Effect of Substrate Negative Bias on the Microstructural, Optical, Mechanical, and Laser Damage Resistance Properties of HfO₂ Thin Films Grown by DC Reactive Magnetron Sputtering

Abstract

Hafnium oxide thin films have attracted great attention as promising materials for applications in the field of optical thin films and microelectronic devices. In this paper, hafnium oxide thin films were prepared via DC magnetron sputtering deposition on a quartz substrate. The influence of various negative biases on the structure, morphology, and mechanical and optical properties of the obtained films were also evaluated. XRD results indicated that (1¯11)-oriented thin films with a monoclinic phase could be obtained under the non-bias applied conditions. Increasing the negative bias could refine the grain size and inhibit the grain preferred orientation of the thin films. Moreover, the surface quality and mechanical and optical properties of the films could be improved significantly along with the increase in the negative bias and then deteriorated as the negative bias voltage arrived at −50 V. It is evident that the negative bias is an effective modulation means to modify the microstructural, mechanical, and optical properties of the films.

Keywords

• HfO₂
• reactive magnetron sputtering
• negative bias
• optical properties
• laser-induced damage threshold