摘要
用改进的溶胶凝胶(sol-gel)法逐层制备钛酸锶钡(Ba0.6Sr0.4TiO3,BST)薄膜,研究中间热处理(preheating,PT)对薄膜结构及介电性能的影响.X射线衍射(XRD)表明,BST薄膜主要沿(110)方向生长,对应立方钙钛矿结构,PT使晶化增强.X射线光电子能谱(XPS)表明,PT促使表面非钙钛矿结构向钙钛矿结构转变.原子力显微镜(AFM)和介电性能测试表明,随着PT频次的增加,薄膜形貌改善,表面粗糙度降低,介电调谐率大幅度提高,其中,在20V偏压下逐层PT的薄膜对应超过55%的调谐率.对奇数层进行PT的薄膜对应适中的电容、较小的介电损耗及在20V偏压下接近50%的调谐率,显著提高了综合介电性能,能很好满足微波调谐器件的要求.同时,就有关PT高调谐机理进行了讨论.
Six-layer Ba0.6Sr0.4TiO3 （BST） films are prepared by an improved sol-gel method. The effects of various preheating methods on morphology and dielectric properties are studied. XRD results reveal that all BST films preferentially grow along the （110） direction and have cubic perovskite structures, and that preheating can obviously enhance crystallization. XPS results show that the preheating can also decrease surface non-perovskite structure and cause perovskite structure to increase markedly. AFM results display that as the preheating number increases, BST films show significant improvement on morphology with surface roughness reducing. The dielectric property measurement exhibits that tunability is remarkably increased with the increase of preheating number. BST film with all layers preheated shows that its tunability exceeds 55% at 20V bias voltage, while BST film with odd number layers preheated presents a moderate capacitance, lower dielectric loss, approximately 50% tunability at 20V bias voltage and significant increase in figure of merit （FOM） with the bias voltage. The excellent combination of dielectric properties can satisfy the application demand of microwave tunable devices. Also, the relevant mechanism of high tunability is discussed.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2011年第7期723-728,共6页
Acta Physica Sinica
基金
电子科技大学中青年学术带头人培养计划(批准号:Y02018023601053)
中央高校基本科研业务费专项资金(批准号:ZYGX2009X018)资助的课题~~
