusted according to needs, which is not limited in the embodiment.

[0124] In addition, as shown, Figure 29 the insulating material layer also covers the end surface of the second active layer 122 at the first gap 123 and the end surface of the second P-type layer 132 at the second gap 133. It can be understood that the inner wall of the first opening H1 is attached with an insulating material layer.

[0125] Step S028, please refer to Figure 30 ,Figure 30 This is a schematic diagram of the cross-sectional structure for fabricating the N-electrode 150. (See attached diagram.) Figure 30 As shown, an N-electrode 150 is fabricated within the first opening H1. Specifically, the insulating layer material covering a portion of the surface of the N-type layer 110 is removed to expose a portion of the surface of the N-type layer 110 from the first opening H1. The method for removing the insulating layer material can be etching or other methods, which are not specifically limited in this application. An N-electrode 150, which can be composed of a Ni / Au vapor-deposited film, is formed on the exposed surface of the N-type layer 110 and inside the first opening H1, so that the N-electrode 150 is connected to the N-type layer 110. It is understood that since the inner wall of the first opening H1 is covered with an insulating material layer, the side of the N-electrode 150 adjacent to the inner wall of the first opening H1 is wrapped with the insulating material layer, so that the N-electrode 150 is insulated from the active layer 120 and the P-type layer 130. This embodiment does not specifically limit the fabrication method and material of the N-electrode 150. Furthermore, in Figure 30 In the embodiment shown, the surface of the N electrode 150 facing away from the etch barrier layer 40 and the surface of the first insulating layer 141 form a complete hemispherical profile.

[0126] Step S029, please refer to Figure 31 , Figure 31 This is a schematic cross-sectional view of the second substrate 90. Figure 31 As shown, a second substrate 90 is disposed on the surface of the first insulating layer 141. The second substrate 90 completely covers the first insulating layer 141 and the surface of the N-electrode 150 facing away from the etch stop layer 40, and the surface of the second substrate 90 facing away from the etch stop layer 40 is a planarized surface. It is understood that the second substrate 90 can be made of materials such as sapphire, quartz, or ceramic; this embodiment does not impose a specific limitation.

[0127] Step S030, please refer to Figure 32 , Figure 32 This is a schematic cross-sectional view of the structure after removing the etch barrier layer 40. Figure 32 In the illustrated embodiment, the positions of the etch barrier layer 40 and the second substrate 90 in space are swapped, thereby exposing the planarized surface of the etch barrier layer 40. The etch barrier layer 40 and the insulating material layer covering its surface are removed using solutions corresponding to those used in this embodiment, thereby exposing the surface of the second substrate 90 adjacent to the etch barrier layer 40 and the end face F3 of the first insulating layer 141.

[0128] Step S031, please refer to Figure 33 , Figure 33A cross-sectional structure of the second insulating layer 142 is shown. An insulating material layer is deposited on the exposed surface of the second substrate 90, the surface of the first P-type layer 131, and the end surface of the first insulating layer 141, and the insulating material layer deposited on the surface of the second substrate 90 is removed. As shown in Figure 33 , the insulating material layer deposited on the surface of the first P-type layer 131 forms the second insulating layer 142 covering the first P-type layer 131, i.e., the second insulating layer 142 is a spherical layer having a spherical surface, and the end surface of the spherical layer of the second insulating layer 142 has the same size as the end surface of the first insulating layer 141. It can be understood that the first insulating layer 141 and the second insulating layer 142 combine to form the insulating layer 140, which is a spherical layer covering the P-type layer 130.

[0129] Step S032, please refer to Figure 34 , Figure 34 A cross-sectional structure of the P electrode 160 is shown. The P electrode 160 ohmically contacts the P-type layer 130 is made on the insulating layer 140 at a distance from the N electrode 150. Specifically, in the embodiment shown in Figure 34 , the P electrode 160 contacting the surface of the P-type layer 130 is formed by Ti / Au evaporation film on the surface of the insulating layer 140 opposite to the N electrode 150, and the orthographic projection of the P electrode 160 on the vertical plane of the central axis where the N electrode 150 is located is linear.

[0130] Please refer to Figure 35 , which is a cross-sectional structure of the light emitting element shown in the third embodiment of the present application Figure 21 . As shown in Figure 35 , the structure of the light emitting element 200 in the present embodiment is basically the same as that of the light emitting element 200 shown in Figure 21 , and the difference is only in the structure and position of the P electrode 160. Specifically, in the embodiment shown in Figure 35 , the orthographic projection of the P electrode 160 on the vertical plane of the central axis where the N electrode 150 is located is a closed ring shape, which can make the current diffuse more uniformly on the P-type layer 130, and does not block light. That is, it does not affect the light emitting efficiency of the light emitting element 200.

[0131] Alternatively, the number and position of the P electrode 160 can be adjusted according to actual needs.

[0132] Please refer to Figure 36 , Figure 36 , which is a cross-sectional structure of the light emitting element 200 in the fourth embodiment of the present application. As shown in Figure 36As shown in the figure, the light emitting element 200 can further comprise a current diffusion layer 170. The current diffusion layer 170 is located between the P-type layer 130 and the insulating layer 140, and has a spherical shape and covers the P-type layer 130. It can be understood that the current diffusion layer 170 can make the current uniformly diffuse and uniformly distribute on the P-type layer 130.

[0133] As shown in the figure, Figure 37 , Figure 37 is a schematic diagram of a cross-sectional structure of the light emitting element 200 in the fourth embodiment of the present application. As shown in the figure, Figure 37 The light emitting element 200 can further comprise an electron blocking layer 180. The electron blocking layer 180 is a spherical layer, located between the active layer 120 and the P-type layer 130, and can cover the active layer 120. It can be understood that the electron blocking layer 180 can block the migration of electrons and avoid the reduction of the light emitting efficiency of the active layer 120, i.e. the electron blocking layer 180 can enhance the light emitting efficiency of the light emitting element 200.

[0134] Alternatively, the current diffusion layer 170 and the electron blocking layer 180 can be adjusted according to actual needs, i.e. the current diffusion layer 170 or the electron blocking layer 180 can be set alone, or the current diffusion layer 170 and the electron blocking layer 180 can be set simultaneously, and the present embodiment does not make specific limitation on this.

[0135] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed in the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for fabricating an epitaxial structure, the method comprising: The application relates to a method for manufacturing a semiconductor laser, and belongs to the technical field of semiconductor laser manufacturing. The method comprises the following steps: depositing an N-type material layer on a first substrate, etching the N-type material layer to form a first protrusion; At least part of the surface of the first protrusion is curved; Depositing a first active layer and a first P-type layer on the first protrusion in sequence; Removing the first substrate, etching the side of the N-type material layer away from the first protrusion to form a second protrusion corresponding to the first protrusion; wherein at least part of the surface of the second protrusion is curved; Depositing a second active layer and a second P-type layer on the second protrusion in sequence; wherein the first protrusion and the second protrusion constitute an N-type layer, the first active layer and the second active layer constitute an active layer, and the first P-type layer and the second P-type layer constitute a P-type layer.

2. The method of claim 1, wherein The first protrusion is mirror-symmetrical to the second protrusion.

3. The method of claim 2, wherein The surface of the first protrusion is hemispherical, and the surface of the second protrusion is hemispherical; the first protrusion with a hemispherical surface and the second protrusion with a hemispherical surface combine to form a sphere.

4. The method of claim 1, wherein The forming step of the first protrusion comprises the following steps: Forming first spherical particles on the N-type material layer; Using the first spherical particles as a mask to etch the N-type material layer to form the first protrusion.

5. The method of claim 1, wherein Before the step of removing the first substrate, the method further comprises the following steps: Forming an etching stop layer on the first P-type layer; wherein the side of the etching stop layer away from the first P-type layer is a planar surface.

6. The method of claim 5, wherein, The forming step of the second protrusion comprises the following steps: Forming second spherical particles on the side of the N-type material layer away from the etching stop layer; Using the second spherical particles as a mask to etch the N-type material layer, the first active layer and the first P-type layer to form the second protrusion; wherein the end surface of the first active layer and the first P-type layer formed after etching is flush with the etching stop layer.

7. The method of claim 6, wherein the epitaxial structure is formed by a method comprising: Before the step of forming the second spherical particles, the method further comprises the following steps: Forming a first photoresist layer on the side of the N-type material layer away from the etching stop layer; Performing a patterning process on the first photoresist layer; Using the first photoresist layer after the patterning process as a mask to etch the N-type material layer, the first active layer and the first P-type layer to form an island-shaped structure corresponding to the first protrusion; wherein the length of the island-shaped structure along the extension direction of the etching stop layer is at least greater than the length of the first protrusion along the extension direction of the etching stop layer; The step of forming second spherical particles on the side of the N-type material layer away from the etching stop layer is the step of forming second spherical particles on the island-shaped structure.

8. The method of claim 6, wherein, The forming step of the second active layer comprises the following steps: Setting a second photoresist layer on one side of the second protrusion; wherein the second photoresist layer covers the end surface of the second protrusion, the end surface of the first active layer and the end surface of the first P-type layer; Performing a patterning process on the second photoresist layer to expose the end surface of the first active layer and at least part of the second protrusion; Depositing an active material layer on the exposed surface of at least part of the second protrusion and the end surface of the first active layer to form a second active layer.

9. The method of claim 8, wherein, The forming step of the second P-type layer comprises the following steps: removing the second photoresist layer, and disposing a third photoresist layer on one side of the second protrusion; wherein the third photoresist layer covers the exposed surface of the second protrusion, the second active layer and the end surface of the first P-type layer; performing a patterning process on the third photoresist layer to expose the end surface of the first P-type layer and the second active layer; depositing a P-type material layer on the exposed second active layer and the end surface of the first P-type layer to form a second P-type layer.

10. The method of claim 9, wherein The forming step of the first insulating layer comprises: removing the third photoresist layer, and depositing an insulating material layer on one side of the second protrusion to form the first insulating layer.

11. The method of claim 10, wherein The forming step of the second insulating layer comprises: disposing a second substrate on the surface of the first insulating layer; removing the etching stop layer and part of the first insulating layer to expose the end surface of the first P-type layer and the first insulating layer; depositing an insulating material layer on the surface of the first P-type layer and the end surface of the first insulating layer to form a second insulating layer.

12. An epitaxial structure, characterized in that, The epitaxial structure is fabricated by the method of any one of claims 1-11.

13. A method for manufacturing a light-emitting element, comprising the steps of: comprises: providing an epitaxial structure as claimed in claim 12; forming an N electrode and a P electrode on the epitaxial structure respectively; wherein the N electrode is electrically connected to the N-type layer, and the P electrode is electrically connected to the P-type layer.

14. A light emitting element characterized by comprising: The light emitting element is fabricated by the method of claim 13.

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