Properties of Hafnium Oxide Received by Ultra Violet Stimulated Plasma Anodization

The electrical and structural properties of hafnium oxide (HfO
₂
) 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 HfO
₂
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 (ε = 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.