Selective organic functionalization of polycrystalline silicon-germanium for bioMEMS applications

We selectively immobilized organofunctional silanes on top of polycrystalline silicon-germanium (poly-SiGe) layers, as a first step towards the fabrication of poly-SiGe-based bioMEMS (biomedical MicroElectroMechanicalSystems) by means of standard UV photolithography. 3-aminopropyl-dimethyl-ethoxysilane (APDMES) and 3-aminopropyl-triethoxysilane (APTES) molecules were immobilized onto resist-patterned poly-SiGe surfaces. The protocols for surface hydroxylation and silane immobilization were designed to be CMOS-compatible and to avoid damage to photoresist. Silanized surfaces were investigated both by means of fluorescence microscopy, and by FEG-SEM observation after labeling with 30 nm-diameter gold nanoparticles (NPs). We report the silanization protocols, together with the results indicating successful organic functionalization of the samples.