Wet-chemical nanoscale patterning of GaAs surfaces using atomic force microscope lithography

Sub-100 nm V-grooves in GaAs(001) surfaces have been fabricated by patterni ng a thin photoresist layer with an atomic force microscope (AFM) and subse quent wet-chemical etching. The nanolithography is based on the dynamic plo ughing technique. Anisotropic etchants under investigation are bromine-meth anol-isopropanol, sulfuric acid-hydrogen peroxide-water, citric acid-hydrog en peroxide-water, and ammonium hydroxide-hydrogen peroxide-water. Along th e [110] direction the etched grooves are V-shaped, along [110] the profile is U-shaped. Best results of 50-60-nm wide V-grooves with straight edges an d smooth sidewalls are obtained from bromine-methanol-isopropanol, the othe r etchants form rough grooves. Concerning the reproducibility of the patter ning process, the aqueous etch solutions exceed the bromine etchant. (C) 19 99 Academic Press.