Etching of crystalline and amorphous silicon in CClF₃ plasma

Abstract

Plasma etching of crystalline and hydrogenated amorphous silicon has been studied in CClF₃ gas as a function of pressure and power using a 30 kHz parallel plate plasma-etching system. In contrast to CF₄ plasma, etching of amorphous silicon in CClF₃ is found to be slower than that of crystalline silicon. The selectivity of crystalline silicon over amorphous silicon is observed in the range 1.5-4.0 in CClF₃ plasma as against 0.5-1.0 in CF₄ plasma. The effect of mixing oxygen and hydrogen with CClF₃ is also discussed. Auger electron spectroscopy has been performed in order to identify the residual chemisorbed species on the sample surface during etching in CClF₃ plasma.