A bismuth selenide two-dimensional vertical fin array and a wafer-level batch preparation method thereof

Abstract

The application discloses a kind of bismuth selenide two-dimensional vertical fin (Fin) array and its wafer-level batch preparation method.The method comprises the following steps: using LaAlO3(100), LaAlO3(110) and SrTiO3(110) single crystal wafer as substrate, Bi2O3 powder, Bi2Se3 bulk and high-purity oxygen as raw material for chemical vapor deposition, and the two-dimensional Bi2O2Se vertical fin array wafer is obtained after deposition is completed.The method is economical, simple and easy to operate, and the obtained wafer-level two-dimensional Bi2O2Se vertical fin array has broad application prospect.

Description

Technical Field

[0001] This invention belongs to the fields of semiconductor materials and chemical vapor deposition (CVD) preparation technology, and specifically relates to a two-dimensional vertical fin (Fin) array of bismuth selenide oxide semiconductor and its wafer-level mass production method, which is suitable for large-scale mass production of wafer-level bismuth selenide oxide semiconductor two-dimensional vertical fin (Fin) arrays. Background Technology

[0002] Vertical fins (Fin) have dominated modern transistor miniaturization as the device channel structure. Since the 22nm semiconductor process, vertical fins have successfully maintained the reliability of transistor channel length reduction and are the mainstream channel structure for the most advanced commercial 5nm process integrated circuits. In the post-Moore's Law era, vertical fins remain a focus, with consideration being given to developing vertical fin gate-around (VGAA) devices or vertical transport field-effect transistors (VTFETs) based on vertical fin structures to meet the requirements of nodes after 2nm and continue to uphold Moore's Law. In particular, VTFET devices fabricated on vertical fin channels are considered a breakthrough in semiconductor design and have attracted significant attention from manufacturers such as IBM and Samsung. Unlike traditional three-dimensional semiconductors such as Si, GeSi, Ge, and III-V compounds, two-dimensional layered semiconductors possess characteristics such as no dangling bonds on the surface, atomic-level thickness, and high mobility, making them a promising alternative to bulk silicon. Furthermore, the International Device and System Roadmap (IRDS), shared by manufacturers and material suppliers, has recommended two-dimensional semiconductors as channel materials for the post-silicon era to enhance device gate control, increase device drive current, and improve the integration density of logic circuits. Therefore, fabricating two-dimensional layered semiconductors into vertical two-dimensional fins would mark a milestone in its advancement towards next-generation transistors with very large scale. However, fabricating self-supporting vertical two-dimensional fin arrays of high-mobility two-dimensional layered semiconductors has remained a challenge and has not been reported.

[0003] Bismuth selenide oxide (Bi₂O₂Se) is a novel high-mobility two-dimensional semiconductor belonging to the tetragonal crystal system. Z=2), from (Bi2O2) n Layers and Se n Bi₂O₂Se exhibits a two-dimensional layered crystal structure due to its alternating connections. Its unique crystal and band structure endows it with excellent environmental stability, as well as superior physicochemical properties, including electrical, optical, and optoelectronic performance. As a two-dimensional semiconductor layered material with ultra-high mobility, Bi₂O₂Se nanosheets prepared by conventional chemical vapor deposition can achieve a low-temperature Hall mobility exceeding 20,000 cm⁻¹. 2 V -1 s -1 Its field-effect electron mobility is as high as 2200 cm⁻¹ at room temperature.2 V -1 S -1 The on / off ratio is as high as 10. 6 With a subthreshold swing as low as 65 mV / dec, it has the potential application in the field of novel high-performance nano-logic devices. However, to date, two-dimensional vertical fins based on two-dimensional Bi₂O₂Se semiconductors have not been reported. The controllable synthesis of wafer-level two-dimensional Bi₂O₂Se vertical fin arrays will bring new opportunities for the application of two-dimensional semiconductor materials and the development of novel devices. Summary of the Invention

[0004] The purpose of this invention is to provide a high-quality two-dimensional vertical fin array of bismuth selenide oxide and a wafer-level mass production method for chemical vapor deposition. This method has the advantages of low cost, simple process and good controllability, and therefore can be regarded as an ideal method for mass production of two-dimensional vertical fin arrays of bismuth selenide oxide semiconductors.

[0005] The two-dimensional Bi2O2Se vertical fins are obtained by nucleating vertically oriented on a positive polar surface and growing vertically to obtain a two-dimensional Bi2O2Se Fin array.

[0006] The method for mass production of wafer-level two-dimensional Bi₂O₂Se vertical fin arrays provided by this invention includes the following steps:

[0007] Using a single-crystal wafer as the growth substrate, Bi2O3 powder and Bi2Se3 bulk or Bi2Se3 bulk and high-purity oxygen as raw materials, chemical vapor deposition is performed to obtain the two-dimensional Bi2O2Se vertical fin array after deposition.

[0008] In the above chemical vapor deposition method, the raw material reaction method is of two types: oxidation method and co-volatilization method;

[0009] Using Bi2Se3 bulk and high-purity oxygen as raw materials, the corresponding reaction method is oxidation; using Bi2O3 powder and Bi2Se3 bulk as raw materials, the corresponding reaction method is co-volatilization.

[0010] In the oxidation process, the molar ratio of Bi2Se3 bulk to high-purity oxygen is 1:3; the SeO2 produced by the oxidation process is automatically discharged with the tail gas.

[0011] In the co-volatilization method, the molar ratio of Bi2O3 powder to Bi2Se3 bulk is 2:1.

[0012] The chemical vapor deposition is performed on a single-crystal wafer substrate;

[0013] The wafer substrate is selected from at least one of the following: lanthanum aluminate (100) single crystal wafer, lanthanum aluminate (110) single crystal wafer, and strontium titanate (110) single crystal wafer, with the chemical formulas LaAlO3, LaAlO3, and SrTiO3, respectively.

[0014] The wafer substrate size can be 1-3 inches, specifically 1, 1.5, 2 or 3 inches.

[0015] In the chemical vapor deposition step, the carrier gas is argon.

[0016] The argon flow rate is 50-150 sccm, specifically 50, 100, or 150 sccm.

[0017] The system pressure is 300-500 Torr, specifically 300, 400 or 500 Torr.

[0018] The deposition temperature is 610-710℃, specifically 610℃, 620℃, 630℃, 640℃, 650℃, 680℃ or 710℃.

[0019] The deposition time is 1-5 minutes, specifically 1, 2, 3, 4 or 5 minutes.

[0020] The chemical vapor deposition can be carried out in a tube furnace;

[0021] The tube furnace has a tube diameter of 1.5–4.5 inches, specifically 1.5, 2, 3 or 4.5 inches.

[0022] More specifically, the raw material is located at the center of the tubular furnace.

[0023] The wafer substrate is located downstream of or at the center of the tube furnace. Specifically, downstream refers to a location 8-10 cm from the center. In this invention, "downstream" aligns with the downstream direction of the carrier gas flow.

[0024] The method further includes the following step: after the chemical vapor deposition step, the system is rapidly cooled to room temperature.

[0025] Figure 1 This is a schematic diagram of the method for growing a two-dimensional Bi2O2Se vertical fin array according to the present invention. The two-dimensional Bi2O2Se vertical fins are obtained by nucleating vertically oriented by polarity induction on a positive polarity surface, and the vertical nuclei grow to obtain a two-dimensional Bi2O2Se Fin array.

[0026] Figure 2 This is a crystal structure diagram of Bi2O2Se and LaAlO3(100), LaAlO3(110) and SrTiO3(110) wafer substrates introduced in this invention.

[0027] Figure 3 This is a schematic diagram of three methods for growing two-dimensional Bi2O2Se vertical fin arrays by chemical vapor deposition according to the present invention.

[0028] The wafer-level two-dimensional Bi2O2Se vertical fin array prepared by the above method and its application in the preparation of Fin Field Effect Transistors (FinFETs) based on the two-dimensional Bi2O2Se vertical fin array wafer are also within the scope of protection of this invention.

[0029] In this invention, the wafer-level two-dimensional Bi2O2Se vertical fin array prepared by this chemical vapor deposition method can reach a size of more than 3 inches. This method is economical, simple and easy to implement, and the resulting vertical fins have high mobility and broad application prospects.

[0030] The features and beneficial effects of this invention are:

[0031] 1. This invention employs chemical vapor deposition technology, using LaAlO3(100), LaAlO3(110), and SrTiO3(110) single crystal wafers as growth substrates, and utilizes the polar surface of the epitaxial surface to grow a two-dimensional Bi2O2Se vertical fin array.

[0032] 2. The process of this invention is simple, easy to operate, and low in cost, and it is expected to be applied to the mass production of wafer-level two-dimensional Bi2O2Se vertical fin arrays; laying the foundation for the application of two-dimensional Bi2O2Se vertical fin arrays in nanoelectronic devices, FinFET, VTFET or VGAA devices and other nanoelectronic fields. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the method for growing a two-dimensional Bi2O2Se vertical fin array according to the present invention.

[0034] Figure 2 Crystal structure diagrams of Bi2O2Se, LaAlO3, and SrTiO3 as described in this invention;

[0035] Figure 3 This is a schematic diagram of three methods for growing two-dimensional Bi2O2Se vertical fin arrays by chemical vapor deposition according to the present invention;

[0036] Figure 4 These are optical and SEM images of the two-dimensional Bi₂O₂Se vertical fin array wafer obtained in Embodiment 1 of this invention.

[0037] Figure 5 This is a two-dimensional Bi₂O₂Se vertical fin array SEM image obtained in Embodiment 2 of the present invention;

[0038] Figure 6 These are SEM images of the two-dimensional Bi2O2Se vertical fin array obtained in embodiments 3 and 4 of this invention. Detailed Implementation

[0039] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments. Unless otherwise specified, the methods described are conventional methods. Unless otherwise specified, the raw materials are all available from publicly available commercial sources.

[0040] Example 1

[0041] Weigh 3.0 g of Bi₂O₃ powder and 2.5 g of Bi₂Se₃ bulk and place them in the center of the quartz tube of a tube furnace. Next, place a 3-inch LaAlO₃(100) single crystal wafer (Hefei Kejing Materials Technology Co., Ltd.) in the center of the tube furnace. Introduce argon as the carrier gas and maintain the system pressure at 400 Torr. Raise the temperature to 630°C and maintain it for 1 minute to perform chemical vapor deposition. After deposition, stop introducing the carrier gas, allow it to cool naturally to 400°C, and then rapidly air-cool it to room temperature. Remove the LaAlO₃(100) wafer with the deposited two-dimensional Bi₂O₂Se vertical fin array to obtain the two-dimensional Bi₂O₂Se vertical fin array wafer.

[0042] Figure 4 The image shows optical and SEM images of a two-dimensional Bi2O2Se vertical fin array grown on a LaAlO3(100) single crystal wafer obtained in this embodiment. As can be seen from the image, the obtained two-dimensional Bi2O2Se vertical fins are square nanosheets with two orientations of 0° and 90°, and are strictly perpendicular to the substrate surface.

[0043] Example 2

[0044] Weigh 3.0 g of Bi₂O₃ powder and 2.5 g of Bi₂Se₃ bulk and place them in the center of the quartz tube of the tube furnace. Next, place a 1-inch LaAlO₃(110) and SrTiO₃(110) single crystal wafer in the center of the tube furnace. Introduce argon as the carrier gas and maintain the system pressure at 400 Torr. Raise the temperature to 630 degrees Celsius and maintain it for 1 minute to perform chemical vapor deposition. After deposition, stop the introduction of the carrier gas, allow it to cool naturally to 400 degrees Celsius, and then rapidly air-cool it to room temperature. Remove the LaAlO₃(110) and SrTiO₃(110) wafers with the two-dimensional Bi₂O₂Se vertical fin array deposited on them to obtain the two-dimensional Bi₂O₂Se vertical fin array wafer.

[0045] Figure 5 The image shows a SEM image of the two-dimensional Bi2O2SeFin array grown on a single crystal wafer of LaAlO3(110) and SrTiO3(110) obtained in this embodiment. As can be seen from the image, the obtained two-dimensional Bi2O2Se vertical fins are triangular nanosheets, the array is unidirectional, and is strictly perpendicular to the substrate surface.

[0046] Example 3

[0047] Weigh 3.0 g of Bi₂O₃ powder and 2.5 g of Bi₂Se₃ bulk and place them in the center of the quartz tube of the tube furnace. Next, place a 3-inch LaAlO₃(100) single crystal wafer 8 cm downstream of the center of the tube furnace. Introduce argon as the carrier gas and maintain the system pressure at 400 Torr. Raise the temperature to 710°C and maintain it for 1 minute to perform chemical vapor deposition. After deposition, stop the introduction of the carrier gas, allow it to cool naturally to 400°C, and then rapidly air-cool it to room temperature. Remove the LaAlO₃(100) wafer with the two-dimensional Bi₂O₂Se vertical fin array deposited on it to obtain the two-dimensional Bi₂O₂Se vertical fin array wafer.

[0048] Figure 6 Image (B) is a SEM image of the two-dimensional Bi2O2Se vertical fin array grown on a LaAlO3(100) single crystal wafer obtained in this embodiment; as can be seen from the image, the obtained two-dimensional Bi2O2Se vertical fin array is strictly perpendicular to the substrate surface.

[0049] Example 4

[0050] Weigh 2.5 grams of Bi₂Se₃ bulk and place it in the center of the quartz tube of the tube furnace. Next, place a 3-inch LaAlO₃(100) single crystal wafer in the center of the tube furnace. Introduce argon as the carrier gas and 50 ppm of high-purity oxygen to maintain the system pressure at 400 Torr. Raise the temperature to 620 degrees Celsius and maintain it for 1 minute to perform chemical vapor deposition. After deposition, stop the introduction of the carrier gas, allow it to cool naturally to 400 degrees Celsius, and then rapidly air-cool it to room temperature. Remove the LaAlO₃(100) wafer with the two-dimensional Bi₂O₂Se vertical fin array deposited on it to obtain the two-dimensional Bi₂O₂Se vertical fin array wafer.

[0051] Figure 6 Image (D) is a SEM image of the two-dimensional Bi2O2Se vertical fin array grown on a LaAlO3(100) single crystal wafer obtained in this embodiment; as can be seen from the image, the obtained two-dimensional Bi2O2Se vertical fin array is strictly perpendicular to the substrate surface.

Claims

1. A method for batch fabrication of wafer-level two-dimensional Bi₂O₂Se vertical fin arrays, comprising the following steps: Using a single-crystal wafer as the growth substrate, Bi2O3 powder and Bi2Se3 bulk as raw materials or Bi2Se3 bulk and high-purity oxygen as raw materials, chemical vapor deposition is performed to obtain the wafer-level two-dimensional Bi2O2Se vertical fin array after deposition. The chemical vapor deposition is performed on a single-crystal wafer substrate; The single-crystal wafer substrate is selected from at least one of the following: lanthanum aluminate (100) single-crystal wafer, lanthanum aluminate (110) single-crystal wafer, and strontium titanate (110) single-crystal wafer.

2. The method according to claim 1, characterized in that: Bi2O3 powder and Bi2Se3 bulk are used as raw materials, and the reaction method of the raw materials is co-volatilization; the molar ratio of Bi2O3 powder and Bi2Se3 bulk is 2:

1.

3. The method according to claim 1, characterized in that: Using Bi2Se3 bulk and high-purity oxygen as raw materials, the reaction method of the raw materials is oxidation; in the oxidation method, the molar ratio of Bi2Se3 bulk to high-purity oxygen is 1:

3.

4. The method according to any one of claims 1-3, characterized in that: The size of the single-crystal wafer substrate is 1-3 inches.

5. The method according to any one of claims 1-3, characterized in that: In the chemical vapor deposition step, the carrier gas is argon. The argon gas flow rate is 50-150 sccm; The system pressure is 300-500 Torr; The deposition temperature is 610-710℃; The deposition time is 1-5 minutes.

6. The method according to any one of claims 1-3, characterized in that: The chemical vapor deposition is carried out in a tube furnace; The tube furnace has a tube diameter of 1.5-4.5 inches.

7. The method according to claim 6, characterized in that: The raw material is located at the center of the tubular furnace; The wafer substrate is located downstream of or at the center of the tube furnace; specifically, downstream is a position 8-10 cm from the center.

8. The method according to any one of claims 1-3, characterized in that: The method further includes the following step: after the chemical vapor deposition step, the system is rapidly cooled to room temperature.

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