Ferroelectric Bi3.25La0.75Ti3O12 films of uniform a-axis orientation on silicon substrates
Ferroelectric Bi3.25La0.75Ti3O12 films of uniform a-axis orientation on silicon substrates
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DOI：
10.1126/science.1069958
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发表时间：
2002-06-14
期刊：
影响因子：
56.9
通讯作者：
Gösele, U
中科院分区：
文献类型：
--
作者：
Lee, HN;Hesse, D;Gösele, U
铋层状钙钛矿膜用于平面型非易失性铁电随机存取存储器需要具有垂直于生长平面的自发极化的膜。采用脉冲激光沉积法，以SrRuO3为底电极，在氧化钇稳定的ZrO2缓冲Si（100）衬底上生长了自发极化完全沿薄膜法线方向沿着取向的a轴孪晶La掺杂Bi_4Ti_3O_（12）（BLT）薄膜。尽管（118）取向与（100）取向竞争，但使用非常薄的应变SrRuO3电极层和动力学生长条件（包括高生长速率和高氧背景压力以促进氧并入生长膜中）生长具有几乎纯（100）取向的外延膜。具有a轴取向并且其极化完全沿着垂直于膜平面的方向的膜可以实现每平方厘米32微库仑的反射极化。
The use of bismuth-layered perovskite films for planar-type nonvolatile ferroelectric random-access memories requires films with spontaneous polarization normal to the plane of growth. Epitaxially twinned a axis-oriented La-substituted Bi4Ti3O12 (BLT) thin films whose spontaneous polarization is entirely along the film normal were grown by pulsed laser deposition on yttria-stabilized zirconia-buffered Si(100) substrates using SrRuO3 as bottom electrodes. Even though the (118) orientation competes with the (100) orientation, epitaxial films with almost pure (100) orientation were grown using very thin, strained SrRuO3 electrode layers and kinetic growth conditions, including high growth rates and high oxygen background pressures to facilitate oxygen incorporation into the growing film. Films with the a-axis orientation and having their polarization entirely along the direction normal to the film plane can achieve a remanent polarization of 32 microcoulombs per square centimeter.