Toward the origins of binding energy shifts and "satellites" formation during plasma-XPS measurements

Published

February 17, 2026

Author(s)

Andrei Kolmakov

Abstract

In plasma X-ray photoelectron spectroscopy (plasma-XPS) emerges as a powerful platform for real-time, in situ chemical analysis under conditions relevant to semiconductor processing and other plasma-enabled technologies. This study investigates the origins of binding energy (BE) shifts and satellite peaks formation observed during plasma-XPS measurements across conductive, dielectric, and gas-phase systems. Using a standard laboratory-based APXPS apparatus coupled with an AC-driven capacitively coupled plasma source, we show that metastable surface species, such as transient Au oxides, can be detected during plasma exposure, revealing chemical states hardly accessible using conventional UHV XPS. In dielectric samples (e.g., undoped diamond, sapphire), we observe pressure- and plasma-type-dependent BE shifts up to >50 eV, attributed to X-ray-induced and plasma-mediated surface charging. These shifts are mitigated at higher pressures/plasmas or in electronegative plasmas (e.g., O₂), the latter due to enhanced charge compensation mechanisms involving slow negative ions. For gas-phase species, AC-plasma excitation leads to spectral broadening and the emergence of satellite peaks with a few eV energy separations, linked to oscillating local plasma potentials in the probing volume. These findings highlight the important and complex interplay of plasma parameters, surface charging, and local electric fields in shaping XPS spectra. Overall, plasma-XPS emerges as a critical metrological tool for probing transient surface chemistry, with implications for semiconductor processing, material synthesis, and plasma diagnostics.

Citation

Journal of Vacuum Science and Technology A

Volume

44

Issue

2

Pub Type

Journals

Download Paper

https://doi.org/10.1116/6.0005249

Local Download

Keywords

Plasma, XPS, Charging

Citation

Kolmakov, A. (2026), Toward the origins of binding energy shifts and "satellites" formation during plasma-XPS measurements, Journal of Vacuum Science and Technology A, [online], https://doi.org/10.1116/6.0005249, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=961023 (Accessed March 3, 2026)