DIGITAL ETCHING OF GAAS - NEW APPROACH OF DRY ETCHING TO ATOMIC ORDERED PROCESSING

A new approach to dry etching of GaAs, digital etching, has been demonstrated. In digital etching, the etchant and an energetic beam, which induces chemical sputtering at the surface, alternately impinge onto the surface. Electrons and Cl2 gas were used as the energetic beam and the etchant, respectively, in the present experiment. Etching rates of 1/3 monolayer/cycle, independent of Cl2 flux and electron current density, were obtained. The present results show that an inherent self-limiting mechanism is involved and that the etching process is limited by the adsorption of etchant. This digital etching technique is expected to be applied to the fabrication of well-defined quantum wire and quantum box structures.