Ge／Si纳米多层膜的光致发红光研究

采用磁控溅射设备，当衬底温度为500℃时，在Si（100）基片上磁控溅射生长Ge／Si多层膜样品，使用Raman和低角X射线技术对样品进行检测和研究。在红光波段对样品的光致发光进行了研究，结果表明在红光波段发光峰位来源于薄膜的非晶结构及其薄膜所产生的缺陷；发光峰的强度和峰形受Ge子层和Si子层厚度的影响。     

Mo／Si和Mo／B4C软X射线多层膜的界面热稳定性研究

用磁控射法制备Ｍｏ／Ｓｉ多层膜和Ｍｏ／Ｂ４Ｃ多层膜，并在真这中加热３０ｍｉｎ，温度为２００，４００，６００，８００和１０００℃。用小角Ｘ射线衍射法和透射电镜研究不同温度下加热的样品。实验结果表明，当加热温度达６００℃时，Ｍｏ／Ｓｉ多层膜周期被破坏。     

Mo/Si和Mo/B_4C软X射线多层膜的界面热稳定性研究

用磁控溅射法制备Mo／Si多层膜（周期为25nm，20层）和Mo／B4C多层膜（周期为3．9nm，121层），并在真空中加热30min，温度为200，400，600，800和1000℃。用小角X射线衍射法和透射电镜研究不同温度下（保温0．5h）加热的样品。实验结果表明，当加热温度达600℃时，Mo／Si多层膜周期被破坏。而Mo／B4C多层膜在800℃加热温度下仍保持周期性层状结构。说明Mo／B4C多层膜不仅周期只有3．9nm，而且具有很好的热稳定性，可以作为较短波长的软X射线多层膜推广应用。     

用Raman光谱研究纤维复合材料

本文以Raman光谱方法的基本原理为依据,结合纤维复合材料研究对结构表征和性能测试技术的要求,评述了Raman光谱在本领域中应用所取得的成果。通过分析在测定界面应力分布、评价界面性质、表征界面和基体结构、测量残留应力等方面应用Raman光谱所遇到的问题,探讨了在研究纤维复合材料本构关系和跟踪复合材料加工过程等领域采用现代Raman光谱技术的前景。     

Ge/Si纳米多层膜的埋层调制结晶研究

采用磁控溅射设备,当衬底温度为500℃时,在Si(100)基片上磁控溅射生长Ge/Si多层膜样品.使用Raman,AFM和低角X射线技术对样品进行检测和研究,结果表明通过控制Ge埋层的厚度,可以调制Ge膜的结晶及晶粒尺寸,获得晶粒平均尺寸和空间分布较均匀的多晶Ge/Si多层膜.     

Ti过渡层对TiO2/Ag/TiO2复合多层膜热稳定性影响研究

2～3nm的Ti过渡层有效的提高了TiO2/Ag/TiO2多层膜的热稳定性同时对原始膜层的光学性能影响较小.通过AFM形貌分析表明Ti膜促进了Ag膜的连续性和抗结块性能.XRD分析表明在沉积态Ti层已经发生了氧化形成Ti2O3,从而提高了Ag膜与TiO2的结合力.热处理后促进了Ag(111)取向的发展,因此,Ag膜稳定性得到了提高.     

纳米TiO2的Raman光谱研究进展

Raman光谱是研究纳米TiO2结构的最常用工具之一。纳米TiO2的Raman光谱研究是建立在以前对TiO2体材料的Raman光谱研究的基础之上。但是纳米TiO2与体相材料的表面性质和结构有较大的不同，其Raman光谱会产生明显变化。研究人员对纳米TiO2的Raman光谱已展开研究。本文概述了晶粒大小、结构、氧空位、退火温度、压力、相组成等因素对纳米TiO2的Raman光谱的影响。     

溅射Si/Ge多层膜及其发光誊性研究

采用离子束溅射技术,在玻璃衬底上制备了不同周期数的Si/Ge多层膜样品.利用X射线小角衍射、Raman散射光谱和室温光致发光(PL)对样品进行表征.结果表明,2.0～2.3eV之间的发光带是由薄膜中的各种缺陷形成的;1.77～1.84eV之间的发光带来自薄膜中的非晶结构和晶粒间的缺陷;1.53eV发光峰则可能源于纳米Ge晶粒发光.     

离子束溅射制备Si／Ge多层膜研究

采用离子束溅射方法在Si衬底上制备Si／Ge多层膜，通过改变生长温度、溅射速率等因素得到一系列Si／Ge多层膜样品；通过X射线衍射、Raman散射等表征方法研究薄膜结构与生长条件的关系。在小束流（10mA）、室温条件下制备出界面清晰、周期完整的Si／Ge多层膜。     

离子束溅射Si／Ge多层膜的界面结构研究

采用离子束溅射技术，在玻璃衬底上制备了不同周期数的Si／Ge多层膜样品。通过Raman光谱和X射线小角衍射对薄膜进行了表征和分析，发现随着生长周期数的增加，层与层之间的互扩散效应逐渐减弱，界面结构逐渐清晰，生长周期为25的样品界面最平整。     

Characterization of sputter deposited Au/Ni/Al multilayers on Si substrates

Multilayered Au/Ni/Al thin film metallization deposited by DC sputtering on n⁺Si substrates has been investigated. AES depth profiling was performed to reveal the concentration depth profiles of the Au/Ni/Al multilayers before and after annealing at different temperatures in the range 623-723 K. It was found that Ni aluminide layers begin to form during heat treatments at temperatures above 623 K. In addition to this process, Ni was found to diffuse significantly through the Au layer and segregates at the surface, proportionally to the increased annealing temperature. Consequently, the Ni oxidation process was found to take place thus causing the degradation of electrical contact. On the other hand Ni diffuses faster as well toward the Si/Al interface. No contamination traces at interfaces were observed. Electrical measurements of the metallized diode forward characteristics showed minor influence of the metallization heat treatment on the series resistance. Degradations were observed only in the reverse characteristics if the annealing was performed above 723 K.     

溅射气压对Ge/Si纳米点表面形貌的影响

利用磁控溅射技术在Si(100)衬底上直接外延生长一系列不同压强下的Ge纳米点样品,并利用AFM、Raman和XRF对Ge纳米点样品形貌和结构进行了研究。结果表明Ge薄膜表面粗糙度在某一临界压强下发生突变,高能粒子热化的临界值与这种转变密切相联;分析讨论了Ge岛在不同溅射气压下的生长过程,在一定范围随着压强的增大会显示典型生长阶段的特征。     

Investigation of thermal stability of hydrogenated amorphous Si/Ge multilayers

Thermal stability of hydrogenated amorphous Si/Ge multilayers has been investigated by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Small-Angle X-Ray Diffraction (SAXRD) techniques. Amorphous H-Si/Ge multilayers were prepared by RF sputtering with 1.5 and 6 ml/min H₂ flow-rate. It is shown by Elastic Recoil Detection Analysis (ERDA) that the hydrogen concentration increased by increasing the H₂ flow-rate. Annealing of the samples was carried out at 400 and 450 °C for several hours. It has been observed that samples prepared with 6 ml/min flow-rate at both annealing temperatures underwent significant structural changes: the surface of the samples was visibly roughened, gas bubbles were formed and craters were created. The decay of the periodic structure of Si and Ge layers in these types of multilayers was faster than in non-hydrogenated samples. Samples prepared with 1.5 ml/min flow-rate have similar behaviour at 450 °C, but at 400 °C the decay of the first order SAXRD peaks was slower than in case of the non-hydrogenated multilayers. Qualitatively the observed behaviour can be explained by the fast desorption of the saturated hydrogen, leading to the formation of bubbles and craters at 450 °C, as well as, at 400 °C in the sample with lower H-content, by the possible passivation of the dangling bonds resulting in a slowing down of the diffusion intermixing.     

退火温度对Ge/SiO2多层膜的结构和光学性能的影响

采用磁控溅射技术在石英衬底上制备出(Ge/SiO2)15多层膜,并在不同温度下对其进行退火处理。XRD和Raman结果表明:溅射态的薄膜为非晶态,当退火温度为500℃时开始出现明显的结晶衍射峰,随后晶化率明显增大,当600℃后,薄膜的晶化率几乎不变。FESEM和小角度X射线衍射结果表明:溅射态薄膜的层与层之间存在明显的界面,具有良好的周期性,升高退火温度,晶粒尺寸增大,但仍保持周期性结构。薄膜的紫外-可见光吸收光谱表明:随着退火温度的升高,吸收边发生红移,光学带隙从溅射态的1.86eV减小到600℃时的1.59eV。     

Island formation in Ge/Si epitaxy

We review current understanding of the island formation process, and outline some of the remaining problems. The initial island formation is coherent, with islands stabilised by the elastic relaxation associated with deformation of the substrate. We use finite element analysis to demonstrate the degree of relaxation associated with these deformations. The islands then relax further by introduction of dislocations. The first dislocations introduced in the large coherent islands are shown to be inclined burgers vectors (about 60°) adopting a nearly semicircular path around the island perimeter. The outstanding anomaly in Ge/Si growth is the temperature dependence of islanding, with slower relaxation rates and greater metastability associated with higher temperatures. We describe various possible explanations for this problem.     

Si基富Ge含量Si1-x-yGexCy异质结构的热退火行为研究

研究了Si基富Ge含量的Si1-x-yGexCy异质结构的热退火地为,采用等离子体增强化学气相淀积（PECVD）法在Si(100）衬底上淀积一层厚度为170nm的Si1-x-yGexCy薄膜（x-0.7,y-0.15),并在其上覆盖－Ge层,将样品分别在650度和800度下进行N2氛围下热退火20min。用拉曼谱（Raman),俄歇电子能谱（AES）以及X射线光电子能谱XPS等方法对样品进行研究。研究结果表明,低温PECVD法生长的Si1-x-yGexCy薄膜是一种亚稳结构,Ge/Si1-x-yGexCy/Si异质结构在650度下呈现不稳定性,薄膜中的Ge,C相对含量下降,且在界面处出现Ge,C原子的堆积,经过800度下退火20min的样品中C 含量基本为0,Ge相对含量下降至约20％左右,且薄膜的组分比较均匀。