Effect of annealing on optical properties and band alignments of ZrO₂/Si(1 0 0) by nitrogen-assisted reactive sputtering

Abstract

ZrO2 films were prepared by nitrogen-assisted radio frequency (RF) reactive sputtering on n-type silicon (100). Optical properties and band alignments of ZrO2 films on Si have been investigated by using x-ray photoelectron spectroscopy (XPS) and spectroscopy ellipsometry (SE). The improved film quality was obtained after annealing in N2/O2 ambient with stable interfacial properties. Optical properties were analysed based on the SE fitting results. According to the valence-band spectrum results, the zero-field energy-band alignments for ZrO2/SiO2/Si stacks were also extracted. Our results indicate that the nitrogen-assisted process shows its outstanding ability in the control of interfaces and has potential application in microelectronics.