Linear polarization Micro-LED with high extinction ratio and preparation method thereof

Abstract

The invention relates to a 3D display technology, in particular to a high-extinction-ratio linear polarization Micro-LED and a preparation method thereof.The high-extinction-ratio linear polarization Micro-LED comprises an unetched area and a table top, silicon dioxide passivation layers are deposited on the top of the unetched area, the outer side wall of the table top and the top of the table top, and the silicon dioxide passivation layers are deposited on the outer side wall of the table top and the top of the table top. According to the invention, the silicon dioxide passivation layers are deposited on the top of the non-etched area, the outer side wall of the table top and the top of the table top, and then the avoiding step is formed on the periphery of the top of the table top after silicon dioxide passivation, so that the top of the ITO layer is covered with the silicon dioxide passivation layer; according to the invention, the preparation of the silicon dioxide transition layer is completed without an additional process, and the layer of silicon dioxide can also play a role of an antireflection film, so that the light transmittance is increased, and the luminous efficiency of the linearly polarized Micro-LED is improved.

Description

Technical Field

[0001] The present invention relates to a 3D display technology, and in particular to a linearly polarized Micro-LED with a high extinction ratio and a preparation method thereof. Background Art

[0002] As an inorganic light-emitting diode display technology, Micro-LED is considered to be a highly competitive and promising candidate in the next generation of display technology. Micro-LED chips have many similar characteristics to the LED chips used for light emission today, but the pixel size of Micro-LED displays has been reduced to the micron level. Therefore, this micro display technology not only inherits the high luminous efficiency, high stability and ultra-long service life of traditional LED displays, but also, thanks to the reduction in size, Micro-LED can also achieve ultra-high resolution, low power consumption and high brightness, and other advantages that are difficult to achieve with other display technologies. People soon thought of applying Micro-LED to 3D displays, which can transform the advantages of Micro-LED displays into advanced 3D displays.

[0003] Polarized 3D display technology is the current mainstream stereoscopic display technology, with a strong sense of stereoscopic, relatively low production cost, and a relatively high proportion of products on the market. Its principle is to display the images of the right eye and the left eye on the screen at the same time in different polarization states, and receive them by the left eye and the right eye respectively through polarized glasses, forming binocular parallax and realizing 3D display. At present, the Micro-LED used for polarized 3D display mainly integrates the metal grating into the top of the Micro-LED. After passing through the metal grating, the light will form polarized light. There are two main problems. First, because the metal grating will block the passage of part of the light, the efficiency of the light of the Micro-LED passing through the metal grating is low, and the brightness is lost. Second, there will be serious leakage of light on the side wall of the Micro-LED and through the sapphire. The leaked light does not pass through the metal grating on the top of the Micro-LED, so it is non-polarized, which will reduce the extinction ratio of polarized light. These problems have a serious impact on the display effect of polarized light Miro-LED.

[0004] Therefore, those skilled in the art are committed to developing a method to improve the brightness of polarized light Micro-LEDs, reduce light leakage, and improve the extinction ratio of the device, so as to better realize the array display of polarized light Micro-LEDs. Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a method for improving the brightness of polarized light Micro-LED, reducing light leakage, and improving the extinction ratio of the device, so as to better realize the array display of polarized light Micro-LED.

[0006] To achieve the above objectives, the present invention provides a linearly polarized Micro-LED with a high extinction ratio, comprising an unetched area and a table, wherein a silicon dioxide passivation layer is deposited on the top of the unetched area, the outer wall of the table and the top of the table, and a yield step is opened on the silicon dioxide passivation layer at the periphery of the top of the table.

[0007] Further: the unetched area includes a Sapphire layer and an unetched N-GaN layer stacked sequentially from bottom to top;

[0008] The mesa includes an etched N-GaN layer, an MQW layer, a P-GaN layer and an ITO layer.

[0009] Furthermore: a first contact hole is opened in the silicon dioxide passivation layer at the top of the unetched area, and the first contact hole penetrates the silicon dioxide passivation layer.

[0010] Further: a positive electrode is disposed in the first contact hole, the bottom of the positive electrode is inserted into the first contact hole and connected to the top of the unetched area, and the top extends out of the first contact hole;

[0011] A negative electrode corresponding to the positive electrode is arranged on the top of the unetched area away from the positive electrode.

[0012] Further: a first side wall electrode is arranged on the giving way step;

[0013] Second side wall electrodes are arranged on all outer side walls of the table, and third side wall electrodes are connected to the bottom of the second side wall electrodes in a circumferential direction;

[0014] The first sidewall electrode, the second sidewall electrode and the third sidewall electrode are connected to each other and formed in one piece.

[0015] Furthermore: metal leads are arranged between the positive electrode and the first side wall electrode, the second side wall electrode and the third side wall electrode.

[0016] Furthermore: a plurality of metal gratings are arranged in the first sidewall electrode, both sides of the metal gratings in the length direction are respectively connected to the inner sidewalls of the first sidewall electrode, and the bottom of the metal gratings is connected to the ITO layer through a silicon dioxide passivation layer.

[0017] A method for preparing a linearly polarized Micro-LED with a high extinction ratio comprises the following steps:

[0018] Depositing a silicon dioxide passivation layer on the top of the mesa, the outer wall of the mesa and the top of the unetched area by PECVD, so that the silicon dioxide completely covers the top of the mesa, the outer wall of the mesa and the top of the unetched area, and opening a step around the top of the mesa;

[0019] Furthermore: the unetched area includes a Sapphire layer and an unetched N-GaN layer stacked in sequence from bottom to top, and the mesa includes an etched N-GaN layer, an MQW layer, a P-GaN layer and an ITO layer.

[0020] The following steps are also included:

[0021] Further: a first contact hole is opened on the silicon dioxide passivation layer at the top of the unetched area, wherein the first contact hole penetrates the silicon dioxide passivation layer;

[0022] Further: subsequently, a metal electrode is prepared, and a positive electrode, a negative electrode, a first sidewall electrode, a second sidewall electrode and a third sidewall electrode are prepared by magnetron sputtering, wherein the positive electrode fills the first contact hole, the bottom of the positive electrode is inserted into the first contact hole and connected to the top of the unetched area, and the top extends out of the first contact hole;

[0023] The negative electrode is arranged on the top of the unetched area and on a side away from the positive electrode;

[0024] The first side wall electrode fills the step, and the second side wall electrode is arranged on all the outer side walls of the table, the top of the second side wall electrode is connected to the outer side of the first side wall electrode, and the bottom of the second side wall electrode is connected to the third side wall electrode in the circumferential direction, and the first side wall electrode, the second side wall electrode and the third side wall electrode are connected to each other and formed in one piece;

[0025] Further: a metal lead is provided between the positive electrode and the first side wall electrode, the second side wall electrode and the third side wall electrode, for connecting the positive electrode, the first side wall electrode, the second side wall electrode and the third side wall electrode;

[0026] Further: a metal grating is prepared by electron beam exposure and lift-off process, the metal grating is located in the first sidewall electrode, both sides of the metal grating in the length direction are connected to the inner sidewall of the first sidewall electrode, and the bottom is connected to the ITO layer through a silicon dioxide passivation layer;

[0027] The beneficial effects of the present invention are as follows: the present invention deposits a silicon dioxide passivation layer on the top of the unetched area, the outer wall of the table and the top of the table, and then opens a clearance step on the periphery of the top of the table after the silicon dioxide is passivated, so that a layer of silicon dioxide passivation layer is also covered on the top of the ITO layer, and the preparation of the silicon dioxide transition layer is completed without additional processes. This layer of silicon dioxide can also play the role of an anti-reflection film, increase the transmittance of light, and increase the light output efficiency of the linearly polarized Micro-LED. Moreover, the sidewall electrode designed by the present invention can not only be normally turned on, but also effectively reduce the light output of the sidewall and sapphire of the Micro-LED. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1It is a structural schematic diagram of a specific implementation mode of the present invention.

[0029] Figure 2 It is an exploded schematic diagram of each component of the present invention.

[0030] Figure 3 It is a front view of the present invention.

[0031] Figure 4 It is a left side view of the present invention.

[0032] Figure 5 yes Figure 4 Sectional view of AA in the figure.

[0033] 1. Unetched area; 2. Terrace; 91. Sapphire layer; 92. Etched N-GaN layer; 921. Unetched N-GaN layer; 93. MQW layer; 94. P-GaN layer; 95. ITO layer; 3. Silicon dioxide passivation layer; 4. First contact hole; 5. Positive electrode; 6. Negative electrode; 7. First sidewall electrode; 8. Second sidewall electrode; 9. Third sidewall electrode; 10. Metal lead; 11. Metal grating DETAILED DESCRIPTION

[0034] The present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that in the description of the present invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific manner, and therefore cannot be understood as limiting the present invention. The terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0035] like Figure 1-4 As shown, the present invention provides a linearly polarized Micro-LED with a high extinction ratio. In this embodiment:

[0036] A linearly polarized Micro-LED with a high extinction ratio includes an unetched area and a table, and is characterized in that a silicon dioxide passivation layer is deposited on the top of the unetched area, the outer wall of the table and the top of the table, and a yield step is opened on the silicon dioxide passivation layer at the periphery of the top of the table.

[0037] In the production process of Micro-LED, the unetched area 1 and the mesa 2 are formed by etching on the epitaxial wafer. The unetched area 1 and the mesa 2 are formed in one piece. Because in the preparation process of Micro-LED, ICP etching of the mesa will damage its side walls, resulting in reduced efficiency, a silicon dioxide passivation layer 3 is deposited on the top of the unetched area 1, all the outer walls of the mesa 2 and the top of the mesa 2 to repair the damage. A yield step is opened on the silicon dioxide passivation layer 3 on the outer periphery of the top of the mesa 2, and the yield step is a "U"-shaped structure.

[0038] In this embodiment: the unetched area includes a Sapphire layer and an unetched N-GaN layer stacked sequentially from bottom to top;

[0039] The mesa includes an etched N-GaN layer, an MQW layer, a P-GaN layer and an ITO layer.

[0040] The unetched region 1 includes a Sapphire layer 91 and an unetched N-GaN layer 92 stacked sequentially from bottom to top;

[0041] The mesa 2 includes an etched N-GaN layer 92, an MQW layer 93, a P-GaN layer 94 and an ITO layer 95, wherein the unetched N-GaN layer 92 in the unetched area 1 and the etched N-GaN layer 921 in the mesa 2 are originally integrated and formed by etching definition. Now, for the convenience of writing this application, they are divided into two parts. The ITO layer 95 on the top of the mesa can be deposited by a dual-cavity magnetron sputtering device to serve as a current expansion layer.

[0042] In this embodiment: a first contact hole is opened on the silicon dioxide passivation layer at the top of the unetched area, and the first contact hole penetrates the silicon dioxide passivation layer.

[0043] A first contact hole 4 is formed on the silicon dioxide passivation layer 3 at the top of the unetched area 1 , and the first contact hole 4 penetrates the silicon dioxide passivation layer 3 .

[0044] In this embodiment: a positive electrode 5 is disposed in the first contact hole 4, the bottom of the positive electrode 5 is inserted into the first contact hole 4 and connected to the top of the unetched area 1, and the top extends out of the first contact hole 4;

[0045] A negative electrode 6 corresponding to the positive electrode 5 is arranged on the top of the unetched region 1 away from the positive electrode 5 .

[0046] A positive electrode 5 is disposed in the first contact hole 4. The positive electrode 5 cooperates with the first contact hole 4. The bottom of the positive electrode 5 is inserted into the first contact hole 4 and connected to the top of the unetched area 1. The top of the positive electrode 5 extends out of the first contact hole 4.

[0047] A negative electrode 6 is arranged on the top of the unetched region 1 away from the positive electrode 5 .

[0048] In this embodiment: a first side wall electrode 7 is provided on the step to give way;

[0049] Second side wall electrodes 8 are arranged on all outer side walls of the table 2, and third side wall electrodes 9 are connected to the bottom circumference of the second side wall electrodes 8;

[0050] The first side wall electrode 7 , the second side wall electrode 8 and the third side wall electrode 9 are connected to each other and formed integrally.

[0051] A first side wall electrode 7 is arranged on the step to make way. The first side wall electrode 7 is arranged circumferentially around the top of the table 2 in a "U"-shaped structure to fill the step to make way. A second side wall electrode 8 is arranged on all outer walls of the table 2. The bottom of the second side wall electrode 8 is circumferentially connected to a third side wall electrode 9. The first side wall electrode 7, the second side wall electrode 8 and the third side wall electrode 9 are connected to each other and formed as one piece.

[0052] In this embodiment, metal leads 10 are provided between the positive electrode 5 and the first side wall electrode 7 , the second side wall electrode 8 and the third side wall electrode 9 .

[0053] A metal lead 10 is provided between the positive electrode 5 and the first side wall electrode 7, the second side wall electrode 8 and the third side wall electrode 9 to connect the positive electrode 5, the first side wall electrode 7, the second side wall electrode 8 and the third side wall electrode 9. Such an electrode design can not only conduct normally, but also effectively reduce the light emission from the side wall and sapphire of the Micro-LED.

[0054] In this embodiment: a plurality of metal gratings 11 are arranged in the first sidewall electrode 7 , and both sides of the metal gratings 11 in the length direction are respectively connected to the inner sidewall of the first sidewall electrode 7 , and the bottom of the metal gratings 11 is connected to the ITO95 layer through the silicon dioxide passivation layer 3 .

[0055] A number of metal gratings 11 are arranged in the first side wall electrode 7. Both sides of the metal gratings 11 in the length direction are respectively connected to the corresponding inner walls of the first side wall electrode 7. The top of the metal grating 11 is flush with the first side wall electrode 7, and the bottom is connected to the ITO95 layer through the silicon dioxide passivation layer 3. The light of the Micro-LED passing through the metal grating 11 will be polarized.

[0056] like Figure 1-4 As shown, the present invention also provides a method for preparing a linearly polarized Micro-LED with a high extinction ratio, comprising the following steps:

[0057] In this embodiment: S1, PECVD is used to deposit a silicon dioxide passivation layer 3 on the top of the mesa 2, the outer wall of the mesa 2 and the top of the unetched area 1, so that the silicon dioxide completely covers the top of the mesa 2, the outer wall of the mesa 2 and the top of the unetched area 1, and a step is opened on the outer periphery of the top of the mesa 2.

[0058] First, ICP etching is used to define the Micro-LED mesa 2. Because in the preparation process of Micro-LED, ICP etching of mesa will damage its side walls, resulting in reduced efficiency. Therefore, a silicon dioxide passivation layer 3 is deposited on the top of the unetched area 1, all the outer walls of the mesa 2 and the top of the mesa 2 to repair the damage, and a step is opened on the top of the mesa 2. The step is a "U"-shaped structure opened around the outer periphery of the top of the mesa 2. The purpose is to retain part of the silicon dioxide passivation layer 3 on the top of the mesa 2 as a transition layer between the metal grating 11 and the ITO layer. This realizes the preparation of the silicon dioxide transition layer by opening holes. Because the refractive index of silicon dioxide is about 1.5, which is less than the refractive index of gallium nitride, the silicon dioxide passivation layer 3 can be used as an anti-reflection film to increase the transmittance of light and increase the light output efficiency of the linearly polarized Micro-LED.

[0059] In this embodiment: a first contact hole 4 is opened on the silicon dioxide passivation layer 3 at the top of the unetched area 1, and the first contact hole 4 penetrates the silicon dioxide passivation layer 3;

[0060] A first contact hole 4 is opened at the top of the unetched area 1 , and the first contact hole 4 completely penetrates the silicon dioxide passivation layer 3 .

[0061] In this embodiment: S3, metal electrodes are then prepared, and a positive electrode 5, a negative electrode 6, a first sidewall electrode 7, a second sidewall electrode 8 and a third sidewall electrode 9 are prepared by magnetron sputtering, wherein the positive electrode 5 fills the first contact hole 4, the bottom of the positive electrode 5 is inserted into the first contact hole 4 and connected to the top of the unetched area 1, and the top extends out of the first contact hole 4;

[0062] The negative electrode 6 is arranged on the top of the unetched area 1 and on a side away from the positive electrode 5;

[0063] The first side wall electrode 7 fills the giving way step, and the second side wall electrode 8 is arranged on all the outer walls of the table 2. The top of the second side wall electrode 8 is connected to the outer edge of the first side wall electrode 7, and the bottom of the second side wall electrode 8 is circumferentially connected to the third side wall electrode 9. The first side wall electrode 7, the second side wall electrode 8 and the third side wall electrode 9 are connected to each other and formed as one piece.

[0064] Subsequently, metal electrodes are prepared, and a positive electrode 5, a negative electrode 6, a first side wall electrode 7, a second side wall electrode 8 and a third side wall electrode 9 are prepared by magnetron sputtering. The positive electrode 5 fills the first contact hole 4. The first side wall electrode 7 is a "U"-shaped structure arranged on the outer periphery of the top of the table 2 to fill the step. The first side wall electrode 7, the second side wall electrode 8 and the third side wall electrode 9 are interconnected and integrally formed. Such an electrode design can not only conduct normally, but also effectively reduce the side wall light and sapphire light of the Micro-LED.

[0065] In this embodiment: S4, a metal lead 10 is provided between the positive electrode 5 and the first side wall electrode 7, the second side wall electrode 8 and the third side wall electrode 9 to connect the positive electrode 5, the first side wall electrode 7, the second side wall electrode 8 and the third side wall electrode 9.

[0066] A metal lead 10 is provided between the positive electrode 5 and the first side wall electrode 7, the second side wall electrode 8 and the third side wall electrode 9, and the metal lead 10 is used to connect the positive electrode 5, the first side wall electrode 7, the second side wall electrode 8 and the third side wall electrode 9;

[0067] In this embodiment: S5, a metal grating 11 is prepared by electron beam exposure and stripping process, the metal grating 11 is located inside the first side wall electrode 7, both sides of the metal grating 11 in the length direction are connected to the inner wall of the first side wall electrode 7, and the bottom is connected to the ITO layer 95 through the silicon dioxide passivation layer 3.

[0068] A number of metal gratings 11 are prepared by electron beam exposure and stripping processes. The metal gratings 11 are located inside the first sidewall electrode 7. Both sides of the metal gratings 11 in the length direction are respectively connected to the inner side walls of the first sidewall electrode 7. The bottom of the metal grating 11 is connected to the ITO layer 95 through the silicon dioxide passivation layer 3. Light from the Micro-LED passing through the metal grating 11 will be polarized.

[0069] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A linearly polarized Micro-LED with a high extinction ratio, comprising an unetched area (1) and a mesa (2), characterized in that: A silicon dioxide passivation layer (3) is deposited on the top of the unetched area (1), the outer side wall of the table (2) and the top of the table (2), and a clearance step is opened on the silicon dioxide passivation layer (3) at the periphery of the top of the table (2).

2. The linearly polarized Micro-LED with high extinction ratio according to claim 1, characterized in that: The unetched region (1) comprises a Sapphire layer (91) and an unetched N-GaN layer (92) stacked in sequence from bottom to top; The mesa (2) comprises an etched N-GaN layer (92), an MQW layer (93), a P-GaN layer (94) and an ITO layer (95).

3. The linearly polarized Micro-LED with high extinction ratio according to claim 1, characterized in that: A first contact hole (4) is opened on the silicon dioxide passivation layer (3) at the top of the unetched area (1), and the first contact hole (4) penetrates the silicon dioxide passivation layer (3).

4. The linearly polarized Micro-LED with high extinction ratio according to claim 3, characterized in that: A positive electrode (5) is arranged in the first contact hole (4), the bottom of the positive electrode (5) is inserted into the first contact hole (4) and connected to the top of the unetched area (1), and the top extends out of the first contact hole (4); A negative electrode (6) corresponding to the positive electrode (5) is arranged on the top of the unetched area (1) away from the positive electrode (5).

5. The linearly polarized Micro-LED with high extinction ratio according to claim 4, characterized in that: A first side wall electrode (7) is arranged on the step to give way; Second side wall electrodes (8) are arranged on all outer side walls of the table (2), and the bottom of the second side wall electrode (8) is connected to a third side wall electrode (9) in a circumferential direction; The first side wall electrode (7), the second side wall electrode (8) and the third side wall electrode (9) are connected to each other and formed as one piece.

6. The linearly polarized Micro-LED with high extinction ratio according to claim 5, characterized in that: Metal leads (10) are provided between the positive electrode (5) and the first side wall electrode (7), the second side wall electrode (8) and the third side wall electrode (9).

7. The linearly polarized Micro-LED with high extinction ratio according to claim 5, characterized in that: A plurality of metal gratings (11) are arranged inside the first side wall electrode (7); both sides of the metal gratings (11) in the length direction are respectively connected to the inner side wall of the first side wall electrode (7); and the bottom of the metal gratings (11) is connected to the ITO layer (95) via a silicon dioxide passivation layer (3).

8. A method for preparing a linearly polarized Micro-LED with a high extinction ratio, characterized in that: The following steps are involved: S1. Using PECVD, a silicon dioxide passivation layer (3) is deposited on the top of the mesa (2), the outer wall of the mesa, and the top of the unetched area (1), so that the silicon dioxide completely covers the top of the mesa (2), the outer wall of the mesa (2), and the top of the unetched area (1), and a step is opened on the periphery of the top of the mesa (2).

9. The method for preparing a linearly polarized Micro-LED with a high extinction ratio according to claim 8, characterized in that: The unetched area (1) comprises a Sapphire layer (91) and an unetched N-GaN layer (92) stacked in sequence from bottom to top, and the mesa (2) comprises an etched N-GaN layer (92), an MQW layer (93), a P-GaN layer (94) and an ITO layer (95).

10. The method for preparing a linearly polarized Micro-LED with a high extinction ratio according to claim 9, characterized in that: The following steps are also included: S2, opening a first contact hole (4) on the silicon dioxide passivation layer (3) at the top of the unetched area (1), wherein the first contact hole (4) penetrates the silicon dioxide passivation layer (3); S3, then preparing metal electrodes, using magnetron sputtering to prepare a positive electrode (5), a negative electrode (6), a first sidewall electrode (7), a second sidewall electrode (8) and a third sidewall electrode (9), wherein the positive electrode (5) fills the first contact hole (4), the bottom of the positive electrode (5) is inserted into the first contact hole (4) and connected to the top of the unetched area (1), and the top extends out of the first contact hole (4); The negative electrode is arranged on a side of the top of the unetched area (1) away from the positive electrode (5); The first side wall electrode (7) fills the step, and second side wall electrodes (8) are arranged on all outer side walls of the table (2), the top of the second side wall electrode (8) is connected to the outer side edge of the first side wall electrode (7), and the bottom of the second side wall electrode (8) is connected to the third side wall electrode (9) in the circumferential direction, and the first side wall electrode (7), the second side wall electrode (8) and the third side wall electrode (9) are connected to each other and are integrally formed; S4, a metal lead (10) is provided between the positive electrode (5) and the first side wall electrode (7), the second side wall electrode (8) and the third side wall electrode (9), so as to connect the positive electrode (5), the first side wall electrode (7), the second side wall electrode (8) and the third side wall electrode (9); S5. A metal grating (11) is prepared by electron beam exposure and stripping processes, wherein the metal grating (11) is located inside the first side wall electrode (7), both sides of the metal grating (11) in the length direction are connected to the inner side walls of the first side wall electrode (7), and the bottom is connected to the ITO layer (95) via a silicon dioxide passivation layer (3).

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