阅读说明：本技术 一种高迁移率的SiC基石墨烯器件及其制备方法 (High-mobility SiC-based graphene device and preparation method thereof ) 是由 李京波 赵艳 汪争 岳倩 郑涛 张龙 周贝尔 于 2021-06-09 设计创作，主要内容包括：本发明涉及一种高迁移率的SiC基石墨烯器件及其制备方法,方法包括：清洗衬底层,所述衬底层包括n～(+)SiC衬底层和位于所述n～(+)SiC衬底层上的n-SiC衬底层；将石墨烯转移到所述衬底层上；在所述石墨烯和所述衬底层上制备若干霍尔电极；对所述衬底层、所述石墨烯和所述霍尔电极进行退火处理,以得到SiC基石墨烯器件。本发明所提供的SiC基石墨烯器件的制备方法工艺简单,价格低廉,非常适用于商用化应用,并且所获得的石墨烯保持着比较完美的晶体结构,缺陷含量比较低。(The invention relates to a SiC-based graphene device with high mobility and a preparation method thereof, wherein the method comprises the following steps: cleaning a substrate layer comprising n + SiC substrate layer and the layer located at n + An n-SiC substrate layer on the SiC substrate layer; transferring graphene onto the substrate layer; preparing a plurality of Hall electrodes on the graphene and the substrate layer; and annealing the substrate layer, the graphene and the Hall electrode to obtain the SiC-based graphene device. The preparation method of the SiC-based graphene device provided by the invention is simple in process, low in price and very suitable for useThe method is applied to commercial application, and the obtained graphene keeps a relatively perfect crystal structure and has relatively low defect content.)

1. A preparation method of a SiC-based graphene device with high mobility is characterized by comprising the following steps:

cleaning a substrate layer comprising n⁺SiC substrate layer and the layer located at n⁺N on SiC substrate layer^-A SiC substrate layer;

transferring graphene onto the substrate layer;

preparing a plurality of Hall electrodes on the graphene and the substrate layer;

and annealing the substrate layer, the graphene and the Hall electrode to obtain the SiC-based graphene device.

2. The method of preparing a SiC-based graphene device of claim 1, wherein cleaning the substrate layer comprises:

treating the substrate layer by BOE, and then ultrasonically cleaning the substrate layer by acetone and isopropanol respectively.

3. The method of making a SiC-based graphene device of claim 1, wherein transferring graphene onto the substrate layer comprises:

firstly, stripping graphene, and then transferring the graphene onto the substrate layer by a wet method transfer method.

4. The method of manufacturing a SiC-based graphene device according to claim 3, wherein the graphene is first exfoliated and then transferred onto the substrate layer by a wet transfer method, including:

firstly spin-coating a PMMA anisole solution on a silicon wafer, then drying the silicon wafer coated with the PMMA anisole solution, placing the silicon wafer in a KOH solution for etching, then separating PMMA from the silicon wafer, cleaning the silicon wafer with deionized water, then fishing out a PMMA film and graphene positioned on the lower surface of the PMMA film by using a substrate layer, then drying, then softening the PMMA film with acetone steam, then soaking with acetone and blow-drying to obtain the graphene positioned on the substrate layer.

5. The method for preparing the SiC-based graphene device according to claim 1, wherein preparing a plurality of Hall electrodes on the graphene and the substrate layer comprises:

preparing an electrode pattern by utilizing a laser direct writing technology;

and depositing metal electrodes on the graphene and the substrate layer by using electron beam evaporation deposition, and dissolving and removing to obtain the Hall electrode.

6. The method for preparing the SiC-based graphene device according to claim 1, wherein the annealing treatment of the substrate layer, the graphene and the Hall electrode comprises:

and annealing the substrate layer, the graphene and the Hall electrode in a nitrogen atmosphere.

7. The method of manufacturing a SiC-based graphene device according to claim 1, wherein the n is⁺The thickness of the SiC substrate layer is 180-375 mu m, and n is^-The thickness of the SiC substrate layer is 0.5-11 mu m.

8. The method for preparing the SiC-based graphene device according to claim 1, wherein the thickness of the graphene is in a range of 0.3-10 nm.

9. The method of claim 1, wherein the hall electrode comprises Au, Ti/Au, or Gr/Au.

10. A high-mobility SiC-based graphene device, characterized by being produced by the method for producing a SiC-based graphene device according to any one of claims 1 to 9, the SiC-based graphene device comprising:

a substrate layer comprising n⁺SiC substrate layer and the layer located at n⁺An n-SiC substrate layer on the SiC substrate layer;

graphene on the substrate layer;

and the Hall electrodes are positioned on the substrate layer and the graphene.

Technical Field

The invention belongs to the technical field of semiconductor devices, and relates to a SiC-based graphene device with high mobility and a preparation method thereof.

Background

The mobility is one of important parameters reflecting the conductivity of a current carrier in a semiconductor, the current carrier generated by a certain reason in a semiconductor material is in random thermal motion, when a voltage is applied, the current carrier is acted by an electric field force and makes directional motion to form a current, and the higher the mobility is, the faster the current carrier moves, and the higher the conductivity of the semiconductor material is. Graphene is a two-dimensional hexagonal honeycomb structure formed by hybridization of carbon atoms sp2, has excellent electrical properties, is considered to be a material with the most potential to replace silicon, and particularly in the field of high-frequency electronics, and shows huge utilization potential. SiC is a wide-bandgap semiconductor, has the characteristics of high critical breakdown field strength, high thermal conductivity, high electron saturation drift velocity, large forbidden bandwidth and the like, and is an ideal electronic material for manufacturing high-temperature, high-frequency and high-power electronic devices. The silicon carbide-based graphene can be used for manufacturing a nanometer device and an integrated circuit through a conventional semiconductor process, and has good compatibility with the conventional semiconductor process.

However, although graphene films with flatness, large area and high electron mobility can be grown by using SiC epitaxial growth, the growth conditions are very harsh, the process is complex and the cost is high, SiC can form an extremely thin graphene layer on the surface through a series of complex surface reconstructions, and the number and quality of the prepared graphene layer are difficult to control.

Disclosure of Invention

In order to solve the above problems in the prior art, the present invention provides a high mobility SiC-based graphene device and a method for manufacturing the same. The technical problem to be solved by the invention is realized by the following technical scheme:

the embodiment of the invention provides a preparation method of a high-mobility SiC-based graphene device, which comprises the following steps:

cleaning a substrate layer comprising n⁺SiC substrate layer and the layer located at n⁺N on SiC substrate layer^-A SiC substrate layer;

transferring graphene onto the substrate layer;

preparing a plurality of Hall electrodes on the graphene and the substrate layer;

and annealing the substrate layer, the graphene and the Hall electrode to obtain the SiC-based graphene device.

In one embodiment of the invention, cleaning a substrate layer comprises:

treating the substrate layer by BOE, and then ultrasonically cleaning the substrate layer by acetone and isopropanol respectively.

In one embodiment of the invention, transferring graphene onto the substrate layer comprises:

firstly, stripping graphene, and then transferring the graphene onto the substrate layer by a wet method transfer method.

In one embodiment of the present invention, the first peeling of the graphene and the subsequent transfer of the graphene onto the substrate layer by a wet transfer method include:

firstly spin-coating a PMMA anisole solution on a silicon wafer, then drying the silicon wafer coated with the PMMA anisole solution, placing the silicon wafer in a KOH solution for etching, then separating PMMA from the silicon wafer, cleaning the silicon wafer with deionized water, then fishing out a PMMA film and graphene positioned on the lower surface of the PMMA film by using a substrate layer, then drying, then softening the PMMA film with acetone steam, then soaking with acetone and blow-drying to obtain the graphene positioned on the substrate layer.

In one embodiment of the present invention, preparing a plurality of hall electrodes on the graphene and the substrate layer includes:

preparing an electrode pattern by utilizing a laser direct writing technology;

and depositing metal electrodes on the graphene and the substrate layer by using electron beam evaporation deposition, and dissolving and removing to obtain the Hall electrode.

In one embodiment of the present invention, annealing the substrate layer, the graphene, and the hall electrode includes:

and annealing the substrate layer, the graphene and the Hall electrode in a nitrogen atmosphere.

In one embodiment of the invention, said n⁺The thickness of the SiC substrate layer is 180-375 mu m, and n is^-The thickness of the SiC substrate layer is 0.5-11 mu m.

In one embodiment of the invention, the thickness of the graphene is in a range of 0.3-10 nm.

In one embodiment of the invention, the Hall electrode comprises Au, Ti/Au or Gr/Au.

Another embodiment of the present invention provides a high-mobility SiC-based graphene device prepared by the preparation method according to any one of the above embodiments, including:

a substrate layer comprising n⁺SiC substrate layer and the layer located at n⁺An n-SiC substrate layer on the SiC substrate layer;

graphene on the substrate layer;

and the Hall electrodes are positioned on the substrate layer and the graphene.

Compared with the prior art, the invention has the beneficial effects that:

the preparation method of the SiC-based graphene device provided by the invention is simple in process, low in price and very suitable for commercial application, and the obtained graphene keeps a perfect crystal structure and has low defect content.

The SiC-based graphene device prepared by the method has high room temperature Hall mobility.

Other aspects and features of the present invention will become apparent from the following detailed description, which proceeds with reference to the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

Drawings

Fig. 1 is a schematic flow chart of a method for manufacturing a high-mobility SiC-based graphene device according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a high-mobility SiC-based graphene device according to an embodiment of the present invention;

fig. 3 is an optical microscope image of a high mobility SiC-based graphene device provided by an embodiment of the present invention.

Reference numerals:

a substrate layer-1; 2, graphene-2; a Hall electrode-3; n is⁺A SiC substrate layer-11; n is^-SiC substrate layer-12.

Detailed Description

The present invention will be described in further detail with reference to specific examples, but the embodiments of the present invention are not limited thereto.

Example one

Referring to fig. 1, fig. 2 and fig. 3, fig. 1 is a schematic flow chart of a method for manufacturing a high-mobility SiC-based graphene device according to an embodiment of the present invention, fig. 2 is a schematic structural diagram of a high-mobility SiC-based graphene device according to an embodiment of the present invention, and fig. 3 is an optical microscope diagram of a high-mobility SiC-based graphene device according to an embodiment of the present invention. The invention provides a preparation method of a SiC-based graphene device with high mobility, which comprises the following steps:

step 1, cleaning a substrate layer 1, wherein the substrate layer 1 comprises n⁺SiC substrate layer 11 and at n⁺N on SiC substrate layer 11^-A SiC substrate layer 12.

Specifically, the substrate layer 1 is first treated with BOE (buffered Oxide Etch) to remove the silicon Oxide layer on the surface of the silicon Oxide layer, and then the substrate layer 1 is ultrasonically cleaned with acetone and isopropanol respectively to remove organic impurities and other attachments on the substrate layer 1 to remove the organic impurities and other attachments.

In one embodiment, 40g NH is first applied₄F. 18ml HF and 60ml H₂Preparing a BOE solution according to the proportion of O, and then soaking and cleaning the substrate layer 1 by using the BOE solution for 3min so as to completely remove the silicon oxide layer on the surface of the substrate layer 1; then, ultrasonically cleaning the substrate layer 1 by using acetone and isopropanol respectively, wherein the soaking time is 15min, so as to remove organic impurities and other surface attachments on the substrate layer 1; finally, washing with deionized water and drying with a nitrogen gun.

Preferably, n⁺The thickness of the SiC substrate layer 11 is 180-375 mu m, n^-The thickness of the SiC substrate layer 12 is 0.5-11 μm. The thickness of the n-SiC substrate layer 11 is 0.5-11 microns, so that the defect density of the n-SiC substrate layer 11 can be prevented from being too high, and the performance of a device is prevented from being influenced.

Preferably, n⁺The doping concentration range of the SiC substrate layer 11 is 1E 18-1E 19, n^-The doping concentration range of the SiC substrate layer 12 is 1E 15-1E 17.

And 2, transferring the graphene 2 to the substrate layer 1.

In the present embodiment, the graphene 2 may be transferred onto the substrate layer 1 by KOH wet transfer or PVA (polyvinyl alcohol) transfer.

Specifically, the graphene 2 is firstly peeled off, and then the graphene 2 is transferred onto the substrate layer 1 by a wet transfer method.

In a specific embodiment, the adhesive tape is used for stripping graphene, the graphene is transferred to the substrate layer 1 through a wet transfer technology, the specific transfer method comprises the steps of firstly spin-coating a PMMA (polymethyl methacrylate) anisole solution on a silicon wafer, then drying the silicon wafer coated with the PMMA anisole solution, placing the silicon wafer in a KOH solution for etching, then separating PMMA from the silicon wafer, cleaning the silicon wafer with deionized water, then fishing out a PMMA film and graphene 2 on the lower surface of the PMMA film through the substrate layer 1, then drying the PMMA film, softening the PMMA film with acetone steam, and then soaking the PMMA film with acetone and drying the PMMA film to obtain the graphene 2 on the substrate layer 1.

For example: spin coating PMMA anisole solution with the mass fraction of 10% on a silicon wafer, then drying for 15min at 150 ℃ to remove the anisole solvent, placing the solution in 3mol/L KOH solution, etching for 15min at 65 ℃, then separating PMMA and the silicon wafer by using tweezers, cleaning for at least 3 times in deionized water, then fishing up the PMMA film/graphene (namely the PMMA film is positioned on the graphene) by using a substrate layer 1, drying for 15min at 100 ℃, then steaming for 5min by using 65 ℃ acetone to soften the PMMA film, soaking for 3min by using acetone, and finally drying by using a nitrogen gun to obtain the graphene/substrate layer (namely the graphene is positioned on the substrate layer).

Preferably, the thickness of the graphene is in a range of 0.3-10 nm. When the thickness range of the graphene is 0.3-10 nm, the contact between the graphene and the substrate can be ensured, so that the influence on the performance of the SiC-based graphene device due to poor contact between the graphene and the substrate is avoided.

And 3, preparing a plurality of Hall electrodes 3 on the graphene 2 and the substrate layer 1.

And 3.1, preparing an electrode pattern by utilizing a laser direct writing technology.

And 3.2, depositing metal electrodes on the graphene 2 and the substrate layer 1 by electron beam evaporation, and dissolving to obtain the Hall electrode 3.

Preferably, the Hall electrode 3 comprises Au, Ti/Au (i.e., Ti is on Au), or Gr/Au (i.e., Gr is on Au).

Preferably, the number of the hall electrodes 3 is 4, and a part of each hall electrode 3 is located on the graphene 2, and a part of each hall electrode 3 is located on the substrate layer 1, for example, the graphene 2 is square, and then the 4 hall electrodes 3 are respectively located at four corners of the graphene 2.

And 4, annealing the substrate layer 1, the graphene 2 and the Hall electrode 3 to obtain the SiC-based graphene device.

Specifically, the substrate layer 1, the graphene 2 and the hall electrode 3 are annealed in a nitrogen atmosphere, wherein the annealing temperature may be 150 ℃ and the annealing time may be 20 min.

The resistance of the graphene with the thickness of 1nm prepared by the invention is 3-5K omega under the magnetic field intensity of 0.5T, and the Hall mobility at 300K is 600cm²·V^-1·s^-1The doping type is N type; the resistance of 7 nm-thick graphene is measured to be 6-10K omega under the same preparation process and the same test condition, and the Hall mobility at 300K is 280cm²·V^-1·s^-1And the doping type is N type.

The SiC-based graphene device prepared by the method disclosed by the invention is subjected to Hall test system to obtain higher room-temperature Hall mobility (200-600 cm)²·V^-1·s^-1)。

The preparation method of the SiC-based graphene device provided by the invention is simple in process, low in price and very suitable for commercial application, and the obtained graphene keeps a perfect crystal structure and has low defect content.

Example two

Referring to fig. 2, the present embodiment provides a high mobility SiC-based graphene device based on the above embodiments, where the SiC-based graphene device includes:

a substrate layer 1 comprising n⁺SiC substrate layer 11 and at n⁺An n-SiC substrate layer 12 on the SiC substrate layer 11;

graphene 2 positioned on the substrate layer 1;

and the Hall electrodes 3 are positioned on the substrate layer 1 and the graphene 2.

The graphene of the SiC-based graphene device obtained by the invention is prepared by a mechanical stripping method, and the graphene prepared by the method is stripped from a perfect adaptive crystal and has higher crystal quality than the graphene prepared by other methods (such as CVD and the like), so that the graphene keeps a perfect crystal structure and has lower defect content.

The graphene of the SiC-based graphene device prepared by the invention has higher mobility, so that the SiC-based graphene device has higher room temperature Hall mobility.

In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic data point described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.