Study of grains size distribution and electrical activity of heavily boron doped polysilicon thin films

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.