Island-to-percolation transition during the room-temperature growth of sputtered nanoscale Pd films on hexagonal SiC

We have studied the growth of room-temperature sputtered Pd films on 6H-SiC by using the atomic force microscopy technique. In particular, we analyzed the Pd film surface morphology as a function of the film thickness from 3 to 72 nm observing that the Pd grows initially (thickness 2-12 nm) as three-dimensional (3D) islands. Then (thickness 12-36 nm) the Pd film morphology evolves from compact 3D islands to partially coalesced wormlike structures, followed (36-60 nm) by a percolation morphology and finally to a continuous and rough film (at 72 nm). The application of the interrupted coalescence model allowed us to evaluate the critical mean islands diameter R(c) approximate to 6.6 nm for the partial coalescence process while the application of the kinetic freezing model allowed us to evaluate the room-temperature Pd surface diffusion coefficient D(s) approximate to 1.4 x 10(-17) m(2)/s on 6H-SiC. Finally, the application of the Vincent's model allowed us to evaluate the critical Pd coverage P(c)= 68% for the percolation transition. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3361321]