Influence of biofunctionalization process on properties of silicon oxynitride substrate layer

The paper presents investigations of the influence of chemically aggressive biofunctionalization process for histidine-tagged proteins on thickness, optical and mechanical properties of silicon oxynitride (SiOxNy) film, which is often used as substrate material for a number of biosensors. We discuss the biofunctionalization effect for a set of SiOxNy films deposited by the radio frequency plasma-enhanced chemical vapour deposition method with various N2O/(SiH4 + NH3) gas flow rate. It has been found that as an effect of biofunctionalization procedure, the SiOxNy films increase both their refractive index and hardness. Moreover, films deposited with higher N2O flow, which are softer and show lower refractive index, may slightly reduce their thickness as a result of the biofunctionalization process, but their surface favours more formation of on them protein biofilm than on films obtained with lower concentration of N2O. Copyright (C) 2014 John Wiley & Sons, Ltd.