Applied X-ray spectroscopy

How to stop diffusion (and how to peak fit tungsten core levels)

Check out our latest collaboration with colleagues from Infineon Technologies Austria and Kai, diving further into the world of power semiconductor devices. Here, we move away from the groovy science of front-end SiC/SiO2 device technologies, in favour of back-end metallisation architectures. In order to unlock the many advantages of copper metallisation schemes in power electronics, diffusion barriers are required to isolate the metallisation from the underlying silicon substructure. In recent years, the binary alloy of titanium-tungsten (TiW) has been proposed as an effective barrier but in order to have confidence in the material, extensive characterisation of its potential degradation mechanisms need to be conducted.

Using both laboratory SXPS and synchrotron HAXPES we explore the oxidation and thermal stability of TiW, providing insight into two prominent modes of degradation, from multiple depth perspectives. Additionally, we have paired experiment with theory, working with collaborators at Imperial College London and the Barcelona Supercomputing Center to aid with better understanding the observed systematic changes to the electronic structure of the alloy in response to thermal treatments.

This marks the first first author research paper of Curran’s PhD journey, so one down and hopefully many more to come. The paper can be found here in JApplPhys (the preprint is also on arxiv) and we’d love to hear your thoughts.

P.S For all the peak fitting XPS enthusiasts, be sure to check out the SI for a detailed explanation of the W 4f procedure in all its glory 🙂

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