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 SiH_n radicals (n=0–2).