Properties of Hafnium Oxide Received by Ultra Violet Stimulated Plasma Anodization

Abstract

The electrical and structural properties of hafnium oxide (HfO2) received by ultra violet (UV)-stimulated plasma anodizing were investigated. The plasma anodizing process is carried out at a relatively low temperature (400 °C) and distinguished as a clean, vacuum, and easy process. With this technology in 5–10 min the result is a 50–100-nm thickness oxide layer. Our experiments used Hafnium as a metal deposited onto a silicon substrate and following oxidation by plasma anodization. The growing speed of HfO2 was high when the UV lamp was turned on, and grown without the UV stimulation, the process efficiency was low. Electrical properties were characterized by capacitance–voltage (CV) technic and were calculated with a dielectric constant ( $\boldsymbol {\varepsilon =18.5}$ ), flatband voltage, threshold voltage, bulk potential, work function, oxide effective charge, and charge concentration. ${I}$ – ${V}$ characterization revealed negligible leakage current. The ${C}$ – ${V}$ and ${I}$ – ${V}$ measurements were carried out on a Keithley Instrument—Semiconductor Parameter Analyzer 4200-SCS and oxide thickness was measured by a reflectometer—MprobeVis System. X-ray photoelectron spectroscopy showed elemental analysis of the oxide and from the data was calculated ratio of the Hf/O. X-ray diffraction showed high quality of the crystal structure of the hafnium oxide.