  The comparative investigation of pyroelectric response modulation frequency
dependences of structures of "polar active film-Si substrate" type based on PZT
and PVDF and of structures of "polar active film - buffer layer - Si substrate"
type based on PZT and porous silicon (por-Si) has been carried out. By
photopyroelectric modulation method the thermowave pyroelectric "under-surface"
probing was performed and amplitude-to-frequency and phase-to-frequency
dependences of pyroelectric response of investigated systems in the voltage and
current modes were obtained. By performing the analysis of obtained dependences
the thermal diffusivity values of investigated PZT and PVDF films, and also
por-Si interlayer were estimated. The results of theoretical consideration of
the structures under investigation are in a good agreement with the
experimental data. The problem of thermal decoupling and self-decoupling from
position of chain "frequency-thickness-material" and question of complete and
incomplete thermal linkage are briefly discussed. The obtained results show
that a por-Si layer is a suitable material for effective thermal decoupling of
polar active film and heat removing Si-substrate which realized in significant
increase of pyroelectric response value and approach it to that of
characteristic for a free sensitive element.
