A-SIC-H FILMS DEPOSITED BY PECVD FROM SILANE PLUS ACETYLENE AND SILANE PLUS ACETYLENE PLUS HYDROGEN GAS-MIXTURE

This work concerns the deposition and the characterization of a-SiC:H films obtained from C2H2 + SiH4 mixtures, with and without H-2 dilutio n: we present results on a set of films obtained by a UHV-PECVD system , which have been characterized in their compositional, optical, struc tural and defect properties. We show that C2H2 is a very good gas sour ce for obtaining low-defect films and that it has advantages with resp ect to the more used CH4 and C2H4, especially in the region of C/(C+Si ) ratios higher than 0.4; furthermore we show that H-2, dilution does not Improve the film quality and leads to more defective films. (C) 19 97 Elsevier Science S.A.