In-situ Sputtering Yield Measurements of Micro-architectured Materials

Gary Li Chris Dodson Dan Goebel Richard Wirz

We investigate the time-dependent sputtering behavior of materials with micro-architectured surfaces for extending the lifetime of devices with similar plasma environments (electric propulsion/fusion). A hollow cathode generated argon or xenon plasma is directed to a biased target via solenoid magnets to provide energetic ion bombardment. Tested materials include refractory metals (molybdenum, rhenium), carbon-based compounds, and dielectric (Al2O3, Macor). Samples with micron-scale surface features are tested to determine whether the sputtering yield of engineered materials can be reduced significantly.

Angular sputtering profiles are measured using a scanning quartz crystal microbalance, which are then integrated to obtain the total sputtering yield. The in situ capability of the QCM allows us to measure the time-resolved sputtering yield as the material surface evolves as a result of ion-induced erosion. Results for a micro-architectured molybdenum sample are presented in Ref. [1]

[1] Gary Li, Taylor Matlock, Dan Goebel, Chris Dodson, Chris Matthes, Nasr Ghoniem, Richard Wirz. "In situ sputtering yield measurements of molybdenum surfaces bombarded by argon plasma", Submitted to Plasma Sources Science and Technology, 2016.
[2] Chris Matthes, Nasr Ghoniem, Gary Li, Taylor Matlock, Dan Goebel, Chris Dodson, Richard Wirz. "Fluence-Dependent Sputtering Yield of Micro-architecturedMaterials", Submitted to Applied Surface Science, 2016.
[3] Gary Li, Christopher A. Dodson, Richard E. Wirz, Taylor S. Matlock, and Dan M. Goebel. "Implementation of in situ diagnostics for sputter yield measurements in a focused plasma", 52nd AIAA/SAE/ASEE Joint Propulsion Conference, Propulsion and Energy Forum, (AIAA 2016-4841)