EFFECT OF HYDROGEN TERMINATION ON THE WORK OF ADHESION BETWEEN ROUGH POLYCRYSTALLINE SILICON SURFACES

A novel micromachined test structure has been used to measure the work of adhesion between polycrystalline silicon surfaces. The effects of several surface treatments, including a hydrogen- and an ammonium-fluo ride-induced hydrogen termination and a hydrogen peroxide chemical oxi dation, have been investigated with these test structures, A reduction in the average apparent work of adhesion by a factor of 2000 has been observed on the NH4F-treated surface compared to the oxide-coated sur face. By using x-ray photoelectron spectroscopy and atomic force micro scopy, the observed reduction is traced to the combined effect of rite surface chemistry and topography. This work demonstrates that a hydro phobic, rough surface provides a significant reduction of the apparent work of adhesion in polysilicon micromachined devices. (C) 1997 Ameri can Institute of Physics.