A method for manufacturing a light emitting device and a light emitting device

Abstract

The application discloses a preparation method of a light-emitting device and the light-emitting device. The preparation method comprises the following steps: providing a substrate; forming a first mask layer on the front surface of the substrate and performing a patterning process on the first mask layer to form a plurality of front mask openings in the first mask layer; growing a semiconductor epitaxial layer on the front surface of the substrate based on the first mask layer after the patterning process, and doping a first element during the growth of the semiconductor epitaxial layer to form a plurality of first light-emitting units and a plurality of second light-emitting units; wherein the component proportion of the first element of the first light-emitting units is different from the component proportion of the first element of the second light-emitting units; inverting the substrate on a transfer substrate to expose the back surface of the substrate; and forming a plurality of third light-emitting units on the back surface of the substrate. The production yield of the light-emitting device is improved, and the service life and reliability of the light-emitting units in the device are improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a method for preparing a light-emitting device and the light-emitting device thereof. Background Technology

[0002] Micro-LED uses a blue light-emitting structure to excite red and green quantum dots to achieve full-color display. Compared with traditional LED displays, it has the characteristics of higher screen brightness, higher screen contrast, richer dark field details, and more accurate color reproduction.

[0003] In related technologies, the light-emitting layer of LEDs utilizes phosphors or quantum dots for wavelength conversion. The disadvantages of this method are the short lifespan of phosphors or quantum dots and issues with light conversion efficiency. Furthermore, the process of fabricating individual monochrome LEDs and transferring them onto the driving substrate is cumbersome, resulting in low product yield. Summary of the Invention

[0004] This invention provides a method for fabricating a light-emitting device and the light-emitting device itself, thereby improving the production yield of the light-emitting device and the lifespan and reliability of the light-emitting unit in the device.

[0005] According to one aspect of the present invention, a method for fabricating a light-emitting device is provided, comprising:

[0006] A substrate is provided; the substrate includes opposing front and back sides;

[0007] A first mask layer is formed on the front side of the substrate, and the first mask layer is patterned to form a plurality of front mask openings in the first mask layer;

[0008] Based on the patterned first mask layer, a semiconductor epitaxial layer is grown on the front side of the substrate, and a first element is doped during the growth of the semiconductor epitaxial layer to form a plurality of first light-emitting units and a plurality of second light-emitting units; wherein the composition ratio of the first element in the first light-emitting unit is different from the composition ratio of the first element in the second light-emitting unit.

[0009] The substrate is inverted on the transposed substrate to expose the back side of the substrate;

[0010] Multiple third light-emitting units are formed on the back side of the substrate.

[0011] According to another aspect of the present invention, a light-emitting device is provided, comprising:

[0012] Substrate; the substrate includes opposing front and back sides;

[0013] A first mask layer, the first mask layer including a plurality of front mask openings;

[0014] Multiple first light-emitting units and multiple second light-emitting units are located on the front side of the substrate; wherein the composition ratio of the first element in the first light-emitting units is different from the composition ratio of the first element in the second light-emitting units;

[0015] The third light-emitting unit is located on the back side of the substrate.

[0016] The technical solution provided by this invention forms a first mask layer on the front side of a substrate and patterns the first mask layer to form multiple front mask openings. Based on the patterned first mask layer, a first light-emitting unit and multiple second light-emitting units are simultaneously fabricated on the front side of the substrate. This improves the production efficiency of the light-emitting device while eliminating the need to etch the substrate, thus preventing substrate damage and improving the device production yield. Furthermore, by fabricating a third light-emitting unit on the back side of the substrate, light-emitting units of different colors can be synchronously transferred to the driving substrate via a transpose substrate, further improving the production yield of the light-emitting device. In addition, by doping a first element during the growth of the semiconductor epitaxial layer to form multiple first light-emitting units and multiple second light-emitting units, the different emission wavelengths of the first and second light-emitting units are achieved by controlling the different light-emitting layer compositions corresponding to different positions on the front side. This eliminates the need for wavelength conversion using phosphors or quantum dots, extending the lifespan and improving the reliability of the light-emitting device. Attached Figure Description

[0017] Figure 1 This is a flowchart of a method for fabricating a light-emitting device according to an embodiment of the present invention;

[0018] Figure 2 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention;

[0019] Figures 3 to 13 This is a cross-sectional structural diagram of steps S210 to S2110 in a method for fabricating a light-emitting device according to an embodiment of the present invention;

[0020] Figure 14 This is a cross-sectional structural schematic diagram of a light-emitting device provided in an embodiment of the present invention;

[0021] Figure 15 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention;

[0022] Figures 16 to 19 This is a cross-sectional structural diagram of steps S370 to S3110 in a method for fabricating a light-emitting device according to an embodiment of the present invention;

[0023] Figure 20This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention;

[0024] Figures 21 to 29 This is a cross-sectional structural diagram of steps S420 to S4110 in the method for preparing a light-emitting device according to an embodiment of the present invention. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0026] This invention provides a method for fabricating a light-emitting device. Figure 1 This is a flowchart of a method for fabricating a light-emitting device according to an embodiment of the present invention, see reference. Figure 1 The methods for fabricating light-emitting devices include:

[0027] S110, Provide a substrate; the substrate includes opposing front and back sides.

[0028] Specifically, the substrate material can be sapphire, silicon carbide, silicon, GaN, AlN, or diamond, etc., and there are no restrictions on this.

[0029] S120. A first mask layer is formed on the front side of the substrate, and the first mask layer is patterned to form a plurality of front mask openings in the first mask layer.

[0030] Specifically, the material of the first mask layer can be a nitride or an oxide, such as at least one of silicon dioxide and silicon nitride. The first mask layer can be formed by physical vapor deposition or chemical vapor deposition, and the patterning process can be achieved by dry etching or wet etching.

[0031] S130. Based on the patterned first mask layer, a semiconductor epitaxial layer is grown on the front side of the substrate, and a first element is doped during the growth of the semiconductor epitaxial layer to form multiple first light-emitting units and multiple second light-emitting units; wherein the composition ratio of the first element in the first light-emitting unit is different from the composition ratio of the first element in the second light-emitting unit.

[0032] Specifically, based on the patterned first mask layer, a semiconductor epitaxial layer is grown on the front side of the substrate. During the growth of the semiconductor epitaxial layer, a first element is doped to form multiple first light-emitting units and multiple second light-emitting units. This eliminates the need to etch the front side of the substrate, preventing issues with controlling etching depth and position that could affect the device fabrication yield. With the semiconductor epitaxial layer grown on the front side of the substrate, both the first and second light-emitting units can be located within the front mask openings; alternatively, some light-emitting units can be located within the front mask openings, while others can be located on the first mask layer. The composition ratio of the first element in the first light-emitting unit differs from that in the second light-emitting unit, enabling the simultaneous presence of two emission wavelengths on the same substrate.

[0033] For example, the first light-emitting unit can be a blue light-emitting unit that emits blue light. The second light-emitting unit can be a green light-emitting unit that emits green light. If the first element is In, the proportion of the first element in the first light-emitting unit is less than the proportion of the first element in the second light-emitting unit; if the first element is Al, the proportion of the first element in the first light-emitting unit is greater than the proportion of the first element in the second light-emitting unit. In other embodiments, other first elements may also be doped.

[0034] S140. Invert the substrate onto the transposed substrate to expose the back side of the substrate.

[0035] Specifically, before inverting the substrate onto the transposed substrate, a first passivation layer can be formed on the front side of the substrate; the first passivation layer at least covers the surfaces of the first light-emitting unit and the second light-emitting unit, ensuring that the substrate can be stably inverted onto the transposed substrate, which is beneficial for subsequent processes.

[0036] S150, Multiple third light-emitting units are formed on the back side of the substrate.

[0037] Specifically, the emission color of the third light-emitting unit is different from that of the first and second light-emitting units; for example, the first light-emitting unit is a blue light-emitting unit, the second light-emitting unit is a green light-emitting unit, and the emission color of the third light-emitting unit can be red.

[0038] The method for fabricating a light-emitting device provided in this invention involves forming a first mask layer on the front side of a substrate and patterning the first mask layer to form multiple front mask openings. Based on the patterned first mask layer, a first light-emitting unit and multiple second light-emitting units are simultaneously fabricated on the front side of the substrate. This improves the production efficiency of the light-emitting device while eliminating the need for substrate etching, reducing the probability of scrap due to substrate over-etching, and thus improving the device production yield. Furthermore, fabricating a third light-emitting unit on the back side of the substrate allows light-emitting units of different colors to be synchronously transferred to the driving substrate via a transpose substrate, further improving the production yield of the light-emitting device. In addition, during the growth of the semiconductor epitaxial layer, a first element is doped to form multiple first light-emitting units and multiple second light-emitting units. By controlling the different light-emitting layer compositions corresponding to different positions on the front side, the emission wavelengths of the first and second light-emitting units are made different, eliminating the need for wavelength conversion using phosphors or quantum dots, extending the lifespan of the light-emitting device, and improving its reliability.

[0039] For example, Figure 2 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention. Figures 3 to 13 This is a cross-sectional structural schematic diagram of steps S210 to S2110 in the fabrication method of a light-emitting device provided in an embodiment of the present invention, with reference to... Figure 2 The methods for fabricating light-emitting devices include:

[0040] S210, Provide a substrate; the substrate includes opposing front and back sides.

[0041] For details, please refer to Figure 3 The substrate 10 can be made of materials such as sapphire, silicon carbide, silicon, GaN, AlN or diamond, and there is no limitation on the material.

[0042] S220. A first mask layer is formed on the front side of the substrate, and the first mask layer is etched to form a plurality of first front mask openings and a plurality of second front mask openings, wherein the opening area of ​​the first front mask opening is larger than the opening area of ​​the second front mask opening; wherein the material of the first mask layer includes silicon oxide and / or silicon nitride.

[0043] For details, please refer to Figure 4 The first mask layer 20 is etched to form a plurality of first front mask openings 201 and a plurality of second front mask openings 202, wherein the opening area of ​​the first front mask opening 201 is larger than the opening area of ​​the second front mask opening 202.

[0044] S230. A first semiconductor layer, a first active layer, and a second semiconductor layer are sequentially formed in the first front mask opening and the second front mask opening, and a first element is doped when the first active layer is formed, so as to form a first light-emitting unit in the first front mask opening and a second light-emitting unit in the second front mask opening; wherein the composition ratio of the first element in the first light-emitting unit is different from the composition ratio of the first element in the second light-emitting unit.

[0045] For details, please refer to Figure 5 The material of the first semiconductor layer 01 can be a group III nitride, specifically including at least one of GaN and AlGaN; the material of the second semiconductor layer 03 can be a group III nitride, specifically including at least one of GaN and AlGaN. Optionally, the first semiconductor layer 01 can be a P-type semiconductor layer and the second semiconductor layer 03 can be an N-type semiconductor layer; or, the first semiconductor layer 01 can be an N-type semiconductor layer and the second semiconductor layer 03 can be a P-type semiconductor layer.

[0046] The first active layer 02 may include at least one of a single quantum well structure, a multiple quantum well (MQW) structure, a quantum wire structure, and a quantum dot structure. The material of the first active layer 02 may be GaN-based, wherein it may be doped with In, specifically InGaN; or it may be doped with Al, specifically AlGaN. The band gap of InN is approximately 0.7 eV, which is smaller than the band gap of GaN (3.4 eV). Therefore, the greater the In doping amount, the longer the emission wavelength of the first active layer 02. The band gap of AlN is approximately 6.2 eV, which is larger than the band gap of GaN (3.4 eV). Therefore, the greater the Al doping amount, the shorter the emission wavelength of the first active layer 02.

[0047] For details, please continue to refer to [the website / information]. Figure 5Taking GaN-based materials as an example, due to the different areas of the first front mask opening 201 and the second front mask opening 202, the flow rates of the reactant gas in the first front mask opening 201 and the second front mask opening 202 are different when doping the first element. This results in different incorporation rates of In / Al and Ga elements, i.e., different incorporation efficiencies of In / Al elements. Consequently, the composition ratio of In / Al elements in the grown first active layer O2 is different. This, in turn, results in different wavelengths of light emitted by the first light-emitting unit 110 and the second light-emitting unit 120. Each first mask opening 201 corresponds to the growth of one first light-emitting unit 110, and each second mask opening 202 corresponds to the growth of one second light-emitting unit 120. Under the same fabrication conditions, the second light-emitting unit 120 grown in the smaller second mask opening 202 can exhibit a tetrahedral shape, emitting light from a transverse planar surface, while the first light-emitting unit 110 grown in the larger first mask opening 201 can exhibit a hexagonal pyramid shape, emitting light from an inclined surface. The shapes of the first front mask opening and the second front mask opening can be arbitrary shapes such as circles, squares, and hexagons.

[0048] When In is doped into the GaN base material of the first active layer O2, the smaller the opening area of ​​the front mask, the better the selectivity of In doping. The doping rate of In is greater than that of Ga. Therefore, the smaller the opening area of ​​the front mask, the higher the In content in the first active layer O2InGaN. Furthermore, the smaller the opening area of ​​the front mask, the greater the thickness of the quantum well within the groove, resulting in a higher wavelength of emitted light due to the quantum Stark effect. Conversely, the larger the opening area of ​​the front mask, the less significant the difference between the doping rates of In and Ga, meaning the lower the doping efficiency of In and the lower the proportion of In in the grown first active layer O2. In this embodiment, the opening area of ​​the first front mask is greater than that of the second front mask, meaning the proportion of In in the first groove is lower than that in the second groove, and the wavelength of the first light-emitting unit in the first groove is less than that of the second light-emitting unit in the second groove. The first light-emitting unit can be a blue light-emitting unit, and the second light-emitting unit can be a green light-emitting unit.

[0049] When Al is doped into the GaN base material of the first active layer O2, the smaller the opening area of ​​the front mask, the less selective the growth of Al, and the lower the doping rate of Al compared to Ga. Therefore, the smaller the opening area of ​​the front mask, the lower the Al content in the first active layer O2AlGaN, resulting in a smaller Al doping amount and a longer emission wavelength of the first active layer O2. Furthermore, the larger the opening area of ​​the front mask, the thinner the grown first active layer O2; conversely, the smaller the opening area of ​​the front mask, the thicker the grown first active layer O2, and the thicker the quantum well. Due to the quantum Stark effect, the emission wavelength will also increase. In this embodiment, the opening area of ​​the first front mask is larger than that of the second front mask, meaning the proportion of Al in the first groove is greater than that in the second groove, and the wavelength of the first light-emitting unit in the first groove is less than that of the second light-emitting unit in the second groove. The first light-emitting unit can be a blue light-emitting unit, and the second light-emitting unit can be a green light-emitting unit.

[0050] S240. A first passivation layer is formed on the front side of the substrate; the first passivation layer at least covers the surfaces of the first light-emitting unit and the second light-emitting unit.

[0051] For details, please refer to Figure 6 The first passivation layer 30 protects the first light-emitting unit 110 and the second light-emitting unit 120, preventing wear during the transposition process. Furthermore, the surface of the first passivation layer 30 away from the substrate 10 can be flat. This allows the first passivation layer 30 to also planarize the surface, ensuring that the substrate 10 can be stably inverted on the transposition substrate, which is beneficial for subsequent processes.

[0052] S250. Invert the substrate onto the transposed substrate to expose the back side of the substrate.

[0053] For details, please refer to Figure 7 The substrate 10 is inverted on the transposed substrate 100 to expose the back side of the substrate 10.

[0054] S260. Thinning process is performed on the substrate from the back side of the substrate.

[0055] For details, please refer to Figure 8Thinning the substrate 10 can reduce the overall thickness of the light-emitting device, which is beneficial for making the device thinner and lighter. Furthermore, thinning the substrate 10 can improve its light transmittance, enabling transparent displays. For example, when the substrate 10 is made of sapphire, which has good light transmittance, thinning the substrate 10 can further improve its light transmittance, achieving a transparent display. When the substrate 10 is made of Si, which has poor light transmittance, thinning the substrate 10 can improve its light transmittance.

[0056] S270. A second mask layer is formed on the back side of the substrate, and the second mask layer is etched to form a plurality of back mask openings that expose the substrate.

[0057] For details, please refer to Figure 9 A second mask layer 40 is formed on the back side of the substrate, and the second mask layer 40 is etched to form a plurality of back mask openings 401 that expose the substrate 10. The second mask layer 40 can be a nitride or an oxide, such as at least one of silicon dioxide and silicon nitride.

[0058] S280. A third semiconductor layer, a second active layer, and a fourth conductor layer are sequentially formed in the back mask opening to form a third light-emitting unit on the back side of the substrate.

[0059] For details, please refer to Figure 10 A third semiconductor layer 04, a second active layer 05, and a fourth semiconductor layer 06 are sequentially formed in the back mask opening 401, thereby forming a third light-emitting unit 130 on the back side of the substrate. The third semiconductor layer 05 and the fourth semiconductor layer 06 have opposite conductivity types. The materials of the third semiconductor layer 04, the second active layer 05, and the fourth semiconductor layer 06 can be referred to in the above embodiments, and will not be repeated here.

[0060] S290, A second passivation layer is formed on the back side of the substrate; the second passivation layer at least covers the surface of the third light-emitting unit.

[0061] For details, please refer to Figure 11 A second passivation layer 50 is formed on the back side of the substrate; the second passivation layer 50 at least covers the surface of the third light-emitting unit 130. The second passivation layer 50 protects the third light-emitting unit 130 from wear during transposition. The material of the second passivation layer 50 can be a nitride or an oxide, such as at least one of silicon dioxide and silicon nitride. The second passivation layer 50 can be formed using physical vapor deposition or atomic layer deposition.

[0062] S2100, Prepare at least a portion of the external electrode of the first light-emitting unit, at least a portion of the external electrode of the second light-emitting unit, and at least a portion of the external electrode of the third light-emitting unit.

[0063] For details, please refer to Figure 12 The first active layer 02 is located between the first semiconductor layer 01 and the second semiconductor layer 03; the second active layer 05 is located between the third semiconductor layer 04 and the fourth semiconductor layer 06. The fabrication of the external electrodes of the first light-emitting unit 110 includes: forming a first positive electrode hole and a first negative electrode hole on the side of the first light-emitting unit 110 away from the transpose substrate 100; wherein, in the first positive electrode hole and the first negative electrode hole, one is etched to the first semiconductor layer 01 of the first light-emitting unit 110, and the other is etched to the second semiconductor layer 03 of the first light-emitting unit 110; an insulating layer is formed on the hole walls of the first positive electrode hole and the first negative electrode hole, and a first external positive electrode B1 is formed in the first positive electrode hole and a first external negative electrode B2 is formed in the first negative electrode hole. Similarly, a second external positive electrode G1 electrically connected to the first semiconductor layer 01 of the second light-emitting unit 120 and a second external negative electrode G2 electrically connected to the second semiconductor layer 03 of the second light-emitting unit 120 are prepared; a third external positive electrode R1 electrically connected to the fourth semiconductor layer 06 of the third light-emitting unit 130 and a third external negative electrode R2 electrically connected to the third semiconductor layer 04 of the third light-emitting unit 130 are prepared. The vertical projections of the first light-emitting unit 110 with external electrodes on the transposed substrate 100, the second light-emitting unit 120 with external electrodes on the transposed substrate 100, and the third light-emitting unit 130 with external electrodes on the transposed substrate 100 do not overlap.

[0064] S2110. The first light-emitting unit, the second light-emitting unit, and the third light-emitting unit are transferred to the driving substrate through the transposition substrate, and the external electrodes are connected to the connection points on the driving substrate one by one.

[0065] For details, please refer to Figure 13 The first light-emitting unit 110, the second light-emitting unit 120 and the third light-emitting unit 130 are transferred to the driving substrate 200 through the transfer substrate 100, and the external electrodes are connected to the connection points on the driving substrate 200 one by one.

[0066] Optional, Figure 14 This is a cross-sectional structural schematic diagram of a light-emitting device provided in an embodiment of the present invention, for reference. Figure 14 The method involves forming a plurality of third light-emitting units 130 on the back side of the substrate 10, including etching the back side of the substrate 10 to form a plurality of grooves; and sequentially forming a third semiconductor layer 04, a second active layer 05 and a fourth conductor layer 06 in the grooves to form the third light-emitting units 130 on the back side of the substrate.

[0067] Figure 15 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention, see reference. Figure 15 , Figures 16 to 19This is a cross-sectional structural diagram of steps S370 to S3110 in a method for fabricating a light-emitting device according to an embodiment of the present invention. The method for fabricating the light-emitting device includes:

[0068] Steps S310 to S360 refer to steps S210 to S260 respectively to fabricate the first light-emitting unit 110 and the second light-emitting unit 120 on the front side of the substrate 10, which will not be described in detail here.

[0069] S370. A third semiconductor layer, a second active layer, and a fourth conductor layer are sequentially deposited on the back side of the substrate to form the third light-emitting unit epitaxial layer.

[0070] For details, please refer to Figure 16 A third semiconductor layer, a second active layer, and a fourth conductor layer are sequentially deposited on the back side of the substrate 10 to form the third light-emitting unit epitaxial layer 1300. Specifically, the materials of the third semiconductor layer, the second active layer, and the fourth conductor layer can be referred to the above embodiments, and will not be repeated here.

[0071] S380, Etch the epitaxial layer of the third light-emitting unit, and form an annular groove at the edge of the preset position of each third light-emitting unit in the epitaxial layer of the third light-emitting unit.

[0072] S390. An insulating material is filled into an annular groove to form a first insulating barrier; wherein, the third semiconductor layer, the second active layer and the fourth conductor layer surrounding each first insulating barrier are used to form a third light-emitting unit.

[0073] For details, please refer to Figure 17 An insulating material is filled into an annular groove to form a first insulating barrier 1301; wherein, the third semiconductor layer 04, the second active layer 05 and the fourth semiconductor layer 06 surrounding each first insulating barrier 1301 are used to form a third light-emitting unit 130.

[0074] S3100: Prepare an external electrode for at least a portion of the first light-emitting unit, an external electrode for at least a portion of the second light-emitting unit, and an external electrode for at least a portion of the third light-emitting unit.

[0075] For details, please refer to Figure 18 The first external positive electrode B1 and the first external negative electrode B2 of the first light-emitting unit 110 are prepared; the second external positive electrode G1 and the second external negative electrode G2 of the second light-emitting unit 120 are prepared; and the third external positive electrode R1 and the third external negative electrode R2 of the third light-emitting unit 130 are prepared. The preparation process can be referred to step S2100, and will not be repeated here.

[0076] S3110. The first light-emitting unit, the second light-emitting unit, and the third light-emitting unit are transferred to the driving substrate through the transposition substrate, and the external electrodes are connected to the corresponding contact points on the driving substrate one by one.

[0077] For details, please refer to Figure 19 The first light-emitting unit 110, the second light-emitting unit 120 and the third light-emitting unit 130 are transferred to the driving substrate 200 through the transfer substrate 100, and the external electrodes are connected to the connection points on the driving substrate 200 one by one.

[0078] Figure 20 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention. Figures 21 to 29 This is a cross-sectional structural schematic diagram of steps S420 to S4110 in a method for fabricating a light-emitting device according to an embodiment of the present invention. (Refer to...) Figure 20 The methods for fabricating light-emitting devices include:

[0079] S410. Provide a substrate; the substrate includes a front side and a back side. See step S210 for details, which will not be repeated here.

[0080] S420. A first mask layer is formed on the front side of the substrate, and the first mask layer is patterned to form a plurality of front mask openings in the first mask layer; wherein the material of the first mask layer includes aluminum nitride.

[0081] For details, please refer to Figure 21 The first mask layer 20 is made of aluminum nitride, which can serve as a stress adjuster. The first mask layer 20 is patterned to form multiple front mask openings 210.

[0082] S430, a buffer layer is formed in the front mask opening of the first mask layer and on the side of the first mask layer away from the substrate; wherein the surface of the buffer layer on the side away from the substrate is planar.

[0083] S440. A first semiconductor layer, a first active layer, and a second semiconductor layer are sequentially formed on the side of the buffer layer away from the substrate, and a first element is doped when the first active layer is formed, so as to form a first light-emitting unit on the side of the first mask layer away from the substrate and a second light-emitting unit on the front mask opening; wherein the composition ratio of the first element in the first light-emitting unit is different from the composition ratio of the first element in the second light-emitting unit.

[0084] For details, please refer to Figure 22A buffer layer 60 is located between the substrate 10 and the light-emitting unit. The buffer layer 60 effectively improves the crystal quality of the light-emitting unit and increases its luminous efficiency. The surface of the buffer layer 60 away from the substrate 10 is planar, allowing the first light-emitting unit 110 and the second light-emitting unit 120 located on the front side of the substrate to have the same height. Specifically, the material of the first mask layer is AlN. Because the lattice constant of the first mask layer is smaller than that of the light-emitting unit, the first light-emitting unit on the first mask layer has a different built-in stress than the second light-emitting unit in the front mask opening. This results in the first light-emitting unit 110 on the first mask layer 20 having a different built-in stress than the second light-emitting unit 120 on the front mask opening 210. Consequently, the first element composition in the first light-emitting unit 110 is smaller than that in the second light-emitting unit 120, achieving the simultaneous presence of two light-emitting wavelengths on the same substrate.

[0085] S450: Invert the substrate onto the transposed substrate to expose the back side of the substrate.

[0086] For details, please refer to Figure 23 The substrate 10 is inverted on the transposed substrate 100 to expose the back side of the substrate 10.

[0087] S460, Thinning the substrate from the back side of the substrate.

[0088] For details, please refer to Figure 24 The substrate 10 is thinned from its back side. The specific function of thinning the substrate 10 is described in step S260, and will not be repeated here.

[0089] S470. A second mask layer is formed on the back side of the substrate, and the second mask layer is etched to form a plurality of back mask openings that expose the substrate.

[0090] For details, please refer to Figure 25 A second mask layer 401 is formed on the back side of the substrate 10, and the second mask layer 401 is etched to form a plurality of mask openings 401 that expose the back side of the substrate 10.

[0091] S480. A third semiconductor layer, a second active layer, and a fourth conductor layer are sequentially formed in the back mask opening to form a third light-emitting unit on the back side of the substrate.

[0092] For details, please refer to Figure 26 A third semiconductor layer, a second active layer, and a fourth semiconductor layer are sequentially formed in the back mask opening 401, thereby forming a third light-emitting unit 130 on the back side of the substrate.

[0093] S490, A second passivation layer is formed on the back side of the substrate; the second passivation layer at least covers the surface of the third light-emitting unit.

[0094] For details, please refer to Figure 27 A second passivation layer 50 is formed on the back side of the substrate 10; the function of the second passivation layer 50 can be referred to in step S290, and will not be repeated here.

[0095] S4100: Prepare an external electrode for at least a portion of the first light-emitting unit, an external electrode for at least a portion of the second light-emitting unit, and an external electrode for at least a portion of the third light-emitting unit.

[0096] For details, please refer to Figure 28 The first external positive electrode B1 and the first external negative electrode B2 of the first light-emitting unit 110 are prepared; the second external positive electrode G1 and the second external negative electrode G2 of the second light-emitting unit 120 are prepared; and the third external positive electrode R1 and the third external negative electrode R2 of the third light-emitting unit 130 are prepared. The preparation process can be referred to step S2100, and will not be repeated here.

[0097] S4110. The first light-emitting unit, the second light-emitting unit, and the third light-emitting unit are transferred to the driving substrate through the transposition substrate, and the external electrodes are connected to the corresponding contact points on the driving substrate one by one.

[0098] For details, please refer to Figure 29 The first light-emitting unit 110, the second light-emitting unit 120 and the third light-emitting unit 130 are transferred to the driving substrate 200 through the transfer substrate 100, and the external electrodes are connected to the connection points on the driving substrate 200 one by one.

[0099] Based on the above embodiments, refer to Figure 28 and Figure 29 Optionally, after forming a plurality of third light-emitting units 130 on the back side of the substrate 10, the method further includes:

[0100] A second insulating barrier 09 is formed between adjacent first light-emitting unit 110 and second light-emitting unit 120 to prevent electrical signal crosstalk between the first light-emitting unit 110 and the second light-emitting unit 120. When the second insulating barrier 09 is made of opaque material, it can prevent light crosstalk between light-emitting units.

[0101] Optionally, a second insulating barrier 09 is formed between adjacent second light-emitting units 120 and third light-emitting units 130, and between adjacent third light-emitting units 130 and first light-emitting units 110, to avoid electrical signal crosstalk between each light-emitting unit. Optionally, the first insulating barrier 1301 and the second insulating barrier 09 can be manufactured simultaneously. Optionally, a portion of the first insulating barrier 1301 can serve as the second insulating barrier 09.

[0102] It should be noted that the front-side process and the back-side process of the substrate in the above embodiments can be combined arbitrarily.

[0103] This invention also provides a light-emitting device, formed by the fabrication method of the light-emitting device described in any of the above embodiments, with reference to... Figure 13 , Figure 19 or Figure 29 The light-emitting devices include:

[0104] Substrate 10; Substrate 10 includes opposing front and back sides;

[0105] The first mask layer 20 includes a plurality of front mask openings;

[0106] Multiple first light-emitting units 110 and multiple second light-emitting units 120 are located on the front side of the substrate 10; wherein the composition ratio of the first element in the first light-emitting unit 110 is different from the composition ratio of the first element in the second light-emitting unit 120.

[0107] The third light-emitting unit 130 is located on the back side of the substrate 10.

[0108] In one embodiment of the invention, optionally, reference is made to... Figure 13 and combined Figure 4 The material of the first mask layer 20 includes silicon oxide and / or silicon nitride; the first mask 20 includes a plurality of first front mask openings 201 and a plurality of second front mask openings 202, the opening area of ​​the first front mask opening 201 is larger than the opening area of ​​the second front mask opening 202; the first light-emitting unit 110 is located in the first front mask opening 201, and the second light-emitting unit 120 is located in the second front mask opening 202.

[0109] Alternatively, in another embodiment of the invention, reference is made to... Figure 29 and combined Figure 21 The material of the first mask layer 20 includes aluminum nitride; the first light-emitting unit 110 is located in the non-opening area of ​​the first mask layer 20, and the second light-emitting unit 120 is located in the front mask opening 210.

[0110] Based on the above embodiments, optionally, the back side of the substrate 10 includes a plurality of grooves, and the third light-emitting unit 130 is located in the grooves.

[0111] Or, refer to Figure 13 and combined Figure 9 A second mask layer 40 is provided on the back side of the substrate 10, and the second mask layer 40 includes a plurality of back mask openings 401 that expose the substrate 10; the third light-emitting unit 130 is located in the back mask openings 401.

[0112] Or, refer to Figure 19 and combined Figure 16The back side of the substrate 10 includes a third light-emitting unit epitaxial layer 1300. A ring-shaped first insulating barrier 1301 is provided around a preset position of each third light-emitting unit 130 in the third light-emitting unit epitaxial layer 1300. The third light-emitting unit epitaxial layer 1300 surrounded by the first insulating barrier 1301 is used to form a third light-emitting unit 130.

[0113] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A method for fabricating a light-emitting device, characterized in that, include: A substrate (10) is provided; the substrate (10) includes opposing front and back sides; A first mask layer (20) is formed on the front side of the substrate (10), and the first mask layer (20) is patterned to form a plurality of front mask openings in the first mask layer (20); Based on the patterned first mask layer (20), a semiconductor epitaxial layer is grown on the front side of the substrate (10), and a first element is doped during the growth of the semiconductor epitaxial layer to form a plurality of first light-emitting units (110) and a plurality of second light-emitting units (120); wherein the composition ratio of the first element in the first light-emitting unit (110) is different from the composition ratio of the first element in the second light-emitting unit (120); The substrate (10) is inverted on the transposed substrate (100) to expose the back side of the substrate (10); A plurality of third light-emitting units (130) are formed on the back side of the substrate (10). The material of the first mask layer (20) includes aluminum nitride; forming a plurality of first light-emitting units (110) and a plurality of second light-emitting units (120) includes: sequentially forming a first semiconductor layer, a first active layer and a second semiconductor layer in the front mask opening and on the side of the first mask layer (20) away from the substrate (10), and doping the first element when forming the first active layer, so as to form the first light-emitting unit (110) on the side of the first mask layer (20) away from the substrate (10) and the second light-emitting unit (120) in the front mask opening.

2. The preparation method according to claim 1, characterized in that, Before forming the plurality of first light-emitting units (110) and the plurality of second light-emitting units (120), the method further includes: A buffer layer is formed in the front mask opening of the first mask layer (20) and on the side of the first mask layer (20) away from the substrate (10); wherein the surface of the buffer layer on the side away from the substrate (10) is planar.

3. The preparation method according to claim 2, characterized in that, Before inverting the substrate (10) onto the transposed substrate (100), the method further includes: A first passivation layer (30) is formed on the front side of the substrate (10), and the first passivation layer (30) covers at least the surfaces of the first light-emitting unit (110) and the second light-emitting unit (120).

4. The preparation method according to claim 2, characterized in that, A plurality of third light-emitting units (130) are formed on the back side of the substrate (10), including: The back side of the substrate (10) is etched to form multiple grooves; A third semiconductor layer, a second active layer and a fourth conductor layer are sequentially formed in the groove to form the third light-emitting unit (130) on the back side of the substrate (10).

5. The preparation method according to claim 2, characterized in that, A plurality of third light-emitting units (130) are formed on the back side of the substrate (10), including: A second mask layer (40) is formed on the back side of the substrate (10). The second mask layer (40) is etched to form a plurality of back mask openings (401) that expose the substrate (10). A third semiconductor layer, a second active layer and a fourth conductor layer are sequentially formed in the back mask opening (401) to form the third light-emitting unit (130) on the back side of the substrate (10).

6. The preparation method according to claim 2, characterized in that, A plurality of third light-emitting units (130) are formed on the back side of the substrate (10), including: A third semiconductor layer, a second active layer and a fourth conductor layer are sequentially deposited on the back side of the substrate (10) to form a third light-emitting unit epitaxial layer (1300). The epitaxial layer (1300) of the third light-emitting unit is etched, and an annular groove is formed at the edge of a predetermined position of each third light-emitting unit (130) in the epitaxial layer (1300); An insulating material is filled into the annular groove to form a first insulating barrier (1301); wherein, the third semiconductor layer, the second active layer and the fourth conductor layer surrounding each of the first insulating barriers are used to form a third light-emitting unit (130).

7. The preparation method according to claim 1, characterized in that, Before forming the plurality of the third light-emitting units (130) on the back side of the substrate (10), the method further includes: The substrate (10) is thinned from the back side of the substrate (10).

8. The preparation method according to claim 1, characterized in that, After forming a plurality of third light-emitting units (130) on the back side of the substrate (10), the method further includes: A second insulating barrier (09) is formed between adjacent first light-emitting unit (110) and second light-emitting unit (120).

9. A light-emitting device, characterized in that, Formed by the method for preparing the light-emitting device according to any one of claims 1 to 8, comprising: Substrate (10); the substrate (10) includes opposing front and back sides; A first mask layer (20) includes a plurality of front mask openings; Multiple first light-emitting units (110) and multiple second light-emitting units (120) are located on the front side of the substrate (10); wherein the composition ratio of the first element in the first light-emitting unit (110) is different from the composition ratio of the first element in the second light-emitting unit (120); The third light-emitting unit (130) is located on the back side of the substrate (10).

10. The light-emitting device according to claim 9, characterized in that, The material of the first mask layer (20) includes aluminum nitride, the first light-emitting unit (110) is located in the non-opening area of ​​the first mask layer (20), and the second light-emitting unit (120) is located in the front mask opening.

11. The light-emitting device according to claim 10, characterized in that, The back side of the substrate (10) includes a plurality of grooves, and the third light-emitting unit (130) is located in the grooves; Alternatively, a second mask layer (40) is provided on the back side of the substrate (10), the second mask layer (40) including a plurality of back mask openings (401) exposing the substrate (10); the third light-emitting unit (130) is located in the back mask openings (401); Alternatively, the back side of the substrate (10) includes a third light-emitting unit epitaxial layer (1300), and an annular first insulating barrier (1301) is provided around a preset position of each third light-emitting unit (130) in the third light-emitting unit epitaxial layer (1300); the third light-emitting unit epitaxial layer (1300) surrounded by the first insulating barrier (1301) is used to form a third light-emitting unit (130).

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