LAYER-BY-LAYER CONTROLLED DIGITAL ETCHING BY MEANS OF AN ELECTRON-BEAM-EXCITED PLASMA SYSTEM

Characteristics o digital etching using an electron-beam-excited plasma system in GaAs are reported. In digital etching, etchant gas pulses and Ar ions are sequentially impinged onto the substrate surface to be etched. When the energy of Ar ion is -17 eV, etch rates which correspond to the 0.5 monolayer (ML) per cycle of GaAs (0.142 nm) are obtained between 0.3 and 0.5 seconds of Cl2feed time by using Cl radicals as etchants. With these etching parameters, a rectangular cross-sectional etch profile with smooth surface is obtained. Damages induced in digital etching was characterized by current-voltage measurement of the diode fabricated after the etching. © 1990 IOP Publishing Ltd.