Total and differential sputter yields of boron nitride
Date
2011
Authors
Topper, James Leo IV, author
Yalin, Azer, advisor
Williams, John, committee member
Menoni, Carmen, committee member
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Abstract
A quartz crystal microbalance (QCM) based system was used to measure total and differential sputter yields of Boron Nitride targets due to Xenon ion bombardment. The system used a four-grid ion source to generate a (nearly) mono-energetic beam of ions with a low singles-to-doubles ratio that remains well-collimated at low energies. Boron Nitride sputter yields were measured as a function of Xenon ion energy and incidence angle. Total yield measurements are found by integrating differential yield data taken by the QCM. The measurement system was validated by sputtering Molybdenum, for which the measured yields compared well with published data. For Boron Nitride, complementary weight loss sputter yield measurements were conducted, but were found to be less accurate due to moisture absorption effects when samples were exposed to atmosphere. The effects of neutralization of both the ion beam and target surface were investigated, and a plasma bridge neutralizer (PBN) was used to prevent surface charge buildup on the target. The measured total sputter yields were found to vary strongly due to neutralization conditions, and were found to be approximately a factor of two higher than those available in the literature when aggressive target and beam neutralization was applied. The angular shape of the differential sputter yield profiles was described with fit parameters from the Modified Zhang equation.
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Subject
ion
sputtering
boron nitride
QCM