2 WAYS TO PYROELECTRIC P(VDF TRFE) THIN-FILM SENSORS AND ARRAYS/

A central problem of the sensor design is the thermal insulation of th e P(VDF/TrFE) thin film from the read-out circuit. Two variations have been examined - thin carrier membranes of SiO2/Si3N4 produced by back etching and thick thermal insulating layers out of spin-coated polyme rs with via holes. For both variants an optimal design could be establ ished by simulation and measurements on single element sensors and lin ear arrays. Membrane sensors consisting of 1 mu m P(VDF/TrFE) thin fil m deposited on a 0.65 mu m thick membrane show within the frequency ra nge of 10 Hz to 1 kHz comparatively higher values for responsivity and specific detectivity than insulating layer sensors. The insulating la yer sensors have in the most favourable case a thermal cut-off frequen cy of about 100 Hz, below that the responsivity remains constant while the specific detectivity and NEP deteriorate again. The optimal layer thickness for the compound of BCB (benzocyclobutene) and P(VDF/TrFE) for a chopper frequency of about 100 Hz is at approximately 18...25 mu m. The advantages of the design with insulating layer er are however, that a filling factor of almost 100% independently of the pixel size is reachable and that very small pixels of about (50x50) mu m(2) are r ealisable too.