Real-time study of the correlation between stress development and nanopattern formation of Si during low-energy ion bombardment

Low-energy Ar+ ion bombardment can cause self-organized nanopatterns to form on the surface of Si wafers. This phenomenon can provide applications across various fields, such as surface modification, solar cells, LEDS, and more. However, there is difficulty in implementing controlled nanopattern formations to these applications due to the fundamental process being partially unclear. There are several theories proposing explanations for this process. Some theories suggest that stress is the driving factor in pattern evolution. Therefore, it is important to study the relationship between stress development and pattern formation. The relationship is explored using a Multi-Beam Optical Stress Sensor (MOSS) System mounted on a vacuum chamber to track stress development during bombardment in real-time. The Si sample surface topography and morphology is studied using Atomic Force Microscopy (AFM) and Grazing-Incidence Small Angle X-ray Scattering (GISAXS). Given the critical role of co-deposited impurities in pattern formation, the samples' surface chemical composition is analyzed using X-ray Photoelectron Spectroscopy (XPS) post-bombardment.