Study of surface morphology and refractive index of dielectric and metallic films used for the fabrication of monolithically integrated surface plasmon resonance biosensing devices

摘要

Integration in a single chip using localized optical phenomena is one of the possible approaches to attain the accuracy, portability and affordability required for future biosensing devices. We address this problem by investigating a grating-coupled quantum well (QW) surface plasmon resonance (SPR) device that comprises a monolithically integrated source of light and a bio-sensitive surface. The successful operation of such a device requires, in addition to the optimization of its architecture, the use of high quality thin films with smooth surface morphology. Here, we present the results of studying a variety of dielectric and Au films intended for the fabrication of QW-SPR devices. For dielectrics, we found that SiO_2 films obtained by plasma-enhanced chemical vapor deposition have the best surface morphology and optical properties appropriate for our device. The films of Au fabricated with deposition rates exceeding 0.3 nm/s exhibited relatively smooth surface morphology, however the presence of surface micro-inclusions reduced the attractiveness of such films. To avoid sample overheating that occurs at extremely slow deposition rates, we optimized the fabrication of Au films at 0.05 and 0.2 nm/s.