PYROELECTRIC SENSORS AND ARRAYS BASED ON P(VDF TRFE) COPOLYMER FILMS/

The central problem of the sensor design is a good thermal insulation of the P(VDF/TrFE) thin film from the read-out circuit. Two variations were examined - thin carrier membranes of SiO2/Si3N4 produced through back etching and thick thermal insulating layers out of spin-coated p olymers with via holes. Through simulation and measurements on single element sensors and linear arrays for both variants an optimal design could be established. Membrane sensors consisting of 1 mu m P(VDF/TrFE ) thin film deposited on a 0.65 mu m thick membrane show within the fr equency range of 10 Hz to 1 kHz comparatively higher values for respon sivity and specific detectivity than insulating layer sensors. The ins ulating layer sensors have in the most favourable case a thermal cutof f frequency of about 100 Hz, below that the responsivity remains const ant while the specific detectivity and NEP deteriorate again. The opti mal layer thickness for the compound of BCB and P(VDF/TrFE) for a chop per frequency of about 100 Hz is at approximately 18...25 mu m. The ad vantages of the design with insulating layer are however, that a filli ng factor of almost 100 % independently of the pixel size is reachable and that very small pixels of about (50x50) mu m(2) are realisable to o.