Morphological and Fractal Analysis of Thin Ge Films Deposited by Nanosecond Pulsed Laser Ablation

Abstract

We studied the formation and growth of thin Ge films deposited by pulsed laser ablation of a Ge target onto Si substrate at room temperature in helium protective atmosphere. 4 nsec long laser pulses at 1064 nm were applied at different pulse numbers. The morphology of the process was followed by atomic force microscopy (AFM) and grazing incidence small angle X-ray scattering (GISAXS), starting from isolated particles deposition to their coalescence into film and further film growth. The analysis in the real space gives a good description of the process, however, due to a large variation in the morphology, and thus the data, the resulting information may not be so clear. We have shown that fractal analysis provides additional insight into the process. Comparing the two techniques AFM and GISAXS the latter one is much more precise since it has a more precise probing length.