Optical measurement of the elastic moduli and thermal diffusivity of a C–N film

The elastic properties of carbon nitride (CN_x) film adhered to a silicon substrate were characterized through impulsive stimulated thermal scattering (ISTS). The lowest-order pseudo-Rayleigh acoustic mode of the film was excited and monitored optically. From the measured acoustic phase velocities, the elastic moduli of the film were determined. The ISTS technique also permits measurements of the CN_x thermal diffusivity. The noninvasive optical measurements described can provide a useful guide to refinements in thin film fabrication procedures and for optimization of mechanical and thermal transport properties.