MASKLESS SUB-MU-M PATTERNING OF SILICON-CARBIDE USING A FOCUSED ION-BEAM IN COMBINATION WITH WET CHEMICAL ETCHING

Two methods for maskless patterning of SiC using a focused Ga+ beam an demonstrated: the enhancement of the chemical etching rate by amorphi zation of c-SiC to a-SiC and physical sputtering if deep structures ar e required. Both methods are followed by wet chemical etching in HF:HN O3 =1:1 at 80 degrees C to remove the remaining a-SiC. Assuming the cr itical displacement density for amorphization to be about the same as for the onset of etching, the measured depths of the structures were c ompared with the depths of amorphization estimated with TRIM 87 calcul ations. To find optimum sputtering parameters the energy dependence of the sputter yield was investigated and compared with TRIM 87 simulati ons, too. Damage after implantation and after wet chemical etching was investigated by means of Raman spectroscopy. No damaged material rema ining after wet chemical etching could be detected. (C) 1998 American Vacuum Society. [S0734-211X(98)05402-X].