CVD of oxide materials for thermal imaging - the role of precursor chemistry

Thermal detectors exploiting ferroelectric lead zirconate titanate (PZT) or the metal insulator phase change material vanadium oxide are used widely to detect infra red radiation. Higher performance systems need to exploit improved materials as the detector element. Such materials are the ferroelectric perovskite, lead scandium tantalate (PST) and the metal insulator phase change material lanthanum barium manganite (LBMO). This paper presents work on the selection of precursors for liquid injection CVD of PZT and the high performance detector materials PST and LBMO. Control of the chemistry for the CVD process is an important step in the realisation of the large area, high quality deposition. In order to achieve this it is necessary to tailor the precursor properties so that vaporisation is efficient and decomposition leads to the desired material composition. It demonstrates how through careful precursor selection it is possible to match precursors in order to deposit high quality materials. It is shown that CVD offers a competitive route for the large area uncooled infrared devices.