Micro display unit

Abstract

The embodiment of the utility model discloses a micro-display unit, at least two light-emitting units are vertically stacked in space, and at least one light-emitting unit further comprises a tunneling layer and a second semiconductor supplement layer which are located on one side, far away from a light-emitting layer, of a first semiconductor layer. The micro-display unit further comprises first electrode connecting structures corresponding to the light-emitting units, at least one first electrode connecting structure is electrically connected to the second semiconductor supplementary layer, and the first electrode connecting structures and the second semiconductor supplementary layer exposed through etching are easier to form effective ohmic contact. A PN junction is formed by the structures of the second semiconductor supplement layer, the tunneling layer and the first semiconductor layer, current can pass through the tunneling layer to penetrate through the whole PN junction, and therefore it can be guaranteed that the first electrode connection structure is electrically connected with the first semiconductor layer by being connected with the second semiconductor supplement layer, and the device performance can be improved.

Description

Technical Field

[0001] This utility model relates to the field of display technology, and in particular to a micro display unit. Background Technology

[0002] Micro-LEDs have advantages such as high efficiency, low power consumption, ultra-high resolution, ultra-fast response speed, and wide viewing angle, and are considered a "next-generation display technology".

[0003] In existing technologies, after etching some layers of the epitaxial layer, it is difficult to form effective ohmic contacts, which affects the performance of the device. Utility Model Content

[0004] This invention provides a micro-display unit to ensure an effective electrical connection between the first electrode connection structure and the first semiconductor layer, which is beneficial to improving device performance.

[0005] According to the present invention, a micro display unit is provided, comprising: at least two light-emitting units stacked along the thickness direction of the micro display unit, wherein the light-emitting unit comprises a first semiconductor layer, a light-emitting layer and a second semiconductor layer stacked together;

[0006] At least one light-emitting unit further includes a tunneling layer and a second semiconductor supplementary layer located on the side of the first semiconductor layer away from the light-emitting layer, with the tunneling layer located between the second semiconductor supplementary layer and the first semiconductor layer;

[0007] The microdisplay unit also includes a first electrode connection structure corresponding to the light-emitting unit, and at least one first electrode connection structure is electrically connected to the second semiconductor supplementary layer.

[0008] Optionally, the microdisplay unit also includes a connection contact point and a first via corresponding to the first electrode connection structure. The connection contact point is located in the thickness direction of the microdisplay unit, on the side of the outermost light-emitting unit away from the adjacent light-emitting unit.

[0009] The first electrode connection structure is located in the first via and is electrically connected to the corresponding connection contact point, and at least one first via penetrates at least one light-emitting unit.

[0010] Optionally, the microdisplay unit includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit stacked together; the connection contact point is located on the side of the first light-emitting unit away from the second light-emitting unit;

[0011] The second light-emitting unit and the third light-emitting unit each include a tunneling layer and a second semiconductor supplementary layer located on the side of the first semiconductor layer away from the light-emitting layer;

[0012] One of the first electrode connection structures is connected to a contact point and the second semiconductor supplementary layer of the second light-emitting unit; the other first electrode connection structure is connected to another contact point and the second semiconductor supplementary layer of the third light-emitting unit.

[0013] Optionally, the microdisplay unit also includes an ohmic contact layer, which is located on the side of the first semiconductor layer of the first light-emitting unit away from the light-emitting layer; wherein a series of contact points are connected to the ohmic contact layer.

[0014] Optionally, the microdisplay unit further includes at least one second electrode connection structure and a second via, the at least one second via passing through at least one light-emitting unit, the second electrode connection structure being located in the second via, and the second electrode connection structure being electrically connected to the second semiconductor layer.

[0015] Optionally, the microdisplay unit further includes a first interconnect structure, which is electrically connected to each of the second electrode connection structures and connected to the second electrode pads, which are located on the outside of each light-emitting unit.

[0016] Optionally, the thickness of the second electrode pad is greater than or equal to the sum of the thicknesses of each light-emitting unit.

[0017] Optionally, the microdisplay unit includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit stacked together;

[0018] One of the second electrode connection structures extends from the second semiconductor layer of the third light-emitting unit to the second semiconductor layer of the first light-emitting unit; the other second electrode connection structure extends from the second semiconductor layer of the third light-emitting unit to the second semiconductor layer of the second light-emitting unit.

[0019] A second interconnect structure is provided on the side of the second semiconductor layer of the third light-emitting unit away from the light-emitting layer. The second interconnect structure is connected to the second semiconductor layer of the third light-emitting unit and each second electrode connection structure. The second interconnect structure is connected to the first interconnect structure.

[0020] Optionally, in the light-emitting unit, the thickness of the second semiconductor supplementary layer is less than the thickness of the second semiconductor layer; and / or, the thickness of the tunneling layer is less than the thickness of the second semiconductor supplementary layer.

[0021] Optionally, the first semiconductor layer is a P-type semiconductor layer, and the second semiconductor layer and the second semiconductor supplementary layer are both N-type semiconductor layers.

[0022] In this embodiment of the invention, at least two light-emitting units of the microdisplay unit are vertically stacked in space. This reduces the planar area occupied by the microdisplay unit, thereby improving the resolution of the display device when it is applied. At least one light-emitting unit further includes a tunneling layer and a second semiconductor supplementary layer located on the side of the first semiconductor layer away from the light-emitting layer. The microdisplay unit also includes a first electrode connection structure corresponding to the light-emitting unit. At least one first electrode connection structure is electrically connected to the second semiconductor supplementary layer. The first electrode connection structure and the etched-exposed second semiconductor supplementary layer more easily form an effective ohmic contact. The structure of the second semiconductor supplementary layer, the tunneling layer, and the first semiconductor layer forms a PN junction. Current can pass through the tunneling layer and thus through the entire PN junction. Therefore, it can be ensured that the first electrode connection structure achieves electrical connection with the first semiconductor layer through the connection to the second semiconductor supplementary layer, which is beneficial for improving device performance.

[0023] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the structure of a micro-display unit provided in an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of another micro-display unit provided in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of another micro-display unit provided in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of a multi-color stacked epitaxial structure;

[0029] Figures 5-10 This is a schematic diagram of the fabrication process of the microdisplay unit. Detailed Implementation

[0030] 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. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0032] Figure 1 This is a schematic diagram of the structure of a micro-display unit provided in an embodiment of this utility model, for reference. Figure 1 The microdisplay unit includes at least two light-emitting units 100 stacked along the thickness direction y of the microdisplay unit. Each light-emitting unit 100 includes a first semiconductor layer 110, a light-emitting layer 120, and a second semiconductor layer 130 stacked together. At least one light-emitting unit 100 also includes a tunneling layer 140 and a second semiconductor supplementary layer 150 located on the side of the first semiconductor layer 110 away from the light-emitting layer 120. The tunneling layer 140 is located between the second semiconductor supplementary layer 150 and the first semiconductor layer 110. The microdisplay unit also includes a first electrode connection structure 160 corresponding to the light-emitting unit 100. At least one first electrode connection structure 160 is electrically connected to the second semiconductor supplementary layer 150.

[0033] Specifically, at least two light-emitting units 100 of the microdisplay unit are vertically stacked in space. This reduces the planar area occupied by the microdisplay unit, thereby improving the resolution of the display device when it is applied. Optionally, the stacked light-emitting units 100 emit different colors. An insulating layer 170 may be provided between adjacent light-emitting units 100, making each light-emitting unit 100 electrically independent. Optionally, the insulating layer 170 may be made of AlN.

[0034] Optionally, the microdisplay unit includes at least two light-emitting units 100 with different emitting colors. In some optional embodiments of this invention, such as... Figure 1 As shown, the microdisplay unit includes two light-emitting units 100, namely a first light-emitting unit 101 and a second light-emitting unit 102. The first light-emitting unit 101 and the second light-emitting unit 102 emit different colors. For example, the first light-emitting unit 101 and the second light-emitting unit 102 can be respectively... Figure 1 In other optional embodiments of the present invention, the blue and green light-emitting units shown may emit red and green light or red and blue light, respectively, as shown in the blue and green light-emitting units. In another optional embodiment of the present invention, the microdisplay unit includes at least three light-emitting units 100, which are vertically stacked. Figure 2 This is a schematic diagram of another micro-display unit provided in an embodiment of the present invention, for reference. Figure 2 The micro-display unit includes a first light-emitting unit 101, a second light-emitting unit 102, and a third light-emitting unit 103 stacked sequentially from bottom to top. The first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103 are all of different colors. For example, the light-emitting colors of the first light-emitting unit 101, the third light-emitting unit 102, and the third light-emitting unit 103 are blue, green, and red, respectively. In the micro-display unit, different light-emitting units 100 can emit light independently. When a light-emitting unit 100 of one color emits light independently, the micro-display unit can achieve monochrome display; when at least two light-emitting units 100 of different colors emit light simultaneously, the micro-display unit can achieve dual-color display; when at least three light-emitting units 100 of different colors (red, green, and blue) emit light simultaneously, the micro-display unit can achieve full-color display. In this embodiment, by setting the micro-display unit to include at least two light-emitting units 100 stacked along the thickness direction y, it is convenient to stack the epitaxial structures of light-emitting units 100 with different light-emitting colors and then fabricate the structure of the stacked light-emitting units 100. Full-color display can be achieved without mass transfer, which helps to reduce costs and improve fabrication efficiency.

[0035] Optionally, the microdisplay unit further includes a substrate 180, on which at least two light-emitting units 100 are vertically stacked. A driving circuit may be provided in the substrate 180 to drive the light-emitting units for display. In some optional embodiments, the vertical projections of at least two light-emitting units 100 on the substrate overlap; in other optional embodiments of this invention, the vertical projections of each light-emitting unit 100 on the substrate 180 may not overlap, and this embodiment is not specifically limited here. Optionally, the light-emitting units 100 are light-transmitting, such that when the upper light-emitting unit 100 does not emit light, but the lower light-emitting unit 100 emits light, the light emitted by the lower light-emitting unit 100 can still be displayed through the upper light-emitting unit 100.

[0036] Optionally, the light-emitting unit 100 includes a first semiconductor layer 110, a light-emitting layer 120, and a second semiconductor layer 130 stacked together. The first semiconductor layer 110 is an N-type semiconductor layer, and the second semiconductor layer 130 is a P-type semiconductor layer; or the first semiconductor layer 110 is a P-type semiconductor layer, and the second semiconductor layer 130 is an N-type semiconductor layer. The N-type semiconductor layer may include n-GaN, and the P-type semiconductor layer may include p-GaN. The light-emitting layer 120 may be a quantum well layer, optionally a multi-quantum well layer, such as an InGaN / GaN multi-quantum well layer. The light-emitting unit 100 may have the first semiconductor layer 110, the light-emitting layer 120, and the second semiconductor layer 130 stacked from bottom to top, or the first semiconductor layer 110, the light-emitting layer 120, and the second semiconductor layer 130 stacked from top to bottom.

[0037] Specifically, etching the first semiconductor layer 110 can damage its surface, making it difficult for the exposed semiconductor layer 110 to form an effective ohmic contact. In this embodiment, the at least one light-emitting unit 100 also includes a tunneling layer 140 and a second semiconductor supplementary layer 150 located on the side of the first semiconductor layer 110 away from the light-emitting layer 120. The microdisplay unit also includes a first electrode connection structure 160 corresponding to the light-emitting unit 100. The first electrode connection structure 160 can be used to connect the first electrode of the microdisplay unit, and at least one first electrode connection structure 160 is electrically connected to the second semiconductor supplementary layer 150. Figure 1 The diagram illustrates a scenario where the first electrode connection structure 160 corresponding to the first light-emitting unit 101 can be connected to the ohmic contact layer 400 on the side of the first semiconductor layer 110 of the first light-emitting unit 101 away from the light-emitting layer 120, and the first electrode connection structure 160 corresponding to the second light-emitting unit 102 is connected to the second semiconductor supplementary layer 150 of the second light-emitting unit 102. Figure 2The diagram schematically illustrates the following scenarios: the first electrode connection structure 160 corresponding to the first light-emitting unit 101 can be connected to the ohmic contact layer 400 on the side of the first semiconductor layer 110 of the first light-emitting unit 101 away from the light-emitting layer 120; the first electrode connection structure 160 corresponding to the second light-emitting unit 102 is connected to the second semiconductor supplementary layer 150 of the second light-emitting unit 102; and the first electrode connection structure 160 corresponding to the third light-emitting unit 103 is connected to the second semiconductor supplementary layer 150 of the third light-emitting unit 103.

[0038] The tunneling layer 140 can be made of InGaN. The material of the second semiconductor supplementary layer 150 can be the same as that of the second semiconductor layer 130. Compared to the first semiconductor layer 110, the second semiconductor layer 130 can be a semiconductor layer less affected by etching, making it easier for the exposed second semiconductor supplementary layer 150 to form an effective ohmic contact. Optionally, the first semiconductor layer 110 is a P-type semiconductor layer, and the second semiconductor layer 130 and the second semiconductor supplementary layer 150 are N-type semiconductor layers. In some optional embodiments of this invention, an ohmic base layer can also be provided between the first electrode connection structure 160 and the second semiconductor supplementary layer 150, so that the first electrode connection structure 160 and the second semiconductor supplementary layer 150 form a more effective ohmic contact. The structure of the second semiconductor supplementary layer 150, the tunneling layer 140, and the first semiconductor layer 110 forms a PN junction. Current can pass through the tunneling layer 140 and thus through the entire PN junction. Therefore, it can be ensured that the first electrode connection structure 160 is connected to the first semiconductor layer 110 by connecting the second semiconductor supplementary layer 150, thereby illuminating the light-emitting unit 100.

[0039] In this embodiment, the microdisplay unit has at least two light-emitting units vertically stacked in space. This reduces the planar area occupied by the microdisplay unit, improving the resolution of the display device when it is applied. At least one light-emitting unit also includes a tunneling layer and a second semiconductor supplementary layer located on the side of the first semiconductor layer away from the light-emitting layer. The microdisplay unit also includes a first electrode connection structure corresponding to the light-emitting unit. At least one first electrode connection structure is electrically connected to the second semiconductor supplementary layer. The first electrode connection structure and the etched-exposed second semiconductor supplementary layer more easily form an effective ohmic contact. The structure of the second semiconductor supplementary layer, the tunneling layer, and the first semiconductor layer forms a PN junction. Current can pass through the tunneling layer and thus through the entire PN junction. Therefore, it can be ensured that the first electrode connection structure achieves electrical connection with the first semiconductor layer through the connection to the second semiconductor supplementary layer, which is beneficial for improving device performance.

[0040] Continue to refer to Figure 2Optionally, the microdisplay unit further includes a connection contact point 200 and a first via 300 corresponding to the first electrode connection structure 160. The connection contact point 200 is located in the thickness direction y of the microdisplay unit, with the outermost light-emitting unit 100 on the side away from the adjacent light-emitting unit 100. The first electrode connection structure 160 is located in the first via 300 and electrically connected to the corresponding connection contact point 200. At least one first via 300 penetrates at least one light-emitting unit 100. The outermost light-emitting unit 100 in the thickness direction y of the microdisplay unit can be either the uppermost or the lowermost light-emitting unit. In this embodiment, the first electrode connection structure 160 is located in the first via 300, and the first via 300 passes through at least one light-emitting unit 100, so that the first electrode connection structure 160 does not occupy additional area other than the light-emitting unit 100, which is beneficial for reducing the size of the microdisplay unit.

[0041] In some optional embodiments, the connecting contact 200 serves as the first electrode of the light-emitting unit 100; in other optional embodiments, the connecting contact 200 can serve as a transition structure between the first electrode connection structure 160 and the first electrode connection. Optionally, the connecting contacts 200 corresponding to different light-emitting units 100 are mutually insulated. During the fabrication of the microdisplay unit, a first via 300 corresponding to the light-emitting unit 100 can be fabricated first, and then a first insulating dielectric layer 301 can be formed on the sidewall of the first via 300. The material of the first insulating dielectric layer 301 can be SiO2 or SiNx, etc. Afterwards, a conductive material is filled into the first via 300 to form the first electrode connection structure 160. (Reference) Figure 2 In the case where the micro-display unit includes a first light-emitting unit 101, a second light-emitting unit 102 and a third light-emitting unit 103 stacked together, the first via 300 corresponding to the second light-emitting unit 102 passes through the first light-emitting unit 101, and the first via 300 corresponding to the third light-emitting unit 103 passes through the first light-emitting unit 101 and the second light-emitting unit 102.

[0042] like Figure 2As shown, optionally, the microdisplay unit includes a first light-emitting unit 101, a second light-emitting unit 102, and a third light-emitting unit 103 stacked together; the connection contact 200 is located on the side of the first light-emitting unit 101 away from the second light-emitting unit 102; the second light-emitting unit 102 and the third light-emitting unit 103 respectively include a tunneling layer 140 and a second semiconductor supplementary layer 150 located on the side of the first semiconductor layer 110 away from the light-emitting layer 120; wherein a first electrode connection structure 160 is respectively connected to a connection contact 200 (second connection contact 220) and the second semiconductor supplementary layer 150 of the second light-emitting unit 102; another first electrode connection structure 160 is respectively connected to another connection contact 200 (third connection contact 230) and the second semiconductor supplementary layer 150 of the third light-emitting unit 103.

[0043] Optionally, the first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103 are respectively a blue light-emitting unit, a green light-emitting unit, and a red light-emitting unit. The first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103 are stacked from bottom to top. A dielectric bonding layer 190 can be provided on the side of the first light-emitting unit 101 away from the second light-emitting unit 102. The material of the dielectric spacer layer 190 can be an insulating material such as SiO2 or Pi adhesive. The connection contact 200 is located on the side of the dielectric bonding layer 190 away from the first light-emitting unit 101. In the prior art, when fabricating the first via 300, the first via 300 corresponding to the second light-emitting unit 102 is usually opened into the first semiconductor layer 110 of the second light-emitting unit 102. However, the opening of the first via 300 affects the performance of the first semiconductor layer 110, making it difficult for the first electrode connection structure 160 to form an effective ohmic contact with the first semiconductor layer 110 exposed after etching. The same applies to the third light-emitting unit 103. In this embodiment, by setting the second light-emitting unit 102 and the third light-emitting unit 103 to include a tunneling layer 140 and a second semiconductor supplementary layer 150 located on the side of the first semiconductor layer 110 away from the light-emitting layer 120, respectively; wherein a first electrode connection structure 160 is respectively connected to a connecting contact point 200 (second connecting contact point 220) and the second semiconductor supplementary layer 150 of the second light-emitting unit 102; and another first electrode connection structure 160 is respectively connected to another connecting contact point 200 (third connecting contact point 230) and the second semiconductor supplementary layer 150 of the third light-emitting unit 103, the first electrode connection structure 160 of the second light-emitting unit 102 can form an effective electrical connection through the second semiconductor supplementary layer 150, thereby realizing the connection between the first electrode connection structure 160 and the first semiconductor layer 110. The same applies to the third light-emitting unit 103, which helps to ensure device performance.

[0044] Continue to refer to Figure 2Optionally, the microdisplay unit further includes an ohmic contact layer 400, which is located on the side of the first semiconductor layer 110 of the first light-emitting unit 101 away from the light-emitting layer 120; wherein a connecting contact point 200 (first connecting contact point 210) is connected to the ohmic contact layer 400. Specifically, the connecting contact point 200 corresponding to the first light-emitting unit 101 can be connected to the ohmic contact layer 400 through the dielectric bonding layer 190.

[0045] In another optional embodiment of this utility model, the ohmic contact layer 400 on one side of the first light-emitting unit 101 can also be replaced with a tunneling layer and a second semiconductor supplementary layer. In this case, the connection contact point corresponding to the first light-emitting unit can be connected to the second semiconductor supplementary layer of the first light-emitting unit.

[0046] Continue to refer to Figure 1 and Figure 2 Optionally, the microdisplay unit further includes at least one second electrode connection structure 500 and a second via 501, the at least one second via 501 passing through at least one light-emitting unit 100, the second electrode connection structure 500 being located in the second via 501, and the second electrode connection structure 500 being electrically connected to the second semiconductor layer 130.

[0047] The second electrode connection structure 500 can be used to connect the second electrode of the microdisplay unit, thereby realizing the electrical connection between the second electrode and the second semiconductor layer 130. The sidewall of the second via 501 is provided with a second insulating dielectric layer 505, which can be made of SiO2 or SiNx, etc. In this embodiment, the second electrode connection structure 500 is located in the second via 501, which passes through at least one light-emitting unit 100. This ensures that the second electrode connection structure 500 does not occupy additional area beyond the light-emitting unit 100, thus reducing the size of the microdisplay unit.

[0048] Continue to refer to Figure 2 Optionally, the microdisplay unit also includes a first interconnect structure 502, which is electrically connected to each of the second electrode connection structures 500 and connected to the second electrode pads 503, which are located on the outside of each light-emitting unit 100.

[0049] The first interconnect structure 502 can be made of a transparent conductive material. The first interconnect structure 502 electrically connects each of the second electrode connection structures 500, enabling the microdisplay units to form a structure with a common second electrode. In this case, the first electrodes of the microdisplay units are independent of each other. For example, for... Figure 2The microdisplay unit shown has interconnected contacts 200 of the first light-emitting unit 101, the second light-emitting unit 102, and the third light-emitting unit 103, which are mutually insulated. The second electrode pad 503 can be made of metal and can assist in current expansion and facilitate connection between the microdisplay unit and external devices.

[0050] Figure 3 This is a schematic diagram of another micro-display unit provided in an embodiment of the present invention, for reference. Figure 3 Optionally, the thickness of the second electrode pad 503 is greater than or equal to the sum of the thicknesses of each light-emitting unit 100; in this way, the second electrode pad 503 can block and / or reflect the light emitted from the side of the micro-display unit, reduce the optical crosstalk between adjacent micro-display units in the display device, and help improve the display effect.

[0051] Continue to refer to Figure 2 and Figure 3 Optionally, the microdisplay unit includes a first light-emitting unit 101, a second light-emitting unit 102, and a third light-emitting unit 103 stacked together; wherein a second electrode connection structure 500 extends from the second semiconductor layer 130 of the third light-emitting unit 103 to the second semiconductor layer 130 of the first light-emitting unit 101; another second electrode connection structure 500 extends from the second semiconductor layer 130 of the third light-emitting unit 103 to the second semiconductor layer 130 of the second light-emitting unit 102; a second interconnect structure 504 is provided on the side of the second semiconductor layer 130 of the third light-emitting unit 103 away from the light-emitting layer 120, the second interconnect structure 504 is respectively connected to the second semiconductor layer 130 of the third light-emitting unit 103 and each second electrode connection structure 500, and the second interconnect structure 504 is connected to the first interconnect structure 502. The second interconnect structure 504 forms an ohmic contact with the second semiconductor layer 130 of the third light-emitting unit 103. The second interconnect structure 504 is also connected to the second electrode connection structure 500 corresponding to the first light-emitting unit 101 and the second electrode connection structure 500 corresponding to the second light-emitting unit 102, so that the second semiconductor layers 130 of the first light-emitting unit 101, the second light-emitting unit 102 and the third light-emitting unit 103 are interconnected to form a structure with a common second electrode.

[0052] In some optional embodiments of this utility model, the thickness of the second semiconductor supplementary layer 150 in the light-emitting unit 100 is less than the thickness of the second semiconductor layer 130. This arrangement ensures that the first semiconductor layer 110, the tunneling layer 140, and the second semiconductor supplementary layer 150 can form a PN junction in the light-emitting unit 100. Furthermore, it prevents the thickness of the light-emitting unit 100 from increasing excessively due to the addition of the second semiconductor supplementary layer 150, thus preventing the overall thickness of the microdisplay unit from becoming too thick.

[0053] Optionally, in the light-emitting unit 100, the thickness of the tunneling layer 140 is less than the thickness of the second semiconductor supplementary layer 150.

[0054] Figure 4 This is a schematic diagram of a multicolor stacked epitaxial structure, which is used to form... Figures 1-3 The microdisplay unit shown includes a multi-color stacked epitaxial structure that can include epitaxial structures corresponding to at least two light-emitting units 100 of different colors, with the different epitaxial structures stacked along the thickness direction y. Table 1 shows... Figure 4 The material composition and thickness of each film layer from top to bottom in the multicolor stacked epitaxial structure shown.

[0055] Table 1

[0056]

[0057]

[0058] It should be noted that the thickness of each film layer in the stacked epitaxial structure can be adjusted according to the actual situation, and this embodiment of the present invention does not impose specific limitations.

[0059] Figures 5-10 This is a schematic diagram illustrating the fabrication process of the microdisplay unit. Figure 5 This is the structure formed by vertically stacking a first epitaxial structure 11 (corresponding to the first light-emitting unit), a second epitaxial structure 12 (corresponding to the second light-emitting unit), and a third epitaxial structure 13 (corresponding to the third light-emitting unit), and then fabricating the first vias 300 corresponding to the second and third light-emitting units. A tunneling layer 140 and a second semiconductor supplementary layer 150 are provided on one side of the first semiconductor layer 110 of the second epitaxial structure 12, and the same applies to the first semiconductor layer 110 of the third epitaxial structure 13. When fabricating the first vias 300, the first via 300 corresponding to the second light-emitting unit can be opened from the first semiconductor layer 110 of the first epitaxial structure 11 to the second semiconductor supplementary layer 150 of the second epitaxial structure 12; similarly, the first via 300 corresponding to the third light-emitting unit can be opened from the first semiconductor layer 110 of the first epitaxial structure 11 to the second semiconductor supplementary layer 150 of the third epitaxial structure 13. Then, a first insulating dielectric layer 301 is fabricated on the sidewall of the first via 300 to obtain... Figure 6 The structure shown is then formed in the first via 300, resulting in... Figure 7A conductive material 600 intermediate structure is formed on one side of both the first via 300 and the first semiconductor layer 110 of the first epitaxial structure 11. Then, patterning is performed to obtain the first electrode connection structure 160 in the first via 300 corresponding to the second and third light-emitting units, respectively. A dielectric bonding layer 190 is formed on one side of the first semiconductor layer 110 of the first epitaxial structure 11, resulting in... Figure 8 The structure is shown. Then, the first epitaxial structure 11 is bonded to the temporary substrate 700, and the original substrate of the third epitaxial structure 13 is removed, resulting in... Figure 9 The structure is shown. A second via 501 can then be formed on one side of the second semiconductor layer 130 of the third epitaxial structure 13. The second via 501 corresponding to the first light-emitting unit extends from the second semiconductor layer 130 of the third epitaxial structure 13 to the second semiconductor layer 130 of the first epitaxial structure 11, and the second via 501 corresponding to the second light-emitting unit extends from the second semiconductor layer 130 of the third epitaxial structure 13 to the second semiconductor layer 130 of the first epitaxial structure 11, thus obtaining... Figure 10 The structure shown. Afterwards, it can be... Figure 10 A second electrode connection structure is formed in the second via 501, and a first interconnect structure is formed to interconnect the second electrode connection structure. A temporary substrate on one side of the first light-emitting unit is removed, and connection points are formed corresponding to the first, second, and third light-emitting units, thus forming... Figure 2 and Figure 3 The structure of the microdisplay unit is shown.

[0060] As can be seen from the above-described fabrication process of the micro-display unit, the structure of the micro-display unit in this embodiment of the present invention is fabricated by stacking the epitaxial structures of light-emitting units of different emitting colors, thereby eliminating the need for mass transfer to achieve full-color display, which helps to reduce costs and improve fabrication efficiency.

[0061] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.

[0062] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A micro-display unit, characterized in that, include: At least two light-emitting units are stacked along the thickness direction of the microdisplay unit, and the light-emitting unit includes a first semiconductor layer, a light-emitting layer and a second semiconductor layer stacked together; At least one of the light-emitting units further includes a tunneling layer and a second semiconductor supplementary layer located on the side of the first semiconductor layer away from the light-emitting layer, wherein the tunneling layer is located between the second semiconductor supplementary layer and the first semiconductor layer; The microdisplay unit further includes a first electrode connection structure corresponding to the light-emitting unit, and at least one of the first electrode connection structures is electrically connected to the second semiconductor supplementary layer.

2. The micro-display unit according to claim 1, characterized in that, It also includes a connection contact point and a first via corresponding to the first electrode connection structure. The connection contact point is located in the thickness direction of the microdisplay unit, and the outermost light-emitting unit is located on the side away from the adjacent light-emitting unit. The first electrode connection structure is located in the first via and is electrically connected to the corresponding connection contact point, and at least one of the first vias penetrates at least one of the light-emitting units.

3. The microdisplay unit according to claim 2, characterized in that, It includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit stacked together; the connecting contact point is located on the side of the first light-emitting unit away from the second light-emitting unit; The second light-emitting unit and the third light-emitting unit respectively include a tunneling layer and a second semiconductor supplementary layer located on the side of the first semiconductor layer away from the light-emitting layer; One of the first electrode connection structures is connected to one of the connection contacts and the second semiconductor supplementary layer of the second light-emitting unit; the other first electrode connection structure is connected to another connection contact and the second semiconductor supplementary layer of the third light-emitting unit.

4. The micro-display unit according to claim 3, characterized in that, It also includes an ohmic contact layer, which is located on the side of the first semiconductor layer of the first light-emitting unit away from the light-emitting layer; wherein a contact point is connected to the ohmic contact layer.

5. The micro-display unit according to claim 1, characterized in that, It also includes at least one second electrode connection structure and a second via, wherein at least one second via passes through at least one of the light-emitting units, the second electrode connection structure is located in the second via, and the second electrode connection structure is electrically connected to the second semiconductor layer.

6. The microdisplay unit according to claim 5, characterized in that, It also includes a first interconnect structure, which is electrically connected to each of the second electrode connection structures and connected to the second electrode pads, which are located on the outside of each of the light-emitting units.

7. The microdisplay unit according to claim 6, characterized in that, The thickness of the second electrode pad is greater than or equal to the sum of the thicknesses of each of the light-emitting units.

8. The microdisplay unit according to claim 6, characterized in that, It includes a first light-emitting unit, a second light-emitting unit, and a third light-emitting unit stacked together; One of the second electrode connection structures extends from the second semiconductor layer of the third light-emitting unit to the second semiconductor layer of the first light-emitting unit; the other second electrode connection structure extends from the second semiconductor layer of the third light-emitting unit to the second semiconductor layer of the second light-emitting unit. A second interconnect structure is provided on the side of the second semiconductor layer of the third light-emitting unit away from the light-emitting layer. The second interconnect structure is respectively connected to the second semiconductor layer of the third light-emitting unit and each of the second electrode connection structures. The second interconnect structure is connected to the first interconnect structure.

9. The micro-display unit according to claim 1, characterized in that, In the light-emitting unit, the thickness of the second semiconductor supplementary layer is less than the thickness of the second semiconductor layer; and / or, the thickness of the tunneling layer is less than the thickness of the second semiconductor supplementary layer.

10. The microdisplay unit according to claim 1, characterized in that, The first semiconductor layer is a P-type semiconductor layer, and the second semiconductor layer and the second semiconductor supplementary layer are both N-type semiconductor layers.

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