Impact of cluster size on sputtering effects in hybrid organic/inorganic materials during cluster SIMS depth profiling

This study systematically investigates the sputtering effects and optimized analytical performance of various cluster ion beams for the depth profiling of tandem perovskite solar cell devices by cluster secondary ion mass spectrometry. We evaluated the behavior of Arn, (CO2)n, (H2O)n gas cluster ion beams (GCIBs) at 70 keV, and C60 cluster beams at 20 and 40 keV, across diverse conditions, focusing on the kinetic energy per nucleon (E/N) and cluster size (n). The systematic optimization of sputter yields, sputtering rates, and fragmentation ratios revealed a critical energy regime: preferential sputtering, particularly in hard inorganic layers, was minimized, and sputter rates increased significantly across all cluster species when the kinetic energy per nucleon exceeded 1 eV/N. Under this optimization, we achieved (i) low fragmentation of organic molecules, (ii) rapid sputtering rates across soft and hard hybrid layers, (iii) high depth resolution, and (iv) reduced preferential sputtering. The results demonstrate that the most efficient cluster beams for the depth profiling of hybrid materials are cluster 100–300 size of GCIBs at 70 keV or the 40 keV C60 cluster beam. Furthermore, we confirm that the sputtering behavior across all validated cluster species and conditions is accurately described by existing universal equations for GCIBs. This work establishes a comprehensive and empirical guide for selecting optimal GCIB parameters for the analysis of hybrid organic–inorganic materials, extending its applicability to other GCIB-utilizing techniques such as XPS and SEM.