Investigation of amorphous SiOx layer on gold surface for Surface Plasmon Resonance measurements

Abstract

The present study demonstrates that thin layers of amorphous silicon oxide (SiOx) grown by inductively-coupled plasma enhanced chemical vapor deposition (ICPECVD) technology at lower temperatures can be successfully combined with biosensors. In particular, gold-amorphous silica (Au/SiOx) interfaces were investigated for their potential applications as a low-cost Surface Plasmon Resonance (SPR) sensor chip. ICPECVD silicon dioxide films up to 25nm-thick were deposited at different pressure. Details of the SiOx thin layer properties in terms of refractive index, deposition rate, roughness, chemical bonds, Si2p and O1s bending energies, residual stress and contact angle were studied. The refractive index was found to decrease with increasing pressure for all the films. The depositions rates were lower for films deposited at higher pressures. We report here on the fabrication and characterization of stable and good reliabilities of SiOx deposited at two temperature 80°C and 130°C at pressures ranging from 2Pa to 20Pa. The results show that the SPR responses were very sensitive to any changes in the deposition parameters. In this study, we have shown that SiOx has good potential for further developments, as a wideband biosensor application with a higher sensitivity in SPR response.