ATOMIC STEP NETWORKS AS SELECTIVE EPITAXIAL TEMPLATES

A technique to control epitaxial growth laterally across a wafer is pr esented, which does not use a mask A vicinal Si(111) substrate was pat terned by optical lithography and heated to fabricate a regular patter n of bunches of atomic steps. Under appropriate growth conditions, it is seen that epitaxial material, here GaAs, sticks only to the step bu nches, not to the terraces. It is possible to fabricate large-scale co mplex networks of GaAs with micron scale and submicron scale features. The conditions required to obtain selective growth are presented. It is shown that there are two regimes of selective growth-high temperatu re (> 550 degrees C), or low temperature (< 400 degrees C). Selectivit y is obtained via two distinct mechanisms: desorption and diffusion, r espectively. (C) 1998 American Institute of Physics.