Spherical YF3 Yttrium Fluoride film has a lower refractive index (refractive index is about 1.4), a wider transmission band (0.35 ~ 12μm), and has a higher refractive index than other fluorides (barium fluoride, calcium fluoride, etc.) The hardness makes the film widely used in the design of AR coatings on various substrates.

The preparation method is realized by the following steps:

1. The ZnS substrate was ultrasonically cleaned with CH3COCH3 for 15 to 30 minutes, cleaned with alcohol for 15 to 30 minutes, and then cleaned with deionized water for 30 minutes, and then the ZnS substrate was placed on the rotating heating table in the magnetron sputtering vacuum chamber, and passed The vacuum obtaining system evacuates the vacuum chamber to a vacuum degree of 1.0×10-4～9.9×10-4Pa, then heats it to 25～1000℃ and keeps the temperature for 30～120min;

2. Pour Ar gas into the vacuum chamber until the pressure in the vacuum chamber is 3-5Pa, and perform backsplash cleaning on the surface of the ZnS substrate for 10-20min;

3. After the reverse sputtering cleaning, apply the sputtering power, the sputtering power is 60-500 watts, the pre-sputtering is 20-50min, and then the O2 flow agent switch is turned on, the O2 flow rate is controlled at 1sccm-100sccm, and the gas pressure in the vacuum chamber is After 0.1～2Pa, coat the ZnS substrate surface, turn off the O2 flow agent switch after 1～3h of coating, and continue coating for 10～300min;

4. After the coating is completed, evacuate to 2.0×10-4Pa and heat up to 200～1000℃, keep warm for 2～5h, and when the temperature in the vacuum chamber drops to room temperature, the preparation of oxygen-stabilized Spherical YF3 Yttrium Fluoride film is completed.