La掺杂对BLT薄膜微观结构与性能的影响

采用sol-gel工艺低温制备了Si基Bi4–xLaxTi3O12(BLT)铁电薄膜。研究了La掺杂量对薄膜微观结构、介电和铁电性能的影响。结果表明,600～650℃退火处理的BLT薄膜表面平整无裂纹,晶粒均匀,无焦绿石相或其它杂相,薄膜为多晶生长;La掺杂量x在0.5～0.85的BLT薄膜介电与铁电性能优良,其εr和tanδ分别介于284～289和(1.57～1.63)×10–2,4V偏压下薄膜的漏电流密度低于10–8A/cm2,Pr可达(13.0～17.5)×10–6C/cm2,Ec低至(102.5～127.8)×103V/cm。

Effect of La Doping on Microstructure and Properties of BLT Thin Films

Bi4–xLaxTi3O12 (BLT) thin films were prepared on p-Si substrates by using sol-gel method at low temperature. The effect of lanthanum content on microstructure, dielectric and ferroelectric properties of BLT films were investigated. The results show that the BLT thin films are uniform and crack free as well as exhibit a polycrystalline structure, with no pyrochlore phase or no other phases at 600 or 650 ℃. BLT thin films have good dielectric properties with La content between 0.5 and 0.85. Dielectric constant and dielectric loss of BLT thin films are from 284 to 289 and from 1.57×10–2 to 1.63×10–2 respectively. The current density of BLT thin films is lower 10–8 A/cm2 at 4 V. The Pr get to (13.0～17.5) ×10–6 C/cm2 and the Ec decrease to(102.5～127.8)×103 V/cm.