Substrate-dependent structural evolution during the oxidation of SiN_x thin films

SiN_x thin films have garnered attention as promising barrier films, primarily due to their low impurity diffusion rates, making them suitable for various technological applications. Despite their potential, these films face challenges because they are prone to degradation in hostile environments. This study investigated the oxidation behavior of SiN_x thin films, particularly when deposited on two different types of substrates: rigid silicon (Si) and flexible polyethylene terephthalate (PET) films. A thorough microstructural analysis of the SiN_x films reveals their detailed morphological and compositional characteristics, enabling a comparison between the SiN_x/Si and SiN_x/PET films. This study further investigates the impacts of high-temperature and humidity exposure on SiN_x thin films, systematically elucidating the degradation behaviors and underlying mechanisms. The structural evolution during SiN_x film oxidation is illustrated at the nanoscale, and the factors contributing to the oxidation were analyzed. This study deepens our understanding of the interplay between oxidation processes and the unique environmental conditions of substrates, offering insights into enhancing the stability and reliability of these materials.