Developing new manufacturing methods for the improvement of AlF3 thin films

Area of Science:

• Materials Science
• Thin Film Deposition
• Plasma Etching

Background:

• Aluminum fluoride (AlF(3)) thin films are crucial for optical coatings.
• Optimizing deposition processes is key for enhancing film properties and industrial scalability.

Purpose of the Study:

• To investigate the plasma etching mechanism for AlF(3) thin film deposition.
• To determine the optimal gas ratios and sputtering power for high-quality AlF(3) films.
• To enhance the deposition rate for industrial applications.

Main Methods:

• Sputtering process with varying oxygen (O(2)) to tetrafluoromethane (CF(4)) gas ratios.
• Analysis of optical properties and microstructure of deposited thin films.
• Optimization of sputtering power (30 W to 200 W) and gas flow rates.

Main Results:

• Optimal optical quality and minimal surface roughness achieved with an O(2):CF(4) ratio of 12:60 sccm at 30 W.
• Deposition rate increased 7.43 times at 200 W compared to 30 W.
• Extinction coefficients remained below 6.8 x 10(-4) from 190 nm to 700 nm at 200 W.
• Extinction coefficient at 193 nm improved from 4.4 x 10(-3) to 6 x 10(-4) with O(2) addition.
• Films deposited at 200 W exhibited an amorphous-like structure and 0.8 nm surface roughness.

Conclusions:

• The addition of O(2) gas significantly enhances the optical properties of AlF(3) thin films.
• Increased sputtering power to 200 W dramatically improves deposition rates while maintaining excellent optical quality.
• The optimized plasma etching process is suitable for industrial-scale production of high-performance AlF(3) thin films.