ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The microstructure and the annealing behavior of N-rich SiNx films are studied with x-ray absorption measurements at the N-K edge. The SiNx films were fabricated with ion implantation of 35 keV N+ ions into Si substrates, in the dose range 2×1017–2×1018 ions/cm2. The near-edge x-ray absorption fine structure (NEXAFS) spectra of the N-rich films are characterized by a strong resonance line (RL2) at 403.3±0.1 eV whose intensity increases with the implantation dose. RL2 is attributed to dipole electron transitions, from 1s to unoccupied p orbitals, at a defect site containing a N dangling bond defect. The defect related to RL2 has high thermal stability and is practically unaffected by vacuum annealing up to 1000 °C. One more defect-related resonance (RL1) is detected at 401.1±0.3 eV in the films fabricated with the lower and intermediate used implantation doses (2×1017 and 1×1018 cm−2, respectively). The activation energy for the annealing of RL1 is 0.50±0.05 eV. Extended x-ray absorption fine structure spectroscopy (EXAFS) on the as-implanted and annealed films reveals that subnitrides are formed upon implantation. These nitrides are characterized by a Si-N nearest-neighbor distance which is comparable to that of the reference nitride, while the coordination number in the first nearest-neighbor shell N1 depends on the implantation dose. The stoichiometry deviation, as measured from the value of N1 which takes values between 1.7 and 2.8 for the limiting doses of 2×1018 and 2×1017 cm−2, respectively, shows the correlation between the RL2 in the NEXAFS spectra and the presence of N dangling bonds in the as-implanted films. © 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.367436
