Surface functionalization of SIC for biosensor applications

SiC is a biocompatible material and a candidate as a transducer for biosensors. Here we have investigated the possibility to functionalize SiC with biomolecules. We have also processed very simple devices and performed electrical characterization. Double polished SiC samples with a C-face substrate and Si-face low doped epilayer have been functionalized on both sides. The SiC was first treated by HF in order to remove the native oxide, partly successful on the Si-face side but probably not on the C-face side. MPTMS, 3-mercaptopropyl trimethoxysilane, was chosen as the biomolecule since it has both a silanol group to be used as an anchoring group to the substrate and a thiol group available for further linking possibilities. The functionalization was evaluated by XPS, contact angle experiments, AFM and electrical measurements. The MPTMS molecules attached with the thiol (or sulphur containing) group pointing out from the surface on both faces of the SiC. Interesting differences between the two faces are however revealed by the analysis.