Method for etching surface pyrolytic graphene of si c by using metal ag nanoparticles and application thereof

Abstract

The application is a method for etching SiC surface pyrolytic graphene by using metal Ag nanoparticles and application, and belongs to the technical field of two-dimensional material patterning. The method is that the SiC pyrolytic graphene with a metal nano Ag film on the surface is placed in a closed limited container, vacuum high-temperature annealing is carried out, and the metal Ag nanoparticles can realize etching of the graphene layer in the volatilization process. The limited annealing etching technology is simple and effective, has no requirement for the surface polarity of the SiC substrate, and is expected to promote the large-scale uniform patterning preparation of SiC pyrolytic graphene, and provides guidance and reference value for the practical application of two-dimensional materials in the microelectronic field.

Description

Technical Field

[0001] This invention belongs to the technical field of two-dimensional material patterning, specifically a method and application of etching SiC surface pyrolytic graphene using Ag nanoparticles. Background Technology

[0002] According to Moore's Law, the channel size of traditional silicon-based transistors has reached its physical limit of less than 5 nm. Therefore, the development of integrated circuits currently faces technological bottlenecks in manufacturing. From the perspective of new material research and development, seeking new alternatives to single-crystal silicon materials is urgently needed for the development and application of future microelectronic devices. Pyrolytic graphene (SiC) is prepared by high-temperature pyrolysis of single-crystal SiC substrates and possesses excellent electron mobility and thermal conductivity. Due to the semiconductor properties of the SiC substrate, pyrolytic graphene can be directly applied to electronic devices without transfer, and its fabrication process is integrated with traditional silicon-based processes. Pyrolytic graphene (SiC) is expected to become an ideal candidate semiconductor material in the post-Moore's Law era and has already shown broad application prospects in the field of microelectronics. Since its discovery, SiC pyrolytic graphene has attracted much attention. The collaborative research between Professor Ma Lei's team at Tianjin University and Professor Walter A. de Heer's research group at Georgia Institute of Technology has achieved a major breakthrough. Based on quasi-equilibrium annealing technology, a regular and ordered monolayer of graphene can be prepared on the surface of SiC, creating the world's first functional SiC-based graphene semiconductor, thus opening up the practical application of SiC pyrolytic graphene in the semiconductor field.

[0003] The nanoscale width of graphene strips can be tuned to control their surface electron migration properties, opening up their energy band gaps and laying the foundation for high-performance electronic device applications. In the past decade, the patterning of SiC pyrolytic graphene surfaces has been a particularly active research area, attracting considerable attention. Scientists have developed various strategies for graphene structure control and patterning, leading to a variety of graphene etching methods. Catalytic cutting by metal nanoparticles is a promising technique. Metal nanoparticles, through the synergistic action of multiple metal atoms, "bite off" edge carbon atoms, creating smooth-edged, orderly arranged graphene nanostructures using a "Pac-Man" cutting mechanism. Based on the size effect of metal nanoparticles, the reaction rates of different types of edge sites vary, and the overall carbon atom etching rate is linearly dependent on the nanoparticle surface area. Exploring these mechanisms opens new avenues for improving the controllability of graphene cutting. However, the patterning of SiC pyrolytic graphene has always been challenging; how to uniformly and effectively control the graphene pattern on the SiC surface is difficult, and further research is warranted. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the prior art by combining the catalytic cutting mechanism of metal nanoparticles and providing a method for etching pyrolytic graphene on the surface of SiC using metal Ag nanoparticles, thereby solving the problem of large-scale uniform etching of pyrolytic graphene on SiC in the prior art.

[0005] This invention is achieved through the following technical solution: A method for etching pyrolytic graphene on the surface of SiC using metallic Ag nanoparticles includes the following steps: S1: Heat-treat a single-crystal SiC substrate to obtain SiC pyrolytic graphene.

[0006] S2: A layer of metallic nano-Ag film is grown on the surface of SiC pyrolysis graphene.

[0007] S3: The SiC pyrolytic graphene with a metal nano Ag film grown on its surface is placed upside down in a confined annealing container for vacuum high-temperature annealing treatment to achieve etching of the SiC pyrolytic graphene surface by metal Ag nanoparticles.

[0008] This invention utilizes the "pecking" mechanism of Ag atoms during annealing, crystallization, and volatilization to achieve uniform etching of pyrolytic graphene on SiC surfaces simply and quickly. The inverted sample placement creates a confined space within a limited area, and under reheating and annealing conditions, the rapid volatilization of Ag atoms is suppressed, increasing the probability of interaction between Ag and C atoms.

[0009] As a preferred technical solution, in step S1, the single-crystal SiC substrate is pretreated before heat treatment. The pretreatment involves heating the single-crystal SiC substrate to 600-700 ℃ under vacuum conditions and holding it at that temperature for 8 h.

[0010] As a preferred technical solution, in step S1, the heat treatment temperature is 1300 – 1400 ℃ and the heat treatment time is 10 – 20 min, which can grow a graphene thin layer on the SiC substrate surface.

[0011] As a preferred technical solution, in step S2, a metal nano Ag film is grown on the surface of SiC pyrolytic graphene using molecular beam epitaxy. During the molecular beam epitaxy growth process, the heating temperature of the metal Ag source material is 700-900 ℃, and the growth time is 10-20 min.

[0012] As a preferred technical solution, in step S3, when the SiC pyrolytic graphene with a metal nano Ag film grown on its surface is placed upside down, a tiny gap is set at the contact surface.

[0013] As a preferred technical solution, in step S3, during the vacuum high-temperature annealing treatment, the vacuum degree range is 1×10⁻⁶. -1 – 5×10 -1 Torr; the heating rate is 20 – 30 ℃ / min, and the sum of the heating time and holding time does not exceed 1h; the annealing temperature is 800 – 900 ℃, and the annealing time is 30 – 60 min, which allows the metal Ag particles to etch SiC pyrolytic graphene.

[0014] As a preferred technical solution, in step S2, the thickness of the grown metal nano Ag film is 10-20 nm, which allows the surface of SiC pyrolytic graphene to be uniformly covered by Ag atoms.

[0015] Furthermore, the present invention also provides a SiC pyrolytic graphene whose surface is etched by metal Ag nanoparticles, the pattern of which is prepared by the above-mentioned method of etching SiC surface pyrolytic graphene with metal Ag nanoparticles.

[0016] Furthermore, the present invention also provides the application of the above-mentioned SiC pyrolytic graphene with surface etched by metal Ag nanoparticles in integrated circuits.

[0017] In summary, the method of this invention involves placing SiC pyrolytic graphene with a metal nano-Ag film grown on its surface in a sealed confined container and subjecting it to vacuum high-temperature annealing. During the volatilization process, the metal Ag nanoparticles can etch the graphene layer. This confined annealing etching technique is simple and effective, requires no specific surface polarity of SiC, and is expected to advance the large-scale, uniform patterning of SiC-based graphene. It provides guidance and reference value for the practical application of two-dimensional materials in the microelectronics field. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the atom-confined annealing process for metal Ag in Embodiment 1 of the present invention.

[0020] Figure 2 This is a schematic diagram illustrating the principle of etching the surface of SiC pyrolytic graphene by metallic Ag atoms in the method of this invention.

[0021] Figure 3The above are the SEM characterization results of the surface morphology of SiC pyrolytic graphene after etching with Ag atoms in Example 2 of this invention.

[0022] Figure 4 The Raman characterization results are for SiC pyrolytic graphene after etching of metal Ag atoms in Example 3 of this invention. Detailed Implementation

[0023] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore merely examples and should not be used to limit the scope of protection of the present invention. It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0024] This invention provides a method for etching pyrolytic graphene on the surface of SiC using Ag nanoparticles. This method primarily utilizes the confined volatilization process of Ag atoms to achieve large-scale, uniform etching of the pyrolytic graphene on SiC. Specifically, it includes the following steps: S1: First, pre-treat the single-crystal SiC substrate, then perform high-temperature annealing heat treatment, and finally obtain SiC pyrolytic graphene.

[0025] In this step, the SiC substrate is a Grade A sample, and either the Si side or the C side can be used, with single-sided polishing.

[0026] The pretreatment process is as follows: a clean single-crystal SiC substrate is introduced into a vacuum chamber. Under vacuum conditions, the single-crystal SiC substrate is heated and degassed using a direct current to remove impurities such as water vapor and adsorbates from its surface. The direct current used for pretreatment is 0.5–0.7 A, resulting in a heating temperature of 600–700 °C, and the degassed holding time is 8 h. In this step, the background vacuum level of the sample preparation chamber is less than 5 × 10⁻⁶. -9 Torr.

[0027] The high-temperature annealing heat treatment process is as follows: the single-crystal SiC substrate is heated by a direct current of 2.0 – 2.5 A, the heat treatment temperature is 1300 – 1400 ℃, and the heating time is 10 – 20 min.

[0028] S2: A layer of metallic nano-Ag film is grown on the surface of SiC pyrolysis graphene.

[0029] The specific process is as follows: a metal nano Ag film layer is grown on the surface of SiC pyrolytic graphene using molecular beam epitaxy (MBE). During the MBE growth process, a K-Cell evaporation source is used to heat the metal Ag source material to 700–900 °C using a direct current of 1.9–2.3 A, and the growth time is 10–20 min. The thickness of the finally grown metal nano Ag film is 10–20 nm.

[0030] S3: Pyrolytic graphene of SiC with a metal nano-Ag film grown on its surface is placed upside down in a confined annealing container for vacuum high-temperature annealing, achieving etching of the SiC pyrolytic graphene surface by the metal Ag nanoparticles, such as... Figure 1 and Figure 2 As shown, when SiC pyrolytic graphene with a metal nano Ag film grown on its surface is placed upside down, a tiny gap is set between the metal nano Ag film and the bottom of the container, forming only a tiny void.

[0031] The vacuum high-temperature annealing process is as follows: the vacuum degree range of the confined annealing vessel is 1×10⁻⁶. -1 – 5×10 -1 Torr; heating rate is 20 – 30 ℃ / min, and the sum of heating time and holding time does not exceed 1h; annealing temperature is 800 – 900 ℃, and annealing time is 30 – 60 min.

[0032] This invention utilizes a confined etching technique involving confined Ag atoms to achieve simple and rapid large-area uniform etching of SiC pyrolytic graphene. The inverted sample placement creates a confined space within a limited area, which, under heating and annealing conditions, suppresses the rapid volatilization of Ag atoms and increases the probability of interaction between Ag and C atoms. This etching technique is simple and effective, and can be extended to the surface etching of various types of SiC pyrolytic graphene, providing guidance and reference for advancing the practical application of SiC pyrolytic graphene in microelectronics and other fields.

[0033] The etching technique in the method of this invention will be explained in detail with reference to the etching principle and accompanying drawings: Etching principle: such as Figure 1 As shown, SiC pyrolytic graphene with a metal nano-Ag film grown on its surface is placed face-up in a confined annealing container. This method can construct a confined space within a limited area, effectively suppressing the volatilization rate of metal Ag atoms under heating annealing conditions and increasing the probability of mutual utilization between metal Ag atoms and C atoms. The pre-deposited metal Ag atoms recrystallize into larger particles during high-temperature annealing and volatilize under continuous annealing conditions, forming an etching on the surface of the SiC pyrolytic graphene, such as... Figure 2 As shown.

[0034] Furthermore, the present invention also provides a SiC pyrolytic graphene whose surface is etched by metal Ag nanoparticles, the pattern of which is prepared by the above-mentioned method of etching SiC surface pyrolytic graphene with metal Ag nanoparticles.

[0035] Furthermore, the present invention also provides the application of the above-mentioned SiC pyrolytic graphene with surface etched by metal Ag nanoparticles in integrated circuits.

[0036] The main technical solution of this invention utilizes confined intercalation technology to achieve large-scale, uniform Ag atom intercalation in SiC pyrolytic graphene. The following are several specific preparation method implementation examples to further illustrate the technical solution of this invention: Example 1

[0037] The Si-terminated single-crystal 6H-SiC(0001) substrate was heated to 600 °C under DC conditions of 0.61 A and degassed for 8 h; the vacuum degree of the sample preparation chamber was maintained at 2.5 × 10⁻⁶. -9 Torr rapidly heated the single-crystal SiC substrate to 1300 °C using a DC current of 2.0 A for 20 mins, and then cooled the sample for later use.

[0038] The Ag metal source material was heated to 700 °C using a K-Cell evaporation apparatus with a heating current of 1.9 A and a growth time of 20 mins. The sample is transferred out of the growth chamber and placed upside down in a confined annealing container. The placement method and principle are as follows: Figure 1 As shown; the confined annealing vessel was heated to 800 °C at a heating rate of 20 °C / min, and maintained for annealing for 60 mins, while the vacuum degree was maintained at 5.0 × 10⁻⁶. -1 Torr. Example 2

[0039] The single-crystal 6H-SiC(0001) substrate was heated to 650 °C under DC conditions of 0.69 A and degassed for 8 h; the vacuum degree of the sample preparation chamber was maintained at 4.5 × 10⁻⁶. -9 Torr rapidly heated the single-crystal SiC substrate to 1350 °C using a DC current of 2.1 A for 15 mins, and then cooled the sample for later use.

[0040] The Ag metal source material was heated to 750 °C using a K-Cell evaporation apparatus with a heating current of 2.0 A and a growth time of 13 mins. The sample is transferred out of the growth chamber and placed upside down in a confined annealing container. The placement method and principle are as follows: Figure 1As shown; the confined annealing vessel was heated to 800 °C at a heating rate of 30 °C / min, and the annealing time was maintained for 40 mins, while the vacuum degree was maintained at 1.0 × 10⁻⁶. -1 Torr.

[0041] Figure 3 The SEM characterization results show that a uniform circular pattern appeared on the surface of the SiC pyrolytic graphene through confined etching of Ag atoms. SEM characterization revealed that during the volatilization of Ag nanoparticles, the C atoms in the Ag-bonded regions were etched, leaving a circular etched pattern on the SiC pyrolytic graphene surface. After high-temperature annealing, the Ag nanoparticles volatilized completely, leaving no metal particle residue on the surface. The edges of the Ag-etched graphene were smooth and clean, with a certain degree of warping. This embodiment demonstrates that Ag atoms can be easily and rapidly etched into SiC pyrolytic graphene under confined annealing conditions to obtain a uniform circular pattern. Example 3

[0042] The single-crystal 6H-SiC (000-1) substrate with the C-terminated surface was heated to 680 °C under DC conditions of 0.70 A and degassed for 8 h; the vacuum degree of the sample preparation chamber was maintained at 3.5 × 10⁻⁶. -9 Torr rapidly heated the single-crystal SiC substrate to 1370 °C using a DC current of 2.2 A for 12 mins, and then cooled the sample for later use.

[0043] The Ag metal source material was heated to 800 °C using a K-Cell evaporation apparatus with a heating current of 2.3 A and a growth time of 10 mins.

[0044] The sample is transferred out of the growth chamber and placed upside down in a confined annealing container. The placement method and principle are as follows: Figure 1 As shown; the confined annealing vessel was heated to 850 °C at a heating rate of 25 °C / min, and maintained for annealing for 35 mins, while the vacuum degree was maintained at 1.5 × 10⁻⁶. -1 Torr.

[0045] Figure 4 The results show the Raman spectroscopy characterization. Circular patterns can be obtained under this etching process, and Raman spectroscopy was performed at an excitation wavelength of 633 nm. The results show that in the etched area, the characteristic peaks of SiC are mainly observed, as shown in curve B, without the Raman characteristic information of graphene; in the unetched area, the Raman characteristic information of graphene is very obvious, as shown in curve A, where the D peak (~1350 cm⁻¹) is particularly prominent. -1 G peak (~1580 cm) -1 ), 2D (~2700 cm) -1Both exhibit good symmetry and high strength. This example demonstrates that metallic Ag nanoparticles effectively etch SiC pyrolytic graphene. Example 4

[0046] The single-crystal 6H-SiC (000-1) substrate with C-terminated surface was heated to 680 °C under DC conditions of 0.5 A and degassed for 8 h; the vacuum degree of the sample preparation chamber was maintained at 3.5 × 10⁻⁶. -9 Torr rapidly heated the single-crystal SiC substrate to 1350 °C using a DC current of 2.2 A for 15 mins, and then cooled the sample for later use.

[0047] The Ag source material was heated to 850 °C using a K-Cell evaporation apparatus with a heating current of 2.1 A and a growth time of 10 mins.

[0048] The sample is transferred out of the growth chamber and placed upside down in a confined annealing container. The placement method and principle are as follows: Figure 1 As shown; the confined annealing vessel was heated to 850 °C at a heating rate of 28 °C / min, and the annealing time was maintained for 35 mins, while the vacuum degree was maintained at 1.7 × 10⁻⁶. -1 Torr. Example 5

[0049] The single-crystal 6H-SiC(0001) substrate with Si termination was heated to 700 °C under DC conditions of 0.70 A and degassed for 8 h; the vacuum in the sample preparation chamber was maintained at 2.8 × 10⁻⁶. -9 Torr rapidly heated the single-crystal SiC substrate to 1400 °C using a DC current of 2.5 A for 10 mins, and then cooled the sample for later use.

[0050] The Ag source material was heated to 900 °C using a K-Cell evaporation apparatus with a heating current of 2.2 A and a growth time of 10 mins.

[0051] The sample is transferred out of the growth chamber and placed upside down in a confined annealing container. The placement method and principle are as follows: Figure 1 As shown; the confined annealing vessel was heated to 900 °C at a heating rate of 22 °C / min, and maintained for annealing for 30 mins, with the vacuum level maintained at 2.7 × 10⁻⁶. -1 Torr.

[0052] This invention utilizes a technique involving the etching of SiC pyrolytic graphene surfaces by metallic Ag atoms under confined annealing conditions, achieving large-area, uniform etching of SiC-based graphene. This invention solves the technical challenges of etching Si and C-faced pyrolytic graphene, providing insights for the practical modification and application of SiC pyrolytic graphene.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.

Claims

1. A method for etching pyrolytic graphene on the surface of SiC using metallic Ag nanoparticles, characterized in that, Includes the following steps: S1: Heat-treat a single-crystal SiC substrate to obtain SiC pyrolytic graphene; S2: A layer of metallic nano-Ag film is grown on the surface of SiC pyrolysis graphene; S3: The SiC pyrolytic graphene with a metal nano Ag film grown on its surface is placed upside down in a confined annealing container for vacuum high-temperature annealing treatment to achieve etching of the SiC pyrolytic graphene surface by metal Ag nanoparticles.

2. The method for etching pyrolytic graphene on the surface of SiC using metallic Ag nanoparticles according to claim 1, characterized in that: In step S1, the single-crystal SiC substrate is pretreated before heat treatment. The pretreatment involves heating the single-crystal SiC substrate to 600-700 ℃ under vacuum conditions and holding it at that temperature for 8 h.

3. The method for etching pyrolytic graphene on the surface of SiC using metallic Ag nanoparticles according to claim 1, characterized in that: In step S1, the heat treatment temperature is 1300 – 1400 ℃ and the heat treatment time is 10 – 20 min.

4. The method for etching pyrolytic graphene on the SiC surface using Ag nanoparticles according to claim 1, characterized in that: In step S2, a metal nano Ag film is grown on the surface of SiC pyrolytic graphene using molecular beam epitaxy. During the molecular beam epitaxy process, the heating temperature of the metal Ag source material is 700-900 ℃, and the growth time is 10-20 min.

5. The method for etching pyrolytic graphene on the surface of SiC using metallic Ag nanoparticles according to claim 1, characterized in that: In step S3, when the SiC pyrolytic graphene with a metal nano Ag film grown on its surface is placed upside down, a tiny gap is set at the contact surface.

6. The method for etching pyrolytic graphene on the surface of SiC using metallic Ag nanoparticles according to claim 1, characterized in that: In step S3, during the vacuum high-temperature annealing process, the vacuum level is within the range of 1×10⁻⁶. -1 – 5×10 -1 Torr; heating rate is 20 – 30 ℃ / min, and the sum of heating time and holding time does not exceed 1h; annealing temperature is 800 – 900 ℃, and annealing time is 30 – 60 min.

7. The method for etching pyrolytic graphene on the SiC surface using metallic Ag nanoparticles according to claim 4, characterized in that: In step S2, the thickness of the grown metal nano Ag film is 10 – 20 nm.

8. A SiC pyrolytic graphene with a surface etched by metallic Ag nanoparticles, characterized in that: It is prepared by the method described in any one of claims 1-7.

9. The application of SiC pyrolytic graphene with surface etched by metallic Ag nanoparticles as described in claim 8 in integrated circuits.

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