Electrolytic processes for etching and metal deposition towards nanometre quantum structures

New processes of etching and metal deposition in the submicron range have been developed by using electrolytic solutions. Etching of towers and ridges with dimensions of less than 300 nm out of a GaAs substrate is achieved. Similarly, submicron metallisation with dots and lines of less than 100 nm in size is demonstrated by direct electrolytical writing using an STM-type sharp needle point. Both processes appear to be promising for the realisation and further development of mesoscopic devices.