Self-assembly of porous Cu structures during steady-state condensation of weakly supersaturated vapors

A new technological approach to the porous layers formation with various structural and morphological forms has been developed on the example of copper. It is based on a copper magnetron sputtering in high-purity argon under near-equilibrium conditions. It has been established that the layers geometrical characteristics can be effectively controlled by varying the discharge power, the deposition temperature, and the negative bias applied to the growth surface. The low supersaturation serves as a prerequisite for the porosity formation and causes the cyclically repeated processes of nucleation on active centers, incomplete intergrowth of the structural fragments and new active centers formation. When the negative bias is applied to the growth surface, the growing crystals are elongated, weakly bound with each other and oriented strictly perpendicularly to the substrate surface.