钾和镁复合掺杂BST薄膜介电特性研究
发布时间：2018-11-06 08:39
【摘要】：BST薄膜因其介电常数随外加电场变化呈现出非线性关系而成为现有的发展微波调谐器件的一种重要的候选材料。本论文采用改进的溶胶凝胶法在添加STO薄膜的基础上,制备了K、Mg单一掺杂及复合掺杂的异质多层BST薄膜,借助XRD、SEM及C-V测试对薄膜的微观结构和介电性能进行分析,并重点对K和Mg的掺杂浓度和掺杂方式进行优化研究,研究成果如下:1.添加STO薄膜层后,BST薄膜的(110)特征峰右移,平均晶粒尺寸变小,薄膜表面晶粒分布更加均匀,致密程度增加,薄膜介电损耗大幅度下降,综合介电性能明显提升。2.在不同的薄膜结构下进行5mol%K和Mg的单一掺杂研究,结果表明掺杂后薄膜的介电损耗均大幅度下降。在BST/STO/BST三明治7层结构下5mol%Mg掺杂的BST多层薄膜在10V偏压下介电损耗下降至0.02左右,优质系数18.1,而5mol%K掺杂的薄膜保持了相对较高的调谐率,优质系数达到22.3。在STO/BST/STO结构下,5mol%Mg掺杂的BST多层薄膜10V偏压下介电调谐率下降至21.9,介电性能有所下降,而5mol%K掺杂的薄膜在10V偏压下不仅调谐率增加到了41.2%,介电损耗也下降至0.012,优质系数达到34.3。3.在BST/STO/BST结构下对K和Mg的复合掺杂进行创新性研究,并在掺杂方式和掺杂浓度上进行优化。5mol%K和Mg复合掺杂的KMg/STO薄膜在5mol%Mg单一掺杂的基础上介电调谐率有所提升,优质系数为16.2。保持K和Mg的总掺杂浓度为5mol%不变,4mol%K和1mol%Mg复合掺杂的薄膜具有最佳的综合介电性能,10V偏压下的介电调谐率高达51.7%,介电损耗下降至0.011,优质系数达到47。保持K掺杂浓度为1mol%条件下,Mg掺杂浓度过高将使得薄膜介电调谐率不断减小,当Mg掺杂浓度为3mol%时复合掺杂BST多层薄膜综合介电性能最好,在10V偏压下的介电调谐率和介电损耗分别为40%和0.011,优质系数达到36.4。在低浓度掺杂优化研究中,当K和Mg的掺杂浓度均为2mol%时复合掺杂多层BST薄膜的综合介电性能大幅度提升,10V偏压下薄膜的介电调谐率达到52.3%,而介电损耗在0.008~0.014之间,优质系数高达65.4,完全满足微波调谐应用的需求。
[Abstract]:BST thin films have become an important candidate for microwave tuners due to the nonlinear relationship between dielectric constant and applied electric field. In this paper, the modified sol-gel method was used to fabricate the single and composite doped STO multilayer BST films on the basis of adding STO thin films. The microstructure and dielectric properties of the films were analyzed by means of XRD,SEM and C-V measurements. The doping concentration and mode of K and Mg are optimized. The results are as follows: 1. With the addition of STO film layer, the (110) characteristic peak of the BST thin film shifts to the right, the average grain size becomes smaller, the grain distribution on the surface of the film becomes more uniform, the density degree increases, the dielectric loss of the film decreases greatly, and the comprehensive dielectric properties increase obviously. 2. The single doping of 5mol%K and Mg was carried out under different structure of the films. The results showed that the dielectric loss of the films decreased significantly after doping. The dielectric loss of BST multilayer films doped with 5mol%Mg at 10V bias voltage decreased to about 0.02 with a good quality coefficient of 18.1, while that of 5mol%K doped films kept a relatively high tuning rate. The quality coefficient is 22.3. Under STO/BST/STO structure, the dielectric tuning rate of BST multilayer films doped with 5mol%Mg decreased to 21.9 at 10V bias voltage, while the dielectric properties of BST multilayer films doped with 5mol%K decreased to 41.2 at 10V bias voltage. The dielectric loss also decreased to 0.012, and the quality coefficient reached 34.3.3. The innovative research on the composite doping of K and Mg in BST/STO/BST structure was carried out. The dielectric tunability of KMg/STO films doped with 5mol%K and Mg was improved on the basis of 5mol%Mg single doping, and the excellent quality coefficient was 16.2. Keeping the total doping concentration of K and Mg at 5 mol%, the composite doped films of 4mol%K and 1mol%Mg have the best comprehensive dielectric properties. The dielectric tuning rate of 10V bias voltage is as high as 51.7%, and the dielectric loss decreases to 0.011. The coefficient of good quality is 47. When the concentration of K doping is kept at 1 mol%, the dielectric tuning rate of the films decreases when the concentration of Mg is too high. When the concentration of Mg is 3 mol%, the composite doped BST multilayer films have the best comprehensive dielectric properties. The dielectric tuning rate and dielectric loss at 10V bias voltage are 40% and 0.011, respectively, and the high quality coefficient is 36.4%. In the study of low concentration doping optimization, when the doping concentration of K and Mg is both 2 mol%, the comprehensive dielectric properties of multilayer BST films doped with the composite are greatly improved, and the dielectric tuning rate of the films reaches 52.3% at 10V bias voltage. The dielectric loss is between 0.008 and 0.014, and the high quality coefficient is up to 65.4, which fully meets the needs of microwave tunable applications.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2
本文编号：2313774
[Abstract]:BST thin films have become an important candidate for microwave tuners due to the nonlinear relationship between dielectric constant and applied electric field. In this paper, the modified sol-gel method was used to fabricate the single and composite doped STO multilayer BST films on the basis of adding STO thin films. The microstructure and dielectric properties of the films were analyzed by means of XRD,SEM and C-V measurements. The doping concentration and mode of K and Mg are optimized. The results are as follows: 1. With the addition of STO film layer, the (110) characteristic peak of the BST thin film shifts to the right, the average grain size becomes smaller, the grain distribution on the surface of the film becomes more uniform, the density degree increases, the dielectric loss of the film decreases greatly, and the comprehensive dielectric properties increase obviously. 2. The single doping of 5mol%K and Mg was carried out under different structure of the films. The results showed that the dielectric loss of the films decreased significantly after doping. The dielectric loss of BST multilayer films doped with 5mol%Mg at 10V bias voltage decreased to about 0.02 with a good quality coefficient of 18.1, while that of 5mol%K doped films kept a relatively high tuning rate. The quality coefficient is 22.3. Under STO/BST/STO structure, the dielectric tuning rate of BST multilayer films doped with 5mol%Mg decreased to 21.9 at 10V bias voltage, while the dielectric properties of BST multilayer films doped with 5mol%K decreased to 41.2 at 10V bias voltage. The dielectric loss also decreased to 0.012, and the quality coefficient reached 34.3.3. The innovative research on the composite doping of K and Mg in BST/STO/BST structure was carried out. The dielectric tunability of KMg/STO films doped with 5mol%K and Mg was improved on the basis of 5mol%Mg single doping, and the excellent quality coefficient was 16.2. Keeping the total doping concentration of K and Mg at 5 mol%, the composite doped films of 4mol%K and 1mol%Mg have the best comprehensive dielectric properties. The dielectric tuning rate of 10V bias voltage is as high as 51.7%, and the dielectric loss decreases to 0.011. The coefficient of good quality is 47. When the concentration of K doping is kept at 1 mol%, the dielectric tuning rate of the films decreases when the concentration of Mg is too high. When the concentration of Mg is 3 mol%, the composite doped BST multilayer films have the best comprehensive dielectric properties. The dielectric tuning rate and dielectric loss at 10V bias voltage are 40% and 0.011, respectively, and the high quality coefficient is 36.4%. In the study of low concentration doping optimization, when the doping concentration of K and Mg is both 2 mol%, the comprehensive dielectric properties of multilayer BST films doped with the composite are greatly improved, and the dielectric tuning rate of the films reaches 52.3% at 10V bias voltage. The dielectric loss is between 0.008 and 0.014, and the high quality coefficient is up to 65.4, which fully meets the needs of microwave tunable applications.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2
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相关期刊论文 前2条
1 庄后荣;杨继安;李艳红;甘雪萍;张斗;周科朝;;钛酸锶钡陶瓷的制备及介电性能[J];粉末冶金材料科学与工程;2012年05期
2 廖家轩;魏雄邦;潘笑风;张佳;傅向军;王洪全;;交替中间热处理BST薄膜介电性能研究[J];无机材料学报;2009年05期
，本文编号：2313774
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