岩盐结构氮化铪薄膜的结构与性质研究
发布时间：2019-03-30 23:56
【摘要】：氮化铪（HfNx）薄膜具有优良的力学和电学性质，使其广泛地应用于电子器件、微机械系统和刀具保护涂层等领域。HfNx薄膜的力学与电学性质决定了其在实际服役过程中的使用领域、寿命和性能，，因此，了解如何调控这些薄膜结构、力学和电学性质是十分必要的。尽管国内外的科学研究工作者对HfNx薄膜的研究已经得到了很多重要成果，但我们发现仍存有两点不足： （1）尽管已有研究表明N/Hf原子比可能是控制岩盐结构氮化铪（-HfNx）薄膜结构和性质的一个重要因素，但大部分研究只给出了现象的描述，缺乏现象背后的原因分析，N/Hf原子比对-HfNx薄膜的结构、电学和力学性质的影响规律及机理研究仍有待于深入系统地开展； （2）离子轰击也是控制-HfNx薄膜结构和性质的一个重要因素，但相关研究开展地较少，离子轰击对-HfNx薄膜结构、电学和力学性质影响规律和机理尚不清楚。 针对上述问题，本文利用磁控溅射沉积了岩盐结构的氮化铪（-HfNx）薄膜通过X射线衍射谱（XRD）、X射线光电子能谱（XPS）、高分辨透射电子显微镜（HR-TEM）、轮廓仪、纳米压痕仪、原子力显微镜（AFM）、拉曼光谱（Raman）结合第一性原理计算研究了N/Hf原子比和离子轰击对-HfNx薄膜的结构、电学和力学性质的影响，主要发现点如下： （1）证明了N或Hf空位的引入对-HfNx薄膜结构、力学和电学性质会产生一定的“负效应”。尽管我们制备的所有-HfN膜仍保持岩盐结构，但其不是完美对称的立方结构，而是沿着（111）方向被拉长，发生了从立方结构向斜方结构的晶格扭曲，这归因于所有膜都呈现（111）择优取向且处于压应力状态。与近标配薄膜相比，低化学配比和高化学配比的晶格扭曲更加剧烈，这归因于Hf和N空位的引入导致了晶格收缩，尤其（111）以外的其他面的间距减小得更快，因而加剧了-HfN立方结构向斜方结构的晶格扭曲变形。此外，因为Hf比N空位体积大，引起的晶格收缩更大，因此前者带来的晶格扭曲比后者也更大。与近标配薄膜相比，低化学配比和高化学配比的硬度和电导率明显降低。前者归因于N或Hf空位的引入降低了体模量，进而削弱了薄膜抵抗变形的能力。电阻率的降低归因于N或Hf空位的形成增加了散射电子的缺陷中心，进而减小了电子的运动自由程。 （2）发现低能量的离子轰击有利于减少-HfNx薄膜的点缺陷浓度，进而增加薄膜的硬度和电导率，同时降低薄膜表面的粗糙度，这归因于在低衬底偏压时，随着衬底负偏压绝对值的增加，轰击离子的能量增加，进而增加了沉积离子在薄膜表面的动能，使其填补薄膜表面的空位等缺陷，降低了薄膜的点缺陷浓度。相反，过高能量的离子轰击不断轰击薄膜表面，会产生点缺陷，增加薄膜的点缺陷浓度，对薄膜的结构和性质不利。此研究对获得性质优异的-HfNx薄膜提供了依据。
[Abstract]:Hafnium nitride (HfNx) thin films are widely used in electronic devices because of their excellent mechanical and electrical properties. Micromechanical systems and tool protection coatings. The mechanical and electrical properties of HfNx films determine their use, life, and properties in actual service. Therefore, understand how to regulate the structure of these films. Mechanical and electrical properties are essential. Although many important achievements have been made in the research of HfNx thin films by scientific researchers both at home and abroad, However, we found that there are still two deficiencies: (1) although previous studies have shown that N/Hf atom ratio may be an important factor in controlling the structure and properties of hafnium nitride (- HfNx) thin films with rock salt structure, However, most of the studies only give the description of the phenomenon, the reasons behind the lack of phenomenon, N/Hf atomic ratio-HfNx film structure, electrical and mechanical properties of the influence of the rule and mechanism are still to be carried out in-depth and systematic research; (2) Ion bombardment is also an important factor to control the structure and properties of-HfNx thin films, but the related researches are few. The influence of ion bombardment on the structure, electrical and mechanical properties of-HfNx thin films is still unclear. In order to solve these problems, hafnium nitride (- HfNx) thin films with rock salt structure were deposited by magnetron sputtering using X-ray diffraction spectrum (XRD), X-ray photoelectron spectroscopy (XPS),) high-resolution transmission electron microscope (HR-TEM) and profilometer. The effects of N/Hf atom ratio and ion bombardment on the structure, electrical and mechanical properties of-HfNx thin films were investigated by nano indentation instrument, atomic force microscope (AFM) (AFM), Raman spectroscopy (Raman) and first principle calculations. The main findings are as follows: (1) it is shown that the introduction of N or Hf vacancies will have a negative effect on the structure, mechanical and electrical properties of-HfNx thin films. Although all of the-HfN films prepared by us still maintain the rock salt structure, they are not perfectly symmetric cubic structures, but are elongated along the (111) direction, resulting in lattice distortions from cubic structure to diagonal structure. This is due to the (111) preferred orientation and compressive stress state of all films. Compared with the near-standard film, the lattice distortion at low and high chemical ratios is more severe, which is attributed to the lattice contraction caused by the introduction of Hf and N vacancies, especially the decrease of the spacing between the other faces other than (111). As a result, the lattice distortion of the-HfN cubic structure is aggravated. In addition, because the volume of Hf is larger than that of N-vacancy, the lattice contraction of the former is larger than that of N-vacancy, so the lattice distortion of the former is larger than that of the latter. Compared with the near-standard film, the hardness and conductivity of the films with low chemical ratio and high chemical ratio decreased obviously. The former is attributed to the decrease of bulk modulus due to the introduction of N or Hf vacancies, which in turn weakens the film's ability to resist deformation. The decrease in resistivity is attributed to the increase in the defect center of scattering electrons due to the formation of N or Hf vacancies, which in turn reduces the free path of electron movement. (2) it is found that low energy ion bombardment can reduce the point defect concentration of the-HfNx thin film, increase the hardness and conductivity of the film, and decrease the roughness of the film surface, which is attributed to the low substrate bias. With the increase of absolute value of substrate negative bias, the energy of bombardment ion increases, and then the kinetic energy of deposition ion on the film surface is increased, which makes it fill the vacancy on the film surface and reduces the point defect concentration of the film. On the contrary, the high energy ion bombardment bombarded the surface of thin film continuously, which will produce point defects and increase the concentration of point defects, which is disadvantageous to the structure and properties of the films. This study provides a basis for the preparation of HfNx thin films with excellent properties.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2;O614.413
本文编号：2450629
[Abstract]:Hafnium nitride (HfNx) thin films are widely used in electronic devices because of their excellent mechanical and electrical properties. Micromechanical systems and tool protection coatings. The mechanical and electrical properties of HfNx films determine their use, life, and properties in actual service. Therefore, understand how to regulate the structure of these films. Mechanical and electrical properties are essential. Although many important achievements have been made in the research of HfNx thin films by scientific researchers both at home and abroad, However, we found that there are still two deficiencies: (1) although previous studies have shown that N/Hf atom ratio may be an important factor in controlling the structure and properties of hafnium nitride (- HfNx) thin films with rock salt structure, However, most of the studies only give the description of the phenomenon, the reasons behind the lack of phenomenon, N/Hf atomic ratio-HfNx film structure, electrical and mechanical properties of the influence of the rule and mechanism are still to be carried out in-depth and systematic research; (2) Ion bombardment is also an important factor to control the structure and properties of-HfNx thin films, but the related researches are few. The influence of ion bombardment on the structure, electrical and mechanical properties of-HfNx thin films is still unclear. In order to solve these problems, hafnium nitride (- HfNx) thin films with rock salt structure were deposited by magnetron sputtering using X-ray diffraction spectrum (XRD), X-ray photoelectron spectroscopy (XPS),) high-resolution transmission electron microscope (HR-TEM) and profilometer. The effects of N/Hf atom ratio and ion bombardment on the structure, electrical and mechanical properties of-HfNx thin films were investigated by nano indentation instrument, atomic force microscope (AFM) (AFM), Raman spectroscopy (Raman) and first principle calculations. The main findings are as follows: (1) it is shown that the introduction of N or Hf vacancies will have a negative effect on the structure, mechanical and electrical properties of-HfNx thin films. Although all of the-HfN films prepared by us still maintain the rock salt structure, they are not perfectly symmetric cubic structures, but are elongated along the (111) direction, resulting in lattice distortions from cubic structure to diagonal structure. This is due to the (111) preferred orientation and compressive stress state of all films. Compared with the near-standard film, the lattice distortion at low and high chemical ratios is more severe, which is attributed to the lattice contraction caused by the introduction of Hf and N vacancies, especially the decrease of the spacing between the other faces other than (111). As a result, the lattice distortion of the-HfN cubic structure is aggravated. In addition, because the volume of Hf is larger than that of N-vacancy, the lattice contraction of the former is larger than that of N-vacancy, so the lattice distortion of the former is larger than that of the latter. Compared with the near-standard film, the hardness and conductivity of the films with low chemical ratio and high chemical ratio decreased obviously. The former is attributed to the decrease of bulk modulus due to the introduction of N or Hf vacancies, which in turn weakens the film's ability to resist deformation. The decrease in resistivity is attributed to the increase in the defect center of scattering electrons due to the formation of N or Hf vacancies, which in turn reduces the free path of electron movement. (2) it is found that low energy ion bombardment can reduce the point defect concentration of the-HfNx thin film, increase the hardness and conductivity of the film, and decrease the roughness of the film surface, which is attributed to the low substrate bias. With the increase of absolute value of substrate negative bias, the energy of bombardment ion increases, and then the kinetic energy of deposition ion on the film surface is increased, which makes it fill the vacancy on the film surface and reduces the point defect concentration of the film. On the contrary, the high energy ion bombardment bombarded the surface of thin film continuously, which will produce point defects and increase the concentration of point defects, which is disadvantageous to the structure and properties of the films. This study provides a basis for the preparation of HfNx thin films with excellent properties.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.2;O614.413
【参考文献】
相关期刊论文 前1条
1 CAO Hong;ZHANG ChuanJun;CHU JunHao;;The effect of working gas pressure and deposition power on the properties of molybdenum films deposited by DC magnetron sputtering[J];Science China(Technological Sciences);2014年05期
本文编号：2450629
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