Selective area chemical vapor deposition of titanium oxide films: Characterization of TI(OC3H7)(4) as an electron beam resist

We have shown that condensed multilayer films of titanium isopropoxide [Ti( -OC3H7)(4)] on cold GaAs(001) substrates are easily converted to nonvolatil e titanium oxide deposits by exposure to a 10 keV electron beam. Using spat ially resolved Auger electron spectroscopy, we have measured the initial ki netics of this electron beam induced decomposition reaction and have found it to be zeroth order (in precursor concentration) with an extremely high z eroth-order reaction cross section of (1.5 +/- 0.6) x 10(-14) cm(2)/electro n. Consequently. exposures as low as 23 mu C/cm(2) result in titanium oxide films with thicknesses on the order of 5 Angstrom. Moreover, the remaining unexposed precursor simply desorbs upon annealing to room temperature, ens uring selective area oxide deposition. The etch resistance of these titaniu m oxide patterns were characterized by etching in Cl-2 at a substrate tempe rature of 250 degrees C. We found that exposures above 23 mu C/cm(2) produc e robust, etch resistant oxide films which result in efficient pattern tran sfer to the underlying GaAs(001) substrate by etching. Moreover, clear unde rcut- and V-etch profiles were observed in the orthogonal [011] and [01 (1) over bar] directions, respectively, characteristic of a crystallographic e tch mechanism on the GaAs(001) surface. (C) 1999 American Vacuum Society. [ S0734-211X(99)03104-2].