Crystallization behavior of ion beam sputtered HfO2 thin films and its effect on the laser-induced damage threshold

Abstract

In this work, we present our results about the thermal crystallization of ion beam sputtered hafnia on 0001 SiO2 substrates and its effect on the laser-induced damage threshold (LIDT). The crystallization process was studied using in-situ X-ray diffractometry. We determined an activation energy for crystallization of 2.6 ± 0.5 eV. It was found that the growth of the crystallites follows a two-dimensional growth mode. This, in combination with the high activation energy, leads to an apparent layer thickness-dependent crystallization temperature. LIDT measurements @355 nm on thermally treated 3 quarter-wave thick hafnia layers show a decrement of the 0% LIDT for 1 h @773 K treatment. Thermal treatment for 5 h leads to a significant increment of the LIDT values.

Plasma-Enhanced Atomic Layer Deposition of HfO2 with Substrate Biasing: Thin Films for High-Reflective Mirrors

“…In the plasma-assisted process, an increase in crystallinity is observed due to an increase in ion energies. 88,91 A similar evolution of the microstructure with varying bias voltage is seen for the HfO 2 films deposited in the FlexAL system. The absence of peaks in the films deposited without bias indicates an amorphous microstructure.…”

“…This indicates an increase in the small crystalline fraction of polycrystalline centers in an amorphous matrix of the HfO 2 films. In the plasma-assisted process, an increase in crystallinity is observed due to an increase in ion energies. , …”

Multilayer redox-based HfOx/Al2O3/TiO2 memristive structures for neuromorphic computing

“…1 e show two distinct peaks at and . While the former corresponds to the (100) planes of the Si substrate, the latter can be assigned to the planes of monoclinic HfO 2 (m-HfO 2 ) 49 . Therefore, we assume the presence of nanocrystalline m-HfO 2 in our films, as demonstrated in previous investigations on hafnium oxide thin films 50 – 52 .…”

Controlling the optical properties of hafnium dioxide thin films deposited with electron cyclotron resonance ion beam deposition

“…HfO 2 has optical transparency over a wide spectral range, from ultraviolet (UV) to mid-infrared (mid-IR) region, due to its wide bandgap of 5.3 -5.7 eV [11,12], alongside high laser induced damage threshold (LIDT), allowing it to often be utilized as the coating for optics in high power laser systems. These HfO 2 coated optics are utilize in filters or mirrors for laser spectroscopy, laser diodes, and multilayer high reflection mirrors for Gravitational-wave interferometers, for example [13][14][15]. Although, from previous studies by many authors over the years, it shows that HfO 2 has its favorable and advantages characteristics for different applications, but the optical and structural properties of the thin films can vary depending on the deposition methods, as well as the deposition parameters [1,2].…”