Influence of low-energy argon ion bombardment and vacuum annealing on the silicon nitride surface properties

摘要

The influence of Argon ion bombardment and vacuum annealing on chemical composition and bonding characteristics of the surface layer of low-pressure chemical vapour deposited (LPCVD) Si_3N_4 were investigated. After being bombarded with low-energy (3 keV) argon ions, both Auger electron spectroscopy and electron energy loss spectroscopy results indicated that some of the Si-N bonds were broken and Si-Si bonds were created in the nitride film and the Si-Si bonds can be restored to Si-N bonds with proper vacuum annealing. Valence band structure of the bombarded and annealing samples are also investigated by using soft X-ray photoelectron spectroscopy (MgKα line with energy of 132.3 eV was used). Three feature peaks in Si_3N_4 valence band related to Si-Si and N-N bonds were observed in samples with argon ion bombardment. Mechanisms of the surface modification of Si_3N_4 by low-energy argon ion bombardment and vacuum annealing are discussed.