Vapor Phase Self-assembled Monolayers for Anti-stiction Applications in MEMS

We have investigated the anti-stiction performance of self-assembled monolayers (SAMs) that were grown in vapor phase from six different organosilane precursors: CF3(CF2)5 (CH2)2SiCl3 (FOTS), CF3 (CF2)5(CH2)2 Si(OC2H5)3 (FOTES), CF3 (CF2)5(CH2)2Si(CH3) Cl2 (FOMDS),CF3(CF2)5 (CH2)2Si(CH3)2Cl (FOMMS), CF3(CF2)7(CH2) 2SiCl3 (FDTS), and CH3(CH2) 17(CH2)2SiCl3 (OTS). The SAM coatings that were grown on silicon substrates were characterized with respect to static contact angle, surface energy, roughness, nanoscale adhesive force, nanoscale friction force, and thermal stability. The best overall anti-stiction performance was achieved using FDTS as precursor for the SAM growth, but all coatings show good potential for solving in-use stiction problems in microelectromechanical systems devices