Influence of the deposition conditions on the as-grown photoluminescence of silicon nanoclusters embedded in silicon nitride matrix obtained by PECVD

Monroy, B. M.; Santana, G.; Benami, A.; García, M. F.; Ortiz, A.; Alonso, J. C.; Fandiño, J.; Aguilar-Hernandez, J.; Contreras-Puente, G. Mexico

Silicon nanoclusters (nc-Si) embedded in silicon nitride films were grown by direct plasma enhanced chemical vapour deposition (PECVD) at 300°C, using mixtures of SiH₂Cl₂/H₂/NH₃. The photoluminescence (PL) of the as-grown samples is studied as a function of the plasma power, hydrogen dilution and [SiH₂Cl₂]/[NH₃] ratio. Low plasma powers seem to promote nc-Si formation in the films increasing the PL emission. An optimum [SiH₂Cl₂]/[NH₃] ratio and hydrogen dilution balance that yields intense PL emission from the as-grown samples was found. This is explained in terms of the silicon availability to produce nc-Si embedded in the silicon nitride matrix and hydrogen availability to passivate the nc-Si surface and avoid non-radiative recombination processes. The changes in the composition and optical properties of the films, as a function of the deposition conditions, were also studied by means of Fourier Transform Infrared Spectroscopy and ellipsometry measurements.

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