Radical analysis and residence-time effect of silicon nitride atomic layer deposition processes with trisilylamine and NH_3 plasmas

摘要

The residence time effect of SiNx plasma atomic layer deposition processes was investigated. The reactive species (H-x, NHy, SiHz) were analysed by a mass spectrometer. In the NH3 plasma step, a strong SiH4 peak was observed and is attributed to the desorption of SiH4 from the SiNx surface. A relatively low N/Si ratio of 1.16 was identified owing to the re-deposition of the desorbed SiH4. The re-deposition was decreased by reducing the residence time of reactants. The re-deposition species were quantitatively analysed using optical emission spectrometry, and the N/Si ratio increased nearly to the ideal stoichiometric value of 1.33.