STABILITY OF SELF-ASSEMBLED MONOLAYERS ON GOLD FOR MEMS/NEMS APPLICATIONS

Stability of self-assembled monolayers on gold under various environmental conditions is a crucial component in many biological, chemical and mechanical surface-functionalizations. In this study, we investigate the effects of relative humidity, ambient conditions (air, nitrogen-purged) and temperature on the structural stability of alkanethiols on gold at different chain length using contact angle measurements and time-of-flight secondary ions mass spectroscopy (TOF-SIMS). The ability of self-assembled monolayers functioning under these conditions is critical in protecting gold metal surfaces especially, from surface contamination. This in turn, affects the bonding conditions required in wafer level bonding process which is a key fabrication step in microelectromechanical (MEMs) and nanoelectromechanical (NEMs) systems. Such findings are particularly important in bioMEMs or bioNEMs since gold is one of the most common micro fabrication material used in MEMs drug delivery devices due to its superior biocompatibility and reduced biofouling.