Comprehensive analysis of the deposition caused by scattered Ga ions during focused ion-beam-induced deposition

The authors report a detailed study on the deposition because of scattered Ga ions during the focused ion beam chemical vapour deposition (FIB-CVD). The scattered ions strike the surface of the substrate nearby the base of the structure being fabricated by the primary ions, and decompose the organometallic molecules adsorbed on it, leading to the broadening of the base. Such deposition is dominant up to several micron distances from the base of the nanostructures depending on the primary ion flux. During the FIB-CVD, similar deposition occurs on the surface of nearby pre-fabricated structures, situated up to a few micrometre distances from the nanostructure being fabricated. The scattered-ion-induced deposition complicates the fabrication of complex 3D structures. The authors present the parametric dependence of the deposition because of scattered Ga ions during FIB-CVD.