Abstract: Polysilicon Microelectromechanical systems (MEMS) are the subject of intensive researches.Surface chemistry and topography of a MEMS test structure fabricated at Sandia National Laboratory, USA, were studied by means of scanning electron microscopy(SEM), X-ray photoelectron spectroscopy(XPS) and atomic force microscopy (AFM).XPS C_1s and Si_2p, spectra from the polysilieon components, silicon nitride substrate and a reference silicon wafer were compared.The results confirm the presence of a self-assembled monolayer (SAM) on the MEMS surface.An island-like morphology was found on both polysilicon and silicon nitride surfaces of the MEMS.The islands take the form of caps, being up to 0.5 μm in diameter and 20 nm in height.It is concluded that the co-existence of columnar growth and equiaxed growth during the low pressure chemical vapor deposition(LPCVD) of these layers leads to the observed morphology and the islands are caps to the columnar structures.

Key words: Microelectromechanical systems, XPS, Atomic force microscopy