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In this work, the effect of the high silicon nanocrystals density as well as the radiated waves interference on the photoluminescence (PL) spectrum of silicon nanocrystal (Si-nc) embedded in silicon nitride film is studied. The film is prepared using low pressure chemical vapor deposition (LPCVD) following by a high temperature annealing. It was found that for silicon nitride of a high silicon content sample, the interference effect based on only the thickness of the film is unable to satisfactory explain the distortion on the PL spectrum. Using Monte Carlo analysis, it was shown that the simulated and the experimental PL spectra accurately superpose when taking into account the contribution of the reflection from silicon nanocrystals as well as the distance traveled by the radiated waves.

In the present study, the deposition process of SiNx thin films obtained by a low-pressure chemical vapor deposition technique with a mixture of disilane (Si2H6) and ammonia (NH3) was simulated by using the kinetic Monte Carlo method. A new pattern describing the distribution of ammonia molecules in the simulation matrix was proposed. The influences of the NH3/Si2H6 gas flow ratio and the deposition temperature on the obtained films structure in terms of silicon cluster size and density were analyzed. The simulation results indicate that an increase in the gas flow ratio leads to the deposition of amorphous silicon clusters characterized by small sizes. Nevertheless, an increase in the temperature values of the process provokes an enhancement in the silicon cluster size along with a decrease in their density.

In this work, we propose an analytical model allowing the calculation of nanocrystalline silicon thin film transistors surface potential by considering a granular morphology of silicon nanocrystallites forming the channel. Results show that, according to the quantum effects on dielectric constant and band gap, the surface potential values are strongly related to the silicon crystallites structure in terms of size and geometry. The comparison of our results with existing research data shows a good agreement between the surface potential shapes and an interesting difference in the surface potential variations related to the morphology specificity considered in our theoretical approach.

The grain size distribution (GSD) and related electrical activity of boron heavily doped amorphous LPCVD thin films were studied according to the heat treatment durations. Results show that GSD approaches a logarithmic-normal form at a short annealing duration and for crystalline fractions around 5%, demonstrating that the crystallization process occurs with depletion nucleation sites; and becomes a pure log-normal for crystalline fractions around 25% after 15 min anneal. The fast change from log-linear to log-normal distribution in the GSD allows boron to acquire its maximum activity during a short annealing duration under 700 °C annealing temperature.

In this work we study the boron diffusion and its activation into recrystallized nitrogen doped silicon thin films (NIDOS) and we also discuss the influence of the chemical interaction between boron and nitrogen in NIDOS films. These films are deposited by low pressure chemical vapor (LPCVD) for the development of a P + polysilicon gate for MOS structures. The reduction of boron diffusion with increasing nitrogen content is observed by SIMS profiles. SUPREM IV software is used in order to estimate the boron diffusion coefficients in NIDOS films. FTIR analyses show the appearance of a B–N complex whose density strongly depends on the annealing treatment in terms of temperature and duration. It is deduced through resistivity measurements and SEM observation that the formation of B–N complexes tends to degrade the electrical properties of polysilicon thin layers through the decrease of both electrically active boron and polycrystalline grains growth.