Synthesis and characterization of HfO 2 and ZrO 2 thin films deposited by plasma assisted reactive pulsed laser deposition at low temperature

Abstract

A plasma assisted reactive pulsed laser deposition process was demonstrated for low-temperature deposition of thin hafnia (HfO 2) and zirconia (ZrO 2) films from metallic hafnium or zirconium with assistance of an oxygen plasma generated by electron cyclotron resonance microwave discharge. The structure and the interface of the deposited films on silicon were characterized by means of Fourier transform infrared spectroscopy, which reveals the monoclinic phases of HfO 2 and ZrO 2 in the films with no interfacial SiO x layer between the oxide film and the Si substrate. The optical properties of the deposited films were investigated by measuring the refractive indexes and extinction coefficients with the aid of spectroscopic ellipsometry technique. The films deposited on fused silica plates show excellent transparency from the ultraviolet to near infrared with sharp ultraviolet absorption edges corresponding to direct band gap.