Semiconductor device based on internally doped carbon nanotube heterojunction and preparation method thereof
By internally doping carbon nanotubes and filling carbon nanotubes with perovskites, building a heterojunction of internally doped carbon nanotubes has been solved, and the preparation of high-performance carbon nanotube semiconductor devices has been achieved.
Patent Information
- Application Number
- CN202510365242.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2025-06-27
AI Technical Summary
Existing carbon nanotube semiconductor devices have low performance, and external adjustment and doping are difficult, making it difficult to meet the requirements of building high-performance integrated circuits.
By internal doping of carbon nanotubes, perovskites are filled into carbon nanotubes by gas-phase filling method, a heterojunction of internal doped carbon nanotubes is constructed, and a perovskite/carbon nanotube heterojunction is formed, and the carrier concentration and performance are adjusted.
The performance of carbon nanotube semiconductor devices has been improved, and the charge doping effect of carbon nanotubes is accurately adjusted through internal doping technology, the electrical performance of the device is improved, and the band gap tunneling transistor is achieved accurately breaking and sub-threshold swing is reduced.
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Figure CN120224898A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of semiconductors, and particularly relates to a semiconductor device based on an internally doped carbon nanotube heterojunction and a preparation method thereof. Background Art
[0002] As the feature size of semiconductor devices reaches the nanometer level and gradually approaches the physical limit, traditional silicon-based semiconductor technologies face many problems such as short-channel effects and tunneling effects. Physical limitations have begun to seriously hinder the development of semiconductor devices, and the improvement of semiconductor device performance has entered a bottleneck period. As a one-dimensional nanomaterial, carbon nanotube (CNT) has unique electrical properties, such as ultra-high carrier mobility, ballistic transport characteristics, and an intrinsic sub-nanometer scale, etc., and is a strong candidate for breakthrough semiconductor materials in the post-Moore era. However, although carbon nanotubes have many advantages, there are still some problems at the present stage, such as the mixing of carbon nanotubes with different chiralities in carbon nanotubes, the mixing of metallic carbon nanotubes and semiconductor carbon nanotubes, etc. The performance of the constructed carbon nanotube semiconductor devices is poor and it is difficult to meet the requirements for constructing high-performance integrated circuits.
[0003] Therefore, it is necessary to regulate traditional carbon nanotubes to improve the performance of carbon nanotube semiconductor devices. Traditional silicon-based semiconductors achieve lattice substitution doping through processes such as ion implantation and diffusion, thereby precisely regulating the type and concentration of carriers. However, carbon nanotubes are composed of a six-membered ring honeycomb structure formed by C-C sp2 bonds, showing extremely high chemical stability and structural integrity, making it very difficult to perform substitution doping on carbon nanotubes. In the prior art, the electrical properties of carbon nanotubes are adjusted from the outside, such as undoped processes and gate dielectric doping. Although the polarity of carbon nanotubes can be adjusted to construct high-performance devices, this kind of doping is not precise enough and lacks stability.
[0004] Therefore, it is necessary to seek a more precise and stable method for doping carbon nanotubes, and at the same time, it can improve the performance of carbon nanotube semiconductor devices. Summary of the Invention
[0005] Object of the Invention: To solve the technical problems of the low performance of existing carbon nanotube devices and the difficulty of external regulation and doping, the first object of the present invention is to provide a semiconductor device based on an internally doped carbon nanotube heterojunction with high performance, and the second object of the present invention is to provide a preparation method for the above-mentioned semiconductor device based on an internally doped carbon nanotube heterojunction.
[0006] Technical Solution: The semiconductor device based on an internally doped carbon nanotube heterojunction described in the present invention includes a substrate, an internally doped perovskite heterojunction layer of carbon nanotubes, a gate dielectric layer, and a gate electrode in sequence from bottom to top, and a source electrode and a drain electrode are respectively provided at both ends of the gate dielectric layer.
[0007] Further, the doping method of the perovskite is full doping or partial internal doping.
[0008] Further, the perovskite is cesium lead halide perovskite, cesium tin iodide or perovskite oxide, preferably CsPbBr3.
[0009] Further, the substrate is a SiO2 / Si substrate; the gate dielectric layer is a high-K gate dielectric HfO2, Al2O3, ZrO2 or TiO2; the metals used for the source electrode, drain electrode and gate electrode are gold, palladium or titanium.
[0010] The preparation method of the above semiconductor device based on the internally doped carbon nanotube heterojunction includes the following steps:
[0011] (1) Based on the gas-phase filling method, fill the perovskite into the interior of the carbon nanotubes to obtain a carbon nanotube internally doped perovskite heterojunction;
[0012] (2) Disperse the carbon nanotube internally doped perovskite heterojunction in a solvent, drop it onto the substrate, and obtain a carbon nanotube internally doped perovskite heterojunction layer after drying treatment;
[0013] (3) Prepare a source electrode and a drain electrode on the carbon nanotube internally doped perovskite heterojunction layer;
[0014] (4) Deposit a gate dielectric layer between the source electrode and the drain electrode;
[0015] (5) Prepare a gate electrode on the gate dielectric layer.
[0016] Further, in step (1), the preparation process of the carbon nanotube internally doped perovskite heterojunction is as follows: Place a small quartz tube containing bulk perovskite on the quartz with carbon nanotubes, and perform high-temperature filling treatment in a vacuum-sealed environment. After completion, wash and dry to obtain it.
[0017] Further, the carbon nanotubes are subjected to pre-opening treatment: calcine in air at a temperature of 693 - 695K for 15 - 30 min; the mass ratio of the perovskite to the carbon nanotubes is 2 - 3:1; the vacuum degree of the vacuum seal < 10 -4 Pa.
[0018] Further, the conditions for the high-temperature filling treatment are: heat at 820 - 850K for 1 - 12h.
[0019] Principle of the Invention: Carbon nanotubes have a unique one-dimensional tubular structure. In this invention, internal doping of carbon nanotubes is carried out by filling the host material perovskite into the carbon nanotubes to construct an internally doped carbon nanotube heterojunction, thereby improving the performance of carbon nanotube semiconductor devices. The internally filled host material can interact with the carbon nanotubes to conduct charge exchange, change the carrier concentration, and regulate the performance of the carbon nanotubes. At the same time, the carbon nanotubes and the internally filled host material form a heterojunction. By designing the composition of the heterojunction, high-performance carbon nanotube semiconductor devices can be constructed. Through the interface states of the heterojunction, the energy band structure differences of different materials are regulated, promoting the separation and transmission of carriers, improving the efficiency of the device, reducing the subthreshold swing, and a Schottky barrier can also be formed to achieve rectifying characteristics or tunneling effects, thus enhancing the device performance. Meanwhile, when constructing a heterojunction by internal filling doping of carbon nanotubes, the types and positions of the filled host materials can be freely selected. By adjusting the filling method and filling conditions, the filling length and filling rate of the host material filled into the carbon nanotubes can be effectively controlled to construct partially filled and fully filled carbon nanotube heterojunctions. By controlling the types and filling positions of the host materials, the interface states of the heterojunction can be changed to achieve a sharp interface of the heterojunction and effectively increase the interband tunneling probability, realizing a quasi-breakbandgap tunneling transistor and enhancing the performance of carbon nanotube heterojunction semiconductor devices.
[0020] Advantages: Compared with the prior art, the present invention has the following remarkable advantages: By internally doping carbon nanotubes and filling the host material into the carbon nanotubes to construct an internally doped carbon nanotube heterojunction, it has better electrical properties. The internally filled host material interacts with the carbon nanotubes, resulting in the transfer of charges, regulating the concentration of electron holes, and changing the performance of the carbon nanotubes. At the same time, the internally doped carbon nanotubes form a heterojunction. By controlling the diameter of the carbon nanotubes, the types and filling positions of the host materials, the interface states of the heterojunction can be changed to achieve a sharp interface of the heterojunction and effectively increase the interband tunneling probability, realizing a quasi-breakbandgap tunneling transistor and enhancing the performance of carbon nanotube semiconductor devices. Description of the Drawings
[0021] Figure 1 It is a schematic structural diagram of a semiconductor device including an internally doped carbon nanotube heterojunction;
[0022] Figure 2 It is a schematic model diagram of carbon nanotubes internally doped with perovskite;
[0023] Figure 3 It is a STEM diagram of unfilled, fully filled, and semi-filled carbon nanotubes;
[0024] Figure 4 It is a transfer curve diagram of an unfilled internally doped carbon nanotube heterojunction;
[0025] Figure 5Measurement diagram of the transfer curve of a carbon nanotube heterojunction with partial internal doping of carbon nanotubes;
[0026] Figure 6 Transfer curve diagram of a fully doped carbon nanotube carbon nanotube heterojunction;
[0027] Figure 7 Comparison diagram of the subthreshold swing of an undoped carbon nanotube device and a partially doped carbon nanotube heterojunction device. Specific implementation manners
[0028] Next, the present invention will be further described in conjunction with specific embodiments and the accompanying drawings.
[0029] Embodiment 1: The semiconductor device based on an internally doped carbon nanotube heterojunction provided in this embodiment, as Figure 1 shown, sequentially includes a substrate, an internally doped perovskite heterojunction layer of carbon nanotubes, a gate dielectric layer, and a gate from bottom to top. Source and drain electrodes are respectively provided at both ends of the gate dielectric layer. Among them, the doping method of perovskite is full doping, the perovskite is CsPbBr3, and the schematic model diagram after the carbon nanotubes are internally doped with perovskite is as Figure 2 shown.
[0030] Cesium lead tribromide (CsPbBr3) is used as the guest substance for filling. The filling position and amount are all of the carbon nanotubes to construct a coaxial perovskite / carbon nanotube heterojunction to realize a high-performance carbon nanotube heterojunction semiconductor device. The specific preparation process is as follows:
[0031] (1) Internal doping of carbon nanotubes: Using the gas-phase filling method, a small quartz tube containing 10 mg of bulk perovskite is placed on quartz with 5 mg of carbon nanotubes. Among them, the carbon nanotubes are opened in air at a temperature of 693 K, and then the entire system is also sealed under a vacuum of 10 - 4 Pa and heated at 823 K for 12 h. Then each filled carbon nanotube is washed repeatedly with ethanol and deionized water.
[0032] (2) Preparation of semiconductor FET device: Drop the sample solution of carbon nanotubes internally doped with perovskite onto a silicon dioxide / silicon substrate. Based on the position information, source / drain electrodes are patterned by electron beam lithography (EBL), and 20 / 40 nm palladium (Pd) / gold (Au) is evaporated by electron beam evaporation (EBE) as the source / drain electrodes. Next, the top gate window is patterned by EBL, and then a 10-nm-thick hafnium dioxide (HfO2) is grown by atomic layer deposition (ALD) at 90 degrees as the gate dielectric layer. Finally, the gate metal and the upper interconnect area are patterned by EBL, and then 0.3 / 20 nm titanium (Ti) / gold (Au) is evaporated by EBE as the gate electrode.
[0033] Example 2: The difference from Example 1 is that cesium lead tribromide perovskite (CsPbBr3) is used as the guest material for filling, and the filling position and amount are half of that of the carbon nanotubes.
[0034] Comparative Example 1: The difference from Example 1 is that the carbon nanotubes are not filled.
[0035] The carbon nanotubes and devices prepared in Examples 1 - 2 and Comparative Example 1 were characterized and tested, and the results are shown in Figures 3 - 7 .
[0036] Figure 3 Scanning transmission electron microscope (STEM) images of carbon nanotubes with unfilled, fully filled, and half-filled perovskite doping are shown. It can be seen from the images that the number and position of perovskite atoms filled in the fully doped and partially internally doped cases are different. The interior of the fully doped carbon nanotubes is completely filled with perovskite, while only a part of the partially internally doped carbon nanotubes is filled with perovskite.
[0037] Figure 4 This is the transfer curve measured for the undoped carbon nanotube heterojunction device, which has obvious bipolarity and a poor subthreshold swing of the curve.
[0038] Figure 5 This is the transfer curve measured for the partially internally doped carbon nanotube heterojunction device. It can be found that its subthreshold swing reaches 27 mV / dec, having an extremely low subthreshold swing, and can be regarded as a quasi-bandgap tunneling transistor.
[0039] Figure 6 This is the transfer curve measured for the fully internally doped carbon nanotube heterojunction device, which also has obvious bipolarity and a poor subthreshold swing.
[0040] Figure 7 This is a comparison chart of the subthreshold swings of the undoped carbon nanotube device and the partially internally doped carbon nanotube heterojunction device. The subthreshold swing of the ordinary carbon nanotube device is above 60 mV / dec, while that of the partially filled internally doped carbon nanotube heterojunction device can reach nearly 20 mV / dec.
[0041] In summary, the present invention improves the performance of carbon nanotube semiconductor devices by internally doping carbon nanotubes to construct internally doped carbon nanotube heterojunctions. Compared with traditional carbon nanotube semiconductor devices, internally doped carbon nanotubes can stably and precisely adjust the charge doping effect on the carbon nanotubes in the channel or source / drain regions, improving the performance of carbon nanotube devices. At the same time, by selecting the type and position of the internally doped substance, the interface contact and interaction of the internally filled carbon nanotube heterojunction can be regulated, achieving an increase in the interband tunneling probability, a reduction in the subthreshold swing, etc., realizing a quasi-bandgap tunneling transistor, which can be used to construct high-performance semiconductor devices.
Claims
1. A semiconductor device based on an internally doped carbon nanotube heterojunction, characterized in that: The system comprises, from bottom to top, a substrate, a carbon nanotube-doped perovskite heterojunction layer, a gate dielectric layer and a gate electrode, wherein two ends of the gate dielectric layer are provided with a source electrode and a drain electrode respectively.
2. The semiconductor device based on the internally doped carbon nanotube heterojunction according to claim 1, characterized in that: The perovskite is doped in a manner of full doping or partial internal doping.
3. The semiconductor device based on the internally doped carbon nanotube heterojunction according to claim 1, characterized in that: The perovskite is cesium lead halide perovskite, cesium tin iodide or perovskite oxide.
4. The semiconductor device based on the internally doped carbon nanotube heterojunction according to claim 1, characterized in that: The gate dielectric layer is a high-K gate dielectric HfO2, Al2O3, ZrO2 or TiO2.
5. The semiconductor device based on internally doped carbon nanotube heterojunction according to claim 1, characterized in that: The metals used for the source electrode, the drain electrode and the gate electrode are gold, palladium or titanium.
6. The semiconductor device based on internally doped carbon nanotube heterojunction according to claim 1, characterized in that: The substrate is a SiO2 / Si substrate.
7. A method for preparing a semiconductor device based on an internally doped carbon nanotube heterojunction according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Based on the gas phase filling method, perovskite is filled into the interior of carbon nanotubes to prepare a carbon nanotube-doped perovskite heterojunction; (2) dispersing the carbon nanotube-doped perovskite heterojunction in a solvent, dropping the mixture onto a substrate, and drying the mixture to obtain a carbon nanotube-doped perovskite heterojunction layer; (3) preparing source and drain electrodes on the carbon nanotube-doped perovskite heterojunction layer; (4) depositing a gate dielectric layer between the source and drain; (5) A gate is prepared on the gate dielectric layer.
8. The preparation method according to claim 7, characterized in that: In step (1), the preparation process of the carbon nanotube-doped perovskite heterojunction is as follows: a small quartz tube containing bulk perovskite is placed on quartz with carbon nanotubes, and a high-temperature filling treatment is performed in a vacuum-sealed environment, and then washed and dried to obtain the result.
9. The preparation method according to claim 8, characterized in that: The carbon nanotubes are pre-opened: calcined in air at a temperature of 693-695K for 15-30min; the mass ratio of the perovskite to the carbon nanotubes is 2-3:1; the vacuum degree of the vacuum seal is less than 10 -4 Pa.
10. The preparation method according to claim 8, characterized in that: The conditions of the high temperature filling treatment are: heating at 820-850K for 1-12h.