Tailoring the index of refraction of nanocrystalline hafnium oxide thin films

Abstract

Articles you may be interested inEffect of substrate bias and oxygen partial pressure on properties of RF magnetron sputtered HfO2 thin films J. Vac. Sci. Technol. B 32, 03D104 (2014); 10.1116/1.4825234Dynamic in situ spectroscopic ellipsometric study in inhomogeneous TiO 2 thin-film growth Hafnium oxide (HfO 2 ) films were grown by sputter-deposition by varying the growth temperature (T s ¼ 25-700 C). HfO 2 films grown at T s < 200 C were amorphous, while those grown at T s ! 200 C were monoclinic, nanocrystalline with ( 111) texturing. X-ray reflectivity (XRR) analyses indicate that the film-density (q) increases with increasing T s . The index of refraction (n) profiles derived from spectroscopic ellipsometry analyses follow the Cauchy dispersion relation. Lorentz-Lorenz analysis (n (k) ¼ 550 nm) and optical-model adopted agree well with the XRR data/analyses. A direct T s -q-n relationship suggests that tailoring the optical quality is possible by tuning T s and the microstructure of HfO 2 films. V C 2014 AIP Publishing LLC.

Emerging Encapsulation Technologies for Long-Term Reliability of Microfabricated Implantable Devices

“…A high dielectric constant of approximately 20 [44] has been noted by the semiconductor industry to utilize HfO 2 as a high-κ gate dielectric material to replace SiO 2 in ultra-small complementary metal-oxide-semiconductor technology [40,41,45]. Use as an optical coating material is another major application of HfO 2 [43,46]. With positive results regarding the in vitro biocompatibility of HfO 2 in terms of cytotoxicity, hemolysis, and cell imaging [47,48,49] along with the inherently excellent property of HfO 2 as a barrier against liquid water, its applications have been extended to include uses in biological devices, such as in biocompatible passivation or the functionalization of biosensors [49,50,51,52].…”

Influence of Material Composition on Structural and Optical Properties of HfO2-TiO2 Mixed Oxide Coatings

“…Depending on the conditions, hafnium oxide can exist in one of the three polymorphous forms. Monoclinic crystal structure is the most thermodynamically stable form at ambient temperature and pressure; however, in temperatures above 1700˝C it transforms into a tetragonal structure, and into a cubic one above 2200˝C [3,4,6,13,14]. Thin films based on HfO 2 are frequently used as innovative materials in numerous optical devices such as optical filters, ultraviolet heat mirrors, antireflection coatings and in cameras used for space applications [2,15].…”

High-Flux Femtosecond X-Ray Emission from Controlled Generation of Annular Electron Beams in a Laser Wakefield Accelerator

“…On-target peak intensities were thus on the order of 10 19 W=cm 2 . A 3D-printed two-stage gas cell was used as the target [24]. The cell was composed of a 1 mm higher-density injection stage, a 0.5 mm divider slit for stage separation, and an adjustable 5-10 mm low-density acceleration stage.…”