MECHANICAL-PROPERTIES OF AMORPHOUS AND POLYCRYSTALLINE MULTILAYER SYSTEMS

Amorphous and polycrystalline multilayer structures containing materia ls with metallic (Cr, Cr3C2), ionic (Al2O3) and covalent (SiC) bonding have been prepared by magnetron sputtering and ion plating in a dual- source apparatus. Up to 1000 layers have been deposited with a constan t total thickness of 2.3 mum. Below a single-layer thickness of 10-30 nm the mechanical properties stress and hardness show strong variation s. On one hand it is possible that below a certain thickness the mecha nical properties of a single layer change (A. Pan and J. E. Greene, Th in Solid Films, 78 (1981) 25-34). On the other hand electrical resista nce and electron spin density measurements indicate that electronic ef fects may be involved. An attempt is made to explain the observed corr elations by transport mechanisms of the electrons, by saturation of da ngling bonds with delocalized electrons and by changes in the electron ic band structure.