[1P01-32] Poster session

[1P15] Effects of deposition methods on the composition, activation, and pumping capacity of partially nitrided Ti films

*Ryota Iijima¹, Sinya Ohno¹, Hibiki Kurata², Takeo Nakano², Kazuhiko Mase³, Kenichi Ozawa³ (1. Yokohama National University (Japan), 2. Seikei University (Japan), 3. High Energy Accelerator Research Organization (KEK) (Japan))

Non-evaporable getter (NEG) pumps are critical for ultra-high vacuum systems. While conventional DC-sputtered NEG coatings require high activation temperatures (200-300 °C), partially nitrided Ti films deposited via bipolar high-power impulse magnetron sputtering (BP-HPPMS) offer lower activation temperatures. This study compares their distinct activation mechanisms, pumping performances, and compositional variations caused by differing deposition methods, including changes in magnet configurations. Partially nitrided Ti films were prepared using DC and BP-HPPMS, followed by in-situ nitrogen exposure. XPS measurements at the KEK-PF BL-13B beamline revealed that the dense BP-HPPMS film achieved low-temperature activation, with metallic Ti emerging at 350 °C. Conversely, the DC film exhibited delayed activation due to bulk oxidation. However, pumping tests demonstrated that the highly porous DC film provided superior pumping capacity. This highlights a critical trade-off between the chemical reactivity necessary for low-temperature activation and the physical surface area required for high pumping capacity.

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