| (Ba,Sr)TiO3 (BST) thin film is one of the ideal materials applied for Uncooled Focal Plane Array (UFPA) due to its high dielectric constant, low leakage current, good pyroelectric property, the preparation of BST thin film based on inverted cylindrical RF sputtering was studied in this thesis.The sinter of cylindrical BST ceramic target was experimented. The optimal firing process was obtained on the basis of experiments. The measurements show that the dielectric constant of Ba0.65Sr0.35TiO3 ceramic target exceed 104 at 10KHz, 25℃, the Curie temperature is 19℃, which indicate the target is suit for the RF sputtering application.The influence of (Ba,Sr)RuO3 (BSR) buffer on the microstructure and electrical properties of BST films was investigated. The results suggest that the BST thin film with a BSR buffer deposited at 200℃has better crystallization and electrical properties, which is helpful to BST thin films.BST thin films with BSR buffer were deposited on Pt/Ti/SiO2/Si substrates by inverted cylindrical RF sputtering. The influences of substrate temperature, target-substrate distance, sputtering power, deposition pressure, the ratio of oxygen to argon, target self-bias and anneal process on the microstructure and electrical properties of sputtered BST films were systematically investigated. The results show the BST thin films prepared at optimal deposition condition have smooth surface, excellent crystallization and good withstand voltage properties, the pyroelectric coefficients are as high as 6.73×10-7 C.cm-2.K-1 at room temperature.Inverted cylindrical RF sputtering combined with biaxial rotation was used to deposit BST thin film. The advantage of preparing large-area BST thin films in biaxial rotation mode has been confirmed.Single-element infrared detectors based on BST pyroelectric thin films were fabricated. And a detectivity D* of 4.93×107cm.Hz1/2.W-1 is obtained at room temperature, 30Hz, which proves the high pyroelectric property of BST thin films. |
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