Fabrication technology of ultrafine SiO2 masks and Si nanowires using oxidation of vertical sidewalls of a poly-Si layer

A fabrication technology of the vertical ultrafine SiO2 wall masks using ox idation of sidewalls of a polycrystalline silicon (poly-Si) layer and Si na nowires utilizing the SiO2 wall masks have been developed. To obtain the ve rtical SiO2 wall mask, an optimum electron cyclotron resonance (ECR) plasma etching and a suitable wet etching of the poly-Si layer after the sidewall oxidation has been achieved, The vertical ultrafine SiO2 wall masks 10 nm wide and 90 nm high with 33 nm in space have been successfully fabricated f or the first time. The dimensions of width and space become essentially sma ller than the size of an electron beam resist pattern. The height is suffic ient for ECR plasma etching. Si nanowires 10 nm wide and 18 nm thick have b een precisely obtained by the ECR plasma etching of the thinned silicon-on- insulator layer using the vertical ultrafine SiO2 wall masks. The fabricati on technology using the vertical ultrafine SiO2 wall masks has remarkable m erits of fineness, scalability, and wide applicability. It can be utilized for fabricating various designed nanostructures. (C) 1999 American Vacuum S ociety. [S0734-211X(99)02501-9].