Control of tribological properties of ultrathin polysilicon films

The selection of the proper materials for the fabrication of the Micro Electro Mechanical Systems (MEMS) is a very important issue in the MEMS research. The materials should be adequate for the fabrication process as well as they have to demonstrate in particular good adhesive (to avoid stiction between contacting/sliding components) and frictional/tribological properties. We fabricated ultrathin (50 nm thick) polysilicon films on single crystal silicon wafers at various deposition process conditions and observed the effect of the process parameters on surface topography and adhesive as well as frictional properties of the produced films. The Atomic Force Microscope (AFM) was used in these studies equipped with special cantilevers. We identified interesting correlations between the process parameters and adhesive/frictional properties of the studied films which enable to optimize the process to decrease adhesion (stiction) and friction between sliding components of MEMS devices.