Characteristics of TiO2 Surfaces Etched by Capacitively Coupled Radio Frequency N2 and He Plasmas

11th Asia Pacific Conference on Plasma Science and Technology;25th Symposium on Plasma Science for Materials

Kawakami, Retsuo^1 ; Niibe, Masahito^2 ; Nakano, Yoshitaka^3 ; Konishi, Masashi^1 ; Mori, Yuta^1 ; Takeuchi, Hideo^4 ; Shirahama, Tatsuo^1 ; Yamada, Tetsuya^1 ; Tominaga, Kikuo^1

University of Tokushima, 2-1 Minami-Josanjima, Tokushima 770-8506, Japan^1

University of Hyogo, 3-1-2 Kouto, Kamigoori, Ako-gun, Hyogo 678-1205, Japan^2

Chubu University, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan^3

University of Shiga Prefecture, 2500 Hassaka, Hikone, Shiga 522-8533, Japan^4

关键词: Adsorbed oxygen;    Ambient air;    Anatase TiO2;    Capacitively coupled;    Etching time;    Gas pressures;    Radio frequencies;    TiO2 surfaces;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/441/1/012038/pdf
DOI  :  10.1088/1742-6596/441/1/012038

来源: IOP

【 摘 要 】

We have investigated characteristics of anatase TiO2thin film surfaces etched by a capacitively coupled radio frequency N2plasma from the viewpoint of both an experiment and a simulation. The result obtained with use of the N2plasma is compared with that obtained with use of the He plasma. The experimental O/Ti ratio at the surface etched by the N2plasma increases as a function of etching time. The increase in the experimental O/Ti ratio is independent of a change in gas pressure. The above-mentioned experimental results agree with the simulation result that the Ti atoms at the surface are preferentially removed by N2+ions. The experimental O/Ti ratio at the surface etched by the He plasma also increases, which does not agree with the simulation result that the O atoms are preferentially removed by He+ions. The O-1s XPS spectra of the surface etched by the He plasma show the peak associated with oxygen and water adsorbed by the surface. In the case where the component of the adsorbed oxygen and water in each spectrum is subtracted, the experimental O/Ti ratio at the surface etched by the He plasma shows a decrease. This is consistent with the simulation result. The adsorption of oxygen and water seems to be caused by ambient air. Morphology of the surface etched by the N2plasma is almost similar to that of the as-grown surface regardless of the changes both in etching time and in gas pressure. In contrast, morphology of the surface etched by the He plasma changes as the etching time increases. This result is independent of the gas pressure.