In this work we detail the design and the implementation of a very high-resolution FIB nanofabrication instrument able to deliver a 10 nm ion probe (ions Ga +, 30 keV). Some experimental results are presented, showing that a 10 nm experimental resolution can be obtained. Nanolithography on an inorganic resist AlF3 and nanoetching on thin SiC membranes are achieved at a 10 nm length scale. We try to demonstrate that the FIB nanofabrication capabilities can be improved by increasing the extraction voltage of the LMIS thus leading to a significant increase of the axial angular intensity, allowing to produce FIB nanoetched structures with an ultimate resolution of 8 nm, with an excellent reproducibility and homogeneity. The authors also present the limit they have encountered when operating a LMIS under an extremely high extraction voltage (17.5 kV) and for low emission currents. Finally, the performances of this high-resolution FIB nanofabrication instrument are compared with those of existing others nanofabrication methods.