Thin-film sputtering yields for Fe, Cr, and an Fe-Cr alloy measured by proton-induced x rays

Journal Article · Sat Dec 01 04:00:00 EST 1979 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.325980· OSTI ID:5842452

Sartwell, B D

Proton-induced x-ray emission (PIXE) was used to measure the sputtering yields of thin films bombarded by 1.0 keV Ar/sup +/ at normal incidence. The films consisted of vacuum-evaporated iron, chromium, and an Fe-Cr alloy. An integral approximation to the theoretical x-ray yield equation was developed that resulted in the determination of the thicknesses of the thin films. In general, this appoximation can be used to measure film thicknesses up to several hundred nanometers. The sputtering yields were determined by measuring the slope of the straight-line fit to the experimental data which was obtained as film thickness versus accumulated sputtering charge. The chromium sputtering yield, measured by PIXE for a chromium film evaporated onto an electropolished iron substrate, agreed within 5% of that obtained using an energy-dispersive x-ray analyzer attached to an SEM. The sputtering yields measured for iron and chromium films with initial thicknesses between 5 x 10/sup 17/ and 9 x 10/sup 17/ atoms/cm/sup 2/ deposited onto a nickel substrate were S (Fe) =1.23 atoms/ion and S (Cr) =0.93 atoms/ion. The agreement with previously published data for S (Fe) is good; no published data on S (Cr) are known. Using recently derived values for the nuclear stopping power, the measured iron and chromium sputtering yields agree well with Sigmund's theory. The total sputtering yield obtained for an Fe-35Cr alloy was 1.17 atoms/ion, and the elemental sputtering yields for the alloy were in the ratio of their concentrations. The advantages of using the PIXE technique over other techniques currently being used, particularly for compounds, are discussed.

• Research Organization: Bureau of Mines, U.S. Department of the Interior, Avondale, Maryland 20782
• OSTI ID: 5842452
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 50:12; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

640301* -- Atomic
Molecular & Chemical Physics-- Beams & their Reactions
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ALLOYS
ARGON IONS
BARYONS
CHARGED PARTICLES
CHROMIUM
CHROMIUM ALLOYS
COLLISIONS
DATA
DIMENSIONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
EQUATIONS
EVAPORATION
FERMIONS
FILMS
HADRONS
INFORMATION
IONIZING RADIATIONS
IONS
IRON
IRON ALLOYS
MATHEMATICAL MODELS
METALS
NUCLEONS
PHASE TRANSFORMATIONS
PROTONS
RADIATIONS
SPUTTERING
THICKNESS
TRANSITION ELEMENTS
X RADIATION