Tailoring the mechanical properties of SiOxHyCz films deposited by atmospheric pressure microwave plasma torch with a Rechtschaffner design of experiments: A pragmatic statistical approach

SiOxHyCz micrometer thick films are deposited from an argon/hexamethyldisiloxane (HMDSO) mixture on Si (1 0 0) substrate by plasma enhanced chemical vapor deposition (PECVD) process using a Torche à Injection Axiale (TIA) at atmospheric pressure. Both main effects of deposition parameters and first-order interactions on the hardness and elastically modulus are investigated from a Rechtschaffner design of experiments (DOEs). This screening design, based on series of two and three-level saturated design, allows the reduction of the total number of experiments by a factor 1.5 in the present work, without compromising the quality of the results. First conclusions demonstrate that torch–substrate distance and HMDSO flow rates are the main influent factors affecting the mechanical behavior of the deposited films, which is basically explained by their indirect effects both on the precursor dissociation in plasma phase and on film growth mechanisms. Additionally, the use of a desirability approach enables to converge towards a multi-criteria optimum of deposition conditions for the expected mechanical properties.