All hot wire chemical vapor deposition low substrate temperature transparent thin film moisture barrier

We deposited a silicon nitride/polymer hybrid multilayer moisture barrier for flexible electronics in a hot wire chemical vapor deposition process, entirely below 100 °C. We were able to reach a water vapor transmission rate (WVTR) as low as 5 × 10⁻⁶ g/m²/day at a temperature of 60 °C and a relative humidity of 90% for a simple three-layer structure consisting of two low-temperature silicon nitride (SiN_x) layers and a polymer layer in between. This WVTR is low enough for organic and polymer devices. In a second experiment it is investigated how the yield of our samples increases with the number of SiN_x layers, while keeping the total SiN_x thickness constant. Cross sectional scanning electron microscopy images of degraded samples reveal a high structural robustness of our multilayers. - Highlights: ► A multilayer gas barrier was made by hot wire chemical vapor deposition at 100 °C. ► A water vapor transmission rate of 5 × 10⁻⁶ g/m²/day was found. ► Found at 60 °C and a relative humidity of 90%, this is low enough for any device. ► These layers can be deposited directly onto organic of polymeric active devices. ► The adhesion between the organic and inorganic layers, and robustness is high