Spontaneous bonding of hydrophobic silicon surfaces

The initial attraction of silicon surfaces etched in aqueous and buffered HF solutions have been studied, by observing the spontaneity and velocity of the contact wave. Also, the effect of a following water rinse was investigated. The bond strengths were determined by measuring the surface energy of the bonds at room temperature. Surfaces etched in an aqueous HF solution, with no subsequent water rinse before drying and contacting, bond spontaneously. If water rinsing is performed after the etch, the spontaneity is lost and the surfaces bond only if a pressure is applied. Surfaces etched in a buffered HF solution did not bond.