Method for preparing site-specific, plan-view lamellae from multilayered microelectronic devices. A focused ion beam that is directed, with an etch-assisting gas, toward an uppermost layer of a device removes at least that uppermost layer and thereby exposes an underlying layer over, or comprising, a target area from which the site-specific, plan-view lamella is to be prepared, wherein the focused ion beam is in a face-on orientation in removing the uppermost layer to expose the underlying layer. In a preferred embodiment, the etch-assisting gas comprises methyl nitroacetate. In alternative embodiments, the etch-assisting gas is methyl acetate, ethyl acetate, ethyl nitroacetate, propyl acetate, propyl nitroacetate, nitro ethyl acetate, methyl methoxyacetate, or methoxy acetylchloride.