By etching a periodic array of holes through a ;mobility two-dimensional electron gas we define high-a lateral, ``anti-dot-type superlattice with periods a=200 and a=300 nm, much smaller than the electron mean free path in the unpatterned material. The devices are fabricated using electron beam lithography and reactive ion etching techniques, and characterized by magnetotransport experiments. Commensurability effects and the observed quenching of the Hall effect indicate that the electron gas between the etched holes essentially maintains its initial high electron mobility. Applied Physics Letters is copyrighted by The American Institute of Physics.