This study uses a resonance method to determine Young’s modulus (E), shear modulus (G), and Poisson’s ratio (ν) of plasma-enhanced chemical vapor deposited silicon nitride (SiNxHy) thin films deposited under varying process conditions. The resonance method involves exciting the bending and torsional vibration modes of a microcantilever beam fabricated from a film. The E and G values can be extracted directly from the bending and torsional vibration modes, and the ν value can be determined from the calculated E and G values. The density (ρ) of the films was determined using a quartz crystal microbalance method. In order to determine the validity of the resonance method, finite element modeling was used to determine its dependence on microcantilever beam dimensions. Over a deposition temperature range of 100–300°C, measured E, G, and ν values varied within 54–193GPa, 22–77GPa, and 0.20–0.26 with changes in process conditions, respectively. Over the same deposition range, measured ρ values varied within 1.55–2.80g/cm3 with changes in process conditions.