Si nanocrystals were formed by the implantation of Si+ into a SiO2 film, deposited on (100) Si, followed by high-temperature annealing. Transmission electron microscopy (TEM) was used to examine the effect of implantation dose on the microstructure of the Si nanocrystals (Si nc) in the SiO2 film. The size and spatial distribution and concentration of the Si nc in four passivated samples with different implantation doses were investigated using the dark-field imaging technique. The thickness of all the samples was determined by electron energy-loss spectroscopy (EELS). The structure of the Si nc in all the samples was determined using selected area electron diffraction. It was found that the average diameter of the Si nc changes from 2.7 to 3 and to 3.3 nm for the samples with implantation doses of 6 × 1016, 8 × 1016 and 1 × 1017 cm−2; however, it ranges from 2 to 22 nm in the sample with an implantation dose of 3 × 1017 cm−2. The size of the Si nc is comparatively homogeneous throughout the whole implanted layer in the samples with implantation doses of 6 × 1016 and 8 × 1016 cm−2, while in the samples with implantation doses of 1 × 1017 and 3 × 1017 cm−2, the Si nc in the middle region of the implanted layer are bigger than those near the surface or the bottom of the layer. From TEM experimental results, the concentration of the Si nc is estimated to be 6 × 1018, 4 × 1018 and 4 × 1018 cm−3 for the samples with implantation doses of 6 × 1016, 8 × 1016 and 1 × 1017 cm−2, respectively. For the sample with an implantation dose of 3 × 1017 cm−2, the concentration for the Si nc of 3 nm is around 5 × 1018 cm−3; the concentration for Si nc of 6 nm is around 2 × 1018 cm−3; and the concentration for the 12 nm group is about 1 × 1018 cm−3. In addition, the concentration determined from TEM experiments is compared with the calculated one. Combining the TEM results with a Monte Carlo simulation, we also discuss the sputtering effect and the depth distribution of the Si ions implanted in SiO2.

Silicon nanocrystals (Si-nc) were produced by the implantation of Si + in excess into amorphous quartz and a 1 µm SiO 2 film thermally grown on an Si substrate. In the latter, the photoluminescence (PL) spectra from the Si-nc, induced by Ar + laser excitation, are modulated by Fabry-Perot type interference fringes due to the interference of the emitted light reflected at the Si/SiO 2 interface with that propagating directly towards the surface. In this paper, we investigate the spectral modulation and the PL as a function of the incidence angle of the pump laser and the Si + dose implantation. The modulation of the PL spectra is influenced by the distribution in depth of the pump laser intensity in the SiO 2 layer, the depth distribution of the Si-nc and the refractive index distribution of the layered structures. One goal of our work is to modulate the emission spectra by acting on the thickness of the SiO 2 layer. Simulations have been undertaken to establish a relation between the modulation of the PL spectrum and the depth distribution of both the pump laser intensity and the Si-nc. This study required the precise measurements of the depth distribution of both the complex refractive index (n, k) by ellipsometry and the Si-nc by transmission electron microscopy (TEM).