Vanadium oxide physical vapor deposition method

Abstract

The invention provides a vanadium oxide physical vapor deposition method. The method comprises the following steps: sputtering a vanadium oxide film; performing high-pressure or ultrahigh-pressure annealing; and performing low-temperature vacuum secondary annealing. According to the method, high-pressure or ultrahigh-pressure oxygen atmosphere annealing is adopted, oxygen precipitation, caused by high-temperature annealing, of the vanadium oxide thin film is inhibited through high-concentration oxygen, atom arrangement of the thin film tends to be flat, oxygen hole sites and defects in the thin film are repaired, and therefore thin film component distribution is improved; and removing residual oxygen atoms in the thin film through low-temperature vacuum secondary annealing. The TCR performance of the vanadium oxide film prepared by the method is excellent, and the TCR at the temperature of 25 DEG C reaches up to-2.8% or above.

Description

Technical Field

[0001] This invention belongs to the field of vacuum sputtering technology, specifically relating to a vanadium oxide physical vapor deposition method. Background Technology

[0002] Vanadium oxide thin films have advantages such as a large temperature coefficient of resistance, good resistance performance, low 1 / f noise, and compatibility with silicon-based micromachining processes, and are widely used as thermal sensing layers in uncooled infrared imaging systems.

[0003] The temperature resistivity (TCR) of vanadium oxide as a thermistor material is a key factor affecting device performance. A higher TCR in thermistor material results in a higher detector responsivity. Vanadium oxides exist in various phases (such as vanadium dioxide (VO2), vanadium trioxide (V2O3), and vanadium pentoxide (V2O5)). However, while single phases like VO2 and V2O5 have high TCRs, VO2 exhibits a significant temperature hysteresis effect, while V2O5 has too high resistivity at room temperature. V2O3 has low resistivity at room temperature, but its TCR is relatively low. Research indicates that vanadium oxide thin films requiring high TCR and low sheet resistance are generally composed of multiphase vanadium oxide consisting of appropriate proportions of VO2, V2O3, and V2O5. Therefore, exploring flexible and controllable methods for adjusting the multiphase composition of vanadium oxide and efficient, high-precision fabrication techniques for multiphase vanadium oxide thin film microstructured thermistor units is crucial. Traditional methods such as high-temperature annealing and ion doping can be used to adjust vanadium oxide composition, but these methods are difficult to control to form specific proportions of multiphase vanadium oxide, and the preparation process is complex.

[0004] In the prior art, Chinese patent application number CN201410111401.4, entitled "A Method for Preparing Vanadium Oxide Thin Films with High Temperature Coefficient of Resistance," provides a method for preparing vanadium oxide thin films that can produce high-quality vanadium oxide thermistor films with high temperature coefficient of resistance without doping. However, this method requires ion activation treatment of the substrate and preparation of a seed layer, making the process cumbersome and costly.

[0005] Furthermore, existing technologies generally employ vacuum annealing for vanadium oxide thin films, resulting in a significant decrease in film resistance after annealing compared to before annealing. Because annealing is often performed in a vacuum atmosphere (as mentioned in the aforementioned Chinese patent), oxygen atoms are easily released from the film, leading to poor stability of the resulting vanadium oxide thin film. Generally, the higher the annealing temperature, the greater the decrease in resistance before and after annealing. Summary of the Invention

[0006] To address the aforementioned problems, this invention creatively proposes a vanadium oxide physical vapor deposition method, which involves annealing under high pressure or ultra-high pressure in an oxygen atmosphere, followed by a secondary annealing under low temperature vacuum.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A vanadium oxide physical vapor deposition method includes the following steps: Step 1: Sputtering vanadium oxide thin film: Select a suitable vanadium metal target; first, maintain a suitable substrate temperature and a suitable cavity vacuum in the PVD equipment to pre-sputter the vanadium metal target; then transfer the wafer to the carrier stage in the DC magnetron sputtering vacuum cavity, introduce argon and oxygen, and carry out the magnetron sputtering reaction to obtain a vanadium oxide thin film. Step 2: High-pressure or ultra-high-pressure annealing: After step 1 is completed, the wafer is transferred to the stage in another PVD equipment chamber. The stage temperature is maintained at a suitable temperature. The oxygen flow rate is 1000~3000 sccm until the chamber pressure reaches a high-pressure state of 100~760 Torr or an ultra-high-pressure state of 760~1200 Torr. Then the oxygen flow is stopped and annealing is performed. Step 3: Low-temperature vacuum secondary annealing: After the annealing in step 2 is completed, maintain a suitable stage temperature, introduce argon gas, maintain a suitable cavity pressure, and perform annealing to obtain the annealed vanadium oxide film.

[0008] Furthermore, step one specifically includes: selecting a vanadium metal target with a diameter of 320–321 mm and a purity of 99.995%, with a distance of 50–150 mm between the target and the wafer stage; and within the PVD equipment, setting the substrate temperature to 25–200 °C and maintaining the cavity vacuum at 5.0 × 10⁻⁶. -8 Below Torr, a sputtering power of 500~6000W is used for pre-sputtering the target for 1 min; then the wafer is transferred to a DC magnetron sputtering vacuum chamber, and argon gas flow rate is 15~30 sccm, oxygen flow rate is 1.0~5 sccm, chamber reaction pressure is 1.0~2.0 mTorr, target input power is 50~3000W, and sputtering time is 6~15 min to obtain vanadium oxide thin film.

[0009] Furthermore, in step two, the stage temperature is set to 280~400℃, and the annealing time is set to 5~20min.

[0010] Furthermore, in step three, the stage temperature is set to 150~280℃, the argon gas flow rate is 5~30 sccm, the cavity pressure is maintained at 0.4~2 mTorr, and the annealing time is set to 5~20 min.

[0011] The beneficial effects of this invention are as follows: This invention employs high-pressure or ultra-high-pressure oxygen atmosphere annealing. The high oxygen concentration suppresses oxygen precipitation in the vanadium oxide film caused by high-temperature annealing and promotes a more even atomic arrangement, repairing oxygen pores and defects within the film and thus improving the film's composition distribution. A subsequent low-temperature vacuum secondary annealing removes residual oxygen atoms from the film. The vanadium oxide film prepared using this method exhibits excellent TCR performance, with a resistance temperature coefficient (TCR) exceeding -2.8% at 25°C. Attached Figure Description

[0012] Figure 1 This is a resistance-temperature curve of the vanadium oxide thin film in Example 1 of the present invention.

[0013] Figure 2 This is a resistance-temperature curve of the vanadium oxide thin film in Example 2 of the present invention.

[0014] Figure 3 This is a resistance-temperature curve of the vanadium oxide thin film in Comparative Example 1 of the present invention.

[0015] Figure 4 This is a resistance-temperature curve of the vanadium oxide thin film in Comparative Example 2 of the present invention.

[0016] Figure 5 This is a resistance-temperature curve of the vanadium oxide thin film in Comparative Example 3 of the present invention.

[0017] Figure 6 This is a resistance-temperature curve of the vanadium oxide thin film in Comparative Example 4 of the present invention. Detailed Implementation

[0018] The technical solutions provided by the present invention will be described in detail below with reference to specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0019] This invention provides a vanadium oxide physical vapor deposition method based on two PVD (vanadium oxide diffraction) devices. One PVD device is used to sputter a vanadium oxide thin film onto a wafer, while the other PVD device performs high-pressure or ultra-high-pressure annealing and low-temperature vacuum secondary annealing of the wafer. The method specifically includes the following steps: Step 1: Sputtering vanadium oxide thin film.

[0020] Based on the SJI-SEMI Depommerits P188 Pro PVD system, a vanadium metal target with a purity of 99.995% was selected, with a target diameter of 320–321 mm and a distance of 50–150 mm between the target and the wafer stage. First, the substrate temperature was set to 25–200 °C, and the cavity vacuum was maintained at 5.0 × 10⁻⁶. -8Below Torr. A sputtering power of 500-6000W was used for 1 minute of pre-sputtering of the target. Next, the wafer was transferred to a DC magnetron sputtering vacuum chamber, with an argon flow rate of 15-30 sccm and an oxygen flow rate of 1.0-5 sccm. The chamber reaction pressure was 1.0-2.0 mTorr, the target input power was 50-3000W, and the sputtering time was 6-15 minutes, yielding a vanadium oxide thin film.

[0021] Step 2: High-pressure or ultra-high-pressure annealing.

[0022] The high-pressure annealing process is as follows: After step one is completed, the wafer is transferred to the stage inside the chamber of another SJI-SEMI Depommerits P188 Pro PVD equipment, with the stage temperature set to 280~400℃. Oxygen is introduced at a flow rate of 1000~3000 sccm until the chamber pressure reaches a high pressure of 100~760 Torr. Oxygen supply is then stopped, and annealing begins. The annealing time is set to 5~20 minutes.

[0023] The ultra-high pressure annealing process is as follows: After step one is completed, the wafer is transferred to the stage inside the chamber of another SJI-SEMI Depommerits P188 Pro PVD equipment, with the stage temperature set to 280~400℃. Oxygen flow is introduced at a rate of 1000~3000 sccm until the chamber pressure reaches an ultra-high pressure of 760~1200 Torr. Oxygen supply is then stopped, and annealing begins. The annealing time is set to 5~20 minutes.

[0024] In existing technologies, pressure rings are typically used to apply pressure to the wafer towards the stage, or electrostatic adsorption is used to attach the wafer to the stage, allowing the wafer to adhere to the stage surface for better heating. In this step, because the annealing chamber is under high or ultra-high pressure, electrostatic adsorption or mechanical pressure is unnecessary; the wafer adheres directly to the stage surface, thus achieving rapid heating.

[0025] Step 3: Low-temperature vacuum secondary annealing.

[0026] After step two is completed, the stage temperature is set to 150~280℃. The argon gas flow rate is 5~30 sccm, the cavity pressure is maintained at 0.4~2 m Torr, and the time is set to 5~20 min to obtain the annealed vanadium oxide film.

[0027] Example 1: This example uses the high-pressure annealing combined with low-temperature vacuum secondary annealing method proposed in this invention to fabricate vanadium oxide thin films. The sheet resistance of the thin films was measured after sputtering and after secondary annealing for comparison. The specific steps are as follows: Step 1: Sputtering vanadium oxide thin film. Using an SJI-SEMI Depommerits P188 Pro PVD system, a vanadium metal target with a purity of 99.995% was selected, with a target diameter of 320–321 mm and a distance of 150 mm between the target and the wafer stage. First, the substrate temperature was set to 150°C, and the cavity vacuum was maintained at 5.0 × 10⁻⁶. -8 Below Torr. A sputtering power of 3000W was used for 1 minute of target pre-sputtering. Next, the wafer was transferred to a DC magnetron sputtering vacuum chamber, with an argon flow rate of 15 sccm and an oxygen flow rate of 1.5 sccm. The chamber reaction pressure was 1.1 mTorr, the target input power was 500W, and the sputtering time was 10 minutes. A vanadium oxide thin film was obtained, and the sheet resistance of the film was measured and recorded as Rs1.

[0028] Step Two: High-Pressure Annealing. After Step One is completed, the wafer is transferred to the stage inside the chamber of another SJI-SEMI Depommerits P188 Pro PVD instrument, with the stage temperature set to 280°C. Oxygen is introduced at a flow rate of 3000 sccm until the chamber pressure reaches 200 Torr, at which point oxygen supply is stopped, and annealing begins. The annealing time is set to 10 minutes.

[0029] Step 3: Low-temperature vacuum secondary annealing. After completing Step 2, the stage temperature is set to 250℃. The argon gas flow rate is 15 sccm, the cavity pressure is maintained at 1.0 mTorr, and the time is set to 10 min to obtain the annealed vanadium oxide film. The sheet resistance of the film is measured and recorded as Rs2.

[0030] Example 2: This example uses the ultra-high pressure annealing combined with low-temperature vacuum secondary annealing method proposed in this invention to manufacture vanadium oxide thin films. The sheet resistance of the thin films was measured after sputtering and after secondary annealing for comparison. To avoid differences in results due to adjustments in other parameters, all parameters in this example are the same as in Example 1, except for the cavity pressure value in step two annealing. The specific steps are as follows: Step 1: Sputtering vanadium oxide thin film. Using an SJI-SEMI Depommerits P188 Pro PVD system, a vanadium metal target with a purity of 99.995% was selected, with a target diameter of 320–321 mm and a distance of 150 mm between the target and the wafer stage. First, the substrate temperature was set to 150°C, and the cavity vacuum was maintained at 5.0 × 10⁻⁶. -8Below Torr. A sputtering power of 3000W was used for 1 minute of target pre-sputtering. Next, the wafer was transferred to a DC magnetron sputtering vacuum chamber, with an argon flow rate of 15 sccm and an oxygen flow rate of 1.5 sccm. The chamber reaction pressure was 1.1 mTorr, the target input power was 500W, and the sputtering time was 10 minutes. A vanadium oxide thin film was obtained, and the sheet resistance of the film was measured and recorded as Rs3.

[0031] Step Two: Ultra-High Pressure Annealing. After Step One is completed, the wafer is transferred to the stage inside the chamber of another SJI-SEMI Depommerits P188 Pro PVD instrument, with the stage temperature set to 280°C. Oxygen is introduced at a flow rate of 3000 sccm until the chamber pressure reaches 800 Torr, at which point oxygen supply is stopped, and annealing begins. The annealing time is set to 10 minutes.

[0032] Step 3: Low-temperature vacuum secondary annealing. After completing Step 2, the stage temperature is set to 250℃. The argon gas flow rate is 15 sccm, the cavity pressure is maintained at 1.0 mTorr, and the time is set to 10 min to obtain the annealed vanadium oxide film. The sheet resistance of the film is measured and recorded as Rs4.

[0033] Example 3: In this example, the high-pressure annealing combined with low-temperature vacuum secondary annealing method proposed in this invention is used to manufacture vanadium oxide thin films. In step two, during high-pressure annealing, the oxygen flow rate is 1000 sccm, and the oxygen flow is stopped when the chamber pressure reaches 100 Torr. The remaining steps and parameters are the same as in Example 1.

[0034] Example 4: In this example, the ultra-high pressure annealing combined with low-temperature vacuum secondary annealing proposed in this invention is used to manufacture vanadium oxide thin films. In step two, during high-pressure annealing, the oxygen flow rate is 2000 sccm, and the oxygen flow is stopped when the chamber pressure reaches 760 Torr. The remaining steps and parameters are the same as in Example 2.

[0035] Example 5: In this example, the ultra-high pressure annealing combined with low-temperature vacuum secondary annealing proposed in this invention is used to manufacture vanadium oxide thin films. In step two, the ultra-high pressure annealing process involves introducing oxygen at a flow rate of 3000 sccm until the chamber pressure reaches 1200 Torr, at which point the oxygen supply is stopped. The remaining steps and parameters are the same as in Example 2.

[0036] Comparative Example 1: To demonstrate the impact of high-pressure conditions in step two on the overall film quality, this example modifies the chamber pressure in step two to a low-pressure state, based on Example 1. Correspondingly, the oxygen flow rate is also significantly lower than in Example 1. The remaining steps and parameters are the same as in Example 1. The specific steps are as follows: Step 1: Sputtering vanadium oxide thin film. Using an SJI-SEMI Depommerits P188 Pro PVD system, a vanadium metal target with a purity of 99.995% was selected, with a target diameter of 320–321 mm and a distance of 150 mm between the target and the wafer stage. First, the substrate temperature was set to 150°C, and the cavity vacuum was maintained at 5.0 × 10⁻⁶. -8 Below Torr. A sputtering power of 3000W was used for 1 minute of target pre-sputtering. Next, the wafer was transferred to a DC magnetron sputtering vacuum chamber, with an argon flow rate of 15 sccm and an oxygen flow rate of 1.5 sccm. The chamber reaction pressure was 1.1 mTorr, the target input power was 500W, and the sputtering time was 10 minutes. A vanadium oxide thin film was obtained, and the sheet resistance of the film was measured and recorded as Rs5.

[0037] Step Two: Low-Pressure Annealing. After Step One is completed, the wafer is transferred to the stage inside the chamber of another SJI-SEMI Depommerits P188 Pro PVD instrument, with the stage temperature set to 280°C. Oxygen is introduced at a flow rate of 100 sccm until the chamber pressure reaches 2 Torr, at which point oxygen supply is stopped, and annealing begins. The annealing time is set to 10 minutes.

[0038] Step 3: Low-temperature vacuum secondary annealing. After step 2, the stage temperature is set to 250℃. The argon gas flow rate is 15 sccm, the cavity pressure is maintained at 1.0 mTorr, and the time is set to 10 min to obtain the annealed vanadium oxide film. The sheet resistance of the film is measured and recorded as Rs6.

[0039] Comparative Example 2: This example further reduces the oxygen flow rate compared to Comparative Example 1, bringing the primary annealing chamber to a vacuum state. The remaining steps and parameters are the same as in Comparative Example 1 and Example 1. The specific steps are as follows: Step 1: Sputtering vanadium oxide thin film. Using an SJI-SEMI Depommerits P188 Pro PVD system, a vanadium metal target with a purity of 99.995% was selected, with a target diameter of 320–321 mm and a distance of 150 mm between the target and the wafer stage. First, the substrate temperature was set to 150°C, and the cavity vacuum was maintained at 5.0 × 10⁻⁶. -8 Below Torr. A sputtering power of 3000W was used for 1 minute of target pre-sputtering. Next, the wafer was transferred to a DC magnetron sputtering vacuum chamber, with an argon flow rate of 15 sccm and an oxygen flow rate of 1.5 sccm. The chamber reaction pressure was 1.1 mTorr, the target input power was 500W, and the sputtering time was 10 minutes. A vanadium oxide thin film was obtained, and the sheet resistance of the film was measured and recorded as Rs7.

[0040] Step Two: Vacuum Annealing. After Step One is completed, the wafer is transferred to the stage inside the chamber of another SJI-SEMI Depommerits P188 Pro PVD instrument, with the stage temperature set to 280°C. The oxygen flow rate is 1 sccm, the chamber pressure is maintained at 1.0 mTorr, and annealing begins, with the annealing time set to 10 minutes.

[0041] Step 3: Low-temperature vacuum secondary annealing. After completing Step 2, the stage temperature is set to 250℃. The argon gas flow rate is 15 sccm, the cavity pressure is maintained at 1.0 mTorr, and the time is set to 10 min to obtain the annealed vanadium oxide film. The sheet resistance of the film is measured and recorded as Rs8.

[0042] Comparative Example 3: To demonstrate the impact of the secondary annealing step (step 3) on the overall film quality, step 3 was omitted from Example 1, while the remaining steps and parameters remained the same as in Example 1. The specific steps are as follows: Step 1: Sputtering vanadium oxide thin films. Using an SJI-SEMI Depommerits P188 Pro PVD system, a vanadium metal target with a purity of 99.995% was selected, with a target diameter of 320–321 mm. The distance between the target and the wafer stage was 150 mm (50–150 mm). First, the substrate temperature was set to 150°C (25–200°C), and the cavity vacuum was maintained at 5.0 × 10⁻⁶. - 8 Below Torr. A sputtering power of 3000W (500~6000W) was used for 1 min of target pre-sputtering. Next, the wafer was transferred to a DC magnetron sputtering vacuum chamber, with an argon flow rate of 15 sccm (15~30 sccm) and an oxygen flow rate of 1.5 sccm (1.0~5 sccm). The chamber reaction pressure was 1.1 mTorr (1.0~2.0 mTorr), the target input power was 500W (50~3000W), and the sputtering time was 10 min (6~15 min). A vanadium oxide thin film was obtained, and the sheet resistance of the film was measured and recorded as Rs9.

[0043] Step Two: High-Pressure Annealing. After Step One is completed, the wafer is transferred to the stage inside the chamber of another SJI-SEMI Depommerits P188 Pro PVD instrument. The stage temperature is set to 280℃ (280~400℃). The oxygen flow rate is 3000 sccm (1000~3000 sccm) until the chamber pressure reaches 200 Torr (100~760 Torr), at which point the oxygen flow is stopped, and annealing begins. The annealing time is set to 10 min (5~20 min). A vanadium oxide thin film is obtained, and the sheet resistance of the film is measured and recorded as Rs10.

[0044] Comparative Example 4: This example further omits step two from Comparative Example 3, retaining only step one from Example 1. The specific steps are as follows: Step 1: Sputtering vanadium oxide thin films. Using an SJI-SEMI Depommerits P188 Pro PVD system, a vanadium metal target with a purity of 99.995% was selected, with a target diameter of 320–321 mm. The distance between the target and the wafer stage was 150 mm (50–150 mm). First, the substrate temperature was set to 150°C (25–200°C), and the cavity vacuum was maintained at 5.0 × 10⁻⁶. - 8 Below Torr. A sputtering power of 3000W (500~6000W) was used for 1 min of target pre-sputtering. Next, the wafer was transferred to a DC magnetron sputtering vacuum chamber, with an argon flow rate of 15 sccm (15~30 sccm) and an oxygen flow rate of 1.5 sccm (1.0~5 sccm). The chamber reaction pressure was 1.1 mTorr (1.0~2.0 mTorr), the target input power was 500W (50~3000W), and the sputtering time was 10 min (6~15 min). A vanadium oxide thin film was obtained, and the sheet resistance of the film was measured and denoted as Rs11.

[0045] In the above examples and comparative examples, the sheet resistance of the vanadium oxide thin films was measured using the four-probe method. The sheet resistance tester used was a Changzhou Xinyang CXT2665 four-probe sheet resistance tester. The heating stage used was a Shenzhen Xinhaomai X2035TBD constant temperature heating stage. The resistance-temperature curves for Examples 1, 2, and Comparative Examples 1-4 were measured and plotted, and the temperature coefficient of resistance (TCR) was calculated.

[0046] Table 1 records the sheet resistance of the vanadium oxide films in Examples 1, 2, 1, 2, 3, and 4 of this invention, as well as the sheet resistance attenuation rate before and after annealing. The attenuation rate is defined as the percentage of the sheet resistance Rs after annealing to the sheet resistance Rs before annealing.

[0047] Table 1

[0048] As shown in Table 1, the Rs attenuation rates of Comparative Example 3 (high-pressure annealing without vacuum low-temperature secondary annealing), Example 4 (ultra-high-pressure annealing), Example 1 (high-pressure annealing), Comparative Example 1 (low-pressure annealing), and Comparative Example 2 (vacuum annealing) gradually increase. This indicates that the vanadium oxide films obtained by ultra-high-pressure annealing and high-pressure annealing without vacuum low-temperature secondary annealing exhibit the best attenuation rates. During the annealing process, the oxygen atmosphere in the film repairs oxygen vacancies or defects and suppresses sample precipitation during high-temperature annealing, ultimately reducing the resistance attenuation rate. Furthermore, in all the above cases, the sheet resistance of the vanadium oxide film after sputtering is within the range of 610~620kΩ, indicating that the coating process is very stable. The sheet resistances of Examples 2-5 are also within the above range, with attenuation rates of 8.77%, 5.03%, and 4.39%, respectively.

[0049] Table 2 records the TCR values ​​of vanadium oxide films in Examples 1, 2, 1, 2, 3, and 4 of the present invention in the range of 25~30℃.

[0050] Table 2

[0051] From Table 2 and Figures 1-6 It can be seen that, through linear fitting of TCR, within the temperature range of 25~30℃, the absolute values ​​of TCR in Example 2 (ultra-high pressure annealing), Example 1 (high pressure annealing), Comparative Example 1 (low pressure annealing), Comparative Example 2 (vacuum annealing), Comparative Example 3 (high pressure annealing without low-temperature secondary annealing), and Comparative Example 4 (no annealing process) gradually decrease, indicating that the TCR performance of vanadium oxide films obtained by ultra-high pressure annealing and high pressure annealing is significantly better than that of other annealing methods. Among them, the vanadium oxide film obtained by ultra-high pressure annealing has the best TCR performance, and the TCR of the vanadium oxide film without low-temperature vacuum secondary annealing is also significantly lower than that of the vanadium oxide film obtained by low-temperature vacuum secondary annealing. In addition, the TCR values ​​of Examples 2-5 are all above -2.81%.

[0052] It should be noted that the above content merely illustrates the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, various improvements and modifications can be made without departing from the principle of the present invention, and all such improvements and modifications fall within the scope of protection of the claims of the present invention.

Claims

1. A vanadium oxide physical vapor deposition method, characterized in that, Includes the following steps: Step 1: Sputtering vanadium oxide thin film: Select a suitable vanadium metal target; first, maintain a suitable substrate temperature and a suitable cavity vacuum in the PVD equipment to pre-sputter the vanadium metal target; then transfer the wafer to the carrier stage in the DC magnetron sputtering vacuum cavity, introduce argon and oxygen, and carry out the magnetron sputtering reaction to obtain a vanadium oxide thin film. Step 2: High-pressure or ultra-high-pressure annealing: After step 1 is completed, the wafer is transferred to the stage in another PVD equipment chamber. The stage temperature is maintained at a suitable temperature. The oxygen flow rate is 1000~3000 sccm until the chamber pressure reaches a high-pressure state of 100~760 Torr or an ultra-high-pressure state of 760~1200 Torr. Then the oxygen flow is stopped and annealing is performed. Step 3: Low-temperature vacuum secondary annealing: After the annealing in step 2 is completed, maintain a suitable stage temperature, introduce argon gas, maintain a suitable cavity pressure, and perform annealing to obtain the annealed vanadium oxide film.

2. The vanadium oxide physical vapor deposition method according to claim 1, characterized in that, Step one specifically includes: selecting a vanadium metal target with a diameter of 320–321 mm and a purity of 99.995%, with a distance of 50–150 mm between the target and the wafer stage; and setting the substrate temperature to 25–200 °C and maintaining the cavity vacuum at 5.0 × 10⁻⁶. -8 Below Torr, a sputtering power of 500~6000W is used for pre-sputtering the target for 1 min; then the wafer is transferred to a DC magnetron sputtering vacuum chamber, and argon gas flow rate is 15~30 sccm, oxygen flow rate is 1.0~5 sccm, chamber reaction pressure is 1.0~2.0 mTorr, target input power is 50~3000W, and sputtering time is 6~15 min to obtain vanadium oxide thin film.

3. The vanadium oxide physical vapor deposition method according to claim 1, characterized in that, In step two, the stage temperature is set to 280~400℃ and the annealing time is set to 5~20min.

4. The vanadium oxide physical vapor deposition method according to claim 1, characterized in that, In step three, the stage temperature is set to 150~280℃, the argon gas flow rate is 5~30 sccm, the cavity pressure is maintained at 0.4~2 mTorr, and the annealing time is set to 5~20 min.

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