[Back]

M. Weiss, H. Riedl, P.H. Mayrhofer, A. Limbeck:
"Quantification strategies for stoichiometry determination of thin films via LA‐ICP‐MS";
Poster: 30th MassSpec-Forum Vienna, Vienna; 2019-02-19 - 2019-02-20; in: "Book of Abstracts", (2019), 54.

Engineering materials are under constant stress from mechanical burden and thermal influence. To protect their surface from damage, corrosion and abrasion several kinds of hard coatings are applied. Beside the established carbide, nitride and oxide based thin films, borides are gaining attention due to their superior properties, such as the combination of hardness and ductility even at elevated temperatures. The thin films used in this work were produced with physical vapor deposition (PVD), which alloys the combination of different transition metal borides in arbitrary ratios, to vary the properties over a wide range. It is known that during production fractionation effects can occur. Thus, the actual film composition must be determined to optimize the deposition process.
The analysis of boron is challenging, because its low number of electrons make the commonly used X‐Ray based methods, e.g. XRD and XRF, unfeasible. To avoid a timeconsuming dissolution and digestion process, direct analysis using solid sampling methods, like laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS), are preferred. However, quantitative LA‐ICP‐MS is a none trivial task, as the availability of reference materials is sparse, especially for novel materials such as borides.
Here we present a quantification approach based on self‐aliquoting microgrooves. These are micrometer sized trenches filled with a liquid standard solution of the elements of interest. After evaporation of the solvent the standards can be measured by LA‐ICP‐MS in the same
way as the solid samples. This allows to combine the advantages of a direct solid sampling approach, like no sample pretreatment, little sample consumption and the ability to perform spatially resolved measurements, with the ease of the production of liquid standards.
Micrometer thick thin film samples of the diborides of several combinations of transition metals have been investigated using this method. Different statistical approaches for data treatment were compared.

LA-ICP-MS, stoichiometry analysis, ternary boride thin films