A method for manufacturing a light emitting device and a light emitting device
By forming multiple light-emitting units on the front and back sides of the substrate and controlling the compositional differences of the light-emitting layer by doping elements, the problems of short lifespan and complicated processes of phosphors or quantum dots in the prior art are solved, and efficient production and long lifespan light-emitting devices are realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ENKRIS SEMICON
- Filing Date
- 2023-10-11
- Publication Date
- 2026-06-16
Smart Images
Figure CN119836082B_ABST
Abstract
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 comprising opposing front and back sides;
[0007] The front side of the substrate is patterned to form protrusions and grooves;
[0008] A semiconductor epitaxial layer is grown on the protrusion and / or the groove, 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] A substrate; the substrate includes a front side and a back side opposite to each other; wherein the front side includes a protrusion and a groove;
[0013] Multiple first light-emitting units and multiple second light-emitting units are located on the front side of the substrate; wherein the first light-emitting units and the second light-emitting units are located on the protrusion and / or in the groove; the composition ratio of the first element in the first light-emitting unit is different from that in the second light-emitting unit;
[0014] The third light-emitting unit is located on the back side of the substrate.
[0015] The technical solution provided by this invention involves simultaneously fabricating multiple first light-emitting units and multiple second light-emitting units on the front side of a substrate, thereby improving the production efficiency of the light-emitting device. 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. Furthermore, 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, and by controlling the different light-emitting layer compositions corresponding to different positions on the front side, the first light-emitting units and the second light-emitting units can emit different wavelengths. This eliminates the need for wavelength conversion using phosphors or quantum dots, extending the lifespan of the light-emitting device and improving its reliability. Attached Figure Description
[0016] Figure 1 This is a flowchart of a method for fabricating a light-emitting device according to an embodiment of the present invention;
[0017] Figure 2 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention;
[0018] Figures 3 to 9 This is a cross-sectional structural diagram of steps S210 to S270 in a method for fabricating a light-emitting device according to an embodiment of the present invention;
[0019] Figure 10 This is another cross-sectional structural schematic diagram of step S220 in the method for fabricating a light-emitting device provided in an embodiment of the present invention;
[0020] Figure 11 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention;
[0021] Figures 12 to 20 This is a cross-sectional structural diagram of steps S320 to S3100 in a method for fabricating a light-emitting device according to an embodiment of the present invention;
[0022] Figure 21 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention;
[0023] Figures 22 to 30This is a cross-sectional structural diagram of steps S420 to S4110 in a method for fabricating a light-emitting device according to an embodiment of the present invention; Detailed Implementation
[0024] 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.
[0025] 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:
[0026] S110, Provide a substrate, the substrate including opposing front and back sides.
[0027] Specifically, the substrate material can be sapphire, silicon carbide, silicon, GaN, AlN or diamond, or a combination thereof, without limitation.
[0028] S120: The front side of the patterned substrate is used to form protrusions and grooves.
[0029] Specifically, the front side of the substrate can be patterned using etching, forming protrusions and grooves on the front side of the substrate, making the front side of the substrate an uneven surface.
[0030] S130. A semiconductor epitaxial layer is grown in the protrusion and / or groove, 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 that in the second light-emitting unit.
[0031] Specifically, a semiconductor epitaxial layer is grown on the protrusion, or in the groove, or both on the protrusion and in the groove. 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 can be understood as the first and second light-emitting units being located either entirely on the protrusion, entirely in the groove, or partially on the protrusion and partially in the groove. The composition ratio of the first element in the first light-emitting unit differs from that in the second light-emitting unit, thus achieving the simultaneous presence of two emission wavelengths on the front side of the substrate.
[0032] For example, the first light-emitting unit can be a blue light-emitting unit that emits blue light, and 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.
[0033] S140. Invert the substrate onto the transposed substrate to expose the back side of the substrate.
[0034] 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.
[0035] S150, Multiple third light-emitting units are formed on the back side of the substrate.
[0036] 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.
[0037] The method for fabricating a light-emitting device provided in this invention involves simultaneously fabricating multiple first light-emitting units and multiple second light-emitting units on the front side of a substrate, thereby improving the production efficiency of the light-emitting device. 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. Furthermore, 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 of the light-emitting device and improving its reliability.
[0038] 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 9 This is a cross-sectional structural schematic diagram of steps S210 to S270 in a method for fabricating a light-emitting device according to an embodiment of the present invention. (Refer to...) Figure 2 The methods for fabricating light-emitting devices include:
[0039] S210, Provide a substrate, the substrate including opposing front and back sides.
[0040] 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.
[0041] S220. Etch the front side of the substrate to form a groove, the groove including a plurality of first grooves and a plurality of second grooves; wherein the shape or size of the first groove is different from the shape or size of the second groove.
[0042] S230. A first semiconductor layer, a first active layer, and a second semiconductor layer are sequentially formed in the first groove and the second groove. A first element is doped during the formation of the first active layer to form a first light-emitting unit in the first groove and a second light-emitting unit in the second groove. Specifically, first active layers with different amounts of the first element are formed in grooves of different shapes or sizes to achieve different emission wavelengths.
[0043] Optional, see reference Figure 5 In step S220, the size of the first groove 11 formed is different from the size of the second groove 12. The groove area of the first groove 11 is larger than that of the second groove 12. This results in different flow rates of the reactant gas in the first and second grooves when doping with the first element, leading to different doping rates of In / Al and Ga elements, i.e., different doping efficiencies of In / Al elements. This results in different proportions of In / Al elements in the grown first active layer O2. Consequently, the wavelengths of light emitted by the first light-emitting unit 110 and the second light-emitting unit 120 are different.
[0044] Specifically, in a cross-section perpendicular to the substrate, the grooves are rectangular, triangular, or trapezoidal. When viewed from above the substrate, the first and second grooves can be circular, square, or hexagonal. A first semiconductor layer 01, a first active layer 02, and a second semiconductor layer 03 are epitaxially grown sequentially in each groove. The second semiconductor layer 03 has the opposite conductivity type to the first semiconductor layer 01. The material of the first semiconductor layer 01 can be a III-V group nitride, specifically including at least one of GaN and AlGaN. The material of the second semiconductor layer 03 can also be a III-V group nitride, specifically including at least one of GaN and AlGaN. 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. In some other embodiments, 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.
[0045] 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.
[0046] It should be noted that, taking the first groove as an example, the groove area refers to the opening area of the first groove when viewed from above the substrate.
[0047] When In is doped into the GaN base material of the first active layer O2, the smaller the groove opening area, the better the selectivity of In doping, and the greater the doping rate of In compared to Ga. Therefore, the smaller the groove opening area, the higher the In content in the first active layer O2InGaN. Furthermore, a smaller groove opening area also increases the thickness of the quantum well within the groove, resulting in a higher wavelength of emitted light due to the quantum Stark effect. Conversely, a larger groove opening area results in a less significant difference between the In and Ga doping rates, meaning a lower In doping efficiency and a lower In content in the grown first active layer O2. In this embodiment, the groove opening area of the first groove is larger than that of the second groove, meaning the In content 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 shorter 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.
[0048] When Al is doped into the GaN base material of the first active layer O2, the smaller the groove opening area, the less selective the growth of Al, and the lower the doping rate of Al compared to Ga. Therefore, the smaller the groove opening area, 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 groove opening area, the thinner the grown first active layer O2; conversely, the smaller the groove opening area, the thicker the grown first active layer O2, and the thicker the quantum well also increases. Due to the quantum Stark effect, the emission wavelength increases accordingly. In this embodiment, the groove opening area of the first groove is larger than that of the second groove, meaning the Al content in the first groove is greater than that in the second groove. The wavelength of the first emitting unit in the first groove is shorter than the wavelength of the second emitting unit in the second groove. The first emitting unit can be a blue emitting unit, and the second emitting unit can be a green emitting unit.
[0049] The bottom surface of the first groove (11) is an inclined surface, and the bottom surface of the second groove (12) is parallel to the plane of the substrate (10).
[0050] S240. Invert the substrate onto the transposed substrate to expose the back side of the substrate.
[0051] For details, please refer to Figure 6 The substrate 10 is inverted on the transposed substrate 100 to expose the back side of the substrate 10.
[0052] S250, Etch the back side of the substrate to form a plurality of third grooves that are rectangular in shape in a cross section perpendicular to the substrate.
[0053] For details, please refer to [link / reference]. Figure 6 The back side of the substrate 10 is etched to form a plurality of third grooves 13.
[0054] S260. A third semiconductor layer, a second active layer and a fourth semiconductor layer are sequentially formed in the third groove to form a third light-emitting unit on the back side of the substrate.
[0055] For details, please refer to Figure 7A third semiconductor layer 04, a second active layer 05, and a fourth semiconductor layer 06 are sequentially formed in the third groove 13, thereby forming a third light-emitting unit 130 on the back side of the substrate 10. Specifically, the materials of the third semiconductor layer 04 and the fourth semiconductor layer 06 can refer to the materials of the first semiconductor layer 01 and the second semiconductor layer 03 in the above embodiments, and will not be repeated here; wherein the conductivity types of the third semiconductor layer 04 and the fourth semiconductor layer 06 are opposite. Specifically, the second active layer 05 can refer to the first active layer 02 in the above embodiments, and will not be repeated here. Specifically, the third groove 13 is rectangular, triangular, or trapezoidal in cross-section perpendicular to the substrate 10.
[0056] S270. Prepare at least a portion of the external electrodes of the first light-emitting unit, at least a portion of the external electrodes of the second light-emitting unit, and at least a portion of the external electrodes of the third light-emitting unit; wherein the vertical projections of the first light-emitting unit with external electrodes on the transposed substrate, the vertical projections of the second light-emitting unit with external electrodes on the transposed substrate, and the vertical projections of the third light-emitting unit with external electrodes on the transposed substrate do not overlap.
[0057] For details, please refer to Figure 8 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.
[0058] S280. 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.
[0059] For details, please refer to Figure 9The 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.
[0060] For example, refer to Figures 3 to 9 In a light-emitting device, the front side of the substrate 10 includes a groove, wherein the groove includes a plurality of first grooves 11 and a plurality of second grooves 12; wherein the shape or size of the first groove 11 is different from the shape or size of the second groove 12, specifically, the groove area is different; the first light-emitting unit 110 is located in the first groove 11, and the second light-emitting unit 120 is located in the second groove 12; and / or, the back side of the substrate 10 includes a plurality of third grooves 13; the third light-emitting unit 130 is located in the third groove 13.
[0061] Optional, Figure 10 This is another cross-sectional structural schematic diagram of step S220 in the fabrication method of a light-emitting device provided in an embodiment of the present invention, with reference to... Figure 10 In step S220, the shape of the first groove 11 formed is different from the shape of the second groove 12. The bottom surface of the first groove 11 is an inclined surface, and the bottom surface of the second groove 12 is parallel to the plane of the substrate 10. This makes the doping rate of the first element in the first groove and the second groove different, which in turn makes the wavelength of the light emitted by the first light-emitting unit 110 and the second light-emitting unit 120 different.
[0062] Optional, see reference Figure 9 In the direction perpendicular to the plane of the substrate 10, the first groove 11 and the third groove 13 overlap, and similarly, the second groove 12 and the third groove 13 overlap. This arrangement reduces the distance between the third light-emitting unit and the first and second light-emitting units in the direction perpendicular to the substrate, minimizing the height difference between the light-emitting surfaces of the first, second, and third light-emitting units, and improving the light emission effect. Optionally, substrate thinning is not required before fabricating the third light-emitting unit on the back side, simplifying the process.
[0063] For example, Figure 11 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention. Figures 12 to 20 This is a cross-sectional structural schematic diagram of steps S320 to S3100 in a method for fabricating a light-emitting device according to an embodiment of the present invention. (Refer to...) Figure 11 The methods for fabricating light-emitting devices include:
[0064] S310, Provides a substrate, the substrate including opposing front and back sides.
[0065] S320, Etching the front side of the substrate, the protrusions are multiple conical protrusions that are triangular in shape in a cross section perpendicular to the substrate, and the grooves are located between two adjacent conical protrusions.
[0066] For details, please refer to Figure 12 The front side of the substrate 10 is etched to form a plurality of triangular cone-shaped protrusions 104 in a cross section perpendicular to the substrate 10, with grooves located between two adjacent cone-shaped protrusions 104. Optionally, the substrate 10 is a single substrate made of GaN; or, the substrate 10 is a composite substrate, which is composed of a bottom silicon layer and cone-shaped protrusions 104 made of GaN.
[0067] S330. A first semiconductor layer, a first active layer, and a second semiconductor layer are sequentially formed on the conical protrusion and in the groove, and a first element is doped when the first active layer is formed, so as to form a first light-emitting unit on the conical protrusion and a second light-emitting unit in the groove.
[0068] For details, please refer to Figure 13 A first semiconductor layer 01, a first active layer 02, and a second semiconductor layer 03 are sequentially formed on the conical protrusion 104 and in the groove, and a first element is doped during the formation of the first active layer 02. The different heights of the conical protrusion 104 and the groove result in different growth temperatures for them. Due to temperature and position, the doping efficiency of the first element differs between the conical protrusion 104 and the groove, leading to different component proportions of the first element in the grown first active layer 02. This allows the first light-emitting unit 110 and the second light-emitting unit 120 to emit light of different wavelengths. The materials of the first semiconductor layer 01, the first active layer 02, and the second semiconductor layer 03 can be found in the above embodiments and will not be repeated here.
[0069] S340. 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.
[0070] For details, please refer to Figure 14 The first passivation layer 310 protects the first light-emitting unit 110 and the second light-emitting unit 120 from wear during the transposition process. Furthermore, the surface of the first passivation layer 310 away from the substrate can be flat. This allows the first passivation layer 310 to also planarize the surface, ensuring that the substrate 10 can be stably inverted on the transposition substrate 100, which is beneficial for subsequent processes.
[0071] S350. Invert the substrate onto the transposed substrate to expose the back side of the substrate.
[0072] For details, please refer to Figure 15The substrate 10 is inverted on the transposed substrate 100 to expose the back side of the substrate 10.
[0073] S360, Thinning the substrate from the back side of the substrate.
[0074] For details, please refer to Figure 16 Thinning 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.
[0075] S370. A mask layer is formed on the back side of the substrate, and the mask layer is etched to form multiple openings that expose the back side of the substrate.
[0076] For details, please refer to Figure 17 A mask layer 400 is formed on the back side of the substrate, and the mask layer 400 is etched to form a plurality of openings 401 exposing the back side of the substrate 10. The material of the mask layer 400 can be a nitride or an oxide, such as at least one of silicon dioxide and silicon nitride. The mask layer 400 can be formed by physical vapor deposition or chemical vapor deposition, and the patterning process can be achieved by dry etching or wet etching.
[0077] S380, A third semiconductor layer, a second active layer and a fourth semiconductor layer are sequentially formed in the opening to form a third light-emitting unit on the back side of the substrate.
[0078] For details, please refer to Figure 18 A third semiconductor layer 04, a second active layer 05, and a fourth semiconductor layer 06 are sequentially formed in the opening 401, thereby forming a third light-emitting unit 130 on the back side of the substrate. The third semiconductor layer 04 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.
[0079] S390. Prepare at least a portion of the external electrodes of the first light-emitting unit, at least a portion of the external electrodes of the second light-emitting unit, and at least a portion of the external electrodes of the third light-emitting unit; wherein the vertical projections of the first light-emitting unit with external electrodes on the transposed substrate, the vertical projections of the second light-emitting unit with external electrodes on the transposed substrate, and the vertical projections of the third light-emitting unit with external electrodes on the transposed substrate do not overlap.
[0080] For details, please refer to Figure 19 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 S270, and will not be repeated here.
[0081] Optionally, a second insulating barrier 09 is formed between adjacent first light-emitting units 110 and second light-emitting units 120 to prevent electrical signal crosstalk and optical crosstalk between the first light-emitting units 110 and the second light-emitting units 120. When the second insulating barrier 09 is made of opaque material, it can prevent light crosstalk between light-emitting units.
[0082] S3100: The first light-emitting unit, the second light-emitting unit, and the third light-emitting unit are transferred to the driving substrate through the transfer substrate, and the external electrodes are connected to the corresponding contact points on the driving substrate one by one.
[0083] For details, please refer to Figure 20 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.
[0084] For example, refer to Figures 12 to 20 In a light-emitting device, the front side of the substrate 10 includes protrusions and grooves, wherein the protrusions include a plurality of spaced-apart conical protrusions 104, and the grooves are located between two adjacent conical protrusions 104; a first light-emitting unit 110 is located on the surface of the conical protrusions 104, and a second light-emitting unit 120 is located in the grooves; and / or, a mask layer 400 is provided on the back side of the substrate 10; the mask layer 400 includes a plurality of openings 401 exposing the back side of the substrate 10; and a third light-emitting unit 130 is located in the openings 401.
[0085] Specifically, after the substrate is thinned, a mask layer is formed on the back side of the substrate. The mask layer is then etched to create multiple openings that expose the back side of the substrate, and a third light-emitting unit is formed within these openings. This eliminates the need to etch the back side of the substrate, preventing issues with controlling the etching depth and location, which could negatively impact the device fabrication yield.
[0086] For example, Figure 21 This is a flowchart of another method for fabricating a light-emitting device provided in an embodiment of the present invention. Figures 22 to 30 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 21 The methods for fabricating light-emitting devices include:
[0087] S410, Provides a substrate, the substrate including opposing front and back sides.
[0088] S420: Etch the front side of the substrate to form multiple V-shaped grooves in a triangular shape in a cross section perpendicular to the substrate. The grooves are V-shaped grooves, and the protrusions are located between two adjacent V-shaped grooves.
[0089] For details, please refer to Figure 22 The front side of the substrate is etched to form a plurality of V-shaped grooves 103 in a triangular shape in a cross section perpendicular to the substrate. The grooves are V-shaped grooves 103, and the protrusions are located between two adjacent V-shaped grooves 103.
[0090] S430. A first semiconductor layer, a first active layer, and a second semiconductor layer are sequentially formed in the V-groove and on the protrusion, and a first element is doped when the first active layer is formed, so as to form a first light-emitting unit in the V-groove and a second light-emitting unit on the protrusion.
[0091] For details, please refer to Figure 23 A first semiconductor layer 01, a first active layer 02, and a second semiconductor layer 03 are sequentially formed in the V-groove 103 and on the protrusion, and a first element is doped during the formation of the first active layer 02. Because the material generation rate on the sidewall of the V-groove is lower than that in the planar region, the thickness of the first active layer located on the sidewall of the V-groove is less than the thickness of the first active layer 02 located on the top wall (the top surface of the protrusion between the V-grooves). Since the first active layer 02 has a smaller thickness, it corresponds to a larger bandgap and a shorter emission wavelength; therefore, the emission wavelength of the first active layer 02 located on the V-groove side is less than the emission wavelength of the first active layer located on the protrusion. The emission wavelength of the first light-emitting unit 110 formed in the V-groove is less than the emission wavelength of the second light-emitting unit 120 formed on the protrusion. The materials of the first semiconductor layer 01, the first active layer 02, and the second semiconductor layer 03 can be referred to in the above embodiment, and will not be repeated here.
[0092] S440. 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.
[0093] For details, please refer to Figure 24 A first passivation layer 310 is formed on the front side of the substrate 10. The function of the first passivation layer 310 can be found in step S340, and will not be repeated here.
[0094] S450: Invert the substrate onto the transposed substrate to expose the back side of the substrate.
[0095] For details, please refer to Figure 25 The substrate 10 is inverted on the transposed substrate 100 to expose the back side of the substrate 10.
[0096] S460, Thinning the substrate from the back side of the substrate.
[0097] For details, please refer to Figure 25 and Figure 26 The substrate 10 is thinned from the back side. The function of thinning the substrate 10 is described in S360 and will not be repeated here.
[0098] S470. 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.
[0099] For details, please refer to Figure 27 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.
[0100] S480, 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.
[0101] S490. 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 semiconductor layer surrounding each first insulating barrier are used to form a third light-emitting unit.
[0102] For details, please refer to Figure 28 An insulating material is filled into the 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 within each first insulating barrier 1301 are used to form a third light-emitting unit 130. Specifically, the conductivity type of the third semiconductor layer 04 is opposite to that of the fourth semiconductor layer 06, and the materials of the third semiconductor layer 04, the second active layer 05, and the fourth semiconductor layer 06 can be referred to the above embodiments, and will not be repeated here.
[0103] S4100: Prepare external electrodes for at least a portion of the first light-emitting unit, at least a portion of the second light-emitting unit, and at least a portion of the third light-emitting unit; wherein the vertical projections of the first light-emitting unit with external electrodes on the transposed substrate, the vertical projections of the second light-emitting unit with external electrodes on the transposed substrate, and the vertical projections of the third light-emitting unit with external electrodes on the transposed substrate do not overlap.
[0104] For details, please refer to Figure 29 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 S270, and will not be repeated here.
[0105] Optionally, a second insulating barrier 09 is formed between adjacent first light-emitting unit 110 and second light-emitting unit 120, between adjacent second light-emitting unit 120 and third light-emitting unit 130, and between adjacent third light-emitting unit 130 and first light-emitting unit 110, respectively, to prevent crosstalk of electrical signals between the first light-emitting unit 110, second light-emitting unit 120 and third light-emitting unit 130.
[0106] 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 lead electrode is connected to the connection contact point on the driving substrate one by one.
[0107] For details, please refer to Figure 30 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.
[0108] For example, refer to Figures 22 to 30 In a light-emitting device, the front side of the substrate 10 includes a protrusion and a groove, wherein the groove includes a plurality of spaced V-shaped grooves 103, and the protrusion is located between two adjacent V-shaped grooves 103; a first light-emitting unit 110 is located in the V-shaped groove 103, and a second light-emitting unit 120 is located on the protrusion; and / or, the back side of the substrate 10 includes a third light-emitting unit epitaxial layer 1300, and an annular first insulating barrier is provided around a preset position of each third light-emitting unit 130 in the third light-emitting unit epitaxial layer; the third light-emitting unit epitaxial layer 1300 surrounded by the first insulating barrier is used to form a third light-emitting unit.
[0109] Specifically, the third light-emitting unit epitaxial layer is first fabricated as a whole layer. An annular groove is formed at the edge of each predetermined position of the third light-emitting unit within this epitaxial layer. Insulating material is then filled into the annular groove to form a first insulating barrier, which defines the boundary of the third light-emitting unit. The epitaxial layer of the third light-emitting unit outside the first insulating barrier is retained and does not need to be removed, thus improving the efficiency of device fabrication.
[0110] 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.
[0111] Based on the above embodiments, optionally, after forming a plurality of third light-emitting units 130 on the back side of the substrate 10, the method further includes:
[0112] A second passivation layer is formed on the back side of the substrate 10; the second passivation layer at least covers the surface of the third light-emitting unit 130. The second passivation layer protects the third light-emitting unit 130 from wear during transposition. The material of the second passivation layer can be a nitride or an oxide, such as at least one of silicon dioxide and silicon nitride. The second passivation layer can be formed using physical vapor deposition or chemical vapor deposition.
[0113] After forming the second passivation layer on the back side of the substrate 10, the method further includes:
[0114] A second insulating barrier 09 is formed between adjacent first light-emitting units 110 and second light-emitting units 120 to prevent electrical signal crosstalk between the first light-emitting units 110 and second light-emitting units 120. 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.
[0115] 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 9 , Figure 20 or Figure 30 The light-emitting devices include:
[0116] Substrate 10; Substrate 10 includes a front side and a back side; wherein the front side includes a protrusion and a groove;
[0117] 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 first light-emitting units 110 and the second light-emitting units 120 are located on the protrusions and / or in the grooves; 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);
[0118] The third light-emitting unit 130 is located on the back side of the substrate 10.
[0119] The technical solution provided by this invention involves simultaneously fabricating multiple first light-emitting units and multiple second light-emitting units on the front side of a substrate, thereby improving the production efficiency of the light-emitting device. 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. Furthermore, 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, and by controlling the different light-emitting layer compositions corresponding to different positions on the front side, the first light-emitting units and the second light-emitting units can emit different wavelengths. This eliminates the need for wavelength conversion using phosphors or quantum dots, extending the lifespan of the light-emitting device and improving its reliability.
[0120] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention 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) comprising opposing front and back sides; The front side of the substrate (10) is patterned to form protrusions and grooves; A semiconductor epitaxial layer is grown on the protrusion and the groove, 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 patterning process of the front side of the substrate (10) to form protrusions and grooves includes: The front side of the substrate (10) is etched to form a triangular cone-shaped protrusion (104) in a cross section perpendicular to the substrate (10), and the groove is located between two adjacent cone-shaped protrusions (104); Forming multiple first light-emitting units (110) and multiple second light-emitting units (120), including: A first semiconductor layer, a first active layer, and a second semiconductor layer are sequentially formed on the conical protrusion (104) and in the groove. The first element is doped when the first active layer is formed, so that the first light-emitting unit (110) is formed on the conical protrusion (104) and the second light-emitting unit (120) is formed in the groove. The heights of the conical protrusion (104) and the groove are different. Alternatively, the front side of the substrate (10) is etched to form a triangular V-shaped groove (103) in a cross section perpendicular to the substrate (10), and the protrusion is located between two adjacent V-shaped grooves (103); Forming multiple first light-emitting units (110) and multiple second light-emitting units (120), including: A first semiconductor layer, a first active layer, and a second semiconductor layer are sequentially formed in the V-groove (103) and on the protrusion, and the first element is doped when the first active layer is formed, so as to form the first light-emitting unit (110) in the V-groove (103) and the second light-emitting unit (120) on the protrusion.
2. The preparation method according to claim 1, characterized in that, Before inverting the substrate (10) onto the transposed substrate (100), the method further includes: A first passivation layer (310) is formed on the front side of the substrate (10); the first passivation layer (310) covers at least the surfaces of the first light-emitting unit (110) and the second light-emitting unit (120).
3. The preparation method according to claim 1, 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 a plurality of third grooves (13). A third semiconductor layer, a second active layer and a fourth semiconductor layer are sequentially formed in the third groove (13) to form the third light-emitting unit (130) on the back side of the substrate (10).
4. The preparation method according to claim 1, characterized in that, A plurality of third light-emitting units (130) are formed on the back side of the substrate (10), including: A mask layer (400) is formed on the back side of the substrate (10). The mask layer (400) is etched to form a plurality of openings (401) that expose the back side of the substrate (10). A third semiconductor layer, a second active layer and a fourth semiconductor layer are sequentially formed in the opening (401) to form the third light-emitting unit (130) on the back side of the substrate (10).
5. The preparation method according to claim 1, 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 in the annular groove to form a first insulating barrier (1301); wherein, the third semiconductor layer, the second active layer and the fourth semiconductor layer surrounding each of the first insulating barrier (1301) are used to form a third light-emitting unit (130).
6. The preparation method according to claim 1, characterized in that, Before forming a plurality of 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).
7. The preparation method according to claim 1, characterized in that, After forming a plurality of third light-emitting units (130) epitaxially on the back side of the substrate (10), the method further includes: A second passivation layer is formed on the back side of the substrate (10); the second passivation layer at least covers the surface of the third light-emitting unit (130).
8. The preparation method according to claim 7, characterized in that, After forming the second passivation layer 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, include: Substrate (10); the substrate (10) includes a front side and a back side opposite to each other; wherein the front side includes a protrusion and a groove; 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 first light-emitting units (110) and the second light-emitting units (120) are located on the protrusion and in the groove; 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); The protrusion includes a plurality of spaced conical protrusions (104), and the groove is located between two adjacent conical protrusions (104); the first light-emitting unit (110) is located on the surface of the conical protrusion (104), and the second light-emitting unit (120) is located in the groove; the conical protrusions (104) and the groove are at different heights. Alternatively, the groove may include a plurality of spaced V-shaped grooves (103), and the protrusion may be located between two adjacent V-shaped grooves (103); the first light-emitting unit (110) may be located in the V-shaped groove (103), and the second light-emitting unit (120) may be located on the protrusion.
10. The light-emitting device according to claim 9, characterized in that, The back side of the substrate (10) includes a plurality of third grooves (13); the third light-emitting unit (130) is located in the third groove (13).
11. The light-emitting device according to claim 9, characterized in that, When the protrusion includes a plurality of spaced conical protrusions (104), a mask layer (400) is provided on the back side of the substrate (10); the mask layer (400) includes a plurality of openings (401) that expose the back side of the substrate (10); the third light-emitting unit (130) is located in the openings (401).
12. The light-emitting device according to claim 9, characterized in that, When the groove includes a plurality of spaced V-shaped grooves (103), 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; the third light-emitting unit epitaxial layer (1300) located in the first insulating barrier is used to form a third light-emitting unit.