In situ electron-beam lithography on GaAs substrates using a metal alkoxide resist

Using Auger electron spectroscopy and scanning electron microscopy, we have shown that it is possible to pattern thin films of titanium oxide on GaAs substrates by first condensing multilayers of titanium isopropoxide [Ti(-OC 3H7)(4)] on a cold (< -20 degrees C) GaAs(001) surface and then exposing th e condensed precursor film to a scanning electron beam (incident energy and flux of 10 keV and 0.18 mC/cm(2)/s). Under these conditions, the electron- beam-induced deposition rate was found to be constant and equal to a high v alue of 5.5+/-1.5 Angstrom/s. Deposition of thick films (i. e., greater tha n 50 Angstrom) results after electron exposures above 2 mC/cm(2); however, increased carbon incorporation was observed within these thicker oxide film s. The remaining unexposed precursor was found to desorb upon annealing to room temperature, ensuring selective area pattern definition. Efficient tra nsfer of the written patterns to the underlying GaAs substrate was observed after etching in chlorine (etch depths of 8500 Angstrom were measured afte r etching for 5 min at 180 degrees C in 2 x 10(-4) Torr of Cl-2). (C) 1999 American Institute of Physics.