高级检索

超高真空蒸发制备Pd/Ti吸气薄膜的工艺优化与性能研究

Process Optimization and Performance Study of Pd/Ti Getter Films Prepared by Ultra-High Vacuum Evaporation Coating

  • 摘要: Pd/Ti吸气剂薄膜作为超高真空系统中重要的真空维持材料,具有激活温度低、抽速快等优点。针对薄膜制备过程中蒸发源热变形导致的镀膜均匀性问题,本研究采用COMSOL多物理场仿真分析了靶丝热变形行为,提出了“石英玻璃棒+变距弹簧靶丝”的复合结构设计,将Pd丝和Ti丝的径向最大热变形量分别降至0.0216 mm和0.0494 mm,相比直丝结构分别提升约303倍和63倍。自主设计搭建了超高真空蒸发镀膜系统,系统研究了Pd/Ti薄膜的蒸发工艺参数,确定了Ti丝45 A/60 min、Pd丝18 A/2-10 min的最佳工艺条件。SEM分析表明薄膜呈典型柱状生长结构,Pd覆层连续均匀覆盖Ti底层。镀膜后系统极限真空达到1.41×108Pa,真空维持性能显著提升。定压法吸氢测试结果显示,基底材料对吸气性能影响显著,无氧铜箔基底的稳定抽速(0.006 L/(s·cm2))优于工业钛箔基底(0.002 L/(s·cm2));Pd层厚度存在最优值,约50 nm厚度时吸气性能最佳,抽速达0.005 L/(s·cm2)。本研究为Pd-Ti薄膜吸气剂的工程化制备提供了重要的技术支撑和数据基础。

     

    Abstract: As an important vacuum-sustaining material in ultra-high vacuum systems, the Pd/Ti getter film offers advantages such as a low activation temperature and a fast pumping speed. Targeting the bending deformation problem of traditional evaporation sources caused by thermal expansion during heating, COMSOL Multiphysics simulation was employed to analyze the thermal deformation behavior of target wires. A composite structure design of "quartz glass rod + variable-pitch spring target wire" was proposed, reducing the maximum radial thermal deformation of Pd wire and Ti wire to 0.0216 mm and 0.0494 mm respectively, representing improvements of approximately 303 times and 63 times compared to straight wire structures. An ultra-high vacuum evaporation coating system was independently designed and constructed, and the evaporation process parameters of Pd-Ti films were systematically studied, determining optimal conditions of Ti wire at 45 A/60 min and Pd wire at 18 A/2-10 min. SEM analysis revealed the typical columnar growth structure of the films, with continuous and uniform Pd overlayer coverage on the Ti underlayer. The ultimate vacuum of the system after coating reached 1.41×108Pa, with significantly improved vacuum retention performance. Constant pressure hydrogen absorption tests showed that substrate materials significantly affect gettering performance, with oxygen-free copper foil substrate achieving a stable pumping speed (0.006 L/(s·cm2)) superior to industrial titanium foil substrate (0.002 L/(s·cm2)). An optimal Pd layer thickness exists, with approximately 50 nm thickness showing the best gettering performance and pumping speed of 0.005 L/(s·cm2). This study provides important technical support and data foundation for the engineering preparation of Pd-Ti film getters.

     

/

返回文章
返回