Micro LED, Micro LED Panel and Micro LED Chip

Abstract

The micro LED includes a first type of semiconductor layer, a light emitting layer formed on the first type of semiconductor layer, and a second type of semiconductor layer formed on the light emitting layer, where at least a portion of the sidewalls of the second type of semiconductor layer are misaligned with the sidewalls of the first type of semiconductor layer.

Description

[Technical field]

[0001] The present disclosure relates generally to light emitting diodes, and more particularly to micro light emitting diodes (LEDs), micro LED panels, and micro LED chips. [Background technology]

[0002] Micropixel light-emitting diodes, also known as micro light-emitting diodes, micro-LEDs or μ-LEDs, are gaining importance due to their use in a variety of applications including self-emissive microdisplays, visible light communications, and optogenetics. For display applications, micro-LED-based arrays with pixel dimensions as small as 12 μm have been demonstrated. Micro-LEDs exhibit higher power performance than conventional LEDs due to better strain relief, improved light extraction efficiency, and uniform current spreading. Micro-LEDs also exhibit improved thermal effects and can operate at higher current densities compared to conventional LEDs.

[0003] However, smaller LED pixels with higher current densities experience a red shift at high current densities, lower maximum efficiency, and non-uniform emission, which have been attributed to damage in the manufacturing process resulting in degradation of electrical injection. Furthermore, the peak external quantum efficiency (EQE) and internal quantum efficiency (IQE) decrease significantly with decreasing chip size. The decreased EQE is explained in terms of non-radiative recombination caused by etching damage, while the decreased IQE is attributed to insufficient current injection and electron leakage current in microLEDs.

[0004] The above description is only provided to facilitate understanding of the technical solutions of the present disclosure, and does not constitute an admission that the above is prior art. Summary of the Invention

[0005] An embodiment of the present disclosure provides a micro-LED, which includes a first type of semiconductor layer, a light emitting layer formed on the first type of semiconductor layer, and a second type of semiconductor layer formed on the light emitting layer, where at least a portion of a sidewall of the second type of semiconductor layer is not aligned with a sidewall of the first type of semiconductor layer.

[0006] An embodiment of the present disclosure also provides a micro LED panel, comprising two or more of the above-mentioned micro LEDs, wherein the light emitting layer is continuous between adjacent micro LEDs.

[0007]

[0013] An embodiment of the present disclosure also provides a micro LED chip.

[0014] A micro LED panel includes one or more of the micro LED panels described above.

[0008] Further advantages and features of the present disclosure will be better understood from the following detailed description and the accompanying drawings.

[0009] Embodiments and various aspects of the present disclosure are set forth in the following detailed description and in the accompanying drawings, in which various features are not drawn to scale. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a structural diagram of a first exemplary micro LED according to some embodiments of the present disclosure. [Diagram 2] FIG. 2 is a structural diagram of a second exemplary micro LED according to some embodiments of the present disclosure. [Diagram 3] FIG. 13 is a structural diagram of a third exemplary micro LED according to some embodiments of the present disclosure. [Figure 4] FIG. 1 is a structural diagram of an exemplary micro LED panel according to some embodiments of the present disclosure. [Diagram 5] FIG. 2 is a structural diagram illustrating adjacent micro LEDs according to some embodiments of the present disclosure. [Figure 6]FIG. 13 is a structural diagram illustrating another adjacent micro LED according to some embodiments of the present disclosure. [Figure 7] FIG. 1 is a structural diagram of an exemplary micro LED chip according to some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. The following description refers to the accompanying drawings, in which the same numbers represent the same or similar elements in different drawings, unless otherwise indicated. The embodiments described in the following description of exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of apparatus and methods consistent with aspects related to the present invention as set forth in the appended claims. Certain aspects of the present disclosure are described in more detail below. The terms and definitions provided herein control in the event of a conflict with terms and / or definitions incorporated by reference.

[0012] To overcome the above drawbacks, the present disclosure provides micro-LEDs configured to minimize surface carrier losses and optimize the sidewall area of ​​the quantum wells.

[0013] More specifically, the micro-LED embodiments disclosed herein reduce the dimensions of the second type semiconductor layer to prevent carrier diffusion between adjacent LEDs, and form a continuous quantum well effect on the sidewalls of the quantum well to minimize non-radiative recombination of surface carriers. Also, isolation structures formed between adjacent LEDs can suppress optical and electrical crosstalk. Also, the maximum width of the first electrode is smaller than the minimum width of the first type semiconductor layer to reduce the carrier diffusion area.

[0014] FIG. 1 is a structural diagram showing a side cross-sectional view of an exemplary micro-LED 100 according to some embodiments of the present disclosure. Referring to FIG. 1, the micro-LED 100 includes a first type of semiconductor layer 110, a light emitting layer 120, and a second type of semiconductor layer 130. The light emitting layer 120 is formed on the first type of semiconductor layer 110, and the second type of semiconductor layer 130 is formed on the light emitting layer 120. In this embodiment, the bottom width of the second type of semiconductor layer 130 is smaller than the top width of the first type of semiconductor layer 110. Therefore, at least a portion of the sidewalls of the second type of semiconductor layer 130 are not aligned with the sidewalls of the first type of semiconductor layer 110. In some embodiments, the maximum width of the second type of semiconductor layer 130 is smaller than the minimum width of the first type of semiconductor layer 110. In some embodiments, the width of the second type of semiconductor layer 130 and the width of the first type of semiconductor layer 110 gradually increase from the top to the bottom, as shown in FIG. 1. Thus, the bottom width of the second type semiconductor layer 130 is smaller than the top width of the first type semiconductor layer 110. In this embodiment, the sidewalls of the first type semiconductor layer 110 are not aligned with the sidewalls of the second type semiconductor layer 130, but the sidewalls of the second type semiconductor layer 130 coincide in a straight line. The sidewalls of the light emitting layer 120 extend horizontally beyond the sidewalls of the second type semiconductor layer 130. In some embodiments, the sidewalls of the first type semiconductor layer 110 are aligned with the sidewalls of the light emitting layer 120.

[0015] In some embodiments, the micro LED 100 further includes a first electrode 140 and a second electrode 150. The first electrode 140 is formed on the bottom of the first type semiconductor layer 110, and the second electrode 150 is formed on the top of the second type semiconductor layer 130. The minimum width of the first electrode 140 is the same as the maximum width of the light emitting layer 120, but is larger than the maximum width of the second electrode 150. This structure can ensure the largest light emitting area and improve the light emitting efficiency.

[0016] In some embodiments, the first type semiconductor layer 110, the second type semiconductor layer 130, the light emitting layer 120, the first electrode 140 and the second electrode 150 can have different shapes, such as a truncated cone, a cylinder or a cube. Thus, in some embodiments, from a side cross-sectional view of the structure of the micro-LED 100, each of the first type semiconductor layer 110, the second type semiconductor layer 130, the light emitting layer 120, the first electrode 140 and the second electrode 150 can have the same width from top to bottom.

[0017] In some embodiments, the widths of the first type semiconductor layer 110 and the second type semiconductor layer 130 gradually decrease from top to bottom, and the sidewalls of the first type semiconductor layer 110 are not aligned with the sidewalls of the second type semiconductor layer 130.

[0018] 2 is a structural diagram showing a side cross-sectional view of an exemplary micro LED 200 according to some embodiments of the present disclosure. Referring to FIG. 2, the micro LED 200 includes a second type semiconductor layer 230, and the sidewalls of the second type semiconductor layer 230 are not aligned. The sidewalls of the second type semiconductor layer 230 include one or more staircase structures 231 and 232. The sidewalls of the second type semiconductor layer 230 do not coincide with a straight line, i.e., the sidewalls of the staircase structure 231 and the sidewalls of the staircase structure 232 are not aligned. The bottom width of the second type semiconductor layer 230 (e.g., the bottom width of the staircase structure 231) is smaller than the top width of the first type semiconductor layer 210. The bottom width of the staircase structure 232 is smaller than the top width of the staircase structure 231. The maximum width of the second electrode 250 formed on the top of the staircase structure 232 is smaller than the minimum width of the second type semiconductor layer 230 (e.g., the top width of the staircase structure 232), and the maximum width of the first electrode 240 formed on the bottom of the first type semiconductor layer 210 is smaller than the minimum width of the first type semiconductor layer 210. In some embodiments, the thickness of the top staircase structure 232 of the second type semiconductor layer 230 is thicker than the thickness of the bottom staircase structure 231 of the second type semiconductor layer 230. In some embodiments, the maximum width of the first electrode 240 is equal to or smaller than the minimum width of the second electrode 250.

[0019] FIG. 3 is a structural diagram showing a side cross-sectional view of an exemplary micro LED 300 according to some embodiments of the present disclosure. Referring to FIG. 3, the micro LED 300 includes a second type semiconductor layer 330. The second type semiconductor layer 330 includes one or more staircase structures 331 and 332. The sidewalls of the second type semiconductor layer 330 do not coincide in a straight line, i.e., the sidewalls of the staircase structure 331 and the sidewalls of the staircase structure 332 are not aligned. The bottom sidewalls of the second type semiconductor layer 330 (e.g., the sidewalls of the staircase structure 331) are aligned with the sidewalls of the first type semiconductor layer 310. As shown in FIG. 3, the sidewalls of the bottom staircase structure 331 are further aligned with the sidewalls of the light emitting layer 320 between the first type semiconductor layer 310 and the second type semiconductor layer 330. The maximum width of the first electrode 340 formed on the bottom of the first type semiconductor layer 310 is less than or equal to the minimum width of the second electrode 350 formed on the top of the second type semiconductor layer 330 .

[0020] When the micro LED chip includes one or more of the above-mentioned micro LEDs, the light emitting layer and the first type of semiconductor layer are continuously formed over the micro LED chip. The minimum width of the second type of semiconductor layer is less than the minimum width of the first type of semiconductor layer and less than the minimum width of the first electrode for each micro LED. Also, isolation structures are formed between adjacent micro LEDs to prevent crosstalk between adjacent LEDs.

[0021] FIG. 4 is a structural diagram showing a plan view of an exemplary micro LED panel 400 according to some embodiments of the present disclosure. As shown in FIG. 4, the micro LED panel 400 includes two or more micro LEDs 410. The one or more micro LEDs 410 are arranged in an array on the micro LED panel 400. FIG. 5 is a structural diagram showing a side cross-sectional view of a micro LED as exemplary adjacent micro LEDs 500a and 500b included in the micro LED panel 400 according to some embodiments of the present disclosure. The micro LEDs 500a and 500b may have the same structure as the micro LED 100 as shown in FIG. 1. Referring to FIG. 4 and FIG. 5, the light emitting layer 520 is continuous between the adjacent micro LEDs 500a and 500b. The first type semiconductor layer 510 is also continuous between the adjacent micro LEDs 500a and 500b. The light emitting layer 520 and the first type semiconductor layer 510 are continuously formed throughout the micro LED panel. In some embodiments, the maximum width of the second type semiconductor layer 530 of each micro LED is smaller than the minimum width of the first electrode 540 of each micro LED. Each first electrode 540 is formed on the bottom of the first type semiconductor layer and is approximately aligned with the corresponding second type semiconductor layer 530. In addition, an isolation structure 560 is formed between adjacent micro LEDs 500a and 500b to prevent crosstalk between adjacent LEDs. As shown in FIG. 5, the isolation structure 560 is provided on the light emitting layer 520, and the top surface of the isolation structure 560 is at a height equal to or greater than the top surfaces of the micro LEDs 500a and 500b, for example, the top surfaces of the second electrodes 550 of each micro LED. Each second electrode 550 is formed on the top of the corresponding second type semiconductor layer 530.

[0022] FIG. 6 is a structural diagram showing a side cross-sectional view of a micro-LED as exemplary adjacent micro-LEDs 600a and 600b included in a micro-LED panel 400 according to some embodiments of the present disclosure. The micro-LEDs 600a and 600b may have the same structure as the micro-LED 200, as shown in FIG. 2. Referring to FIG. 4 and FIG. 6, the light-emitting layer 620 is continuous between adjacent micro-LEDs 600a and 600b. The first type semiconductor layer 610 is also continuous between adjacent micro-LEDs 600a and 600b. The light-emitting layer 620 and the first type semiconductor layer 610 are continuously formed throughout the micro-LED panel 400. The second type semiconductor layer 630 includes one or more staircase structures 631 and 632. The sidewalls of the staircase structure 631 and the sidewalls of the staircase structure 632 are not aligned. Each first electrode 640 is formed on the bottom of the first type semiconductor layer 610 and is approximately aligned with the corresponding second type semiconductor layer 630. Each second electrode 650 is formed on top of a corresponding second type semiconductor layer 630. In some embodiments, the maximum width of the first electrode 640 is less than or equal to the maximum width of the second electrode 650. Furthermore, an isolation structure 660 is formed between adjacent micro LEDs 600a and 600b to prevent crosstalk between adjacent micro LEDs.

[0023] 7 is a structural diagram illustrating a top view of an exemplary micro LED chip 700 according to some embodiments of the present disclosure. As shown in Fig. 7, the micro LED chip 700 includes one or more micro LED display panels 710, each having the structure of a micro LED panel described above with reference to Figs. 4-6.

[0024] It should be noted that the number of micro LEDs 410 in the micro LED panel 400 of Figure 4 and the number of micro LED panels 710 shown in Figure 7 are for illustrative purposes only. The number of micro LEDs in a micro LED panel and the number of micro LED panels in a micro LED chip may vary in practice.

[0025] In some embodiments, the light emitting layer is formed by a quantum well layer. The thickness of the quantum well layer (i.e., the light emitting layer) is less than the thickness of the first type of semiconductor layer. The thickness of the first electrode is greater than the thickness of the quantum well layer of the light emitting layer, and the thickness of the second electrode is greater than the thickness of the quantum well layer of the light emitting layer. The thickness of the second type of semiconductor layer is greater than twice the thickness of the first type of semiconductor layer.

[0026] The micro LED chip provided in the present disclosure can prevent the diffusion of carriers between adjacent micro LEDs and form a continuous quantum well effect on the sidewall of the quantum well, thereby minimizing the non-radiative recombination of surface carriers. Also, the isolation structure formed between adjacent LEDs can suppress optical and electrical crosstalk. In addition, the minimum width of the first electrode is smaller than the minimum width of the first type semiconductor layer, thereby reducing the carrier diffusion area.

[0027] It should be noted that relational terms such as "first" and "second" are used herein only to distinguish one entity or operation from another and do not require or imply an actual relationship or order between those entities or operations. Additionally, the words "comprising," "having," "containing," and "including," as well as other similar forms, are intended to be equivalent in meaning and open-ended in that the item or items following any one of these words are not intended to be an exhaustive enumeration of such item or items, nor are they intended to be limited to only the item or items listed.

[0028] As used herein, unless otherwise stated, the term "or" encompasses all possible combinations unless impracticable. For example, if it is stated that a database can include A or B, the database can include A, or B, or A and B, unless otherwise stated or impracticable. As a second example, if it is stated that a database can include A, B, or C, the database can include A, or B, or C, or A and B, or A and C, or A and B and C, unless otherwise stated or impracticable.

[0029] In the foregoing specification, the embodiments have been described with reference to numerous specific details that may vary from implementation to implementation. Certain adaptations and modifications of the described embodiments may be made. Other embodiments may be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. It is also intended that the sequence of steps depicted in the figures is for illustrative purposes only, and is not intended to be limited to the particular sequence of steps. Thus, one skilled in the art can appreciate that these steps may be performed in different orders while implementing the same method.

[0030] In the drawings and specification, illustrative embodiments have been disclosed. However, many variations and modifications to these embodiments are possible. Thus, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A micro LED, a first type semiconductor layer; a light emitting layer formed on the first type semiconductor layer; a second type of semiconductor layer formed on the light emitting layer; Including, At least a portion of the sidewalls of the second type semiconductor layer are not aligned with the sidewalls of the first type semiconductor layer. Micro LED.

2. 10. The micro LED of claim 1 , wherein a maximum width of the second type semiconductor layer is less than a minimum width of the first type semiconductor layer.

3. 3. The micro LED of claim 2, wherein the sidewalls of the second type semiconductor layer coincide with a straight line.

4. 3. The micro LED of claim 2, wherein the sidewalls of the second type semiconductor layer do not coincide with a straight line.

5. 5. The micro LED of claim 4, wherein the sidewalls of the second type semiconductor layer have one or more steps.

6. The microLED according to any one of claims 1 to 5, wherein the sidewalls of the first type semiconductor layer are aligned with sidewalls of the light emitting layer.

7. a first electrode formed on the bottom of the first type semiconductor layer; a second electrode formed on top of the second type semiconductor layer; The microLED according to any one of claims 1 to 6, further comprising:

8. 8. The micro LED of claim 7, wherein a maximum width of the first electrode is less than a minimum width of the first type semiconductor layer.

9. 9. The micro LED of claim 8, wherein the maximum width of the first electrode is less than or equal to a minimum width of the second electrode.

10. 10. The micro-LED according to any one of claims 7 to 9, wherein a maximum width of the second electrode is smaller than a bottom width of the second type semiconductor.

11. 11. A micro LED panel comprising two or more micro LEDs according to any one of claims 1 to 10, wherein the light emitting layer is continuous between adjacent micro LEDs.

12. 12. The micro LED panel of claim 11, wherein the light emitting layer is formed by a quantum well layer.

13. 13. The micro LED panel of claim 11 or 12, further comprising isolation structures between adjacent micro LEDs.

14. 14. The micro LED panel according to any one of claims 11 to 13, wherein the first type semiconductor layer is continuous between adjacent micro LEDs.

15. 14. The micro LED panel according to any one of claims 11 to 13, wherein the first type semiconductor layer is not continuous between adjacent micro LEDs.

16. 16. A micro LED panel comprising one or more micro LED chips according to any one of claims 10 to 15.

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