Described herein is an etching solution suitable for the selective removal of TiSiN over hafnium oxide from a microelectronic device, which consists essentially of: water; at least one alkaline ammonium compound selected from the group consisting of ammonium hydroxide, a quaternary ammonium hydroxide, ammonium fluoride, and a quaternary ammonium fluoride; at least one peroxide compound; a water-miscible organic solvent; at least one nitrogen containing compound selected from the group consisting of a C4-12 alkylamine, a polyalkylenimine, and a polyamine; and optionally at least one chelating agent.