Radical Detection in Deposition Plasmas by Threshold Ionization Mass Spectroscopy

Neutral radicals produced in SiH4 and H2-SiH4 RF discharges are detected by threshold ionization mass spectrometry. Relative radical densities are found similar in all discharges, showing a minor amount (5-9 %) of Si2H2 besides SiH3 and neglectable amounts of other radicals. Absolute radical densities are also determined by calibration of the mass spectrometer with the background gas signal.