Diagnosis of radio-frequency silane and silane-nitrogen plasmas based on field ionization mass spectrometry

Abstract

Field ionization mass spectrometry was applied to identify the neutral species involved in silane and silane-nitrogen plasmas used for manufacturing amorphous Si and SiN films. The most abundant radical in silane plasmas was found to be SiH 3, suggesting that SiH 3 was primarily responsible for growing amorphous Si films. The silane plasmas also comprised Si 2H n radicals, which presumably resulted from chemical reactions of atomic hydrogen with deposited films. The SiN + signal detected for silane-nitrogen plasmas was very weak, so the growth of SiN films was due mainly to reactions between deposited SiH n radicals and atomic nitrogen.