Complete thermal characterization of film-on-substrate system by modulatedthermoreflectance microscopy and multiparameter fitting

Modulated thermoreflectance microscopy is applied to a complete thermal cha racterization of a thin film of gold (78 nm) or YBaCuO (300 nm) on a LaAlO3 substrate. The phase profile, measured at several modulation frequencies c overing an appropriate range, is fitted with a rigorous thermal diffusion m odel. This leads to a simultaneous estimation of the thermal diffusivities of the film and the substrate, as well as of the thermal film/substrate bou ndary resistance. The estimated values for the gold film sample are, respec tively, 4.3x10(-6) m(2) s(-1) (substrate diffusivity), 1.0x10(-4) m(2) s(-1 ) (film diffusivity), and 1.0x10(-8) m(2) KW-1 (thermal boundary resistance ), while for the thermally anisotropic YBaCuO film sample are, 4.1x10(-6) m (2) s(-1), 3.5x10(-6) m(2) s(-1) (in-plane diffusivity), and 8.0x10(-8) m(2 ) KW-1, respectively. (C) 1999 American Institute of Physics. [S0021-8979(9 9)08218-3].