Origins of intrinsic stress in disordered carbon materials: A first-principles study

The origin of intrinsic stress in amorphous and structurally disordered carbon films remains a fundamental challenge. Numerous previous studies have focused on deposition parameters and their relationship with stress, resulting in the hypothesis that a high sp 3 -C fraction is a key factor governing compressive stress. However, the precise role of geometrical parameters in stress generation is still unknown. Here, we show that intrinsic stress is mainly dominated by two geometrical parameters: standardized bond length and density, followed by sp 3 -C fraction. We found that the high sp 3 -C fraction independently contributes to tensile stress, contrary to previous experimental results. A data-driven assisted investigation of various amorphous carbon models prepared using first-principles calculations quantitatively revealed the effect of each parameter by isolating their contributions. As a result, a generalized formula is proposed to correlate the intrinsic stress and fundamental structural parameters.