Wet-chemical etching of FIB lift-out TEM lamellae for damage-free analysis of 3-D nanostructures.

•Site-specific, cross sectional high-resolution TEM characterization of 3-D nanostructures free of ion beam damage detectable by TEM and free of surrounding material is demonstrated.•Sacrificial oxide layer helps protect nanostructures and allows release of protective FIB platinum deposited during fabrication of the cross section.•Wet-chemical etching of FIB lift-out lamella is enabled by notch mounting of the lamella coupled with platinum welding side and bottom of lamella onto TEM grid.