HIGH-RATE ETCHING OF SIC AND SICN IN NF3 INDUCTIVELY-COUPLED PLASMAS

Etch rates of similar to 3,500 Angstrom/min for 6H-SiC and similar to 7,500 Angstrom/min for SiC0.5N0.5 were obtained in inductively coupled plasmas with NF3-based chemistries. Similar etch rate trends were ach ieved with both NF3/O-2 and NF3/Ar mixtures. The rates were strong fun ctions of plasma composition, ion energy and ion fluxes, and were inde pendent of conductivity type for SiC. Surface root-mean-square (RMS) r oughness were 1-2 nm for etched SiC over a wide range of conditions in dicating equi-rate removal of the SIFx and CFx etch products, but SiCN surfaces became extremely rough (RMS roughness > 20 nm) for Fz-rich p lasma conditions. The etched surfaces of SiC were chemically clean and stoichiometric, with small (<0.2 at%) quantities of N-2- or F-2- cont aining residues detected. (C) 1998 Elsevier Science Ltd. All rights re served.