Stoichiometric thin films of LiNbO3have been deposited on (100) silicon by a pulsed excimer laser deposition technique. By studying several cases of depositions in vacuum, oxygen, and argon, as well as oxygen‐argon mixture as ambients, it is brought out that the desired stoichiometry in the film can be attained only by having an appropriate oxygen‐argon mixture during deposition. The films have been characterized by x‐ray diffraction, infrared transmission, and spectroscopic ellipsometry techniques.