低损耗掺杂BST薄膜的射频磁控溅射沉积及其阻抗特性研究
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摘要
利用射频磁控溅射法和快速热退火处理,在高电阻Si基片上制备了具有较低介电损耗的MgO掺杂Ba_(0.25)Sr_(0.75)TiO_3(BST)铁电薄膜。通过XRD和SEM,分别对BST铁电薄膜的微结构和表面形貌进行了分析。利用铁电分析仪和低频阻抗分析仪分别测试了BST薄膜样品的铁电特性和介电性能。研究表明,MgO掺杂的BST薄膜的介电损耗要低于纯的BST薄膜,并且在掺杂浓度为5%(摩尔分数)时,获得最佳的实验结果。在室温和250 Hz的条件下,测得700℃退火的BST铁电薄膜样品的矫顽电场强度(E_C)和剩余极化强(P_r)分别为1.15 V/cm和4.06μC/cm~2,介电常数和介电损耗因子分别为370和0.005。
MgO-doped Ba_(0.25)Sr_(0.75)TiO_3(BST) ferroelectric thin films with low dielectric loss were prepared on high-resistance Si substrates by RF magnetron sputtering and rapid thermal annealing. The microstructure and surface morphology of BST ferroelectric thin films were analyzed by XRD and SEM, respectively. The ferroelectric and dielectric properties of the BST film samples were tested by using a ferroelectric analyzer and a low frequency impedance analyzer. The results show that the dielectric loss of MgO-doped BST thin films was lower than that of pure BST thin films, and the best experimental results were obtained with MgO doping concentration of 5 mol%. The coercive electric field strength(E_C) and residual polarization(P_r) of the ferroelectric thin film sample(annealed at 700 ℃) measured at room temperature and 250 Hz were 1.15 V/cm and 4.06 μC/cm~2, respectively. Its dielectric constant and dielectric loss tangent were 370 and 0.005, respectively.
MgO-doped Ba_(0.25)Sr_(0.75)TiO_3(BST) ferroelectric thin films with low dielectric loss were prepared on high-resistance Si substrates by RF magnetron sputtering and rapid thermal annealing. The microstructure and surface morphology of BST ferroelectric thin films were analyzed by XRD and SEM, respectively. The ferroelectric and dielectric properties of the BST film samples were tested by using a ferroelectric analyzer and a low frequency impedance analyzer. The results show that the dielectric loss of MgO-doped BST thin films was lower than that of pure BST thin films, and the best experimental results were obtained with MgO doping concentration of 5 mol%. The coercive electric field strength(E_C) and residual polarization(P_r) of the ferroelectric thin film sample(annealed at 700 ℃) measured at room temperature and 250 Hz were 1.15 V/cm and 4.06 μC/cm~2, respectively. Its dielectric constant and dielectric loss tangent were 370 and 0.005, respectively.
引文
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[2] Sheng S,Wang P,Zhang X Y,et al.Characterization of microwave dielectric properties of ferroelectric parallel plate varactor [J].J Phys D:Appl Phys,2009,42(1):015501.
[3] Tagantsev A K,Sherman V O,Astafiev K F,et al.Ferroelectric materials for microwave tunable applications [J].J Electroceram,2003,11(1-2):5-66.
[4] Sheng S,Ong C K.Coupled microstrip line microwave phase shifter using ferroelectric thin film varactors [J].J Appl Phys,2012,111(4):044506.
[5] Setter N,Damjanovic D,Eng L,et al.Ferroelectric thin films:review of materials,properties,and applications [J].J Appl Phys,2006,100(5):051606.
[6] Miranda F A,Subramanyam G,Van keuls F W,et al.A K-band (HTS gold)/ ferroelectric thin film/dielectric diplexer for a discriminator-locked tunable oscillator [J].IEEE Trans Appl Supercond,1999,9(2):3581-3584.
[7] Moechly B H,Zhang Y M.Strontium titanate thin films for tunable YBa2Cu3O7 microwave filters [J].IEEE Trans Appl Superconduct,2001,11(1):450-453.
[8] Korn D S,Wu H D.A comprehensive review of microwave system requirements on thin-film ferroelectrics [J].Integrated Ferroelectrics,1999,24(1-4):215-237.
[9] Dionne G F,Oates D E.Tunability of microstrip ferrite resonator in the partially magnetized state [J].IEEE Trans Magn,1997,33(5):3421-3423.
[10] Wu H D,Harsh K F,Irwin R S,et al.MEMS designed for tunable capacitors [C]//Microwave Symposium Digest.America:IEEE MTT-S International,1998:127-129.
[11] Barker N S,Rebeiz G M.Optimization of distributed MEMS transmission-line phase shifters-U-band and W-band designs [J].IEEE Trans Microwave Theory Tech,2000,48(11):1957-1966.
[12] Bao P,Jackson T J,Wang X,et al.Barium strontium titanate thin film varactors for room temperature microwave device applications [J].J Phys D:Appl Phys,2008,41(6):063001.
[13] Joshi P C,Cole M W.Mg-doped Ba0.6Sr0.4TiO3 thin films for tunable microwave applications [J].Appl Phys Lett,2000,77(2):289-291.
[14] Cole M W,Joshi P C,Ervin M H,et al.The influence of Mg doping on the materials properties of Ba1-xSrxTiO3 thin films for tunable device applications [J].Thin Solid Films,2000,374(1):34-41.
[15] Cole M W,Hubbard C,Ngo E,et al.Structure-property relationships in pure and acceptor-doped Ba1-xSrxTiO3 thin films for tunable microwave device applications [J].J Appl Phys,2002,92(1):475-483.
[16] Chang W,Sengupta L.MgO-mixed Ba0.6Sr0.4TiO3 bulk ceramics and thin films for tunable microwave applications [J].J Appl Phys,2002,92(7):3941-3946.