Nanoscale profiling of multilayer graphene films on silicon carbide by a focused ion beam

Abstract

The controlled and reproducible formation of a nanoscale interelectrode gap is crucial for the development of next-generation nanoelectronics devices, such as nano-electromechanical systems or field emission structures. This paper reports an etching of multilayer graphene (MLG) film on silicon carbide using focused ion beam (Ga+). The main task is to obtain nanoscale width trenches for the formation of isolated planar nanostructures based on MLG. MLG were obtained by thermal decomposition of silicon carbide in vacuum. We used 6H-SiC as a substrate. The analysis of the Raman spectrum showed the presence of about 10 layers of graphene in the film. The influence of the focused ion beam (FIB) parameters on the distribution of the Ga+ ions concentration in the SiC substrate was estimated by the Monte Carlo method. We revealed the maximum concentration of Ga+ ions in the SiC substrate is at a depth of 19 nm at the ion energy of 30 keV and the incidence angle of the ion beam on the substrate relative to the normal 0°. The results of local nanoscale etching of MLG on SiC by using FIB are presented. The AFM-studies confirm the dependence of the geometric dimensions of the etching area on the FIB etching parameters. The resolving power of the method is determined on the basis of a number of detectable nanoscale trenches at various currents of the FIB.