鉀和鎂復(fù)合摻雜BST薄膜介電特性研究
發(fā)布時(shí)間：2018-11-06 08:39
【摘要】：BST薄膜因其介電常數(shù)隨外加電場(chǎng)變化呈現(xiàn)出非線性關(guān)系而成為現(xiàn)有的發(fā)展微波調(diào)諧器件的一種重要的候選材料。本論文采用改進(jìn)的溶膠凝膠法在添加STO薄膜的基礎(chǔ)上,制備了K、Mg單一摻雜及復(fù)合摻雜的異質(zhì)多層BST薄膜,借助XRD、SEM及C-V測(cè)試對(duì)薄膜的微觀結(jié)構(gòu)和介電性能進(jìn)行分析,并重點(diǎn)對(duì)K和Mg的摻雜濃度和摻雜方式進(jìn)行優(yōu)化研究,研究成果如下:1.添加STO薄膜層后,BST薄膜的(110)特征峰右移,平均晶粒尺寸變小,薄膜表面晶粒分布更加均勻,致密程度增加,薄膜介電損耗大幅度下降,綜合介電性能明顯提升。2.在不同的薄膜結(jié)構(gòu)下進(jìn)行5mol%K和Mg的單一摻雜研究,結(jié)果表明摻雜后薄膜的介電損耗均大幅度下降。在BST/STO/BST三明治7層結(jié)構(gòu)下5mol%Mg摻雜的BST多層薄膜在10V偏壓下介電損耗下降至0.02左右,優(yōu)質(zhì)系數(shù)18.1,而5mol%K摻雜的薄膜保持了相對(duì)較高的調(diào)諧率,優(yōu)質(zhì)系數(shù)達(dá)到22.3。在STO/BST/STO結(jié)構(gòu)下,5mol%Mg摻雜的BST多層薄膜10V偏壓下介電調(diào)諧率下降至21.9,介電性能有所下降,而5mol%K摻雜的薄膜在10V偏壓下不僅調(diào)諧率增加到了41.2%,介電損耗也下降至0.012,優(yōu)質(zhì)系數(shù)達(dá)到34.3。3.在BST/STO/BST結(jié)構(gòu)下對(duì)K和Mg的復(fù)合摻雜進(jìn)行創(chuàng)新性研究,并在摻雜方式和摻雜濃度上進(jìn)行優(yōu)化。5mol%K和Mg復(fù)合摻雜的KMg/STO薄膜在5mol%Mg單一摻雜的基礎(chǔ)上介電調(diào)諧率有所提升,優(yōu)質(zhì)系數(shù)為16.2。保持K和Mg的總摻雜濃度為5mol%不變,4mol%K和1mol%Mg復(fù)合摻雜的薄膜具有最佳的綜合介電性能,10V偏壓下的介電調(diào)諧率高達(dá)51.7%,介電損耗下降至0.011,優(yōu)質(zhì)系數(shù)達(dá)到47。保持K摻雜濃度為1mol%條件下,Mg摻雜濃度過(guò)高將使得薄膜介電調(diào)諧率不斷減小,當(dāng)Mg摻雜濃度為3mol%時(shí)復(fù)合摻雜BST多層薄膜綜合介電性能最好,在10V偏壓下的介電調(diào)諧率和介電損耗分別為40%和0.011,優(yōu)質(zhì)系數(shù)達(dá)到36.4。在低濃度摻雜優(yōu)化研究中,當(dāng)K和Mg的摻雜濃度均為2mol%時(shí)復(fù)合摻雜多層BST薄膜的綜合介電性能大幅度提升,10V偏壓下薄膜的介電調(diào)諧率達(dá)到52.3%,而介電損耗在0.008~0.014之間,優(yōu)質(zhì)系數(shù)高達(dá)65.4,完全滿足微波調(diào)諧應(yīng)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.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.2
本文編號(hào)：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.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.2
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 莊后榮;楊繼安;李艷紅;甘雪萍;張斗;周科朝;;鈦酸鍶鋇陶瓷的制備及介電性能[J];粉末冶金材料科學(xué)與工程;2012年05期
2 廖家軒;魏雄邦;潘笑風(fēng);張佳;傅向軍;王洪全;;交替中間熱處理BST薄膜介電性能研究[J];無(wú)機(jī)材料學(xué)報(bào);2009年05期
，本文編號(hào)：2313774
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