氟化物单晶的介电性能研究
发布时间：2018-08-31 10:18
【摘要】：由于卓越的光学性能、化学稳定性以及机械性能,氟化物材料具有非常可观的科学研究价值和经济效益,近些年来引起了广泛的科学兴趣和研究。众所周知,微量浓度的缺陷(杂质)即可对材料的性能产生显著的影响。光学性能研究表明氟化物中存在多种本征缺陷。介质谱方法是一种描述缺陷行为的强有效的、非破坏性的研究手段,所以可以充分利用其对缺陷的运动有个全面的了解。同时,作为材料的基本特性之一,介电性能的研究在材料应用上有着重要的意义。本文以一系列氟化物单晶(MFx, M=Ca, La, Mg, Li; x=1,2,3)为研究对象,利用多种介电谱,对其介电性能进行了系统的研究,得到的结果如下：(1)在室温到773 K的温度范围内,对CaF2单晶样品的介电性能进行了研究。观测到一个类德拜弛豫和一个类铁电体弛豫。利用拉曼光谱和差示扫描热量法测量证实了本征缺陷氟空位(VF·)和氟填隙(Fi')的共存以及外来氧离子缺陷的存在。阻抗谱分析显示类德拜弛豫源于缺陷VF·的运动；而类铁电体弛豫行为与O"-V·F复合体有关联。(2)在宽温域110-773 K和频域100 Hz-10 MHz对LaF3单晶样品系统的介电测量中,随着温度的增加,依次观测到了两个热激活弛豫(R1,R2)和一个介电异常(A)。较低温的弛豫R1是氟离子在F1亚晶格中的扩散和跳跃所引起的极化子弛豫；较高温弛豫R2是由于电极阻挡引起的Maxwell-Wagner弛豫,与在F1和F2_3亚晶格以及三个等权亚晶格中的离子交换有关。最高温区出现的介电异常A则与电子-离子耦合感应引起的电感效应有关。(3)利用阻抗谱和模量谱对MgF2单晶样品进行了从室温到1073 K的电学和介电性能研究。阻抗谱分析表明MgF2单晶在低于773 K的温度范围表现出本征介电性质,在更高温观测到一个热激活的类德拜弛豫,证实是由氟填隙运动引起。这些性能表明MgF2单晶可以在栅介质、基板材料以及硅技术中的缓冲层等方面具有广泛的应用前景。(4)LiF单晶在从室温到1073 K温区内表现出两套热激活弛豫(R1,R2)。激活能为0.8 eV的弛豫R1是与锂离子的扩散有关。弛豫R2的Arrhenius曲线被分界温度598 K和698 K分为低、中和高温段三部分。三段弛豫R2依照升温顺序分别由F3、F3+心,F2心和F心引起。一系列氟化物单晶样品利用介质性能测试和弛豫分析,发现宏观介电性能与微观本征缺陷运动有关。
[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.
【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ124.3;O738
本文编号：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.
【学位授予单位】：安徽大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ124.3;O738
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