Method of manufacturing nanorods and nanorods manufactured by the method

Abstract

Methods of fabricating nanorods are provided. The method of fabricating nanorods includes the steps of providing a growth substrate and a support substrate; epitaxially growing a nanomaterial layer on one side of the growth substrate; forming a sacrificial layer on one side of the support substrate; bonding the nanomaterial layer to the sacrificial layer; separating the growth substrate from the nanomaterial layer; planarizing the nanomaterial layer; etching the nanomaterial layer to form nanorods; and removing the sacrificial layer to isolate the nanorods.

Description

Technical Field

[0001] This invention relates to a method for manufacturing nanorods and nanorods manufactured by the method. Background Technology

[0002] Nanorods are nanoscale structures with diameters of tens to hundreds of nanometers and large aspect ratios. Devices utilizing nanorods are used in various fields, such as field-effect transistors (FETs), field emission devices (FEDs), light-emitting diodes (LEDs), solar cells, gas sensors, chemical sensors, and biosensors, depending on their applications.

[0003] The synthesis of these nanorods can be broadly classified into two types: the gas-phase method utilizing a vapor-liquid-solid (VLS) mechanism with a metal catalyst, and the liquid-phase method using a solution.

[0004] The gas-phase method utilizes high temperatures to transform materials into a gaseous state, and synthesizes nanorods of various shapes while simultaneously condensing the gaseous atoms. This method presents challenges in controlling the size and properties of the nanorods, as well as ensuring uniform alignment of the synthesized nanorods.

[0005] Furthermore, compared to nanorods synthesized by the gas phase method, nanorods manufactured by the liquid phase method have more defects and poorer crystal structure and optical properties. Also, like the gas phase method, they have problems with alignment and electrode formation processes.

[0006] Traditional methods for manufacturing nanorods include chemical polymerization, electrochemical polymerization, chemical vapor deposition (CVD), and carbothermal reduction. However, to obtain high-quality nanorods, these methods require high synthesis temperatures or are accompanied by numerous limitations such as reaction time, expensive vacuum equipment, and the use of harmful gases.

[0007] In addition, surface cracks can occur during the previous process of separating nanorods from the substrate, and they may be damaged or thermally damaged due to strong heat energy and heat transfer. Summary of the Invention

[0008] Technical issues

[0009] One embodiment of the present invention aims to provide a method for manufacturing nanorods that can minimize the scrap rate of nanorods and produce high-quality nanorods, as well as nanorods manufactured by the method.

[0010] Problem-solving methods

[0011] According to one aspect of the present invention, a method for manufacturing nanorods is provided, the method comprising the steps of: providing a growth substrate and a support substrate; epitaxially growing a nanomaterial layer on one side of the growth substrate; forming a sacrificial layer on one side of the support substrate; bonding the nanomaterial layer to the sacrificial layer; separating the growth substrate from the nanomaterial layer; planarizing the nanomaterial layer; etching the nanomaterial layer to form nanorods; and removing the sacrificial layer to separate the nanorods.

[0012] At this time, the growth substrate may include at least one of glass substrate, crystal substrate, sapphire substrate, plastic substrate and flexible polymer film that can be bent.

[0013] At this time, the growth substrate may include at least one of gallium nitride (GaN), silicon carbide (SiC), zinc oxide (ZnO), silicon (Si), gallium phosphide (GaP), spinel (MgAl2O4), magnesium oxide (MgO), lithium aluminate (LiAlO2), lithium gallium oxide (LiGaO2), gallium arsenide (GaAs), aluminum nitride (AlN), indium phosphide (InP), and copper (Cu).

[0014] At this time, the supporting substrate may include at least one of sapphire substrate, glass substrate, silicon carbide substrate, silicon substrate, and conductive substrate made of metallic material.

[0015] At this time, the nanomaterial layer may include at least one of zinc oxide (ZnO), gallium nitride (GaN), gallium arsenide (GaAs), silicon carbide (SiC), tin oxide (SnO2), gallium phosphide (GaP), indium phosphide (InP), zinc selenide (ZnSe), molybdenum disulfide (MoS2), and silicon (Si).

[0016] At this point, the nanomaterial layer can be epitaxially grown using metal-organic chemical vapor deposition (MOCVD).

[0017] At this time, the step of epitaxially growing a nanomaterial layer on one side of the growth substrate may include: adjusting the deposition thickness of the nanomaterial layer to adjust the length of the nanorod.

[0018] In this case, the sacrificial layer may be an insulating layer for bonding with the nanomaterial layer and a metal layer deposited on the upper surface of the insulating layer for bonding with the insulating layer.

[0019] At this time, the sacrificial layer can be gold (Au), titanium (Ti), iron (Fe), silicon oxide (SiO2) or silicon nitride (SiN).

[0020] At this time, in the step of separating the growth substrate from the nanomaterial layer, the growth substrate can be separated from the nanomaterial layer by laser lift-off (LLO), chemical lift-off (CLO), and electrochemical lift-off (ELO).

[0021] This may include a process of planarizing the separated nanomaterial layers using chemical mechanical polishing (CMP).

[0022] In the step of removing the sacrificial layer to separate the nanorods, when the sacrificial layer is silicon oxide, a buffered oxide etchant (BOE) can be used to remove the sacrificial layer.

[0023] In the step of removing the sacrificial layer to separate the nanorods, if the sacrificial layer is a metal layer, it can be removed using a metal etchant.

[0024] According to another aspect of the present invention, nanorods manufactured by the aforementioned method for manufacturing nanorods are provided.

[0025] Invention Effects

[0026] According to an embodiment of the present invention, the method for manufacturing nanorods and the nanorods manufactured by the method are easily separated during the nanorod separation process on the support substrate due to the inclusion of a sacrificial layer, thereby minimizing the scrap rate of nanorods and producing high-quality nanorods. Attached Figure Description

[0027] Figure 1 This is a sequence diagram illustrating a method for manufacturing nanorods according to an embodiment of the present invention.

[0028] Figure 2 (a) to Figure 2 (g) is a cross-sectional view showing the manufacturing process of nanorods manufactured by a method for manufacturing nanorods according to an embodiment of the present invention. Detailed Implementation

[0029] In the following detailed description, embodiments of the present invention will be provided with reference to the accompanying drawings, so that those skilled in the art to which this invention pertains may readily implement it. The present invention can be implemented in various different forms, and the embodiments described herein are not limited thereto. For the sake of clarity, parts irrelevant to the description have been omitted from the drawings, and the same or similar reference numerals are used throughout the specification.

[0030] In the specification, terms such as "comprising" or "having" should be understood as indicating the presence of features, figures, steps, actions, constituent elements, components, or combinations thereof described in the specification, rather than precluding the presence or additional possibility of one or more other features, figures, steps, actions, constituent elements, components, or combinations thereof. Furthermore, when a layer, film, region, plate, or other part is referred to as being "on" other parts, it includes not only the case where it is "directly" "on" other parts, but also the case where another part exists between them. Conversely, when a layer, film, region, plate, or other part is referred to as being "below" other parts, it includes not only the case where it is "directly" "below" other parts, but also the case where another part exists between them.

[0031] In the following description, a method for manufacturing nanorods according to an embodiment of the present invention and nanorods obtained by the method will be described in more detail with reference to the accompanying drawings.

[0032] Figure 1 This is a sequence diagram illustrating a method for manufacturing nanorods according to an embodiment of the present invention. Figure 2 (a) to Figure 2 (g) is a cross-sectional view showing the manufacturing process of nanorods manufactured by a method for manufacturing nanorods according to an embodiment of the present invention.

[0033] Reference Figure 1 The method for manufacturing nanorods may include: providing a growth substrate and a support substrate (S10); epitaxially growing a nanomaterial layer on one side of the growth substrate (S20); forming a sacrificial layer on one side of the support substrate (S30); bonding the nanomaterial layer with the sacrificial layer (S40); separating the growth substrate from the nanomaterial layer (S50); planarizing the nanomaterial layer (S60); etching the nanomaterial layer to form nanorods (S70); and removing the sacrificial layer and separating the nanorods (S80).

[0034] Therefore, the method for manufacturing nanorods according to an embodiment of the present invention can minimize the scrap rate of nanorods caused by the process of separating nanorods 1 from the support substrate 13 and produce high-quality nanorods.

[0035] Reference Figure 1 and Figure 2 (a) In the step of providing a growth substrate and a support substrate (S10), a growth substrate 11 for growing the nanomaterial layer 15 and a support substrate 13 for supporting the formation of sacrificial layers 17, 19 are provided.

[0036] Additionally, refer to Figure 2 (a) The growth substrate 11 may be at least one of a glass substrate, a crystal substrate, a sapphire substrate, a plastic substrate, and a flexible polymer film that can be bent. In addition, the growth substrate 11 may include a light-transmitting substrate.

[0037] At this time, the growth substrate 11 may include at least one of gallium nitride (GaN), silicon carbide (SiC), zinc oxide (ZnO), silicon (Si), gallium phosphide (GaP), spinel (MgAl2O4), magnesium oxide (MgO), lithium aluminate (LiAlO2), lithium gallium oxide (LiGaO2), gallium arsenide (GaAs), aluminum nitride (AlN), indium phosphide (InP), and copper (Cu). However, the growth substrate 11 is not limited as long as the nanomaterial layer 15 can be epitaxially grown.

[0038] Additionally, refer to Figure 2 (a) The support substrate 13 can be any one of a sapphire substrate, a glass substrate, a silicon carbide substrate, a silicon substrate, and a conductive substrate made of a metallic material. Furthermore, the support substrate 13 can also be a circuit substrate such as a PCB or a ceramic substrate, including ceramics.

[0039] Reference Figure 1 and Figure 2 (b) In the step (S20) of epitaxially growing a nanomaterial layer on one side of the growth substrate, a nanomaterial layer 15, which is the material of the nanorod 1, can be epitaxially grown on one side of the growth substrate 11.

[0040] At this time, the step (S20) of epitaxially growing a nanomaterial layer on one side of the growth substrate may include: adjusting the deposition thickness of the nanomaterial layer 15 to adjust the length of the nanorod 1.

[0041] Furthermore, in the step (S20) of epitaxially growing a nanomaterial layer on one side of the growth substrate, the growth substrate 11 can be grown on one side (e.g., Figure 2 The nanomaterial layer 15 is epitaxially grown on the upper surface shown in (b).

[0042] At this point, epitaxial growth refers to the method of growing crystals of the same or different materials in a specific direction on a certain crystalline substrate, which can also be called epitaxy.

[0043] Furthermore, the method of growing crystals of the same material on a substrate is called homoepitaxy or simply EPI, while the method of growing crystals of different materials is called heteroepitaxy.

[0044] In addition, the nanomaterial layer 15, as the nanomaterial material constituting the nanorod 1, may include, but is not limited to, any one of zinc oxide (ZnO), gallium nitride (GaN), gallium arsenide (GaAs), silicon carbide (SiC), tin oxide (SnO2), gallium phosphide (GaP), zinc selenide (ZnSe), molybdenum disulfide (MoS2), and silicon (Si).

[0045] In one embodiment of the present invention, the nanomaterial layer 15 can be grown vertically and can be any type of nanomaterial capable of forming nanorods with a large aspect ratio.

[0046] Additionally, refer to Figure 1 The deposition method used in the step (S20) of epitaxially growing the nanomaterial layer may include at least one of atomic layer deposition (ALD), reactive sputtering, ion implantation, magnetron sputtering, laser ablation, ion beam deposition, chemical vapor deposition, and plasma enhanced CVD.

[0047] However, preferably, the epitaxial growth according to an embodiment of the present invention can be performed using metal-organic chemical vapor deposition (MOCVD). That is, a metal-organic chemical vapor deposition apparatus can be used to epitaxially grow the nanomaterial layer 15.

[0048] At this time, the organometallic compounds used in the metal-organic chemical vapor deposition apparatus can be compounds with alkyl groups such as trimethylgallium (Ga(CH3)3), trimethylaluminum (Al(CH3)3), and triethyl phosphate ((C2H5O)3PO), which have methyl or ethyl groups as raw materials.

[0049] Furthermore, the nanomaterial layer 15 is a layer used to form the nanorod 1 through subsequent processes. In one embodiment of the present invention, in the step (S21) of adjusting the deposition thickness of the nanomaterial layer to adjust the length of the nanorod, since the thickness of the nanomaterial layer 15 corresponds to the length of the nanorod 1 formed by the subsequent processes, the length of the nanorod 1 is adjusted by adjusting the deposition thickness of the nanomaterial layer 15.

[0050] In one embodiment of the present invention, although not shown, a buffer layer (not shown) required for epitaxial growth may be formed between the growth substrate 11 and the nanomaterial layer 15 as needed. In this case, the buffer layer may be formed to minimize the lattice mismatch between the growth substrate 11 and the nanomaterial layer 15.

[0051] Reference Figure 1 and Figure 2 (b) In the step (S30) of forming a sacrificial layer on one side of the support substrate, the sacrificial layer may be formed on one side of the support substrate 13 (e.g., as shown in the figure). Figure 2 A sacrificial layer is formed on the upper surface shown in (b).

[0052] In this embodiment of the invention, the sacrificial layer serves as the metal layer 19 and the insulating layer 17. It can be made of metal, oxide, or nitride, and can be gold (Au), titanium (Ti), or iron (Fe), as well as silicon oxide (SiO2) or silicon nitride (SiN), but is not limited thereto.

[0053] In addition, for the sacrificial layer, a thinner metal layer 19 can be deposited on the insulating layer 17 to bond the nanomaterial layer 15 to the insulating layer 17.

[0054] In addition, when a sacrificial layer is formed on the upper surface of the support substrate 13, although a bonding layer (not shown) can be provided on the upper surface of the support substrate 13 to bond the support substrate 13 to the sacrificial layer, the bonding layer can be omitted if the structure or material is formed to bond without the bonding layer.

[0055] Reference Figure 1 and Figure 2 (c) In the step of bonding the nanomaterial layer with the sacrificial layer (S40), the nanomaterial layer 15 is bonded to the insulating layer 17 by bonding the upper surface of the nanomaterial layer 15 with the upper surface of the metal layer 19.

[0056] When the nanomaterial layer 15 is subsequently etched to form the nanorod 1, the metal layer 19 and the insulating layer 17, which serve as sacrificial layers, can act as etch stop layers. This prevents the etchant from the nanomaterial layer 15 from penetrating into the support substrate 13.

[0057] Additionally, refer to Figure 1 and Figure 2 (d) In the step (S50) of separating the growth substrate from the nanomaterial layer, the growth substrate 11 is separated from the nanomaterial layer 15.

[0058] At this time, the method for separating the growth substrate 11 from the nanomaterial layer 15 can be laser lift-off (LLO), chemical lift-off (CLO), or electrochemical lift-off (ELO).

[0059] At this point, laser lift-off (LLO) is a technique that involves growing a nanomaterial layer 15 on a growth substrate 11 and bonding a sacrificial layer 17 to the nanomaterial layer 15, and then irradiating a laser beam to separate the nanomaterial layer 15 from the growth substrate 11.

[0060] At this point, the chemical lift-off (CLO) method is a technique in which a sacrificial layer is grown on the growth substrate 11, a nanomaterial layer 15 is grown, and a sacrificial layer is bonded to the nanomaterial layer 15, and then an etchant is used to separate the nanomaterial layer 15 from the growth substrate 11. In this method, the etchant selectively etches the sacrificial layer.

[0061] At this point, an electrochemical lift-off (ELO) method is used to grow a nanomaterial layer 15 on the growth substrate 11, and a porous nanomaterial layer 15 is formed by electrochemical etching using a metal anode. Then, the nanomaterial layer 15 is grown again, and after a sacrificial layer is bonded to the nanomaterial layer 15, the nanomaterial layer 15 is separated from the growth substrate 11.

[0062] At this point, in the step (S60) of planarizing the separated nanomaterial layer, the planarization process can be performed by chemical mechanical polishing (CMP).

[0063] Additionally, refer to Figure 1 and Figure 2 (e) In the step (S70) of etching the nanomaterial layer to form nanorods, nanorods 1 are formed by selectively etching the nanomaterial layer 15 with or without the injection of etching solution.

[0064] At this point, a mask material layer is formed that is selectively etched with the nanomaterial layer 15, and the mask material layer serves as an insulating layer, which may be silicon oxide (SiO2) or silicon nitride (SiN), but is not limited thereto.

[0065] At this point, the etching solution may include sulfuric acid, phosphoric acid, or potassium hydroxide and sodium hydroxide. Additionally, the nanomaterial layer 15 is dry-etched in a top-down manner to form vertically grown nanorods 1.

[0066] This top-down approach involves arranging micro-LEDs at sub-pixel positions on a large-area glass substrate in a one-to-one correspondence to realize a display. However, in this case, one end of the nanorod 1 is bonded to the sacrificial layer.

[0067] In this paper, the etching gas used in dry etching can be a chlorine (Cl2) or hydrocarbon (CH4) gas, but is not limited to these. In one embodiment of the invention, the sacrificial layer acts as an etching stop layer, meaning it will not be etched by the etching solution when the nanomaterial layer 15 is etched.

[0068] Furthermore, both dry and wet etching methods can be used in the etching process. Unlike wet etching, dry etching can perform unidirectional etching, while wet etching can achieve isotropic etching, thus enabling etching in all directions.

[0069] Reference Figure 1 and Figure 2 (f) In the step (S80) of removing the sacrificial layer to separate the nanorod, the nanorod 1 is easily separated from the support substrate 13 by removing the sacrificial layer that is bonded to one end of the nanorod 1.

[0070] Therefore, the method for manufacturing nanorods according to an embodiment of the present invention can minimize the scrap rate of nanorods and produce high-quality nanorods.

[0071] In this case, if the sacrificial layer is formed of silicon oxide as insulating layer 17, the sacrificial layer can be removed using buffered oxide etchant (BOE).

[0072] At this point, the hydrofluoric acid (HF) in the oxidative etching solution selectively reacts with silicon oxide (SiO2) or silicon nitride (SiN) as the insulating layer 17 to form silicon tetrafluoride (SiF4), thereby removing the sacrificial layer.

[0073] In this case, if the sacrificial layer is a metal layer 19, the sacrificial layer can be removed using a metal etchant. Alternatively, the sacrificial layer can be removed by immersing the substrate in a BOE (Bodied Epoxy Etching) solution.

[0074] According to an embodiment of the present invention, a method for manufacturing nanorods and nanorods manufactured by this method are readily separated in a nanorod separation process involving a sacrificial layer on a support substrate, thereby minimizing the scrap rate of nanorods and producing high-quality nanorods.

[0075] Although one embodiment of the present invention has been described above, the concept of the present invention is not limited to the embodiments set forth in this specification, and those skilled in the art who understand the concept of the present invention can easily propose other embodiments by adding, changing, deleting, or adding constituent elements within the same conceptual scope, and such embodiments should also fall within the conceptual scope of the present invention.

[0076] Industrial availability

[0077] One embodiment of the present invention aims to provide a method for manufacturing nanorods that can minimize the scrap rate of nanorods and produce high-quality nanorods, as well as nanorods manufactured by the method.

Claims

1. A method for manufacturing nanorods, the method comprising: Provide growth substrate and support substrate; A material layer is epitaxially grown on one side of the growth substrate; A sacrificial layer is formed on one side of the support substrate; The upper surface of the material layer is bonded to the upper surface of the sacrificial layer; Separate the growth substrate from the material layer; Nanorods are formed by vertically etching the material layer to the upper surface of the sacrificial layer; as well as The nanorods are separated by removing the sacrificial layer. The epitaxial growth of the material layer includes: A first material layer is formed on the growth substrate; The first material layer is etched using electrochemical etching to form a porous material layer; and A second material layer is formed on the porous material layer. The sacrificial layer is bonded to the upper surface of the second material layer, and The separation of the growth substrate from the material layer includes removing the porous material layer of the growth substrate to separate the growth substrate from the second material layer.

2. The method for manufacturing nanorods as described in claim 1, wherein, The growth substrate includes at least one selected from gallium nitride, silicon carbide, zinc oxide, silicon, gallium phosphide, spinel, magnesium oxide, lithium aluminate, lithium gallium oxide, gallium arsenide, aluminum nitride, indium phosphide, and copper. The supporting substrate includes at least one of sapphire substrate, glass substrate, silicon carbide substrate, silicon substrate, and conductive substrate made of metallic material.

3. The method for manufacturing nanorods as described in claim 1, wherein, The material layer includes at least one of zinc oxide, gallium nitride, gallium arsenide, silicon carbide, tin oxide, gallium phosphide, indium phosphide, zinc selenide, molybdenum disulfide, and silicon.

4. The method for manufacturing nanorods as described in claim 1, wherein, The material layer was epitaxially grown using a metal-organic chemical vapor deposition process, and The precursor for the metal-organic chemical vapor deposition process includes at least one of trimethylgallium, trimethylaluminum, and triethyl phosphate.

5. The method for manufacturing nanorods as described in claim 1, further comprising: After separating the growth substrate from the material layer, the material layer is planarized; The planarization of the material layer is performed by mechanochemical polishing.

6. The method for manufacturing nanorods as described in claim 1, wherein, The process of forming nanorods by etching the material layer includes forming a mask material layer disposed on the material layer and comprising a plurality of patterns spaced apart from each other; as well as Etch the exposed portions between the plurality of patterns in the material layer.

7. The method for manufacturing nanorods as described in claim 6, wherein, The mask material layer includes silicon oxide or silicon nitride.

8. The method for manufacturing nanorods as described in claim 6, wherein, The etching of the exposed portions between the plurality of patterns in the material layer is performed by dry etching or wet etching. The etchant used in the dry etching includes chlorine gas and hydrocarbon gases.

9. The method for manufacturing nanorods as described in claim 1, wherein, The sacrificial layer includes an insulating layer disposed on the support substrate and a metal layer disposed on the insulating layer, and When the upper surface of the material layer is bonded to the upper surface of the sacrificial layer, the upper surface of the material layer is bonded to the upper surface of the metal layer of the sacrificial layer.

10. The method for manufacturing nanorods as described in claim 9, wherein, The metal layer is composed of gold, titanium, or iron, and The insulating layer is composed of silicon oxide or silicon nitride.

11. The method for manufacturing nanorods as described in claim 10, wherein, When the insulating layer of the sacrificial layer is composed of silicon oxide, the separation of the nanorods by removing the sacrificial layer includes removing the sacrificial layer using a buffered oxide etchant.

12. The method for manufacturing nanorods as described in claim 9, wherein, Forming the sacrificial layer on one side of the support substrate includes forming a bonding layer on the upper surface of the support substrate; and The sacrificial layer is formed on the bonding layer to contact the lower surface of the insulating layer and the upper surface of the bonding layer.

13. The method for manufacturing nanorods as described in claim 1, wherein, Epitaxial growth of a material layer on one side of the growth substrate includes forming a buffer layer on the upper surface of the growth substrate; and epitaxial growth of the material layer on the buffer layer.

14. The method for manufacturing nanorods as described in claim 1, wherein, The epitaxial growth of the material layer on one side of the growth substrate includes adjusting the deposition thickness of the material layer to control the length of the nanorods.

15. The method for manufacturing nanorods as described in claim 1, wherein, The step of separating the growth substrate from the material layer includes irradiating the space between the material layer and the growth substrate with a laser beam to separate the growth substrate from the material layer.

16. The method for manufacturing nanorods as described in claim 1, wherein, The sacrificial layer is composed of a metal layer, and the separation of the nanorods by removing the sacrificial layer includes removing the sacrificial layer using a metal etchant.

Images