Atomic force microscope nanoscale lithography for single-electron device applications

Fundamental results obtained in an atomic force microscope (AFM) chemically-induced direct nanolithography process are presented, which is regarded as a simple method for fabricating nm-scale devices such as single electron tunneling transistors (SETs) and quantum effect electronic devices. Using Au-coated Si cantilevers, we have succeeded in drawing nm-scale oxide patterns in GaAs-based semiconductor surfaces by AFM; n⁺-GaAs (100) and self-assembled InGaAs quantum dots grown by molecular beam epitaxy (MBE) on GaAs (100) and (311)B substrates. The effects of AFM drawing parameters such as bias voltage and writing speed on oxide line quality have been explored. GaAs oxide lines as narrow as ~40 nm have been patterned by this technique