Interfacial hydrogen-related species in low-vacuum-deposited coatings on extrinsic substrates: Insights from experimental and theoretical studies

The deposition of thin films has long been developed for multidisciplinary applications in various areas. Residual adsorptions play crucial effects on the film and interface properties in low-vacuum depositions. Localized delamination and blistering have been frequently observed while their physical origins are comprehensive and complex. Here, we report thin film blistering in atomic layer deposition (ALD) of Al2O3 and direct-current (DC) sputtering of Au on extrinsic substrates. Both experimental and theoretical investigations revealed a higher tendency of hydrogen-related species at the film/substrate interface rather than in the coatings. Heat treatment tends to dissociate the hydrogen-related species, leading to pocket of gas (POG) and its driven thin film blistering of the ALD coatings. In comparison, under the low-vacuum DC sputtering, the interaction between moisture adsorptions on the substrate and the film deposition tends to cause pocket of energy concentrations (PEC) that in turn drove the thin film blistering. Both the experimental observations and the calculations based on density-function theory shed new insights into the mechanisms of thin film blistering.