Kolasinski, Robert D. and Polk, James E. and Goebel, Dan and Johnson, Lee K. (2007) Sputtering yield measurements at glancing incidence using a quartz crystal microbalance. Journal of Vacuum Science and Technology A, 25 (2). pp. 236-245. ISSN 0734-2101 http://resolver.caltech.edu/CaltechAUTHORS:KOLjvsta07
See Usage Policy.
Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:KOLjvsta07
Low energy sputtering yields at grazing incidence have been investigated experimentally using a quartz crystal microbalance (QCM) technique. This method involved precoating the QCM with a thin film of the desired target material and relating the resonance frequency shift directly to mass loss during ion bombardment. A highly focused, low divergence ion beam provided a well defined incidence angle. Focusing most of the ion current on the center of the target allowed for higher sensitivity by taking into account the radial mass sensitivity of the QCM. Measurements of Mo, Cu, and W sputtering yields were taken for low energy (80–1000 eV) Xe+ and Ar+ to validate this experimental method. The target films ranged from 3.5 to 8.0 µm in thickness and were deposited so that their crystal structure and density would match those of the bulk material as closely as possible. These properties were characterized using a combination of scanning electron microscope imagery, profilometry, and x-ray diffraction. At normal incidence, the sputtering yields demonstrated satisfactory agreement with previously published work. At angles of incidence up to 40° off normal, the data agreed well with predictions from existing theoretical models. Sputtering yields were found to increase by a factor of 1.6 over this range. The optimum angle for sputtering occurred at 55°, after which the yields rapidly decreased. Measurements were taken up to 80° from the surface normal.
|Additional Information:||©2007 American Vacuum Society. (Received 3 November 2006; accepted 28 December 2006; published 26 January 2007) The research described in this article was conducted in part at the Jet Propulsion Laboratory, California Institute of Technology, and was sponsored by NASA. The authors wish to thank a number of individuals at JPL for their assistance with this project, including Ray Swindlehurst and Allison Owens for numerous helpful discussions on the design and fabrication of the diagnostics and UHV equipment used in this study. In addition, the authors express their appreciation to James Kulleck of JPL for obtaining the SEM images and x-ray diffraction scans of the coated QCM targets.|
|Subject Keywords:||sputtering; microbalances; ion-surface impact; molybdenum; copper; tungsten; metallic thin films; scanning electron microscopy; X-ray diffraction|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Archive Administrator|
|Deposited On:||29 Jan 2007|
|Last Modified:||26 Dec 2012 09:30|
Repository Staff Only: item control page