Influence of wettability on the properties of thin porous platinum films as gates of metal-oxide-semiconductor devices in electrolytes

Thin discontinuous (4 and 35 nm thick) platinum films were used as the gate metal of metal-oxide-semiconductor capacitors. It was observed that the metal film acts as a gas permeable structure in electrolyte solutions when the surface was hydrophobic and sufficiently rough. The probable explanation to this is that the electrolyte does not penetrate into the voids of the metal film. The geometry of the surface was investigated by transsion electron microscopy and profilometer measurements. Surfaces with different contact angles were studied in order to determine whether the electrolyte penetrates into the voids in the platinum film when the surface is sufficiently hydrophilic.