氟化物單晶的介電性能研究
發(fā)布時間：2018-08-31 10:18
【摘要】：由于卓越的光學性能、化學穩(wěn)定性以及機械性能,氟化物材料具有非常可觀的科學研究價值和經(jīng)濟效益,近些年來引起了廣泛的科學興趣和研究。眾所周知,微量濃度的缺陷(雜質)即可對材料的性能產(chǎn)生顯著的影響。光學性能研究表明氟化物中存在多種本征缺陷。介質譜方法是一種描述缺陷行為的強有效的、非破壞性的研究手段,所以可以充分利用其對缺陷的運動有個全面的了解。同時,作為材料的基本特性之一,介電性能的研究在材料應用上有著重要的意義。本文以一系列氟化物單晶(MFx, M=Ca, La, Mg, Li; x=1,2,3)為研究對象,利用多種介電譜,對其介電性能進行了系統(tǒng)的研究,得到的結果如下：(1)在室溫到773 K的溫度范圍內(nèi),對CaF2單晶樣品的介電性能進行了研究。觀測到一個類德拜弛豫和一個類鐵電體弛豫。利用拉曼光譜和差示掃描熱量法測量證實了本征缺陷氟空位(VF·)和氟填隙(Fi')的共存以及外來氧離子缺陷的存在。阻抗譜分析顯示類德拜弛豫源于缺陷VF·的運動；而類鐵電體弛豫行為與O"-V·F復合體有關聯(lián)。(2)在寬溫域110-773 K和頻域100 Hz-10 MHz對LaF3單晶樣品系統(tǒng)的介電測量中,隨著溫度的增加,依次觀測到了兩個熱激活弛豫(R1,R2)和一個介電異常(A)。較低溫的弛豫R1是氟離子在F1亞晶格中的擴散和跳躍所引起的極化子弛豫；較高溫弛豫R2是由于電極阻擋引起的Maxwell-Wagner弛豫,與在F1和F2_3亞晶格以及三個等權亞晶格中的離子交換有關。最高溫區(qū)出現(xiàn)的介電異常A則與電子-離子耦合感應引起的電感效應有關。(3)利用阻抗譜和模量譜對MgF2單晶樣品進行了從室溫到1073 K的電學和介電性能研究。阻抗譜分析表明MgF2單晶在低于773 K的溫度范圍表現(xiàn)出本征介電性質,在更高溫觀測到一個熱激活的類德拜弛豫,證實是由氟填隙運動引起。這些性能表明MgF2單晶可以在柵介質、基板材料以及硅技術中的緩沖層等方面具有廣泛的應用前景。(4)LiF單晶在從室溫到1073 K溫區(qū)內(nèi)表現(xiàn)出兩套熱激活弛豫(R1,R2)。激活能為0.8 eV的弛豫R1是與鋰離子的擴散有關。弛豫R2的Arrhenius曲線被分界溫度598 K和698 K分為低、中和高溫段三部分。三段弛豫R2依照升溫順序分別由F3、F3+心,F2心和F心引起。一系列氟化物單晶樣品利用介質性能測試和弛豫分析,發(fā)現(xiàn)宏觀介電性能與微觀本征缺陷運動有關。
[Abstract]:Because of their excellent optical properties, chemical stability and mechanical properties, fluoride materials have considerable scientific research value and economic benefits, and have attracted extensive scientific interest and research in recent years. It is well known that trace concentrations of defects (impurities) can have a significant impact on the properties of the material. The study of optical properties shows that there are many intrinsic defects in fluoride. The dielectric spectrum method is a powerful and nondestructive method to describe the behavior of defects, so we can make full use of it to understand the motion of defects. At the same time, as one of the basic properties of materials, the study of dielectric properties plays an important role in the application of materials. In this paper, a series of single crystals of fluoride (MFx, Mi Ca, La, Mg, Li; XJ 1 + 2 + 3) are studied. The dielectric properties of the crystals are studied by using various dielectric spectra. The results are as follows: (1) at the temperature range from room temperature to 773 K, the dielectric properties of fluoride monocrystals have been studied in the range of room temperature to 773 K, and the results are as follows: (1) in the range of room temperature to 773 K. The dielectric properties of CaF2 single crystal samples were studied. A Debye-like relaxation and a ferroelectric-like relaxation were observed. Raman spectroscopy and differential scanning calorimetry (DSC) were used to determine the coexistence of fluoride vacancy (VF) and fluorine gap (Fi') and the existence of foreign oxygen ion defects. Impedance spectroscopy analysis shows that Debye relaxation originates from the motion of defective VF, and the ferroelectric-like relaxation behavior is related to O "-V F complex. (2) in the wide temperature range of 110-773 K and the frequency domain of 100 Hz-10 MHz, the dielectric properties of LaF3 single crystal system increase with the increase of temperature. Two thermoactive relaxation (R _ 1 ~ 2) and a dielectric anomaly (A). Were observed in turn. The lower temperature relaxation R1 is the polaron relaxation caused by the diffusion and jump of fluorine ions in F1 sublattice, and the higher temperature relaxation R2 is the Maxwell-Wagner relaxation caused by electrode barrier. It is related to ion exchange in F1 and F2S3 sublattices and in three equal weight sublattices. The dielectric anomaly A at the highest temperature region is related to the inductance induced by electron-ion coupling induction. (3) the electrical and dielectric properties of MgF2 single crystal samples from room temperature to 1073 K have been studied by impedance spectroscopy and modulus spectroscopy. Impedance spectroscopy analysis shows that MgF2 single crystals exhibit intrinsic dielectric properties at temperatures below 773K, and a thermally activated Debye relaxation is observed at higher temperatures, which is confirmed to be caused by the movement of fluorine-filled gaps. These properties indicate that MgF2 single crystals can be widely used in gate dielectrics, substrate materials and buffer layers in silicon technology. (4) LiF single crystals exhibit two sets of thermal activation relaxation (R _ 1 ~ 2) from room temperature to 1073 K. The relaxation R1 with activation energy of 0. 8 eV is related to the diffusion of lithium ions. The Arrhenius curve of relaxation R2 is divided into three parts: low, middle and high temperature by the boundary temperature of 598K and 698K. The three-stage relaxation R2 is caused by F _ 2 and F _ 2 centers of F _ 3 and F _ 3, respectively. The dielectric properties and relaxation analysis of a series of fluoride single crystal samples show that the macroscopic dielectric properties are related to the motion of intrinsic defects.
【學位授予單位】：安徽大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ124.3;O738
本文編號：2214689
[Abstract]:Because of their excellent optical properties, chemical stability and mechanical properties, fluoride materials have considerable scientific research value and economic benefits, and have attracted extensive scientific interest and research in recent years. It is well known that trace concentrations of defects (impurities) can have a significant impact on the properties of the material. The study of optical properties shows that there are many intrinsic defects in fluoride. The dielectric spectrum method is a powerful and nondestructive method to describe the behavior of defects, so we can make full use of it to understand the motion of defects. At the same time, as one of the basic properties of materials, the study of dielectric properties plays an important role in the application of materials. In this paper, a series of single crystals of fluoride (MFx, Mi Ca, La, Mg, Li; XJ 1 + 2 + 3) are studied. The dielectric properties of the crystals are studied by using various dielectric spectra. The results are as follows: (1) at the temperature range from room temperature to 773 K, the dielectric properties of fluoride monocrystals have been studied in the range of room temperature to 773 K, and the results are as follows: (1) in the range of room temperature to 773 K. The dielectric properties of CaF2 single crystal samples were studied. A Debye-like relaxation and a ferroelectric-like relaxation were observed. Raman spectroscopy and differential scanning calorimetry (DSC) were used to determine the coexistence of fluoride vacancy (VF) and fluorine gap (Fi') and the existence of foreign oxygen ion defects. Impedance spectroscopy analysis shows that Debye relaxation originates from the motion of defective VF, and the ferroelectric-like relaxation behavior is related to O "-V F complex. (2) in the wide temperature range of 110-773 K and the frequency domain of 100 Hz-10 MHz, the dielectric properties of LaF3 single crystal system increase with the increase of temperature. Two thermoactive relaxation (R _ 1 ~ 2) and a dielectric anomaly (A). Were observed in turn. The lower temperature relaxation R1 is the polaron relaxation caused by the diffusion and jump of fluorine ions in F1 sublattice, and the higher temperature relaxation R2 is the Maxwell-Wagner relaxation caused by electrode barrier. It is related to ion exchange in F1 and F2S3 sublattices and in three equal weight sublattices. The dielectric anomaly A at the highest temperature region is related to the inductance induced by electron-ion coupling induction. (3) the electrical and dielectric properties of MgF2 single crystal samples from room temperature to 1073 K have been studied by impedance spectroscopy and modulus spectroscopy. Impedance spectroscopy analysis shows that MgF2 single crystals exhibit intrinsic dielectric properties at temperatures below 773K, and a thermally activated Debye relaxation is observed at higher temperatures, which is confirmed to be caused by the movement of fluorine-filled gaps. These properties indicate that MgF2 single crystals can be widely used in gate dielectrics, substrate materials and buffer layers in silicon technology. (4) LiF single crystals exhibit two sets of thermal activation relaxation (R _ 1 ~ 2) from room temperature to 1073 K. The relaxation R1 with activation energy of 0. 8 eV is related to the diffusion of lithium ions. The Arrhenius curve of relaxation R2 is divided into three parts: low, middle and high temperature by the boundary temperature of 598K and 698K. The three-stage relaxation R2 is caused by F _ 2 and F _ 2 centers of F _ 3 and F _ 3, respectively. The dielectric properties and relaxation analysis of a series of fluoride single crystal samples show that the macroscopic dielectric properties are related to the motion of intrinsic defects.
【學位授予單位】：安徽大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ124.3;O738
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