Raman study of light-emitting SiNx films grown on Si by low-pressure chemical vapor deposition

• Published in: Thin solid films Vol. 579; pp. 110 - 115
• Main Authors: Komarov, F., Vlasukova, L., Parkhomenko, I., Milchanin, O., Mudryi, A., Togambaeva, A., Korolik, O.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 31-03-2015
• Subjects: Annealing; Chemical vapor deposition; K-centers; Low pressure chemical vapor deposition; N-centers; Nanostructure; Photoluminescence; Quantum confinement; Raman scattering; Si nanoclusters; Si-rich silicon nitride; Silicon; Silicon nitride; Spectroscopy; Si-rich silicon nitride; Annealing; K-centers; Raman scattering; Photoluminescence; N-centers; Si nanoclusters; Low pressure chemical vapor deposition
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2015.03.003

Si-rich silicon nitride (SRSN) films were deposited on Si wafers by low pressure chemical vapor deposition (LPCVD) technique and, subsequently, annealed at (800–1200) °C to form Si precipitates. The composition of SiNx films was measured by Rutherford backscattering spectrometry (RBS). Two sets of samples differed by the amount of excessive Si (Siexc) in silicon nitride were studied. Evolution of Si nanoclusters from amorphous to crystalline ones during high temperature treatment was examined by Raman scattering (RS) spectroscopy. The amorphous Si clusters were already revealed in as-deposited SiNx while the annealing results in their crystallization. The crystalline nanoprecipitates are only registered in nitride films after annealing at 1200°C. A dependence of Raman scattering intensity from the Si wafer on the temperature of annealing of SiNx/Si structures was revealed. This information was used to explain the phase transformations in SRSNs during high temperature treatments. The peculiarities of photoluminescence (PL) spectra for two sets of Si-rich SiNx films are explained taking into account the contribution from the quantum confinement effect of Si nanocrystals and from the native defects in silicon nitride matrix, such as N- and K-centers.
•The size of Si nanocrystals in Si-rich SiNx films depends on Si excess content.•Excess Si remains in SiN0.46 as randomly distributed Si atoms in atomic network.•In SiN1 films practically all excess Si is aggregated into Si nanoclusters.