Properties of SixNy thin film deposited by plasma enhanced chemical vapor deposition at low temperature using SiH4/NH3/Ar as diffusion barrier film

SixNy thin films were deposited by PECVD using SiH4/NH3/Ar gases and by biasing the substrate at − 50 V as a function of the ratio of R (R = NH3/(NH3 + SiH4)) at a low temperature (< 80 °C), and their properties as the thin film diffusion barrier were investigated. When R was lower than 0.4, the deposited SixNy film showed low optical transmittance and high surface roughness due to the Si–H bonding in the deposited film. When R is higher than 0.6, the deposited SixNy film was transparent, however, possibly due to the N–H bonding in the film, the film became porous and surface roughness was again increased. When R = 0.4, an optically transparent and smooth film could be obtained. When the WVTR was measured with a multilayer film composed of SixNy (R = 0.4) and parylene on PES substrate, PES (200 μm)/parylene (1.2 μm)/SixNy SixNy(120 nm)/parylene (1.2 μm) showed the WVTR lower than the detection limit of 0.01 g/(m2 day).