A method of depositing a SiN film onto a flexible substrate includes providing the flexible substrate, and depositing the SiN film onto the flexible substrate in a plasma enhanced chemical vapour deposition (PECVD) process using SiH4, N2 and H2, in which the temperature of the substrate is 200° C. or less and SiH4 is introduced into the PECVD process at a flow rate of greater than 100 sccm.