Fabrication of columnar structured lanthanum zirconate films by laser CVD

Columnar lanthanum zirconate (LZ) films were deposited by laser chemical vapor deposition (LCVD). The effects of deposition conditions, preheat temperature and laser power, on crystal structure, morphology, and deposition rate were investigated. A large region in the terms of preheat temperature and laser power for the formation of cubic pyrochlore-structured LZ films was mapped under a fixed total pressure of 950 Pa. The morphology of LZ films without laser irradiation showed a dense and glass-like structure with a flat cauliflower surface. It was changed into a columnar structure with an unflat cauliflower surface by low-power laser irradiation during deposition process. The transformation occurred once a critical laser power beyond 16 W/cm(2). Thus, the effect of laser on the deposition of LZ films was a result of double-side action including both pyrolytic effect and photolytic effect. Plasma gas around the substrate resulted in significant increases in deposition temperature and deposition rate due to self-propagating high-temperature reactions between the precursors and O-2. The maximum deposition rate can reach 250 m/h by LCVD.