Effects of low-frequency modulation on rf discharge chemical vapor deposition

Abstract

Low-frequency square-wave modulation of a rf discharge in silane diluted with a rare gas brought about an improvement in the deposition rate of amorphous hydrogenated silicon films and in the film quality as well as a drastic suppression of powder concentration in the discharge space. These results can be explained by a SiH3 density in the modulated discharge that is high compared to that without modulation, because of the electron density enhancement resulting from the modulation and also because the lifetime of SiH3 radicals is much longer than those of SiHn radicals (n=0–2).