MEASUREMENT OF SI ATOM DENSITY IN RADIOFREQUENCY SILANE PLASMA USING ULTRAVIOLET-ABSORPTION SPECTROSCOPY

The Si atom densities at two ground levels (3p23P2 and 3p21D2) were measured in the on-off modulated radio-frequency discharge silane plasma generated in a plasma-enhanced chemical vapor deposition chamber equipped with a parallel-plate electrode through absorption spectroscopy using an ultraviolet hollow cathode lamp, and were investigated as functions of the SiH4 concentration in SiH4/Ar, the input power, and the total pressure in detail. The Si atom density at the 3p21D2 level was measured first here and found to attain to the same order as that at the 3p23P2 level. The SiH4 concentration dependence of the Si atom densities at two ground levels was different from that at two excited levels (3p4s3P2 and 3p4s1P1). These results were used to discuss the generation and removal processes of the Si atom.