Laser assisted chemical vapor deposition based on the ultraviolet laser illuminated in parallel to sample surface has been examined as a useful means to deposit thin films without sample heating or damage. In this study, we investigate the effect of enlarged laser beam towards silicon nitride film deposition on larger sample area, relying on Argon Fluoride excimer laser beam of 193 nm wavelength to induce photolysis in SiH4/NH3 mixture. Advantages and mechanisms of enlarged beam are presented, and further parametric trends including the influences of reactant gas and laser parameters, and substrate temperature are reported.