A carbon nanotube field-effect transistor based on MoTi alloy contacts and its fabrication method

Abstract

This invention belongs to the field of semiconductor devices and micro / nanoelectronics technology, and discloses a CNTFET based on MoTi alloy contacts and its fabrication method. The CNTFET includes a substrate, a gate electrode, a gate dielectric layer, a carbon nanotube channel, and source and drain electrodes, wherein the source and drain electrodes are MoTi alloys or multilayer metal structures coated with MoTi layers. By controlling the Mo / Ti atomic ratio and optimizing deposition process conditions, this invention constructs a contact structure with tunable work function, high oxidation resistance, and excellent thin film quality, effectively reducing the Schottky barrier between the metal and carbon nanotubes, and achieving stable near-ohmic contacts. This device overcomes the shortcomings of existing technologies such as easy oxidation of low work function metals like Sc and Y, poor interface stability, and insufficient process compatibility. It significantly reduces contact resistance and improves the N-type conductivity stability, on-state current, and long-term reliability of the device in air environments, making it suitable for the integration of high-performance carbon-based logic devices and next-generation micro / nanoelectronic systems.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor devices and micro-nano electronics technology, specifically relating to a carbon nanotube field-effect transistor based on MoTi alloy to achieve a stable N-type ohmic contact and its fabrication method. Background Technology

[0002] Carbon nanotubes (CNTs) are considered a key candidate material for building next-generation high-performance field-effect transistors (FETs) and integrated circuits due to their unique quasi-one-dimensional band structure, ultra-high carrier mobility, low scattering properties, and ability to achieve short-channel near-ballistic transport. In CNT-FETs, the contact properties between the metal electrode and the CNT channel play a decisive role in the overall device performance. The metal-CNT contact often forms a Schottky barrier, limiting carrier injection efficiency. Especially for N-type CNT-FETs, finding suitable low work function metals to reduce the electron injection barrier and achieve low-resistance ohmic contacts are crucial for improving the device's on-state current and operating performance.

[0003] In existing technologies, to construct N-type low-barrier contacts, researchers commonly use low work function rare-earth metals such as scandium (Sc) and yttrium (Y) as source / drain electrode contact materials for CNTs. For example, typical self-aligned gate structure devices can achieve strong gate control capabilities by depositing Sc or Y metals and combining them with a high-κ gate dielectric, and exhibit near-ohmic transport characteristics at room temperature or low temperature, significantly improving the transconductance and on / off ratio of the device.

[0004] However, despite the ability of metals such as Sc and Y to achieve low effective work functions, they still present significant drawbacks and problems in practical applications and large-scale manufacturing: Poor chemical stability and easy oxidation: Rare earth metals such as Sc and Y have extremely high chemical reactivity and are easily oxidized and absorb moisture in air or conventional processes. This oxidation effect (such as the formation of loose and porous ScOx) leads to an increase in the interfacial work function and a sharp increase in contact impedance, thereby causing rapid degradation of device performance.

[0005] Interface wettability and film quality issues: These metals have poor wettability with the CNT surface, and tend to grow in an island-like or rough manner during deposition, making it difficult to form a continuous and dense contact interface. This not only affects electron transport, but also limits the yield and consistency of the device.

[0006] Process compatibility and cost issues: Metals such as Sc are extremely sensitive to the cleanliness of the interface before deposition, often requiring rigorous ultra-high vacuum in-situ cleaning, resulting in a narrow process window. In addition, Sc metal is expensive, has a limited supply chain, and is difficult to be compatible with existing CMOS manufacturing processes, hindering the industrial integration of N-type CNT-FETs.

[0007] In summary, there is an urgent need for a novel contact material system that can maintain a low Schottky barrier while possessing excellent oxidation resistance, good thin film morphology, and process compatibility, in order to replace traditional rare earth metals and achieve high-performance, high-stability N-type carbon nanotube field-effect transistors. Summary of the Invention

[0008] The present invention aims to provide a carbon nanotube field-effect transistor based on MoTi alloy contacts and a method for its fabrication, in order to overcome the shortcomings of the prior art. The technical problem to be solved by the present invention is achieved through the following technical solution.

[0009] This invention provides a carbon nanotube field-effect transistor based on a MoTi alloy contact, comprising: Substrate; Carbon nanotube channels formed on the substrate; Source electrode and drain electrode, wherein the source electrode and drain electrode are electrically connected to the carbon nanotube channel; and A gate structure is used to regulate the conductivity state of the carbon nanotube channel; The source electrode and drain electrode are made of MoTi alloy.

[0010] In a preferred embodiment, the source electrode and drain electrode adopt a single-layer MoTi alloy structure, or a multi-layer metal composite structure containing a MoTi alloy layer.

[0011] In a preferred embodiment, the atomic ratio of Mo to Ti in the MoTi alloy is between 3:7 and 7:3, and the thickness of the MoTi alloy is between 30 nm and 50 nm.

[0012] In a preferred embodiment, the interface between the MoTi alloy and the carbon nanotube channel has an interface structure containing Mo-C bonds or a molybdenum carbide phase.

[0013] In a preferred embodiment, the gate structure is a top-gate structure, comprising: a gate dielectric layer covering the carbon nanotube channel and part of the source electrode and drain electrode surface; and a gate electrode located on the gate dielectric layer.

[0014] In a preferred embodiment, the material of the gate dielectric layer is selected from HfO2 or Al2O3.

[0015] In a preferred embodiment, the carbon nanotube channel is a carbon nanotube network structure or a carbon nanotube array structure.

[0016] Another aspect of the present invention provides a method for fabricating a carbon nanotube field-effect transistor based on a MoTi alloy contact, comprising the following steps: A substrate is provided, and the surface of the substrate is cleaned. Carbon nanotube channels are formed on the surface of the substrate, and the carbon nanotube channels are patterned. A mask pattern defining source and drain regions is formed on the substrate; A MoTi alloy metal layer is deposited, and the metal layer in the non-source and drain regions is removed by a stripping process to form the source electrode and drain electrode in contact with the carbon nanotube channel. Forming the gate dielectric layer and gate electrode.

[0017] In a preferred embodiment, the step of depositing the MoTi alloy metal layer is performed using a magnetron sputtering process.

[0018] In a preferred embodiment, after forming the source electrode and the drain electrode, the method further includes modifying the interface between the metal and the carbon nanotube by a heat treatment process.

[0019] Compared with the prior art, the present invention has the following significant advantages: Excellent oxidation resistance and long-term N-type stability: Existing scandium (Sc) or yttrium (Y) contact materials are chemically reactive and readily oxidize upon oxygen absorption in air, leading to increased interfacial barriers and rapid device performance degradation. This invention employs a MoTi alloy as the contact material, utilizing the chemical stability of Mo to form a dense oxide layer on the alloy surface, providing self-passivation protection and effectively inhibiting oxygen diffusion into the interior and interfacial oxidation. This mechanism significantly improves the device's oxidation resistance in air, enabling it to maintain stable N-type conductivity over a long period, solving the problem of unstable operation of N-type carbon nanotube devices in non-vacuum environments.

[0020] Achieving low-resistance ohmic contacts and improving electron injection efficiency: This invention utilizes alloying to modulate the Fermi level of the contact metal to near the conduction band edge of the carbon nanotube, effectively reducing the Schottky barrier for electron injection. Simultaneously, Mo may form an interface structure containing Mo-C bonds or a localized molybdenum carbide phase with the carbon nanotube at the interface, enhancing the electronic coupling between the metal and the carbon nanotube. The synergistic effect of these two elements achieves stable near-ohmic contacts, significantly reducing contact resistance (experimentally measured at approximately 14 kΩ) and substantially improving the device's on-state current and transconductance.

[0021] Improving Interfacial Wettability and Thin Film Quality: Addressing the issue of poor film quality resulting from the island-like growth of metals such as Sc on carbon nanotube surfaces, this invention utilizes the excellent carbon affinity of Ti to effectively improve the wettability of molten metal or atoms on the carbon nanotube surface. Combined with magnetron sputtering deposition, MoTi alloys can form continuous, dense, and strongly adherent thin film structures, reducing interfacial physical gaps and defect density, thereby improving the electrical consistency and yield of devices.

[0022] Excellent process compatibility and low cost advantages: The MoTi alloy system exhibits good compatibility with mainstream silicon-based CMOS processes and is far less sensitive to the surface cleanliness of carbon nanotubes than Sc or Y, eliminating the need for extremely stringent ultra-high vacuum in-situ cleaning processes, thus greatly expanding the process window. Furthermore, compared to the expensive and supply-constrained rare earth metal Sc, Mo and Ti are both conventional metal materials, inexpensive and widely available, which helps reduce the manufacturing cost of high-performance carbon nanotube integrated circuits and has broad prospects for industrial application. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the MoTi alloy contact CNT FET structure of the present invention; Figure 2 This is a SEM schematic diagram of the MoTi alloy contact CNT FET of the present invention; Figure 3 This is the transfer characteristic curve of the MoTi alloy contact CNT FET of the present invention; Figure 4 This is the output characteristic curve of the MoTi alloy contact CNT FET of the present invention; Figure 5 This invention relates to the extraction of contact resistance of MoTi alloy contact CNT FET; Figure 6 The figure shows the electrical performance curves of a CNT FET as a comparative example of the present invention (the left figure is the transfer characteristic curve, and the right figure is the output characteristic curve). Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] One embodiment of the present invention provides a high-performance N-type carbon nanotube field-effect transistor, such as... Figure 1 and Figure 2As shown, this device addresses the structural optimization issues of easy oxidation and poor interface stability in existing low work function metals (such as Sc and Y). The main body of the device is constructed on a substrate, which can be a highly doped silicon substrate 101 covered with an insulating layer 102 of silicon dioxide or hafnium oxide. A carbon nanotube channel layer 103 serves as a carrier channel on the surface of the insulating layer 102. The carbon nanotube channel layer 103 is a high-purity semiconductor-type carbon nanotube network or array. A source electrode 104 and a drain electrode 105 are respectively located at both ends of the carbon nanotube channel layer 103, and the source electrode 104 and drain electrode 105 are electrically connected to the carbon nanotube channel. The material of the source electrode 104 and drain electrode 105 includes a MoTi alloy with a thickness of 30 nm to 50 nm. The interface between the MoTi alloy and the carbon nanotube channel has an interface structure containing Mo-C bonds or a molybdenum carbide phase. In one embodiment, the source electrode 104 and the drain electrode 105 adopt a single-layer MoTi alloy structure.

[0026] A gate structure is also provided on the carbon nanotube channel layer 103 for regulating the conductivity state of the carbon nanotube channel. The gate structure includes a gate dielectric layer 106 covering the carbon nanotube channel and part of the source and drain electrode surfaces; and a gate electrode 107 located on the gate dielectric layer 106. The material of the gate dielectric layer 106 is selected from HfO2 or Al2O3.

[0027] In the device of this embodiment, the Mo (molybdenum) element in the alloy exhibits excellent chemical stability, forming a dense oxide film on the surface to produce a "self-passivation" effect, effectively preventing oxygen from further diffusing inward. This solves the problem of easy oxidation and failure of traditional rare earth metal electrodes in air, ensuring the long-term N-type conductivity stability of the device. At the micro-interface level, the Mo element can also interact with carbon atoms on the surface of carbon nanotubes to form a stable interface structure containing Mo-C bonds or a locally carbide molybdenum phase. This chemical bonding significantly enhances the electronic coupling between the metal and the carbon nanotubes, providing an efficient tunneling path for charge carriers. Meanwhile, the Ti (titanium) element introduced into the alloy plays a dual regulatory role: on the one hand, Ti has a low work function, which can tune the overall Fermi level of the alloy to near the conduction band edge of the carbon nanotubes, thereby significantly reducing the Schottky barrier during electron injection; on the other hand, Ti has extremely strong carbon affinity, which can effectively improve the wettability of the metal layer on the surface of the carbon nanotubes, fill the interfacial voids, and reduce the defect density.

[0028] In a preferred embodiment of the present invention, the MoTi alloy used for the source and drain electrodes has an atomic ratio of Mo to Ti controlled between 3:7 and 7:3. When the atomic percentage of Mo is less than 30% (i.e., the Ti content is too high), the self-passivating oxide layer on the alloy surface is insufficient to completely cover the extremely reactive Ti atoms, resulting in a significant increase in contact resistance and a decrease in oxidation resistance after the device is placed in air for several days, approaching the performance of pure Ti or rare earth metals. When the atomic percentage of Mo is greater than 70% (i.e., the Ti content is too low), although the material has excellent oxidation resistance, the lack of sufficient low work function Ti to modulate the Fermi level and the weakened Ti-C wetting effect at the interface lead to an increase in the Schottky barrier, resulting in varying degrees of attenuation in the device's on-state current and electron injection efficiency.

[0029] Therefore, to simultaneously ensure a low Schottky barrier and long-term air stability, this invention preferably employs an equiatomic alloy with a Mo:Ti ratio of 1:1, or a molybdenum-rich formulation with a slightly higher Mo content (e.g., Mo:Ti = 6:4), to prioritize meeting the stringent oxidation resistance requirements in non-vacuum environments. In the preparation process, this ratio can be achieved either through direct sputtering using alloy targets with specific proportions, or through dual-target co-sputtering of Mo and Ti targets, with precise control over the composition ratio of the deposited film achieved by adjusting the sputtering power of each target.

[0030] Figure 3 The transfer characteristic curves of the device under different drain-source voltage conditions are presented, where the channel length is 200 nm and the channel width is 10 μm. It can be observed that the device exhibits obvious n-type conductivity under positive gate voltage, and the drain current increases significantly with increasing gate-source voltage, indicating that the MoTi contact can effectively achieve electron injection.

[0031] Figure 4 The output characteristic curves of the device under different gate-source voltage conditions are shown, where the gate-source voltage varies from −2 V to 5 V. It can be clearly seen that as the gate-source voltage increases, the drain current rises overall, and the device gradually transitions from a weakly conducting state to a strongly conducting state, exhibiting typical field-effect modulation characteristics. In the lower drain-source voltage region, the current-voltage relationship is approximately linear, indicating that under turn-on conditions, the source-drain contact has relatively little restriction on carrier transport, and the MoTi alloy contact exhibits ohmic characteristics to some extent.

[0032] Figure 5 The source-drain contact resistance was quantitatively extracted, and the contact resistance corresponding to the MoTi alloy source-drain contact was found to be approximately 14 kΩ. This value is relatively low in short-channel carbon nanotube n-type MOSFETs, indicating that a relatively effective ohmic contact can be formed between the MoTi alloy and the carbon nanotubes.

[0033] Another embodiment of the present invention provides a fabrication process for the above-mentioned carbon nanotube field-effect transistor, specifically including the following steps. First, a substrate is provided, comprising a highly doped silicon substrate and an insulating layer formed on the surface of the highly doped silicon substrate, wherein the insulating layer is a silicon dioxide layer or a hafnium oxide layer. The silicon substrate is cleaned with an organic solvent and rinsed with deionized water, and then dried with nitrogen gas to remove surface organic contaminants and particulate impurities. Subsequently, carbon nanotubes are deposited on the substrate surface. The formation of carbon nanotube channels includes, but is not limited to, solution deposition, spin coating, self-assembly, or chemical vapor deposition followed by transfer. After the carbon nanotube deposition is completed, the carbon nanotube channels are patterned. The channel regions are defined by photolithography or electron beam lithography, and combined with plasma etching, the carbon nanotube material in the non-channel regions is removed, thereby forming a carbon nanotube channel structure with controlled size and well-defined location on the substrate surface.

[0034] After forming the carbon nanotube channel, photoresist is coated on the substrate surface, and the photoresist is patterned by photolithography or electron beam exposure to define the source and drain regions in the photoresist, thereby determining the channel length between the source and drain.

[0035] After defining the source and drain regions using photolithography, a MoTi alloy thin film with a thickness of 30-50 nm is deposited using magnetron sputtering. The MoTi alloy ratio can be adjusted according to device performance requirements. Compared to electron beam evaporation, the high-energy particles generated by magnetron sputtering facilitate a tighter adhesion of the metal to the carbon nanotube surface, promoting the formation of Mo-C bonds at the interface and the filling of oxygen vacancies by Ti. By controlling the sputtering power and deposition time, a uniform and dense alloy layer is obtained. Subsequently, a lift-off process to remove the photoresist removes the MoTi alloy metal layer in the non-patterned areas, thereby forming MoTi alloy source and drain electrodes at both ends of the carbon nanotube channel.

[0036] After forming the source and drain electrodes, a gate dielectric layer is deposited on the carbon nanotube channel and the surface of the source and drain electrodes. This gate dielectric layer includes, but is not limited to, HfO2 or Al2O3, and can be formed using atomic layer deposition. Subsequently, the gate electrode is formed on the gate dielectric layer, thus completing the construction of the top-gate structure. This invention achieves effective control of the metal-carbon nanotube contact barrier without relying on complex doping processes or high bias electric fields, significantly reducing the source and drain contact resistance and improving the electrical consistency and long-term stability of the device. Furthermore, the MoTi alloy contact structure exhibits good process compatibility, can be achieved through conventional magnetron sputtering and subsequent heat treatment processes, and is suitable for bottom-gate or top-gate carbon nanotube field-effect transistors, demonstrating good scalability and industrial application prospects.

[0037] To further verify the significant advantages of the MoTi alloy contact proposed in this invention in terms of oxidation resistance and electrical stability, a comparative example was set up in this embodiment. Under the same substrate conditions, the same carbon nanotube material, and the same fabrication process, only the source and drain electrode materials were replaced with yttrium (Y), a low work function metal commonly used in the prior art, to fabricate a comparative device, and its electrical performance was tested.

[0038] Figure 6 The left figure shows the electrical characteristic curves of a comparative device using Y metal as the contact electrode. The left figure illustrates the transfer characteristics of the comparative device at different drain-source voltages, which are close to 10% compared to the MoTi device of this invention. -4 The on-state current of the A-level device in this comparative example, using a Y-contact, is only maintained at 10. -7 A to 10 -6 The performance drops by approximately 2-3 orders of magnitude, on the order of A. ds The curves exhibit severe oscillations and noise in both the subthreshold and on-state regions. This indicates that Y is chemically reactive and readily oxidizes in air, leading to increased interface state density and enhanced carrier scattering. The comparative device shows a slow turn-on process and lacks a steep subthreshold swing, suggesting that the gate electric field cannot effectively control the channel due to the presence of the interface oxide layer, and that the contact interface barrier is severely affected by surface state pinning.

[0039] Figure 6 The right-hand figure shows the output characteristic curve of the comparative device. As can be seen from the figure, at V... ds In the lower V range (0-0.5V), the current increases extremely slowly and exhibits nonlinear characteristics. This indicates that a loose and porous oxide layer (Y₂O₃) forms on the surface of the Y electrode, resulting in a high Schottky barrier or tunneling impedance at the contact interface, failing to achieve the near-ohmic contact characteristics as in the embodiments of this invention. The output curve shows sharp, jagged fluctuations, and the current magnitude is extremely unstable with scanning (some curves even show crossings or sudden drops). This indicates that the wettability of Y metal and carbon nanotubes is relatively poor.

[0040] A comparison of the embodiments of this invention with Comparative Example 1 shows that although the theoretical work function of Y metal (approximately 3.1 eV) is lower than that of Mo in the MoTi alloy (approximately 4.6 eV), the extreme reactivity of Y in practical applications, especially in non-ultra-high vacuum environments, prevents it from forming stable ohmic contacts. Conversely, the MoTi alloy used in this invention, while incorporating the higher work function of Mo, achieves a dense passivation protective layer on the alloy surface due to Mo's excellent chemical stability, effectively suppressing interfacial oxidation. Combined with the excellent wettability of Ti, this ultimately results in superior N-type conductivity and air stability compared to pure low-work-function metals.

[0041] It should be noted that the above detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0042] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0043] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0044] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0045] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatial relative descriptions used herein will be interpreted accordingly.

[0046] In the detailed description above, reference has been made to the accompanying drawings, which form part of this document. In the drawings, similar symbols typically identify similar parts unless the context otherwise indicates otherwise. The illustrated embodiments described in the detailed specification, drawings, and claims are not intended to be limiting. Other embodiments may be used and other changes may be made without departing from the spirit or scope of the subject matter presented herein.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A carbon nanotube field-effect transistor based on MoTi alloy contacts, characterized in that, include: Substrate; Carbon nanotube channels formed on the substrate; Source electrode and drain electrode, wherein the source electrode and drain electrode are electrically connected to the carbon nanotube channel; as well as A gate structure is used to regulate the conductivity state of the carbon nanotube channel; The source electrode and drain electrode are made of MoTi alloy.

2. The carbon nanotube field-effect transistor based on MoTi alloy contacts according to claim 1, characterized in that, The source electrode and drain electrode adopt a single-layer MoTi alloy structure.

3. The carbon nanotube field-effect transistor based on MoTi alloy contacts according to claim 1, characterized in that, The atomic ratio of Mo to Ti in the MoTi alloy is between 3:7 and 7:3, and the thickness of the MoTi alloy is 30-50 nm.

4. The carbon nanotube field-effect transistor based on MoTi alloy contacts according to claim 1, characterized in that, The interface between the MoTi alloy and the carbon nanotube channel has an interface structure containing Mo-C bonds or a molybdenum carbide phase.

5. The carbon nanotube field-effect transistor based on MoTi alloy contacts according to claim 1, characterized in that, The gate structure is a top-gate structure, comprising: a gate dielectric layer covering the carbon nanotube channel and part of the source electrode and drain electrode surface; and a gate electrode located on the gate dielectric layer.

6. The carbon nanotube field-effect transistor based on MoTi alloy contacts according to claim 5, characterized in that, The material of the gate dielectric layer is selected from HfO2 or Al2O3.

7. The carbon nanotube field-effect transistor based on MoTi alloy contacts according to claim 5, characterized in that, The carbon nanotube channels are carbon nanotube network structures or carbon nanotube array structures.

8. A method for fabricating a carbon nanotube field-effect transistor based on a MoTi alloy contact as described in any one of claims 1-7, characterized in that, Includes the following steps: A substrate is provided, and the surface of the substrate is cleaned. Carbon nanotube channels are formed on the surface of the substrate, and the carbon nanotube channels are patterned. A mask pattern defining source and drain regions is formed on the substrate; A MoTi alloy metal layer is deposited, and the metal layer in the non-source and drain regions is removed by a stripping process to form the source electrode and drain electrode in contact with the carbon nanotube channel. Forming the gate dielectric layer and gate electrode.

9. The method for fabricating a carbon nanotube field-effect transistor based on a MoTi alloy contact according to claim 8, characterized in that, The step of depositing the MoTi alloy metal layer adopts a magnetron sputtering process.

10. The method for fabricating a carbon nanotube field-effect transistor based on a MoTi alloy contact according to claim 8, characterized in that, After forming the source electrode and the drain electrode, the method further includes modifying the interface between the metal and the carbon nanotube through a heat treatment process.

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