Structure and roughness analysis of thin epitaxial Pd films grown on Cu/Si(111) surface

Abstract

We investigated growth processes of epitaxial Pd(111) films on Cu(10ML)/Si(111) substrate. We found three stages of growth. In the first stage, up to Pd thickness of 2.6ML, the Pd film is the most disordered. Most of the strains in the Pd film relax in this stage. In the second stage, in the thickness interval from 2.6 to 13ML, the roughness of the Pd does not change significantly and the Pd grows in a layer-by-layer like mode. During the second stage, the lattice parameter of the Pd film gradually increases to volume value. With increasing coverage after 13ML, in the third stage, the lattice parameter does not change, but the roughness of the Pd films increases rapidly. Pd islands grow in height and in lateral size. Epitaxial growth of Pd on Cu(10ML)/Si(111) substrate is compared with the growth of Pd on Cu(111) single crystal; the results obtained are discussed.