Silicon nitride films were synthesized by reactive pulsed laser ablation (PLA) of a Si target in N-2 gas atmosphere. At different laser fluences and N-2 gas pressures the infrared absorption peak attributed to Si-N bond was evaluated. The nitrogen concentration in the film increased with the increasing fluence. Nitrogen concentration depended also on N-2 gas pressure; it increased as N-2 pressure increase up to 10 Pa and then it decreased with further increasing N-2 gas pressure. These results indicate that decomposition of N-2 molecules and collisions of SiNx clusters with N-2 molecules are essential to prepare silicon nitride films by PLA method. The PLA is a promising method to fabricate nitrogen rich silicon nitride films without using poisonous gases such as silane and ammonia. (C) 2002 Elsevier Science B.V. All rights reserved.