Phase-separated Al-Si thin films

Phase-separated Al-Si films composed of Al nanocylinders embedded in an amorphous-Si matrix have been prepared by a sputtering method. By controlling the deposition rate, substrate temperature, and film composition, the average diameter of the Al cylinders can be varied systematically from less than 5 to 13 nm with a cylinder density ranging from 10(15) to in excess of 10(16) cylinders m(-2). A three-dimensional simulation of phase separation in binary thin films was performed using a modified Cahn-Hilliard [J. Chem. Phys. 28, 258 ( 1958 )] equation to understand the growth mechanism. The simulation studies indicate that the surface diffusion length and film composition are important factors which determine film morphology. Experimental and simulation studies are compared and discussed. (c) 2005 American Institute of Physics.