A method for forming an ultra narrow semiconductive gate structure
utilizes a tapered hardmask covered by an oxide liner. The tapered
hardmask is formed over the semiconductive gate material by tapered
etching. After the tapered hardmask structure is formed over the
semiconductive material, an oxide layer is formed over the tapered
hardmask. A sequence of highly selective etch operations are carried out
to etch uncovered portions of the semiconductive gate material while the
portions of the gate material covered by the tapered hardmask and oxide
film remain unetched to form ultra narrow gate structures.