THIN-FILM SEMICONDUCTOR ELECTRODES DEPOSITED ON PYROELECTRIC CERAMICS- APPLICATION TO COMPACT SPECTRALLY SELECTIVE PYROELECTRIC IR SENSORS

Ferroelectric materials like lead calcium titanate ceramics have been demonstrated to be excellent materials for pyroelectric detectors. The y are usually covered with electroded black gold. This material is ext ensively used to obtain both a fair IR absorption and a good electrica l contact. Spectrally selective compact IR sensors for specific applic ations could be obtained by means of vacuum deposition on the pyroelec tric substrate of the specific multilayer IR filter. However, very smo oth substrates are required for proper adhesion of the multilayer, whi ch is not the case for black gold layers. Besides, these layers do not possess the optical properties required in the filter's design and de velopment process. Semiconductors like germanium or silicon are typica l IR optical materials widely used in optical multilayers. Vacuum-evap orated Ge thin films have been deposited onto pyroelectric lead calciu m titanate ceramics. In this work, a new system to improve the perform ance of lead calcium titanate ceramics for an infrared sensor is propo sed. Studies have also been performed in order to establish the behavi our of this material as both an electrode and first layer. The feasibi lity of obtaining compact spectrally selective pyroelectric IR sensors has also been proved.