Modification of Silicon Nitride with Oligo(ethylene glycol)-Terminated Organophosphonate Monolayers

•Organophosphonate-based functional interfaces were prepared on silicon nitride surfaces.•By water contact angle measurements, atomic force microscopy, and X-ray photoelectron spectroscopy a detailed characterization of the morphology, composition, and stability of the organophosphonate functional interface is presented.•Only at 700 K relevant losses of surface phosphorus can be observed suggesting the complete desorption of the organic overlayer.•SAMPs functional interfaces containing only a few numbers of ethylene glycol units exhibit remarkable protective properties against non-specific DNA physisorption.