TWI860669B - Patterning method of micro-led and manufacturing method of micro-led - Google Patents

Abstract

The present invention relates to a patterning method of micro-LED and a manufacturing method of micro-LED using the same. Specifically, the method includes the following steps: preparing a LED semiconductor substrate; and patterning a multiple of pixel regions on the surface of the LED semiconductor substrate using a focused ion beam. The patterning step involves injecting ions into at least a portion of the surface other than the pixel regions using the focused ion beam to form ion-implanted regions with defects.

Description

Micro LED patterning method and micro LED preparation method using the same

The present invention relates to a micro LED patterning method and a micro LED manufacturing method using the same.

Recently, with the boom of small electronic devices such as augmented reality (AR), virtual reality (VR), and wearable devices, the development of ultra-small displays has attracted much attention. Micro LEDs based on GaN materials are used as the next generation display elements with high luminous efficiency, contrast, and response speed.

Micro LEDs are made using mesa etching technology, which physically etches the LED substrate to create the image elements. However, mesa etching may damage the active layer during the etching process, which causes the efficiency of the LED to decrease as the size of the LED decreases.

Selective Area Growth (SAG) is a micro-LED manufacturing technology with high quantum efficiency, but its disadvantage is that it is difficult to combine with thin-film transistors (TFT) to drive pixels due to the step difference.

(Technical Problem to be Solved) As an alternative to the terrace etching method and the SAG method, micro-LEDs can be prepared by ion implantation, but a mask must be formed on the substrate to prevent ions from being implanted into the light-emitting area. However, ions that touch the edge of the mask diffuse horizontally on the substrate, which can cause ions to accumulate in unexpected areas. Therefore, if the thickness of the mask, the type of ions, or the energy is not optimized, it may be difficult to prepare LEDs of the desired size.

To solve the above problems, the present invention provides a micro-LED patterning method, which adopts focused ion beam (e.g., Focused Ion Beam, FIB) patterning technology to minimize the surface damage of the light-emitting area (e.g., the light-emitting body structure), and the light-emitting area can maintain the substrate structure before patterning, thereby achieving high efficiency while maintaining a flat structure. No mask is required during patterning, thereby preparing ultra-small LEDs.

The present invention provides a method for preparing a micro-LED, which can be used to prepare an ultra-small LED by using the micro-LED patterning method of the present invention, and can provide high efficiency, stable luminescence and/or display performance.

The present invention provides a micro LED and a display element including the micro LED, which is manufactured by the micro LED manufacturing method of the present invention and has high efficiency, stable luminescence and/or display performance.

However, the problems to be solved by the present invention are not limited to the above problems, and other problems not mentioned will be clearly understood by ordinary technicians in this field through the following description.

[Technical means for solving the problem] An embodiment of the present invention relates to a micro-LED patterning method, comprising the following steps: preparing an LED semiconductor substrate; and patterning a plurality of image element regions on the surface of the LED semiconductor substrate using a focused ion beam, wherein the patterning step is to use a focused ion beam to inject ions into at least a portion of the surface other than the image element region to form an ion-implanted region with defects.

According to an embodiment of the present invention, in the patterning step, the image element region may be a defect-free region based on a focused ion beam.

According to an embodiment of the present invention, in the patterning step, the picture element region can maintain the surface characteristics of the LED semiconductor substrate before the patterning step.

According to an embodiment of the present invention, in the patterning step, the ion implantation region may be optically inert, electrically inert, or both.

According to one embodiment of the present invention, the shape of the primitive area can be at least one of a line, a circle, a point, an ellipse and a polygon.

According to an embodiment of the present invention, the pixel regions may be arranged regularly or randomly, and the pixel regions may be arranged at a pitch of 300 nm to 100 μm.

According to one embodiment of the present invention, the ion implantation region may be 1% to 70% of the total area of the surface.

According to one embodiment of the present invention, the size of the pixel region is 300 nm to 100 ㎛.

According to one embodiment of the present invention, the ions of the focused ion beam may include at least one selected from the group consisting of He ⁺ , Au ⁺ , Si ⁺ , Ne ⁺ , Ga ⁺ , Bi3 ⁺ , Cs ⁺ , Am ⁺ , Xe ⁺ , Ar ⁺ , Kr ⁺ , O ⁺ , _O2 ⁺ , N ⁺ , _N2 ⁺ , NO ⁺ , and _NO2 ⁺ .

According to an embodiment of the present invention, the focused ion beam may be operated at an acceleration voltage in the range of 0.1 kV to 500 kV, and the ion implantation dose of the focused ion beam may be 10 ¹¹ ˜10 ¹⁶ ions/cm ² .

According to an embodiment of the present invention, the LED semiconductor substrate may include: a substrate; a first semiconductor layer formed on the substrate; an active layer formed on the first semiconductor layer; and a second semiconductor layer formed on the active layer.

An embodiment of the present invention relates to a method for preparing a micro-LED, which may include the following steps: preparing an LED semiconductor substrate; patterning multiple picture element regions on the surface of the LED semiconductor substrate using a focused ion beam; and forming a metal electrode for driving the LED on at least a portion of the LED semiconductor substrate, and using a focused ion beam to inject ions into at least a portion of the surface except the picture element region to form an ion-implanted region with defects.

The patterning step in the micro LED preparation method according to an embodiment of the present invention may use the micro LED patterning method of the present invention.

The micro-LED preparation method according to an embodiment of the present invention may include at least one or all of the following.

According to an embodiment of the present invention, in the patterning step, the image element region may be a defect-free region based on a focused ion beam.

According to an embodiment of the present invention, in the patterning step, the picture element region can maintain the surface characteristics of the LED semiconductor substrate before the patterning step.

According to an embodiment of the present invention, in the patterning step, the ion implantation region may be optically inert, electrically inert, or both.

According to one embodiment of the present invention, the shape of the primitive area can be at least one of a line, a circle, a point, an ellipse and a polygon.

According to an embodiment of the present invention, the pixel regions may be arranged regularly or randomly, and the pixel regions are arranged at a pitch of 300 nm to 100 μm.

According to one embodiment of the present invention, the ion implantation region may be 1% to 70% of the total area of the surface.

According to one embodiment of the present invention, the size of the pixel region is 300 nm to 100 ㎛.

According to one embodiment of the present invention, the ions of the focused ion beam may include at least one selected from the group consisting of He ⁺ , Au ⁺ , Si ⁺ , Ne ⁺ , Ga ⁺ , Bi3 ⁺ , Cs ⁺ , Am ⁺ , Xe ⁺ , Ar ⁺ , Kr ⁺ , O ⁺ , _O2 ⁺ , N ⁺ , _N2 ⁺ , NO ⁺ , and _NO2 ⁺ .

According to an embodiment of the present invention, the focused ion beam may be operated at an acceleration voltage in the range of 0.1 kV to 500 kV, and the ion implantation dose of the focused ion beam may be 10 ¹¹ ˜10 ¹⁶ ions/cm ² .

According to an embodiment of the present invention, the LED semiconductor substrate may include: a substrate; a first semiconductor layer formed on the substrate; an active layer formed on the first semiconductor layer; and a second semiconductor layer formed on the active layer.

According to one embodiment of the present invention, the step of forming a metal electrode may be to form a metal electrode for driving an LED on the picture element region.

According to an embodiment of the present invention, the step of forming a metal electrode may include the following steps: forming a current spreading layer on the pixel region; and forming a metal thin film layer on the current spreading layer.

According to an embodiment of the present invention, the step of forming the metal electrode may include the following steps: etching the LED semiconductor substrate to expose the semiconductor layer; and forming the metal electrode on the semiconductor layer.

According to one embodiment of the present invention, the step of forming a metal electrode is to form a metal electrode on the surface of the LED semiconductor substrate opposite to the surface on which the picture element region is formed. The step of forming a metal electrode may include the following steps: separating a semiconductor layer from a substrate in the LED semiconductor substrate; exposing the semiconductor layer; and forming a metal electrode on the exposed semiconductor layer.

According to an embodiment of the present invention, it may include: an LED semiconductor substrate; a plurality of picture element regions formed on the surface of the substrate; and an ion implantation region formed on at least a portion of the surface other than the picture element regions based on a focused ion beam, wherein the picture element regions may include: a current dispersion layer formed on the surface of the LED semiconductor substrate corresponding to the picture element regions; and a light-emitting body structure including a metal thin film layer formed on the current dispersion layer.

According to an embodiment of the present invention, the plurality of picture element regions may be driven in units of sub-picture elements having red, green and blue light emitting regions based on the light emitting body structure.

One embodiment of the present invention relates to a micro LED display including the micro LED of the present invention.

(Effect of the invention) The present invention uses a technology of injecting ions into an LED substrate using a focused ion beam. There is no need for a mask preparation process. By inputting the pattern into a commercially available program, ions can be injected into the desired area, that is, the desired pattern can be drawn without a mask. Since the present invention does not require a mask preparation process, the process steps can be greatly reduced, and there is no lateral diffusion of ions caused by the mask, so that smaller and higher performance micro-LEDs can be prepared. In addition, since the present invention uses a focused ion beam for patterning, it can maintain the same or almost the same flat plate structure as the substrate before patterning, control the micro-LED light-emitting area (for example, performance and physical properties), and have a variety of designs.

The following is a detailed description of the embodiments of the present invention with reference to the attached drawings. When describing the embodiments, if it is considered that a specific description of the related known functions or structures will unnecessarily confuse the gist of the present invention, the detailed description thereof will be omitted. In addition, the terms in this specification are used to accurately describe the embodiments, and may vary according to the intention of the user or operator or the conventions of the technical field to which the present invention belongs. Therefore, the definition of the terms should be based on the overall content of the specification.

Throughout the specification, when a certain component is described as being "on" another component, this includes not only a case where one component is in contact with another component, but also a case where another component exists between the two components.

Throughout the specification, when it is stated that a part "includes" a certain component, other components may also be included rather than excluding the possibility of the existence of other components.

The micro-LED patterning method and its application of the present invention are described in detail below with reference to the embodiments and drawings. However, the present invention is not limited to these embodiments and drawings.

The present invention relates to a patterning method for a micro light emitting diode (micro LED). According to an embodiment of the present invention, the micro LED patterning method is to inject ions by a focused ion beam, and patterning can be performed in a desired area to prepare a micro LED without a mask. When the focused ion beam is used to inject ions on an LED substrate, it is not necessary to go through a mask preparation process. Ions can be injected into the desired area by inputting the pattern into a commercially available program, and the desired pattern can be drawn without a mask. Since there is no need to prepare a mask, the process steps can be greatly reduced and the process efficiency can be improved. There is no lateral diffusion of ions generated by the mask, and a smaller size (for example, ultra-small) micro LED can be prepared. In addition, the micro-LED patterning method uses a focused ion beam to inject ions, which can reduce the size of the LED while maintaining quantum efficiency and a flat substrate structure (semiconductor substrate structure before patterning). It can overcome the limitations of existing high-bench etching and SAG methods, and can prevent ion injection in unexpected areas even without a mask.

According to an embodiment of the present invention, referring to FIG. 1 and FIG. 2 , the micro-LED patterning method includes: a step S100 of preparing an LED semiconductor substrate; and a step S200 of patterning a plurality of picture element regions on the surface of the LED semiconductor substrate using a focused ion beam.

According to one embodiment of the present invention, step S100 of preparing an LED semiconductor substrate is a step of preparing an LED semiconductor substrate including a single or multiple semiconductor material layers formed on a substrate. The semiconductor material layer can be grown on a lower substrate 100 and the substrate can be cut into a suitable size (for example, a size that can be inserted into a focused ion beam device).

As an example of the present invention, any lower substrate 100 and the semiconductor material layer suitable for micro LEDs can be used without limitation. For example, the LED semiconductor substrate can include a semiconductor material layer formed on the lower substrate 110.

As an example of the present invention, a suitable lower substrate 100 may be selected according to the application field of the micro LED, and non-limiting examples include at least one of wafer, sapphire (Al ₂ O ₃ ), Si, SiC, GaN, and AlN.

As an example of the present invention, the semiconductor material layer may include a first semiconductor layer 200 formed on a lower substrate 100; an active layer 300 formed on the first semiconductor layer 200; and a second semiconductor layer 400 formed on the active layer 300. If necessary, a buffer layer (e.g., a u-type semiconductor, an i-type semiconductor, etc.) may also be added.

As an example of the present invention, the first semiconductor layer 200 and the second semiconductor layer 400 can be selected from a p-type semiconductor substrate layer and an n-type semiconductor substrate layer, respectively. For example, the n-type semiconductor substrate layer 200, the active layer 300 and the p-type semiconductor substrate layer 400 can be included.

As an example of the present invention, an n-type semiconductor substrate layer may be formed on the lower substrate 100 and may include an n-type gallium nitride semiconductor. For example, the n-type gallium nitride semiconductor may include at least one of GaN, GaNP, GaNAs, GaNSb, AlGaN, InGaN, BAlGaN, GaAlNP, GaAlNAs, InAlGaN, GaAlNSb, GaInNP, GaInNAs, and GaInNSb. The n-type semiconductor substrate layer may also include an n-type impurity element, for example, the n-type impurity may be N, P, As, Ge, Si, Cu, Ag, Au, Sb, Bi, etc.

As an example of the present invention, the thickness of the n-type semiconductor substrate layer can be 1 ㎛ to 10 ㎛, preferably, 1 ㎛ to 3 ㎛; or 2 ㎛ to 4 ㎛. When the thickness of the n-type semiconductor substrate layer is less than 1 ㎛, the quality of the micro LED is not good enough; when the thickness exceeds 10 ㎛, the semiconductor substrate layer will crack or the resistance will increase.

As an example of the present invention, the active layer 300 may include at least one of GaN, GaNP, GaNAs, GaNSb, AlGaN, InGaN, BAlGaN, GaAlNP, GaAlNAs, InAlGaN, GaAlNSb, GaInNP, GaInNAs and GaInNSb, preferably InGaN.

As an example of the present invention, the active layer 300 may also include a quantum structure and/or a super lattice layer, and the luminescence wavelength (e.g., long-wavelength luminescence) may be induced by inserting a super lattice layer. For example, the quantum structure may include at least one selected from the group consisting of a quantum well, a multi-quantum well (MQW), a quantum island, a quantum dot, a quantum disk, and a quantum wire. For example, the thickness of the active layer 300 may be 1 nm to 10 ㎛. For example, the layer including the super lattice layer or the quantum structure may be formed to have a thickness of 2 nm to 100 nm; 1 nm to 10 nm, respectively. The superlattice layer may be formed as a single layer or multiple layers, and may include a single layer or multiple layers of quantum well layers.

As an example of the present invention, the p-type semiconductor layer is formed on the active layer 300, and the p-type semiconductor layer may include a p-type gallium nitride semiconductor. For example, the p-type gallium nitride semiconductor may include at least one selected from the group consisting of GaN, GaNP, GaNAs, GaNSb, AlGaN, InGaN, BAlGaN, GaAlNP, GaAlNAs, InAlGaN, GaAlNSb, GaInNP, GaInNAs, and GaInNSb, preferably, it may be a p-type GaN including an AlGaN electron blocking layer. In addition, it may also include a p-type impurity element, and the p-type impurity may be Mg, B, In, Ga, Al, Tl, etc.

As an example of the present invention, the thickness of the p-type semiconductor layer can be 100nm to 10μm; or 1μm to 10μm, preferably 1μm to 3μm; or 2μm to 4μm. When the thickness of the p-type semiconductor layer is less than 1μm, the quality of the micro LED is not good enough; when the thickness exceeds 10㎛, the semiconductor substrate layer will crack or the resistance will increase.

According to an embodiment of the present invention, the step S200 of patterning the plurality of image element regions on the surface of the LED semiconductor substrate using a focused ion beam is to draw the expected pattern and/or draw the pattern in the expected region without using a mask, and the image element region can be formed by patterning part or all of the surface (e.g., 400 in FIG. 1 and FIG. 2 ). That is, ions are implanted in at least a portion of the surface other than the image element region using a focused ion beam to form an ion implantation region with defects (e.g., the surface 400 in FIG. 1 and FIG. 2 ), so as to distinguish the image element region on the semiconductor substrate (e.g., 400 in FIG. 1 and FIG. 2 ) by patterning.

As an example of the present invention, the patterning step S200 can be performed by placing a commercially available focused ion beam device and patterning the expected ion dose at the expected position through a program. The size of the pattern varies according to the program specifications. For example, for a helium device, patterning below the submicron level can be achieved. For example, by using a focused ion beam to inject ions, the expected area of the LED semiconductor substrate can be not excited, thereby inhibiting luminescence and blocking the current. As shown in FIG. 3, a luminescent area where ions are not injected and an area where luminescence is not excited by the injected ions can be formed.

As an example of the present invention, as shown in FIG3 , the image element region in the patterning step S200 may be a region (400 in FIG3 ) that has not been implanted with ions by a focused ion beam, for example, a defect-free region based on the focused ion beam, and maintains the same characteristics as the substrate before the patterning step S200 (for example, 400 in FIG1 and FIG2 ). That is, the image element region in the patterning step S200 may maintain the surface characteristics of the LED semiconductor substrate before the patterning step, which is equivalent to a flat (plane) surface. On the contrary, in the patterning step S200, the ion implanted region based on the focused ion beam (for example, 500 in FIG1 , FIG2 , and FIG3 ) is optically inert, electrically inert, or both, which may improve the luminous efficiency and luminous characteristics of the patterned image element region. This method of preparing micro-LEDs does not require the formation of a mask, which is different from the existing LED preparation method using ion implantation. Therefore, the processes such as mask patterning, deposition, and lift-off can be omitted to significantly reduce the processes required for preparing LEDs. In addition, there will be no lateral spreading of ions reflected by the mask, which can achieve smaller LED pixels than the ion implantation method using a mask.

As an example of the present invention, a desired shape of a primitive region (e.g., an LED light-emitting body structure) can be formed by a patterning method using a focused ion beam, and the shape of the primitive region can be at least one of a line, a circle, a point, an ellipse, and a polygon, and the polygon can be a triangle (e.g., an equilateral triangle, an isosceles triangle, a right triangle), a quadrilateral (e.g., a square, a rectangle, a rhombus, a parallelogram, a trapezoid), a regular n-gon (e.g., a regular hexagon, a regular octagon), etc. As shown in FIG3 , a square primitive region can be formed, and a light-emitting region (e.g., an LED light-emitting body structure) and an effective primitive region composed of the light-emitting regions can be provided by an LED process.

As an example of the present invention, the size of the pixel region may be greater than 300 nm; greater than 1 ㎛; greater than 100 ㎛; 300 nm to 500 ㎛; 300 nm to 100 ㎛; 400 nm to 100 ㎛; 500 nm to 100 ㎛; 80 nm to 50 ㎛; 1 ㎛ to 100 ㎛; or 10 ㎛ to 50 ㎛, as shown in FIG3 , and the above size may be a diameter, a radius, a length, etc., and may be equivalent to the diameter a. By adjusting the size of the pixel region, an ultra-small LED may be realized as required.

As an example of the present invention, the pixel regions may be arranged regularly or randomly, and the pixel regions may be arranged at a spacing of 300 nm or more; 1 ㎛ or more; 100 ㎛ or more; 300 nm to 500 ㎛; 300 nm to 100 ㎛; 400 nm to 100 ㎛; 500 nm to 100 ㎛; 80 nm to 50 ㎛; 1 ㎛ to 100 ㎛; or 10 ㎛ to 50 ㎛, as shown in FIG3, which may be equivalent to the diameter b. By adjusting the spacing of the pixel regions, an ultra-small LED may be realized as required.

As an example of the present invention, as shown in FIG3 , the pixel regions may be arranged at a spacing c. The spacing may be greater than 300 nm; greater than 1 ㎛; greater than 100 ㎛; 300 nm to 500 ㎛; 300 nm to 100 ㎛; 400 nm to 100 ㎛; 500 nm to 100 ㎛; 80 nm to 50 ㎛; 1 ㎛ to 100 ㎛; or 10 ㎛ to 50 ㎛.

As an example of the present invention, the ion implantation region (e.g., 500 of FIG. 1 , FIG. 2 , and FIG. 3 ) can be adjusted within a range of more than 1%; 1% to 90%; 1% to 80%; 1% to 70%; 10% to 70%; 15% to 60%; 20% to 50%; 5% to 20%; or 20% to 30% of the total area of the patterned substrate surface for patterning. The ion implantation region can be controlled to provide a micro LED (e.g., an ultra-small LED) with high efficiency and high performance.

According to an embodiment of the present invention, the ions of the focused ion beam may include at least one selected from the group consisting of He ⁺ , Au ⁺ , Si ⁺ , Ne ⁺ , Ga ⁺ . Bi ³⁺ , Cs ⁺ , Am ⁺ , Xe ⁺ , Ar ⁺ , Kr ⁺ , O ⁺ , O ₂ ⁺ , N ⁺ , N ₂ ⁺ , NO ⁺ and NO ₂ ⁺ . For example, the focused ion beam may use a liquid metal ion source, a plasma ion source, a trimer, etc.

According to an embodiment of the present invention, the focused ion beam can be operated at an accelerating voltage of 0.1 kV to 500 kV; 0.5 kV to 500 kV; or 1 kV to 200 kV. The accelerating voltage can be used to provide micro-LEDs (e.g., ultra-small LEDs) with high efficiency and high performance.

According to an embodiment of the present invention, the ion injection amount (dose) of the focused ion beam can be 1E12~1E17 ions/cm^2; 1E14~1E17 ions/cm^2; 1E13~1E15 ions/cm^2; or 2E12 ion/cm^2, and the defects can be controlled based on the focused ion beam by the ion injection amount. For example, FIG4 shows the voltage-current measurement results of the LED semiconductor substrate based on the He ion injection amount by the He focused ion beam, from which it can be confirmed that the luminescence and current flow can be suppressed by not exciting the ion injection area.

The present invention relates to a method for preparing a micro-LED using the micro-LED patterning method of the present invention. Referring to FIG. 1 and FIG. 2 , the method for preparing a micro-LED does not use a mask, but uses a focused ion implantation technique to inject specific ions into an LED semiconductor substrate, thereby not exciting an active layer outside the pixel region and blocking the flow of current. The micro-LED thus formed is different from an LED prepared by mesa etching and SAG, and has no damaged area and can maintain the substrate structure, so that high efficiency and a flat structure can be achieved at the same time, providing a micro-LED with high efficiency and high performance (such as an ultra-small LED).

According to an embodiment of the present invention, referring to FIG. 1 and FIG. 2 , the method for preparing the micro-LED may include a step of preparing an LED semiconductor substrate (S100); a step of patterning a plurality of pixel regions on the surface of the LED semiconductor substrate using a focused ion beam (S200); and a step of forming a metal electrode for driving the LED on at least a portion of the LED semiconductor substrate (S400 to S600).

According to an embodiment of the present invention, the step S100 of preparing an LED semiconductor substrate; and the step S200 of patterning a plurality of image element regions on the surface of the LED semiconductor substrate using a focused ion beam are the same as the above-mentioned micro-LED patterning method. That is, at least a portion of the surface other than the image element region is implanted with ions using a focused ion beam to form an ion implantation region with defects, and the ion implantation region may include an optically inert, electrically inert, or both region, which can improve the luminous efficiency and luminous properties of the patterned image element region, thereby realizing an ultra-small LED. As shown in FIG. 5 , when preparing a micro-LED by focused ion beam patterning, the focused ion beam scans the pattern specified by the computer program, thereby implanting the desired ions into the desired region of the LED substrate. Since the ion-implanted region forms a point defect, it will not be excited optically and can be electrically insulated, so no current flows and no light is emitted. However, since the region without ion implantation maintains optical and electrical properties, it can operate as a micro-LED element.

According to an embodiment of the present invention, the step of forming a metal electrode (S400 to S600) is to realize the current supply and driving of the micro LED by depositing the metal electrode. For example, the metal electrode for driving the LED can be formed on the pixel region and/or the metal electrode can be formed on at least a portion of the LED semiconductor substrate. For example, it can include at least one of step S300, step S400, step S500, step S600, step S400' and step S500' in Figures 1 and 2.

As an example of the present invention, the metal electrode in the step of forming the metal electrode (S300 to S600) may include at least one of a p-type metal electrode, an n-type metal electrode, and a metal electrode.

As an example of the present invention, the p-type electrode layer may include a transparent semiconductor oxide, a metal, or both, for example, it may include at least one selected from the group consisting of Co, Ir, Ta, Cr, Mn, Mo, Tc, W, Re, Fe, Sc, Ti, Sn, Ge, Sb, Al, Pt, Ni, Au, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), poly (3,4-ethylenedioxythiophene) (poly3,4-ethylenedioxythiophene, PEDOT) and carbon nanotubes (CNT).

As an example of the present invention, the n-type electrode layer may include at least one selected from the group consisting of Co, Ir, Ta, Cr, Mn, Mo, Tc, W, Re, Fe, Sc, Ti, Sn, Ge, Sb, Al, Pt, Ni, Au, ITO and ZnO, and the n-type electrode layer may be composed of a single layer or a plurality of layers.

As an example of the present invention, the thickness of the n-type metal electrode layer and the p-type metal electrode layer can be 30 nm to 200 nm, preferably 150 nm to 180 nm.

According to an embodiment of the present invention, the step of forming the metal electrode (S300 to S600) may include the steps of forming a current spreading layer on the pixel region; and forming a metal thin film layer on the current spreading layer.

As an example of the present invention, the step of forming a current spreading layer on the pixel area is to achieve current injection by depositing a current spreading layer 410 (Current spreading layer) to electrically connect and drive the pixel area (for example, the LED pixel area where the focused ion beam is not injected). The current spreading layer 410 may include a transparent electrode, a metal electrode, or both. Furthermore, the transparent semiconductor oxide, metal or both may be included, for example, at least one selected from the group consisting of Co, Ir, Ta, Cr, Mn, Mo, Tc, W, Re, Fe, Sc, Ti, Sn, Ge, Sb, Al, Pt, Ni, Au, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), indium zinc tin oxide (IZTO), cadmium tin oxide (CTO), poly (3,4-ethylenedioxythiophene) (PEDOT) and carbon nanotubes (CNT), and may be a single layer or multiple layers, and may be an n-type and/or p-type electrode.

As an example of the present invention, the step of forming a metal electrode (S300 to S600) is to deposit a metal film layer 420 or form a metal pad on the current spreading layer 410, which may include the metal electrode described above. For example, it may include at least one of a p-type metal electrode, an n-type metal electrode, and a metal electrode.

In some examples, the step of forming a metal electrode (S300 to S600) may include a step of etching the LED semiconductor substrate to expose a semiconductor layer (S400); and a step of forming a metal electrode on the semiconductor layer (S500), wherein the etching uses a high-beam etching to expose the electrode attachment area, and a photolithography process, reactive ion etching, wet etching, etc. may be used. For example, the photolithography process may use photolithography, laser lithography, electron beam lithography, or nanolithography, etc. For example, an electrode 600 (e.g., an n-type electrode) may be attached after exposing an n-type semiconductor layer (e.g., nGaN) by high-beam etching.

In some examples, the step of forming a metal electrode (S400' to S500') is to form a metal electrode on the opposite side of the surface of the LED semiconductor substrate where the pixel region is formed. As shown in FIG2, the step of forming a metal electrode may include a step of separating a semiconductor layer from the LED semiconductor substrate and a substrate (S400'); a step of exposing the semiconductor layer; and a step of forming a metal electrode on the exposed semiconductor layer (S500'). For example, a lift-off process (e.g., a laser lift-off process) may be used to remove the lower substrate 100 to expose the semiconductor layer and attach an electrode 600' (e.g., an n-type electrode).

As an example of the present invention, the deposition method and growth method proposed in the present invention can adopt conventional process conditions without departing from the scope of the present invention, without special restrictions, and technical personnel in this field can easily understand based on the description of the present invention.

The present invention relates to a micro LED obtained by the preparation method of the present invention. According to an embodiment of the present invention, the micro LED may include an LED semiconductor substrate, a plurality of pixel regions formed on the surface of the substrate, and an ion implantation region formed by a focused ion beam on at least a portion of the surface other than the pixel regions. The pixel regions may include: a current spreading layer formed on the surface of the LED semiconductor substrate corresponding to the pixel regions; and a light emitting body structure including a metal thin film layer formed on the current spreading layer. The micro LED may include the structure mentioned in the preparation method.

According to an embodiment of the present invention, a micro LED display including micro LEDs can be provided. The micro LED display can include a plurality of picture element areas, as shown in FIG3, and is composed of effective picture elements, which can be driven in units of sub-picture elements having red, green, and blue light-emitting areas based on the light-emitting body structure. Thus, the size, arrangement, and light-emitting color of the sub-picture elements and/or picture elements can be accurately controlled, and color or full-color display can be achieved. For example, as shown in FIG5, the width a of the sub-picture element size of the red, green, and blue light-emitting areas corresponding to the light-emitting area can be 2 ㎛ or more, 5 ㎛ or more; 10 ㎛ or more; 20 ㎛ or more; or 20 ㎛ or less; 10 ㎛ or less; 5 ㎛ or less, or 2 ㎛ or less. For example, the shapes of the red, green, and blue light-emitting areas may respectively include at least one of a line, a circle, a dot, an ellipse, and a polygon.

The present invention may also include micro LEDs and known structures in the technical field to which the present invention belongs for driving the micro LED display, which will not be described in detail herein.

This invention is a quantum computing technology development project (R&D) funded by the Ministry of Science and ICT ([Project ID] 1711119729, [Project ID] 2020M3E4A1080112, [Department Name] Ministry of Science and ICT, [Project Management (Professional) Organization Name] Korea Research Foundation, [Research Project Name] Development of Deterministic Quantum Logic Gates Based on Quantum Dot Spin-Photon Interaction, [Project Execution Organization Name] Korea Advanced Institute of Science and Technology, [Research Period] 2020.06.01~2021.02.28).

This invention is a quantum cryptographic communication integration and transmission technology upgrade project (R&D) funded by the Ministry of Science and Technology ICT. ([Project unique number] 1711125894, [Project number] 2020-0-00841-002, [Project management (professional) organization name]) ICT Planning and Evaluation Agency, [Research project name] Quantum cryptographic communication integration and transmission technology upgrade (R&D), [Research topic name] Development of deterministic quantum optical elements combined with optical fiber/integrated optical circuits, [Project execution organization name] Korea Advanced Institute of Science and Technology, [Research period] 2021.01.01~2021.12.31).

This invention is a corporate R&D project funded by the Samsung Future Technology Foundation. ([Project ID] SSTF-BA1602-05, [Project ID] G01210402, [Department Name] Enterprise, [Project Management (Professional) Organization Name] Samsung Future Technology Foundation, [Research Project Name] Corporate R&D Project, [Research Project Name] (G01210402) Research on Room-Temperature Driven High-Bandwidth Migration of Quantum Dots for Optical Communication Wavelength Quantum Light Sources (2021_10th Round) (2021), [Project Execution Organization Name] Korea Advanced Institute of Science and Technology, [Research Period] 2021.07.01 ~ 2021.11.30).

Although the present disclosure includes specific examples, it will be apparent to those skilled in the art that various changes in form and detail may be made in these examples without departing from the spirit and scope of the claims and their equivalents. Appropriate results may be obtained if the described techniques are performed in a different order, and/or if the components in the described systems, architectures, devices, or circuits are combined or combined in a different manner, or replaced or substituted by other components or equivalents.

Therefore, other embodiments, other implementations, and equivalents of the claims are within the scope of the appended claims.

Lower substrate 100 First semiconductor layer 200 Active layer 300 Second semiconductor layer 400 Current spreading layer 410 Metal film layer 420 Ion implantation region 500 Electrodes 600, 600' Width a Diameter b Spacing c

FIG. 1 exemplarily shows a process of a micro-LED patterning method and a micro-LED preparation method using a focused ion beam patterning technique according to an embodiment of the present invention. FIG. 2 exemplarily shows a process of a micro-LED patterning method and a micro-LED preparation method using a focused ion implantation technique according to another embodiment of the present invention. FIG. 3 exemplarily shows an LED semiconductor substrate patterned by the focused ion beam patterning technique of the present invention and a micro-LED realized by an LED process according to an embodiment of the present invention. FIG. 4 is a graph of voltage-current measurement results of an LED substrate based on the He ion implantation amount by the focused ion implantation technique (e.g., He focused ion beam) of the present invention according to an embodiment of the present invention. FIG5 is a luminescence image of a micro-LED prepared by the focused ion beam patterning technology of the present invention according to an embodiment of the present invention, which shows the luminescence image of a micro-LED with a pixel size of (a) 20 μm, (b) 10 μm, (c) 5 μm, (d) 3 μm, and (e) 2 μm.

Claims (3)

A method for preparing a micro LED is characterized in that it includes the following steps: preparing an LED semiconductor substrate; patterning multiple pixel regions on the surface of the LED semiconductor substrate using a focused ion beam; and separating a semiconductor layer from the substrate on at least a portion of the LED semiconductor substrate, using etching to expose the semiconductor layer, forming a metal electrode for driving the LED on the semiconductor layer, and the metal electrode is formed on the opposite side of the surface of the LED semiconductor substrate where the pixel region is formed, and using a focused ion beam to inject ions into at least a portion of the surface other than the pixel region to form an ion injection region with defects. In the micro-LED preparation method as described in claim 1, the step of forming a metal electrode is to form a metal electrode for driving the LED on the pixel area. In the preparation method of the micro-LED as described in claim 1, the step of forming the metal electrode includes the following steps: forming a current spreading layer on the pixel area; and forming a metal thin film layer on the current spreading layer.

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