Differential sputter yield profiles of molybdenum due to bombardment by low energy xenon ions at normal and oblique incidence

Abstract

We report differential sputter yield measurements for Xe+ ions incident on molybdenum for ion incidence angles of 0°, 15°, 30° and 45°, and ion energies of 250, 350, 500 and 750 eV. The angularly resolved profiles are obtained with a quartz crystal microbalance that is moved to a series of locations above the target. Total sputter yields found by integrating the differential sputter yields are in accord with the literature values. For normally incident ions the profiles are under-cosine, while for obliquely incident ions the profiles show azimuthal variation with pronounced forward sputtering lobes. We discuss the use of published expressions from Zhang and Zhang (2004 Radiat. Eff. Defects Solids 159 301–7) for describing the measured profiles. We find that the profiles can be reasonably described with these expressions by using two free parameters: the total sputter yield (Y) and a characteristic energy (E*). We compare changes in angular sputtering profiles from lightly versus heavily sputtered targets.

Simulation of ion beam sputtering with SDTrimSP, TRIDYN and SRIM

“…refs [23,24]) and often reasonable quantitative agreement is obtained. A less comprehensive comparison with experimental data exists on the angular distributions of sputtered atoms and the sputtering yield dependence on ion incidence angle [23,[25][26][27][28][29][30][31][32][33].…”

Total and Differential Sputter Yields of Boron Nitride Measured by Quartz Crystal Microbalance and Weight Loss (Preprint)

“…In these devices, sputter erosion of grids and other components places a fundamental limitation on lifetimes. Additionally, sputtered particles from within the * 8 , collector plates [9][10] , mass spectrometry 11 , quartz crystal microbalance [2][3][4][5][6][12][13][14] , Rutherford backscattering [15][16] , radioactive tracers 17 , and cavity ring-down spectroscopy 18 . In this contribution we present sputter measurements of BN obtained by both weight loss and the quartz crystal microbalance (QCM).…”

“…The measured yields can be used as inputs (and to aid validation) for numeric codes that model sputter erosion (lifetime) and/or effects of sputter redeposition. The current measurement system builds upon our previous work using a quartz crystal microbalance (QCM) for sensitive measurements of angularly resolved differential sputter yields [4][5][6]12 .…”

“…More recent theories, as well as experimental and numerical studies show a range of profile shapes. For normally incident ions on polycrystalline and amorphous targets, cosine-like profiles are generally observed with increasingly under-cosine shapes as ion energy is lowered and increasingly over-cosine shapes for higher ion energies [4][5][11][12][21][22][23] . In comparison to a diffuse profile, an under-cosine profile (n<1) has less sputtering in the surface normal direction and correspondingly more sputtering (with the maximum) at intermediate angles.…”

Development of Real-time Erosion Monitoring System for Hall Thrusters by Cavity Ring-Down Spectroscopy

“…Techniques such as weight loss 10) , collector plate 11) , quartz crystal microbalance 12,13) , radioactive tracers 14) , mass spectrometry 15) , and Rutherford backscattering 16) each have certain advantages and can be appropriate for material sputter characterization studies but none readily meets all of the above criteria. The need for a sensitive nonintrusive measurement suggests the use of optical techniques.…”