Nanocrystal formation in annealed a-SiO_0.17N_0.07:H films

Abstract

Silicon nanocrystals have been fabricated by annealing amorphous hydrogenated silicon-rich oxynitride (SRON) films in vacuum for 4 h over the temperature range 850–1150 °C. X-ray photoelectron spectroscopy confirmed the composition of the film to be SiO0.17N0.07. Glancing angle x-ray diffraction results revealed consistent silicon crystallite sizes of nm for films annealed at temperatures , increasing to nm for films annealed at 1150 °C. The room temperature photoluminescence spectra of the samples annealed at 850 and 950 °C comprised luminescent peaks from silicon nanocrystals and luminescence from the defects in Si–O system. However, only peaks from defects in Si–O system were present in the luminescence spectra from samples annealed at temperatures greater than 950 °C. For the samples annealed at 850 and 950 °C, the presence of strong Si–N bonds prevented the coalescence of smaller silicon crystallites into larger crystallites. Larger, non-luminescent silicon crystallites were only formed in films annealed at temperatures greater than 950 °C, where the energetics of coalescing particles overcame the strong Si–N bonding in SRON films. High-resolution transmission electron microscopy analysis confirmed the presence of silicon nanocrystallites. A proposed growth mechanism of silicon nanocrystals is discussed.

Study of Silicon Nanocrystals Formation in Annealed Amorphous In Situ Nitrogen Doped Silicon Thin Films Obtained by Low Pressure Chemical Vapor Deposition

“…Indeed, it was reported [4] that the presence of strong Si-N bonds prevented the coalescence of smaller silicon crystals into larger crystallites. To evidence this result, FTIR analysis were carried out.…”

“…Several methods tried to form silicon nanocrystals in silicon based materials [2][3][4]. Indeed, Si-nc is a mixed phase material consisting of nanocrystals of silicon embedded within an amorphous silicon matrix.…”

Effect of Annealing on the Interfacial and Structural Properties of Amorphous Silicon-Hafnia Films

“…More details for the experimental conditions and analysis by GAXRD, XRR, and XPS have been published elsewhere. [12] The 2-nm a-Si/10-nm HfO 2 /Si were annealed between 873 K and 1173 K (600°C and 900°C) for 1 hour in a TGA furnace (TA 2950, TA Instruments, New Castle, DE) purged with He gas. The TGA furnace was washed with acetone, dried, and heated in ambient air at 1223 K (950°C) for 3 hours prior to the start of experiments.…”

Spectroscopic ellipsometry and photoluminescence measurements of as-deposited and annealed silicon rich oxynitride films

“…CuK α radiation (E = 8041.3 eV) was used for the GAXRD measurements. The experimental details for GAXRD have been published elsewhere [5,8]. GAXRD measurements in the 2-theta range 5-80°were performed at an angle of incidence of 0.5°.…”

“…Recently, we reported a detailed investigation of the chemical, vibrational and room temperature luminescence properties of as-deposited SiO x N y :H (0.17 ≤ x ≤ 0.96; 0.07 ≤ y ≤ 0.27) films [4]. We had also successfully nucleated Silicon nanocrystals in thermally annealed SiO 0.17 N 0.07 :H films [5].…”