XPS investigation of gas cluster ion beam effects on the Si-face of 4H-SiC towards damage-free surface cleaning

The surface of 4H-SiC has been sputtered with Ar n + GCIBs (gas cluster ion beams) at varying kinetic energies ranging from 2.5 to 8.0 eV/atom with cluster fluences reaching the range of 10 15 cluster·cm −2 to investigate the near-surface chemical modifications after high-energy bombardment. Sputtering was performed in-situ of a XPS (X-ray photoelectron spectroscopy) equipment to monitor the evolution of these modifications compared to an as-received 4H-SiC surface. Changes in core-level spectra, preferential sputtering, peak shift, and the appearance of a new spectral component were observed. The impact of low- and high-intensity GCIB cleaning regimes was demonstrated by detailed analysis of C 1s and Si 2p spectra. While optimized sputtering conditions enable gentle, selective surface cleaning, excessive kinetic energy or cluster fluence can induce the formation of metallic silicon, potentially leading to misinterpretation of XPS data.