Method for preparing large-area Bi2O2Se semiconductor thin film by magnetron sputtering

Abstract

This invention discloses a method for preparing large-area Bi₂O₂Se semiconductor thin films by magnetron sputtering, belonging to the field of semiconductor materials technology. The steps are as follows: using a Bi₂O₂Se target as the target material, vacuum magnetron sputtering is performed on a cleaned substrate, maintaining the temperature between 450°C and 600°C during the sputtering process. This invention utilizes magnetron sputtering technology to change the temperature of the sputtering chamber, thereby controlling the growth temperature of the Bi₂O₂Se thin film, producing large-area continuous thin films with uniform thickness, low process difficulty, simple process flow, high efficiency, and high repeatability.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor thin film material preparation technology, specifically relating to a method for preparing a large-area Bi2O2Se semiconductor thin film. Background Technology

[0002] Two-dimensional materials, with a thickness of only one or a few atoms, confine electrons and phonons within a two-dimensional interlayer lattice, resulting in many novel optical and electrical properties not found in three-dimensional materials, attracting significant attention from academia and the semiconductor industry. While layered two-dimensional materials offer many advantages in information processing device applications, they also present numerous challenges. For example, graphene has high electron mobility but no band gap, transition metal sulfides have band gaps but low mobility, and black phosphorus possesses both a band gap and high mobility but suffers from poor air stability. Therefore, finding high-performance semiconductor materials has become one of the primary issues in the post-Moore's Law era. Bismuth selenide oxide (Bi₂O₂Se) is a layered bismuth oxychalcogenide compound, initially attracting attention and research as a thermoelectric material. Recent studies have revealed that ultrathin layered Bi₂O₂Se semiconductor devices simultaneously possess advantages such as a moderate band gap, high room-temperature Hall mobility, and high environmental stability. These characteristics effectively overcome short-channel effects, making Bi₂O₂Se considered an ideal semiconductor channel material for next-generation high-speed, low-power information processing chips (including logic devices and memory devices).

[0003] To date, the preparation of Bi₂O₂Se semiconductor thin film materials mainly relies on chemical vapor deposition (CVD). However, CVD is a complex process with cumbersome control methods, making stable production difficult. Furthermore, its strong substrate dependence, unstable film quality, and difficulty in obtaining wafer-level continuous films also limit its industrial-scale production. Therefore, there is an urgent need to explore and develop a method for synthesizing stable Bi₂O₂Se semiconductor thin film materials suitable for industrial-scale production. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing a large-area Bi2O2Se semiconductor thin film, which achieves the growth of a continuous Bi2O2Se thin film on the entire substrate using a magnetron sputtering device, and the film thickness is uniform, making it suitable for mass production in industry.

[0005] The technical solution to achieve the purpose of this invention is: a method for preparing a large-area Bi2O2Se semiconductor thin film, using Bi2O2Se target material as the target material, performing vacuum magnetron sputtering on a clean substrate, and maintaining the temperature between 450 ℃ and 600 ℃ during the sputtering process.

[0006] Preferably, the substrate is a silicon oxide substrate or an Al2O3 substrate.

[0007] Specifically, the Al2O3 substrate is an Al2O3 single crystal substrate with a (0001) crystal orientation.

[0008] Specifically, the silicon oxide substrate has a Si thickness of 500 μm ± 10 nm, is p-type doped, has a resistivity of 0.001 ~ 0.005 Ω•cm, and a SiO2 thickness of 300 nm ± 10 nm.

[0009] Preferably, the cleaned substrate is ultrasonically cleaned for 10 minutes in sequence with acetone and anhydrous ethanol, and then removed and dried with nitrogen.

[0010] Preferably, the Bi2O2Se target material has a purity of 99.9%, a thickness of 3 mm, and a diameter of 50.8 mm.

[0011] Preferably, the distance between the Bi2O2Se target and the substrate is 7.2 cm.

[0012] Preferably, the vacuum level is higher than 5 × 10⁻⁶ during sputtering. -5 Pa.

[0013] Preferably, a resistance wire heating device is used to heat the sputtering chamber to 450 ℃ to 600 ℃.

[0014] Preferably, the protective gas is Ar with a purity of 99.995% and a pressure of 0.4 Pa.

[0015] Ideally, during sputtering, the RF power is adjusted to 20 watts and the stage speed is adjusted to 20 revolutions per minute.

[0016] Compared with existing technologies, this invention has the following advantages: This invention utilizes magnetron sputtering technology to change the temperature of the sputtering chamber, thereby controlling the growth temperature of the Bi₂O₂Se thin film and producing a large-area continuous thin film with uniform thickness, low operational difficulty, simple process flow, high efficiency, and high repeatability. Compared with previously reported chemical vapor deposition preparation methods, this thin film preparation method has significant advantages and is a production method suitable for industrial applications. Attached Figure Description

[0017] Figure 1 The image shows the Raman spectrum of the Bi2O2Se thin film prepared in Example 1 of this invention.

[0018] Figure 2 The image shows the Raman spectrum of the Bi2O2Se thin film prepared in Example 2 of this invention.

[0019] Figure 3 The image shows the Raman spectrum of the Bi2O2Se thin film prepared in Example 3 of this invention.

[0020] Figure 4 The image shows the Raman spectrum of the Bi2O2Se thin film prepared in Example 4 of this invention.

[0021] Figure 5 The image shows the Raman spectrum of the Bi2O2Se thin film prepared in Example 5 of this invention.

[0022] Figure 6 The image shows the Raman spectrum of the Bi2O2Se thin film prepared in Example 6 of this invention.

[0023] Figure 7 The image shows the Raman spectrum of the Bi2O2Se thin film prepared in Example 7 of this invention.

[0024] Figure 8 The image shows the Raman spectrum of the Bi2O2Se thin film prepared in Example 8 of this invention. Detailed Implementation

[0025] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. After reading this invention, any modifications of the invention in various equivalent forms by those skilled in the art will fall within the scope defined by the appended claims.

[0026] Example 1

[0027] Step (1): Cut the 4-inch silicon oxide wafer into 20 cm × 20 cm pieces using a silicon cutter.

[0028] Step (2): Clean the cut silicon oxide wafers with an ultrasonic cleaner for 10 minutes each in industrial-grade acetone with a purity of 99.95% or higher and anhydrous ethanol with a purity of 99.97% or higher, and then dry them with nitrogen.

[0029] Step (4): Mount the Bi2O2Se target material with a purity of 99.9% and a diameter of 50.8 mm onto the RF target position of the magnetron sputtering equipment; fix the cleaned silicon oxide substrate on the stage in the sputtering cavity.

[0030] Step (5): Set the distance between the target and the stage to 7.2 cm.

[0031] Step (6): Turn on the mechanical pump and molecular pump to evacuate the sputtering chamber to a vacuum level higher than 5 × 10⁻⁶. -5 Pa.

[0032] Step (7): Turn on the resistance wire heating device, heat the temperature of the sputtering chamber to 450 ℃, introduce Ar with a purity of 99.995% as working gas, adjust the Ar gas pressure to 0.4 Pa, adjust the RF power to 20 W, and adjust the stage speed to 20 revolutions per minute.

[0033] Step (8): Open the baffle to start sputtering for 166.6 seconds, then close the baffle. After the sputtering chamber cools to room temperature, remove the substrate. The thin film preparation is complete, and a Bi2O2Se thin film with a thickness of 15 nm is obtained.

[0034] The Raman spectrum of the Bi₂O₂Se semiconductor thin film prepared in Example 1 is as follows: Figure 1 As shown in the figure, it can be seen that at the horizontal axis of 159 cm... -1 The Raman characteristic peaks of Bi2O2Se observed nearby are consistent with those reported in the literature. Furthermore, tests were conducted at multiple locations on the sample, and the characteristic peaks remained consistent, demonstrating the uniformity of the film.

[0035] Example 2

[0036] The other processes are the same as in Example 1, except that the cavity heating temperature in step (7) is adjusted to 500 °C.

[0037] The Raman spectrum of the Bi₂O₂Se semiconductor thin film prepared in Example 2 is as follows: Figure 2 As shown in the figure, it can be seen that at the horizontal axis of 159 cm... -1 Raman characteristic peaks of Bi2O2Se appeared nearby.

[0038] Example 3

[0039] Similar to Example 1, the difference is that the cavity heating temperature in step (7) of Example 1 is adjusted to 550 °C.

[0040] The Raman spectrum of the Bi₂O₂Se semiconductor thin film prepared in Example 3 is as follows: Figure 3 As shown in the figure, it can be seen that at the horizontal axis of 159 cm... -1 Raman characteristic peaks of Bi2O2Se appeared nearby.

[0041] Example 4

[0042] The other processes are the same as in Example 1, except that the cavity heating temperature in step (7) is adjusted to 600 °C.

[0043] The Raman spectrum of the Bi₂O₂Se semiconductor thin film prepared in Example 4 is as follows: Figure 4 As shown in the figure, it can be seen that at the horizontal axis of 159 cm... -1 Raman characteristic peaks of Bi2O2Se appeared nearby.

[0044] Example 5

[0045] The other processes are the same as in Example 1, except that the silicon wafer in step (1) is replaced with a 20 cm × 20 cm (0001) Al2O3 single crystal substrate, the cavity heating temperature in step (7) is adjusted to 450°C, and the sputtering time in step (8) is adjusted to 66.6 seconds, resulting in a Bi2O2Se thin film with a thickness of 5.5 nm.

[0046] The Raman spectrum of the Bi₂O₂Se semiconductor thin film prepared in Example 5 is as follows: Figure 5 As shown in the figure, it can be seen that at the horizontal axis of 159 cm... -1 Raman characteristic peaks of Bi2O2Se appeared nearby.

[0047] Example 6

[0048] The other processes are the same as in Example 1, except that the silicon wafer in step (1) is replaced with a 20 cm × 20 cm (0001) Al2O3 single crystal substrate, the cavity heating temperature in step (7) is adjusted to 500 ℃, and the sputtering time in step (8) is adjusted to 66.6 seconds.

[0049] The Raman spectrum of the Bi₂O₂Se semiconductor thin film prepared in Example 6 is as follows: Figure 6 As shown in the figure, it can be seen that at the horizontal axis of 159 cm... -1 Raman characteristic peaks of Bi2O2Se appeared nearby.

[0050] Example 7

[0051] The other processes are the same as in Example 1, except that the silicon wafer in step (1) is replaced with a 20 cm × 20 cm (0001) Al2O3 single crystal substrate, and the cavity heating temperature in step (7) is adjusted to 550 °C. The sputtering time in step (8) is 66.6 seconds.

[0052] The Raman spectrum of the Bi₂O₂Se semiconductor thin film prepared in Example 7 is as follows: Figure 7 As shown in the figure, it can be seen that at the horizontal axis of 159 cm... -1 Raman characteristic peaks of Bi2O2Se appeared nearby.

[0053] Example 8

[0054] The other processes are the same as in Example 1, except that the silicon wafer in step (1) is replaced with a 20 cm × 20 cm (0001) Al2O3 single crystal substrate, the cavity heating temperature in step (7) is adjusted to 600 ℃, and the sputtering time in step (8) is adjusted to 66.6 seconds.

[0055] The Raman spectrum of the Bi₂O₂Se semiconductor thin film prepared in Example 8 is as follows: Figure 8 As shown in the figure, it can be seen that at the horizontal axis of 159 cm... -1 Raman characteristic peaks of Bi2O2Se appeared nearby.

[0056] In Examples 1 to 4, silicon oxide wafers were used as the substrates. The thickness of the thin film deposited on the silicon oxide substrate was about 15 nm. The prepared Bi2O2Se semiconductor thin film had obvious Raman characteristic peaks and no obvious impurity peaks. The Raman spectra of multiple samples were consistent, indicating that a large-area Bi2O2Se thin film with uniform performance was obtained.

[0057] In Examples 5 to 8, (0001)Al2O3 single crystal substrates were used, and the thickness of the deposited film was about 5.5 nm. The obtained Bi2O2Se film had obvious Raman characteristic peaks and no obvious impurity peaks. The Raman spectra of multiple samples were consistent, indicating that a large-area Bi2O2Se film with uniform performance was obtained.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Therefore, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims. Furthermore, for those skilled in the art, several improvements and modifications can be made without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a large-area Bi₂O₂Se semiconductor thin film, characterized in that, Using Bi2O2Se target as the target material and silicon oxide or Al2O3 substrate as the substrate, vacuum magnetron sputtering is performed on the cleaned substrate, and the temperature is maintained between 450℃ and 600℃ during the sputtering process. The silicon oxide substrate has the following specifications: Si thickness equal to 500 μm ± 10 nm, p-type doped, resistivity of 0.001 ~ 0.005 Ω×cm, and SiO2 thickness equal to 300 nm ± 10 nm. The Bi2O2Se target material has a purity of 99.9%, a thickness of 3 mm, and a diameter of 50.8 mm. The distance between the Bi2O2Se target and the substrate is 7.2 cm; During sputtering, the vacuum level is higher than 5 × 10⁻⁶. -5 Pa; The protective gas is Ar with a purity of 99.995% and a pressure of 0.4 Pa; During sputtering, the RF power was adjusted to 20 watts and the stage speed was adjusted to 20 revolutions per minute.

2. The method as described in claim 1, characterized in that, The Al2O3 substrate is an Al2O3 single crystal substrate with a (0001) crystal orientation.

3. The method as described in claim 1, characterized in that, The temperature of the sputtering chamber is heated to 450 ℃ to 600 ℃ using a resistance wire heating device.

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