A technique has been developed to pattern single crystal ultrathin Fe films by selective chemical wet etching of the Au capping layer and then simultaneous oxidization of the ferromagnetic Fe layer underneath. The focused magneto-optical Kerr effect and ferromagnetic resonance measurements demonstrate that the intrinsic magnetic anisotropy has not been changed in the patterned elements, showing that the chemical bonding at the metal–semiconductor interface remains the same. Further x-ray energy dispersive spectroscopy measurements show that this selective wet-etching technique is suitable for the patterning of thin Fe films with thicknesses less than around 25 ML.