A statistically designed experiment was run to optimize the deposition of PECVD SiN on GaAs substrates. Five deposition parameters were varied: RF power, temperature, pressure, plasma frequency, and ammonia/silane ratio. Four film properties were used to evaluate the quality of the nitride: the fraction of hydrogen bound to nitrogen atoms, the index of refraction (and its uniformity), thickness uniformity, and stress. From the screening phase of the experiment, it was determined that only the plasma frequency and ammonia/silane ratio influenced the quality of the nitride film. High frequency deposition was preferable to low frequency deposition since it resulted in lower film stress. The results of the optimization phase showed that SiN films with near‐zero stress, low N‐H bond density and good index of refraction could be obtained by deposition at a very low ammonia/silane ratio.