Aluminum fluoride (AlF3) was deposited by a resistive heating boat. To obtain a low optical loss and high laser-induced damage threshold (LIDT) at 193 nm, the films were investigated under different substrate temperatures, deposition rates, and annealing after coating. The optical property (the transmittance, refractive index, extinction coefficient, and optical loss) at 193 nm, microstructure (the cross-sectional morphology, surface roughness, and crystalline structure), mechanical property (stress), and LIDT of AlF3 thin films have been studied. AlF3 thin films deposited at a high substrate temperature and low deposition rate showed a lower optical loss. The highest LIDT occurred at the substrate temperature of 150 °C. The LIDT of the films prepared at a deposition rate of 2 Å/s was higher than that at other deposition rates. The annealing process did not influence the optical properties too much, but it did increase the LIDT and stress.
© 2005 Optical Society of America
Original Manuscript: January 20, 2005
Revised Manuscript: May 31, 2005
Manuscript Accepted: June 2, 2005
Published: December 1, 2005
Cheng-Chung Lee, Ming-Chung Liu, Masaaki Kaneko, Kazuhide Nakahira, and Yuuichi Takano, "Characterization of AlF3 thin films at 193 nm by thermal evaporation," Appl. Opt. 44, 7333-7338 (2005)