Ceramic and polymer thin films in pyroelectric sensors - A comparative study

Recently considerable attention has been centered on the use of ferroelectric thin films in pyroelectric sensor arrays. Integration of the ferroelectric thin film onto technologically important Si wafer offers the possibility to have both the sensor and the electronics on the same substrate. The choice of the material and the optimal thermal isolation of the sensitive film are the two fundamental problems involved in the fabrication of pyroelectric sensor. In this paper the main emphasis has been to compare the suitability of copolymer like poly(vinylidenefluoride/trifluoroethylene, P(VDF/TrFE) and ceramic like lead zirconate titanate, PZT, for pyroelectric single element sensors and sensor arrays. Single element sensors with radiation sensitive area of 1 mm(2) fabricated from both types of materials onto a SiO2/Si3N4 membrane exhibited at room temperature, a specific detectivity of 3x10(8) cmHz(1/2)W(-1). In addition sensor arrays with 128 elements were also fabricated from both the materials.