Comparison of nanomachined III-V semiconductor substrates

Emerging device applications demand surface features on the order of hundre ds of angstroms. Nanolithography by machining with a diamond tip is propose d as a means to reproducibly pattern semiconductor surfaces on this scale. This technique has already been shown to produce controlled features with d epths down to 10 Angstrom on GaAs [S. H. Goss et al., J. Vac. Sci. Technol. B 16, 1439 (1998)]. In this technique, a diamond tip is scanned along the sample surface with a constant force to produce the desired features. In th is article we show the observed quality and reproducibility achieved by thi s technique in the patterning of several semiconductor substrates. The subs trates patterned and examined include GaAs, GaSb, GaP, and InP. The samples were machined at a series of loads ranging from 9.8 to 196 mu N. After mac hining they were cleaned with an appropriate solvent and supercritical CO2 to remove debris caused by the machining. The resulting patterned surfaces were characterized with an atomic force microscope. Lateral resolutions as good as 100 Angstrom were successfully achieved illustrating the ability of this technique to achieve the dimensions required to form quantum dots. Li ne profiles indicated cut depths ranging from 5 to 500 Angstrom. A near lin ear trend was observed in the depth of cut versus applied force over the in vestigated range for most of the substrates. The exact slope and intercepts were material dependent. (C) 1999 American Vacuum Society. [S0734-211X(99) 09704-8].