Characterization of Structural, Optical, Corrosion, and Mechanical Properties of HfO2 Thin Films Deposited Using Pulsed DC Magnetron Sputtering

Abstract

Various properties of HfO2, such as hardness, corrosion, or electrical resistance, depend on the method and the conditions of deposition. In this work, a thorough comparison of scarcely investigated mechanical properties of HfO2 thin films deposited with different conditions of reactive magnetron sputtering process is presented. Four thin films were sputtered in processes that varied in plasma ignition method (continuous or sequential) and target–substrate distance. The structural characteristics of the HfO2 thin films were examined using Raman spectroscopy and X-ray diffraction measurements. Furthermore, the optoelectronic properties were determined based on transmittance and current–voltage characteristics. The mechanical properties of the HfO2 thin films were determined using nanoindentation and scratch test. In turn, the corrosion properties were determined by analyzing the voltametric curves. The transparent HfO2 thin films deposited in the continuous process are characterized by better corrosion resistance than the same layer formed in the sequential process, regardless of the target–substrate distance (8 cm or 12 cm). Furthermore, these samples are also characterized by the highest value of Young’s modulus and scratch resistance. The combination of good corrosion and scratch resistance could contribute to the new application of HfO2 as a corrosion protective material.

Rational Design and Fabrication of Block Copolymer Templated Hafnium Oxide Nanostructures

“…Over the last two decades, hafnium oxide (HfO 2 ) has emerged as a central dielectric material for high κ dielectrics in the semiconductor industry due to its high dielectric permittivity (κ = 16–25), large band gap ( E g = 5.6–5.8 eV), and high thermal stability. − In addition, its high hardness, melting point, and refractive index (1.85–2.1), have made hafnium oxide a potential material for applications such as optical devices, − ferroelectric transistors and capacitors, transparent protective layers, and biomedical applications such as hard tissue replacement and surgical instruments. , Many of the above technologies require the fabrication of HfO 2 nanoscale structures. These are typically fabricated using conventional top-down approaches, based on photolithography, with high fabrication costs, low throughputs, and complex, EUV-based processes when pattern dimensions below 20 nm are needed. , …”