A method of graphene transfer

Abstract

The application relates to a graphene transfer method, which comprises the following steps: graphene growth, stress layer deposition, temporary bonding glue film forming, substrate attaching, peeling, van der waals bonding with a target substrate, debonding, cleaning and stress layer etching. The graphene obtained by the method is undoped, free of metal trace residues, free of damage and wrinkles, and atomically flat, and can be used for large-scale production and semiconductor-compatible graphene, thus having a good market application prospect.

Description

Technical Field

[0001] This invention belongs to the field of integrated circuit manufacturing, and specifically relates to a graphene transfer method. Background Technology

[0002] Graphene's excellent physical and chemical properties have sparked significant scientific and industrial interest, making it a promising candidate for applications in fields including electronics and optoelectronics. CVD growth of graphene provides the foundation for its large-area applications. To achieve wider adoption, graphene needs to be transferred to insulating, semiconductor, or flexible substrates. Currently, methods for transferring large-size graphene mainly include dielectric-assisted wet etching (PMMA-based) and PMMA-assisted electrochemical bubbling. These transfer processes inevitably introduce defects such as breakage, metal residue, wrinkles, and doping caused by water and oxygen adsorbed at the graphene-substrate interface. These defects are inherent to wet transfer and cannot be overcome. Furthermore, these transfer methods are not only inefficient but also struggle to produce high-quality graphene. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a graphene transfer method that can obtain graphene that is free of doping, metal residue, damage, wrinkles, and atomically flat. This method can be used for large-scale production of semiconductor-compatible graphene and has good market application prospects.

[0004] This invention provides a graphene transfer method, comprising the following steps:

[0005] Provide a substrate;

[0006] A graphene layer is grown on the upper surface of the substrate;

[0007] A stress layer is deposited on the upper surface of the graphene layer;

[0008] Spin-coat a temporary bonding adhesive onto the upper surface of the stress layer;

[0009] In a vacuum environment, a temporary rigid substrate is attached to the upper surface of the temporary bonding adhesive;

[0010] The transitional temporary rigid substrate is peeled off from the substrate by mechanical peeling, at which time the stacked structure formed by the graphene layer, stress layer and temporary bonding adhesive is peeled off from the substrate;

[0011] In a vacuum environment, the stacked structure is van der Waals bonded to the target substrate;

[0012] The transitional temporary rigid substrate is separated by debonding;

[0013] Clean and remove the temporary bonding adhesive;

[0014] The stress layer is etched to obtain the graphene structure on the target substrate.

[0015] The substrate includes at least one of copper, nickel, germanium, titanium, platinum, gold, iron, and silver.

[0016] The method for growing the graphene layer includes at least one of chemical vapor deposition and plasma-enhanced chemical vapor deposition.

[0017] The stress layer includes at least one of copper, nickel, germanium, titanium, and platinum layers, or the dielectric layer is at least one of ZrO2, HfO2, Y2O3, Al2O3, MoO3, and SiO2; the method for depositing the stress layer includes at least one of thermal evaporation, sputtering, physical vapor deposition, atomic layer deposition, molecular beam epitaxy, and chemical vapor deposition.

[0018] The chemical vapor deposition method includes metal-organic chemical vapor deposition and plasma-enhanced chemical vapor deposition; the physical vapor deposition method includes electron beam evaporation, thermal evaporation, and magnetron sputtering; the atomic layer deposition method includes conventional atomic layer deposition, plasma-enhanced atomic layer deposition, and spatial atomic layer deposition.

[0019] The temporary bonding adhesive includes at least one of the following: heat-sensitive adhesive, photosensitive adhesive, chemically sensitive adhesive, soluble adhesive, heat-slip adhesive, mechanically release adhesive, and laser adhesive.

[0020] The transitional temporary rigid substrate includes at least one of glass, sapphire, ceramic, metal, and hard polymer.

[0021] The target substrate is a rigid semiconductor substrate, which is at least one of silicon, silicon dioxide, germanium, silicon carbide, silicon nitride, III-V, II-V, sapphire, ITO, and SrTiO3, or a flexible substrate, which is at least one of polyimide, polyethylene naphthalate, polycarbonate, elastomeric polymer, and thermoplastic polymer.

[0022] The debonding methods include at least one of thermal debonding, laser debonding, mechanical peeling debonding, and chemical immersion debonding.

[0023] Using the graphene structure obtained on the target substrate as the target substrate, another layer of graphene is transferred through the same steps to obtain bilayer graphene on the target substrate; through multiple steps, multilayer graphene on the target substrate can be obtained.

[0024] Specifically: Using the graphene structure obtained on the target substrate as the target substrate, another sample is subjected to graphene growth, stress layer deposition, temporary bonding adhesive spin coating, rigid substrate attachment, and mechanical peeling to obtain a stacked structure consisting of another graphene layer, a stress layer, and temporary bonding adhesive. This stacked structure is then van der Waals bonded to the target substrate. Finally, by debonding, the temporary rigid substrate is separated, the temporary bonding adhesive is removed by cleaning, and the stress layer is etched to obtain the bilayer graphene on the target substrate.

[0025] The method is used for the transfer of graphene; or for the transfer of two-dimensional transition metal carbonitrides (including but not limited to Ti3C2, Ti2C, Nb2C, Ti3AlC2, etc.), two-dimensional metal borides (Fe2B2, Cr2B2), transition metal chalcogenides (TMDCs) (including but not limited to MoS2, MoSe2, WSe2, MoTe2, PtSe2, etc.), metal-organic frameworks (MOFs), perovskite (CsPbCl3, CsPbI3, FaPbI3) materials, and two-dimensional materials formed by the arrangement of one-dimensional materials (including but not limited to Ag nanowire thin films, carbon nanotube thin films, etc.).

[0026] The method, through repeated steps, can achieve the stacking of single or multiple two-dimensional materials.

[0027] Beneficial effects

[0028] This invention can obtain graphene that is free of dopants, metal residue, damage, wrinkles, and atomically flat, which can be used for large-scale production and is semiconductor compatible, and has good market application prospects. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process flow of the present invention.

[0030] Figure 2 This is a process flow diagram of the present invention.

[0031] Figure 3 Photograph of a sapphire wafer attached to spin-coated phenolic resin adhesive.

[0032] Figure 4 The left side shows a multilayer composite structure of sapphire / adhesion layer (phenolic resin) / NiAu / Gr, and the right side shows the germanium sheet after peeling.

[0033] Figure 5 Photograph of Gr / SiO2 / Si sample.

[0034] Figure 6 Raman characterization of the Gr / SiO2 / Si sample.

[0035] Figure 7 AFM test for Gr / SiO2 / Si samples. Detailed Implementation

[0036] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0037] Example 1

[0038] This embodiment provides a graphene transfer method, such as... Figure 1 As shown, it includes the following steps:

[0039] S1: Provide a substrate;

[0040] S2: Grow a graphene layer on the upper surface of the substrate;

[0041] S3: Deposit a stress layer on the upper surface of the graphene layer;

[0042] S4: Spin-coat temporary bonding adhesive onto the upper surface of the stress layer;

[0043] S5: In a vacuum environment, attach the temporary rigid substrate to the upper surface of the temporary bonding adhesive;

[0044] S6: The transitional temporary rigid substrate is peeled off from the substrate by mechanical peeling, at which time the stacked structure formed by the graphene layer, stress layer and temporary bonding adhesive is peeled off from the substrate;

[0045] S7: Under vacuum conditions, the stacked structure is van der Waals bonded to the target substrate;

[0046] S8: Separate the transitional temporary rigid substrate by debonding;

[0047] S9: Cleaning to remove the temporary bonding adhesive;

[0048] S10: Etch the stress layer to obtain the graphene structure on the target substrate.

[0049] S1: A substrate is provided; as an example, the substrate includes at least one of copper, nickel, germanium, titanium, platinum, gold, iron, silver, etc. The substrate provides good support for the subsequent fabrication of various layers of material.

[0050] S2: A graphene layer is grown on the upper surface of the substrate; as an example, the method for growing the graphene layer includes at least one of chemical vapor deposition, plasma-enhanced chemical vapor deposition, mechanical exfoliation, and dry transfer. In this embodiment, a germanium substrate is preferably used, and a monolayer of graphene is grown on the surface of the germanium substrate using chemical vapor deposition.

[0051] S3: Deposit a stress layer on the upper surface of the graphene layer; as an example, the stress layer includes a metal layer or a dielectric layer; the metal layer is at least one of a copper layer, a nickel layer, a germanium layer, a titanium layer, and a platinum layer, and the dielectric layer is at least one of ZrO2, HfO2, Y2O3, Al2O3, MoO3, SiO2, etc.; the method of depositing the stress layer includes at least one of thermal evaporation, sputtering, physical vapor deposition, atomic layer deposition, molecular beam epitaxy, and chemical vapor deposition.

[0052] The chemical vapor deposition method includes metal-organic chemical vapor deposition and plasma-enhanced chemical vapor deposition; the physical vapor deposition method includes electron beam evaporation, thermal evaporation, and magnetron sputtering; the atomic layer deposition method includes conventional atomic layer deposition, plasma-enhanced atomic layer deposition, and spatial atomic layer deposition.

[0053] S4: Spin-coat temporary bonding adhesive onto the upper surface of the stress layer; as an example, the temporary bonding adhesive includes at least one of the following: heat-sensitive, photosensitive, chemically sensitive, soluble adhesive, thermal slip adhesive, mechanically release adhesive, and laser adhesive.

[0054] S5: In a vacuum environment, a transitional temporary rigid substrate is attached to the upper surface of the temporary bonding adhesive; as an example, the transitional temporary rigid substrate includes at least one of glass, sapphire, ceramic, metal, and hard polymer.

[0055] S7: Under vacuum conditions, the stacked structure is van der Waals bonded to the target substrate; as an example, the target substrate is a rigid semiconductor substrate, which is at least one of silicon, silicon dioxide, germanium, silicon carbide, silicon nitride, III-V, II-V, sapphire, ITO, and SrTiO3, or a flexible substrate, which is at least one of polyimide, polyethylene naphthalate, polycarbonate, elastomeric polymer, thermoplastic polymer, etc.

[0056] The stacked structure is bonded to the target substrate by van der Waals bonding.

[0057] S8: The transitional temporary rigid substrate is separated by debonding; as an example, the debonding method includes at least one of thermal debonding, laser debonding and mechanical peel debonding, and chemical immersion debonding.

[0058] Using the graphene structure obtained on the target substrate as the target substrate, another layer of graphene is transferred through the same steps to obtain bilayer graphene on the target substrate; through multiple steps, multilayer graphene on the target substrate can be obtained.

[0059] Specifically: Using the graphene structure obtained on the target substrate as the target substrate, another sample is subjected to graphene growth, stress layer deposition, temporary bonding adhesive spin coating, rigid substrate attachment, and mechanical peeling to obtain a stacked structure consisting of another graphene layer, a stress layer, and temporary bonding adhesive. This stacked structure is then van der Waals bonded to the target substrate. Finally, by debonding, the temporary rigid substrate is separated, the temporary bonding adhesive is removed by cleaning, and the stress layer is etched to obtain the bilayer graphene on the target substrate.

[0060] The method is used to transfer two-dimensional transition metal carbonitrides (including but not limited to Ti3C2, Ti2C, Nb2C, Ti3AlC2, etc.), two-dimensional metal borides (Fe2B2, Cr2B2), transition metal chalcogenides (TMDCs) (including but not limited to MoS2, MoSe2, WSe2, MoTe2, PtSe2, etc.), metal-organic frameworks (MOFs), perovskite (CsPbCl3, CsPbI3, FaPbI3) materials, and two-dimensional materials formed by arranging one-dimensional materials (including but not limited to Ag nanowire thin films, carbon nanotube thin films, etc.).

[0061] The method, through repeated steps, can achieve the stacking of single or multiple two-dimensional materials.

[0062] Example 2

[0063] (1) A 5nm Ni / Au alloy stress layer was deposited on the surface of germanium-based graphene;

[0064] (2) Spin-coat a layer of phenolic resin adhesive onto its surface;

[0065] (3) Attach the sapphire sheet to the sample surface coated with spin-coated phenolic resin, see Figure 3 ;

[0066] (4) The sapphire and germanium sheets were mechanically separated, see Figure 4 ;

[0067] (5) The sapphire / adhesion layer (phenolic resin) / NiAu / Gr composite multilayer structure is then bonded to the SiO2 / Si sample under vacuum.

[0068] (6) Finally, the bonded sample is heated to soften the phenolic resin adhesive, and the sapphire and the underlying NiAu / Gr / SiO2 / Si sample are separated at the phenolic resin interface.

[0069] (7) Finally, after cleaning and etching the phenolic resin and NiAu, a clean Gr / SiO2Si sample can be obtained. See Figure 5 .

[0070] Nine points were randomly selected from the sample for Raman characterization, see... Figure 6 The absence of a defect peak (D peak) indicates high-quality graphene. The ratio of 2D to G peaks is greater than 2, indicating that the graphene is all monolayer graphene.

[0071] AFM testing was performed on the sample surface, see... Figure 7 Its surface roughness is 0.368 nm.

Claims

1. A graphene transfer method, comprising the steps of: providing a substrate; growing a graphene layer on an upper surface of the substrate; depositing a stress layer on an upper surface of the graphene layer; the stress layer comprising a metal layer or a dielectric layer; the metal layer being at least one of a copper layer, a nickel layer, a germanium layer, a titanium layer, a platinum layer, the dielectric layer being at least one of Zr02, Hf02, Y203, AI2O3, M0O3, Si02; spin-coating a temporary bonding glue on an upper surface of the stress layer; attaching a transition temporary rigid substrate to an upper surface of the temporary bonding glue in a vacuum environment; peeling off the transition temporary rigid substrate from the substrate by mechanical peeling, at which time a stack structure of the graphene layer, the stress layer and the temporary bonding glue is peeled off from the substrate; completing van der Waals bonding between the stack structure and a target substrate in a vacuum environment; the target substrate being at least one of a hard semiconductor substrate, the hard semiconductor substrate being at least one of silicon, silicon dioxide, germanium, silicon carbide, silicon nitride, III-V, II-V, sapphire, ITO, SrTi03, or a flexible substrate, the flexible substrate being at least one of polyimide, polyethylene naphthalate, polycarbonate, elastomeric polymer, thermoplastic polymer; separating the transition temporary rigid substrate by debonding; cleaning and removing the temporary bonding glue; etching the stress layer to obtain a graphene structure on the target substrate; continuing to use the graphene structure obtained on the target substrate as a target substrate to transfer another layer of graphene by the same steps, thereby obtaining a double-layer graphene on the target substrate; and by repeating the steps, obtaining a multi-layer graphene on the target substrate. The substrate comprises at least one of copper, nickel, germanium, titanium, platinum, gold, iron, silver. The method of growing the graphene layer comprises at least one of chemical vapor deposition and plasma-enhanced chemical vapor deposition. The method of depositing the stress layer comprises at least one of thermal evaporation, sputtering, physical vapor deposition, atomic layer deposition, molecular beam epitaxy, and chemical vapor deposition. The temporary bonding glue comprises at least one of heat-sensitive, light-sensitive, chemical-sensitive, soluble glue, thermal slip glue, mechanical peeling glue, and laser glue. The transition temporary rigid substrate comprises at least one of glass, sapphire, ceramic, metal, and hard polymer. The debonding method comprises at least one of thermal debonding, laser debonding, mechanical peeling debonding, and chemical soaking debonding. The method is used for graphene transfer, or for transferring two-dimensional transition metal carbonitride, two-dimensional metal boride, transition metal chalcogenide material, metal organic framework (MOFs) material, perovskite material, and two-dimensional material formed by one-dimensional material arrangement, or for preparing a stacked structure of different two-dimensional materials. ​ ​ ​ ​ ​ 2. The method of claim 1, wherein: ​ 3. The method of claim 1, wherein: ​ 4. The method of claim 1, wherein: ​ 5. The method of claim 1, wherein: ​ 6. The method of claim 1, wherein: ​ 7. The method of claim 1, wherein: ​ 8. The method of claim 1, wherein: ​

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