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Operando XPS for Plasma Process Monitoring: A Case Study on the Hydrogenation of Copper Oxide Confined under h-BN



Trey Diulus, Andrew Naclerio, J. Anibal Boscoboinik, Ashley Head, Evgheni Strelcov, Piran Kidambi, Andrei Kolmakov


We demonstrate that ambient pressure x-ray photoelectron spectroscopy (APXPS) can be used for in situ studies of dynamic changes in surface chemistry in a plasma environment. Hexagonal boron nitride (h-BN) was used in this study as a model system since it exhibits a wide array of unique chemical, optical, and electrical properties that make it a prospective material for advanced electronics. To better understand the stability and surface chemistry of h-BN during plasma-assisted processing, we used polycrystalline Cu foils with single-layer h-BN, grown via chemical vapor deposition (CVD), and track in real-time the plasma-induced reduction of the underlying Cu oxide using APXPS equipped with 22 kHz 75 W discharge plasma source operating at 13 Pa. Residual gas analysis (RGA) mass-spectra were concurrently collected during plasma-XPS to track reaction products formed during plasma exposure. A clear reduction of CuxO is seen, while an h-BN layer remains intact, suggesting H radical (H•) species can attack the exposed and h-BN covered Cu oxide patches and partially reduce the underlying substrate. In addition to the demonstration and discussion of plasma-XPS capabilities, our results indicate the h-BN encapsulated metallic Cu interface might be repaired without significantly damaging the overlaying h-BN, which is of practical importance for the development of h-BN encapsulated devices and interfaces.
The Journal of Physical Chemistry C


semiconductor process monitoring, XPS, h-BN


Diulus, T. , Naclerio, A. , Boscoboinik, J. , Head, A. , Strelcov, E. , Kidambi, P. and Kolmakov, A. (2024), Operando XPS for Plasma Process Monitoring: A Case Study on the Hydrogenation of Copper Oxide Confined under h-BN, The Journal of Physical Chemistry C, [online],, (Accessed July 20, 2024)


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Created April 29, 2024, Updated June 12, 2024