Evolution of Optical and Structural Properties of Silicon Nanocrystals Embedded in Silicon Nitride Films with Annealing Temperature

Benyahia, Bedra; Tiour, Faiza; Guerbous, L.; Chaoui, R.; Menous, I.; Mahmoudi, B.; Mefoued, A.; Guenda, Abdelkader

doi:10.4028/www.scientific.net/jnanor.49.163

Cited by 8 publications

(2 citation statements)

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“…Besides, RTA results in broadening of the (111) peak as well as formation of a narrow peak set. These narrow peaks indicate the formation of Si nanocrystals 27 − 29 and nanocrystalline phases, α- and β-Si 3 N 4 . 22 Formation of such phases occurs at normal pressure yet at high temperature.…”

Section: Resultsmentioning

confidence: 99%

Effect of Rapid Thermal Annealing on Si-Based Dielectric Films Grown by ICP-CVD

et al. 2023

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Silicon nitride, silicon oxide, and silicon oxynitride thin films were deposited on the Si substrate by inductively coupled plasma chemical vapor deposition and annealed at 1100 °C for 3 min in an Ar environment. Silicon nitride and silicon oxide films deposited at ratios of the reactant flow rates of SiH4/N2 = 1.875 and SiH4/N2O = 3, respectively, were Si-rich, while Si excess for the oxynitride film (SiH4/N2/N2O = 3:2:2) was not found. Annealing resulted in a thickness decrease and structural transformation for SiO x and SiN x films. Nanocrystalline phases of Si as well as α- and β-Si3N4 were found in the annealed silicon nitride film. Compared to oxide and nitride films, the oxynitride film is the least susceptible to change during annealing. The relationship between the structure, composition, and optical properties of the Si-based films has been revealed. It has been shown that the calculated optical parameters (refractive index, extinction coefficient) reflect structural peculiarities of the as-deposited and annealed films.

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Section: Resultsmentioning

confidence: 99%

Effect of Rapid Thermal Annealing on Si-Based Dielectric Films Grown by ICP-CVD

et al. 2023

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“…The existence of an increased absorption on the high energy side is associated with silicon nanocrystals (Si-Ncs). The optical gap varies from 2.4 eV for ratio NH 3 /SIH 4 6 to 1.3 eV for silicon rich SiN x at NH 3 /SIH 4 = 0.5 [22,23]. Further investigations were undergone to assess the effect of Eu incorporation into silicon nitride (SiN x ) matrix (comprising the nanostructures).…”

Section: Introductionmentioning

confidence: 99%

Neodymium-coated PECVD-designed silicon nanostructures: A comprehensive structural, morphological and spectroscopic investigation

Mefoued

Mahmoudi

Benrekaa

et al. 2022

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We report the optical, structural, and spectroscopic properties of thermally evaporated neodymium oxide (Nd2O3) thin films deposietd on a nanostructured silicon (Si-ns) matrix. The Si-ns thin films were grown by depositing silicon nitride (SiN) thin films using plasma enhanced chemical vapour deposition (PECVD). The gas ratio R=NH3/SiH4 was varied between 2.5 and 5 to obtain different stoichiometries and Si amounts in the SiN layers. Two sets of samples were analysed. The first set comprised samples prepared with gas ratios R=2.5, 3, 4, and 5 and annealed at 900°C for 15 min. For the second set, R was 2 and 4 for the samples annealed at 1100°C for 2 h. Both sets were thermally treated under nitrogen (N2) ambient. The nanocrystalline formation and layer thickness were assessed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). UV-Vis absorption spectra revealed that the reflectance was lower for the Nd2O3-coated samples than for to the uncoated ones. This trend remained unchanged after the annealing. Optical band gap (Eg) was found to increase with increasing R (2.5, 3, and 4) with Eg = 1.28, 1.31 and 1.55 eV respectively for annealed samples. Refinement of nanostructures size was observed with higher Eg values. The presence of Nd, Si, oxygen (O) and phosphorus (P) was confirmed by energy dispersive spectroscopy (EDS) and secondary ion mass spectrometry (SIMS) data. Moreover, X-ray diffraction (XRD) and Raman spectroscopy were employed to determine and confirm amorphous silicon (a-Si), crystalline silicon (c-Si), Nd2O3 and SiN phases present in the Nd2O3-SiN bilayers. Crystallite sizes for Nd and Si found to be 40.7 and 6.82 nm respectively. After the annealing process, a Raman shift toward lower wavenumbers was observed for Si peak. XPS data revealed the formation of Nd2O3 thin films with a Nd-O bonding incorporating trivalent Nd ions (Nd3+).

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