Hfo2/Sio2 Anti-Reflection Films For Uv Lasers Via Plasma-Enhanced Atomic Layer Deposition

The laser-induced damage threshold (LIDT) of HfO2/SiO2 anti-reflection (AR) films for ultraviolet (UV) lasers was improved via low-temperature plasma-enhanced atomic layer deposition (PEALD). Focused on the chemical composition, optical absorption, surface scattering, and laser-resistance, the impact of precursor exposure time on PEALD SiO2 film properties and growth temperature on PEALD SiO2 and HfO2 film properties were investigated respectively. When irradiated by UV laser, PEALD SiO2 film exhibits a higher LIDT than the PEALD HfO2 film, which is consistent with their less impurity content and lower absorption. A bilayer structure HfO2/SiO2 AR film for 355 nm laser was designed and experimentally demonstrated via PEALD growth at a temperature of 150 degrees C. The prepared PEALD AR film shows a reflectance <0.2% at 355 nm as designed and better laser-damage resistance with a LIDT of 24.4 J/cm(2) (355 nm, 7.8 ns) than the conventional e-beam deposition method. (C) 2020 Elsevier B.V. All rights reserved.