complementary metal oxide semiconductor device it is desirable to remove one polysilicon gate 14 and to selectively replace it with another metal in one embodiment of the present invention the nmos and pmos transistor structures 12 may receive different gate metal material referring to fig2 the polysilicon gate 14 for the nmos structure 12 a has been removed by a selective etch which is highly selective relative to the p doped gate 14 of pmos structure 12 b as well as to interlayer dielectrics nitride spacers metal gates underlying gate oxides silicon and other high dielectric constant materials to mention a number of examples the selective removal of the polysilicon gate 14 may involve using a 25 percent solution of tetramethylammonium hydroxide tmah in one embodiment in another embodiment tetraethylammonium hydroxide or another tetra alkyl ammonium hydroxide may be used this etch when coupled with sonic energy is particularly selective of n type doped polysilicon gate material thus this embodiment is particularly applicable to removing the polysilicon gate 14 on the nmos transistor structure 12 a by making the polysilicon gates 14 taller than ultimately desired for both the nmos and pmos transistor structures 12 the slight etching indicated at 20 b of the pmos transistor 12 b gate material 14 reduces the gate 14 height down to its desired height as a result the nmos structure 12 a may have its gate 14 removed and even though the height of the gate 14 of the pmos structure 12 b.