XPS study on the thermal stability of oxygen-free Pd/Ti thin film, a new non-evaporable getter (NEG) coating
XPS study on the thermal stability of oxygen-free Pd/Ti thin film, a new non-evaporable getter (NEG) coating
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DOI：
10.1063/1.5084676
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发表时间：
2019-01
期刊：
影响因子：
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通讯作者：
T. Miyazawa;M. Kurihara;S. Ohno;T. Kikuchi;K. Mase
中科院分区：
文献类型：
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作者：
T. Miyazawa;M. Kurihara;S. Ohno;T. Kikuchi;K. Mase
非蒸散型吸气剂（NEG）涂层是一种在真空室内壁涂敷非蒸散型吸气剂薄膜的技术，该薄膜在超高真空（UHV）下通过烘烤而被活化。活化的NEG膜抑制从腔室中的除气并抽空残余气体，从而用小离子泵将UHV保持在10-8 Pa的范围内。最广泛使用的NEG涂层是沉积的TiZrV薄膜，其在180 °C下烘烤24 h后可以完全活化。然而，NEG涂层很少应用于同步辐射装置的光束线和终端站。为了扩大NEG涂层的应用范围，我们开发了一种使用无氧Pd/Ti薄膜沉积的新型NEG涂层。无氧Pd/Ti涂层的优点是：1）它可以通过在133-176 °C下烘烤12小时来活化; 2）即使在反复通风-烘烤循环之后它也不会氧化; 3）它具有潜在的经济性; 4）它不需要熟练的技术人员; 5）它可以应用于具有复杂结构的大型腔室; 6）可应用于可排列钯丝和钛丝的窄管。为了研究无氧Pd/Ti的热稳定性，我们测量了沉积在不锈钢304 L上的无氧Pd（50 nm）/Ti（1 µm）膜的一系列X射线光电子能谱，作为退火温度在100-360 °C范围内的函数。发现Ti在280-300 °C下偏析表面并氧化形成Ti 1+。结果表明，无氧Pd/Ti薄膜的最高允许温度约为260 °C。非蒸散吸气剂（NEG）涂层是一种在真空室内壁涂敷NEG薄膜的技术，这种薄膜可以通过在超高真空（UHV）下烘烤来活化。活化的NEG膜抑制从腔室中的除气并抽空残余气体，从而用小离子泵将UHV保持在10-8 Pa的范围内。最广泛使用的NEG涂层是沉积的TiZrV薄膜，其在180 °C下烘烤24 h后可以完全活化。然而，NEG涂层很少应用于同步辐射装置的光束线和终端站。为了扩大NEG涂层的应用范围，我们开发了一种新的NEG涂层使用无氧Pd/Ti膜沉积。无氧Pd/Ti涂层的优点是：1）它可以在133-176 °C下烘烤12小时活化; 2）即使经过多次排气-烘烤循环也不会氧化; 3）它具有潜在的经济性; 4）它不需要熟练的技术人员; 5）它可以应用于具有复杂结构的大型腔室。
Non-evaporable getter (NEG) coating is a technique to coat the inner walls of vacuum chambers with NEG thin films that can be activated through baking under ultrahigh vacuum (UHV). The activated NEG films suppress outgassing from the chambers and evacuate residual gasses, and consequently maintain UHV in the range 10–8 Pa with small ion pumps. The most widely-used NEG coating is deposited TiZrV films that can be fully activated after baking at 180 °C for 24 h. However, NEG coatings have rarely been applied to beamlines and endstations in synchrotron radiation facilities. To expand the scope of NEG coating applications, we developed a new NEG coating using oxygen-free Pd/Ti film deposition. The advantages of oxygen-free Pd/Ti coating are the following: 1) it can be activated by baking at 133–176 °C for 12 h; 2) it does not oxidize even after repeated venting-baking cycles; 3) it is potentially economical; 4) it does not require skilled technicians; 5) it can be applied to large chambers with a complex structure; and 6) it can be applied to narrow tubes where Pd and Ti filaments can be arranged. To investigate the thermal stability of oxygen-free Pd/Ti, we measured a series of X-ray photoelectron spectra of oxygen-free Pd(50 nm)/Ti(1 µm) film deposited on stainless steel 304L as a function of annealing temperature in the range 100–360 °C. Ti was found to segregate the surface and oxidizes forming Ti1+ at 280–300 °C. The results indicate that the maximum allowable temperature of oxygen-free Pd/Ti films is approximately 260 °C.Non-evaporable getter (NEG) coating is a technique to coat the inner walls of vacuum chambers with NEG thin films that can be activated through baking under ultrahigh vacuum (UHV). The activated NEG films suppress outgassing from the chambers and evacuate residual gasses, and consequently maintain UHV in the range 10–8 Pa with small ion pumps. The most widely-used NEG coating is deposited TiZrV films that can be fully activated after baking at 180 °C for 24 h. However, NEG coatings have rarely been applied to beamlines and endstations in synchrotron radiation facilities. To expand the scope of NEG coating applications, we developed a new NEG coating using oxygen-free Pd/Ti film deposition. The advantages of oxygen-free Pd/Ti coating are the following: 1) it can be activated by baking at 133–176 °C for 12 h; 2) it does not oxidize even after repeated venting-baking cycles; 3) it is potentially economical; 4) it does not require skilled technicians; 5) it can be applied to large chambers with a complex stru...