电子束蒸发制备掺钕钇铝石榴石薄膜特性研究

硅基光电集成技术是当代高速信息化的重要发展方向之一。为了研究制备在硅衬底上的新型发光材料,突破Nd:YAG固体激光工作物质主要是晶体、透明陶瓷等固体形态的限制,采用电子束蒸发沉积工艺,在硅(100)衬底上制备了Nd:YAG薄膜,并对Nd:YAG薄膜的表面形貌、晶体结构、光学特性进行了测试。X射线和扫描电子显微镜测试结果显示,Nd:YAG薄膜经1100℃真空高温退火处理1h后有效结晶,采用钛蓝宝石激光器输出808nm激光激发,液氮冷却的InGaAs阵列探测器室温下得到Nd:YAG薄膜的1064nm主荧光峰的荧光光谱。结果表明,采用电子束蒸发沉积和后续高温退火工艺可以在硅衬底上制备Nd:YAG晶体薄膜。     

Characteristics of Nd:Y3Al5O12 thin film prepared by electron beam evaporation deposition

硅基光电集成技术是当代高速信息化的重要发展方向之一.为了研究制备在硅衬底上的新型发光材料,突破Nd∶YAG固体激光工作物质主要是晶体、透明陶瓷等固体形态的限制,采用电子束蒸发沉积工艺,在硅(100)衬底上制备了Nd∶ YAG薄膜,并对Nd∶YAG薄膜的表面形貌、晶体结构、光学特性进行了测试.X射线和扫描电子显微镜测试结果显示,Nd∶YAG薄膜经1100℃真空高温退火处理1h后有效结晶,采用钛蓝宝石激光器输出808nm激光激发,液氮冷却的InGaAs阵列探测器室温下得到Nd∶YAG薄膜的1064nm主荧光峰的荧光光谱.结果表明,采用电子束蒸发沉积和后续高温退火工艺可以在硅衬底上制备Nd∶YAG晶体薄膜.     

激光脉冲频率对不同衬底上非晶硅薄膜晶化的影响

应用不同频率的YAG激光分别对单晶硅及多晶硅衬底上的非晶硅薄膜进行了退火处理。晶化后的非晶硅薄膜的物相结构和表面形貌用XRD和AFM进行分析。XRD测试结果表明:随着激光频率的增加,两种衬底上的非晶硅薄膜晶化晶粒尺寸均出现了先增加后降低的现象。所有非晶硅样品的衍射峰位与衬底一致,说明非晶硅薄膜的晶粒生长是外延生长。从多晶硅衬底样品的XRD可以看出,随着激光频率的增加,激光首先融化衬底表面,然后衬底表层与非晶硅薄膜一起晶化。非晶硅薄膜最佳晶化激光频率分别为:多晶硅衬底20Hz,单晶硅衬底10Hz。     

用X射线能谱仪测定衬底材料上的薄膜厚度

本文利用薄膜对入射电子束流的衰减作用和薄膜对衬底的x射线的吸收,提出了一种直接利用衬底的x射线的强度比来测量薄膜厚度的方法。并在各种实验条件下,对Cu薄膜的厚度进行了测量,得到了较为满意的结果。     

塑料衬底上制备WO3电致变色薄膜及其特性研究

采用真空电子束蒸发低压反应离子镀技术制备WO3电致变色薄膜,对比研究在玻璃衬底和塑料衬底上制备的WO3薄膜的物理特性、电化学特性和电致变色特性。采用扫描电子显微镜、X射线衍射、和电子探针显微分析技术测试了WO3薄膜的表面形貌、晶体结构和成分比例等。采用分光光度计测试了WO3薄膜在原始态、着色态和退色态的透射光谱、透射率变化的时间响应。     

沉积温度对反应电子束蒸发TiO2薄膜结构和光学性能的影响

TiO2具有较高的折射率,在光学方面有着广泛的应用.文中采用等离子辅助反应电子束真空蒸镀法,以Ti为膜料、纯度为99.99%的O2为反应气体,在玻璃衬底上制备了TiO2薄膜.使用XRD、OM、SEM分别对50℃、150℃、300℃三个不同沉积温度下制备的薄膜及其经过450℃真空退火1 h后的结构进行了分析,并对薄膜的折射率进行测量.实验结果表明,提高沉积温度可以增加成膜原子的能量及其在衬底上的扩散能力,使沉积的薄膜结构平整致密,具有较高的折射率.     

非晶氧化钛薄膜的电学特性研究

室温下,通过采用直流反应磁控溅射法在覆盖有氮化硅薄膜的单晶硅衬底上生长了厚度约为100nm的氧化钛薄膜。掠入射X射线衍射分析结果表明在室温下,不同氧分压下生长的氧化钛薄膜均具有非晶结构。分别采用场发射扫描电子显微镜、X射线光电子能谱对薄膜的表面和断面形貌以及薄膜的组分进行了分析和表征。对薄膜的电学特性测试发现非晶氧化钛薄膜在293～373K的温度范围内主要依靠热激发至扩展态中的电子导电。     

硅基底电子束蒸发铝膜阳极氧化特性

研究了硅衬底上电子束蒸发铝膜 ,在 H2 SO4 水溶液中阳极氧化形成硅衬底多孔氧化铝复合结构的过程 .硅衬底电子束蒸发铝膜的阳极氧化过程主要由多孔氧化铝的生长、氧化铝生长向氧化硅生长的过渡和氧化硅生长三个阶段构成 .硅衬底多孔氧化铝复合结构的透射电子显微镜观察表明 ,在硅衬底上形成了垂直于硅表面的氧化铝纳米孔 ,而孔底可形成 Si O2 层 .有序结构多孔氧化铝的形成不依赖于铝膜的结晶状态 ,而是由阳极氧化过程的自组织作用所决定的 .实验表明将多孔氧化铝制备工艺移植到硅基衬底上直接形成硅基衬底多孔氧化铝复合结构是可行的     

电子束反应蒸发技术生长Mo掺杂In_2O_3薄膜

利用电子束反应蒸发技术,调制衬底温度200～350℃,详细研究了Mo掺杂In2O3(IMO,In2O3:Mo)薄膜的微观结构以及光电性能的变化。随着衬底温度增加,原子力显微镜(AFM)与扫描电子显微镜(SEM)图像均证明IMO薄膜表面趋于粗糙,透过率和Hall测试表明其光学和电学性能逐渐提高。在衬底温度为350℃时,获得薄膜最小电阻率为2.1×10-4Ωcm,载流子迁移率为34.2cm2/Vs,其可见光区及近红外区的平均透过率为78%。衬底温度为200℃时,薄膜表现为黑褐色,经分析X射线光电子能谱(XPS)结果认为与薄膜中钼的低价氧化有关,提高衬底温度可改善薄膜氧化状态。     

硅基底电子束蒸发铝膜阳极氧化特性

研究了硅衬底上电子束蒸发铝膜,在H2SO4水溶液中阳极氧化形成硅衬底多孔氧化铝复合结构的过程.硅衬底电子束蒸发铝膜的阳极氧化过程主要由多孔氧化铝的生长、氧化铝生长向氧化硅生长的过渡和氧化硅生长三个阶段构成.硅衬底多孔氧化铝复合结构的透射电子显微镜观察表明,在硅衬底上形成了垂直于硅表面的氧化铝纳米孔,而孔底可形成SiO2层.有序结构多孔氧化铝的形成不依赖于铝膜的结晶状态,而是由阳极氧化过程的自组织作用所决定的.实验表明将多孔氧化铝制备工艺移植到硅基衬底上直接形成硅基衬底多孔氧化铝复合结构是可行的,它也为硅基纳米材料的制备提供了一种新的自组织模板.     

THE GROWTH OF MONOCRYSTALLINE SILICON THIN FILM ON INSULATOR (SOI) BY SCANNING ELECTRON BEAM

An experiment for preparation of SOI films by using the scanning electron beam to modify the polycrystalline silicon on SiO2 is presented. This method takes on the epitaxial lateral growth of liquid phase with the crystallon to form monocrystalline silicon films. The effects of the beam power density, scanning velocity, temperature of the substrates and the construction of samples on the quality of the monocrystalline silicon films were discussed. A good experimental result has been obtained, the monocrystalline silicon zone is nearly 200×25μm2.     

Processing of titanium films on silicon using a multiscanned electron beam

A multiscanned electron beam has been used to process titanium films thermally on single-crystal silicon. The redistribution of titanium and the composition of the processed films were studied by Rutherford backscattering. Oxygen contamination within the titanium is found to control the reaction rate. Processing conditions have been established which give stoichiometric TiSi2 layers and the removal of oxygen from the system. These results have been confirmed by Auger analysis and the surface texture has been examined using scanning electron microscopy.     

Structural and electrical investigation of BLT films deposited at different times using electron beam evaporation technique

Thin films Bi4Ti3O12 (BLT) were deposited using electron beam evaporation on silicon substrate at several times, also on AlN/Si and SiO2/Si substrates. Thin films morphology and thickness were measured via scanning electron microscopy (SEM). The crystallography was studied using X-ray diffraction (XRD) technique for films which have a (0010) preferred orientation in all substrate types. The capacitance values were contingent on frequency value in C-V measurement. The ferroelectric characterization was investigated for BLT film deposited on isolator layer (SiO2 or AlN) for Al/Bi4Ti3O12/SiO2/Si devices. Memory effect value varied from 1 V to 3 V depending on the thin films isolator on substrate.     

Towards van der Waals Epitaxial Growth of GaAs on Si using a Graphene Buffer Layer

Van der Waals growth of GaAs on silicon using a two‐dimensional layered material, graphene, as a lattice mismatch/thermal expansion coefficient mismatch relieving buffer layer is presented. Two‐dimensional growth of GaAs thin films on graphene is a potential route towards heteroepitaxial integration of GaAs on silicon in the developing field of silicon photonics. Hetero‐layered GaAs is deposited by molecular beam epitaxy on graphene/silicon at growth temperatures ranging from 350 °C to 600 °C under a constant arsenic flux. Samples are characterized by plan‐view scanning electron microscopy, atomic force microscopy, Raman microscopy, and X‐ray diffraction. The low energy of the graphene surface and the GaAs/graphene interface is overcome through an optimized growth technique to obtain an atomically smooth low­ temperature GaAs nucleation layer. However, the low adsorption and migration energies of gallium and arsenic atoms on graphene result in cluster‐growth mode during crystallization of GaAs films at an elevated temperature. In this paper, we present the first example of an ultrasmooth morphology for GaAs films with a strong (111) oriented fiber‐texture on graphene/silicon using quasi van der Waals epitaxy, making it a remarkable step towards an eventual demonstration of the epitaxial growth of GaAs by this approach for heterogeneous integration.     

Microcolumn based low energy e-beam writing

In this paper first results on electron beam lithography with a microcolumn are presented. Our miniaturized e-beam writer is designed to explore the energy range below 1 keV. This range is attractive because the mean free path of the electrons has a minimum at approximately 100 eV. It is expected that resists are extremely sensitive at these energies and that proximity effects are highly reduced. Both effects could help to accelerate the lithography process or to allow the exploration of new processes. Test exposures were made on spin-coated, 50-nm-thick films of PMMA, hydrogen-passivated silicon and self-assembled monolayers on gold-coated silicon. The patterns were analyzed by means of optical, atomic force and scanning electron microscopy where appropriate, as well as with a profilometer. As expected, the depth of the profiles in PMMA were very shallow. Typical values lay between 2 and 7 nm for energies between 100 and 200 eV.     

A laser scan technique for electronic materials surface evaluation

A technique utilizing a scanning laser beam has been implemented to examine the surfaces of materials that are used in the form of flat plates or thin deposited films in the field of microelectronics. Unwanted holes in opaque films deposited onto transparent substrates can be detected by sensing the light transmitted through the holes or defects on a reflective surface can be detected by virtue of their light scattering properties. A typical application is the inspection of silicon wafers that have been highly polished preparatory to film deposition for the planar technology of semiconductor device building. Defects as small as one micron can be detected. An entire wafer 5 cm in diameter can be scanned in 40 seconds to give: 1) a total defect count, and 2) a map of defect locations displayed on an oscilloscope screen.     

Defect-free silicon film on SiO2 formed by zone meltingrecrystallization with high scanning speed

The recrystallization of polysilicon films on silicon dioxide at high scanning speed, in the range of 5≈15 mm/s, with an RF-induced graphite strip heater system is discussed. The films are in (100) orientation and contain subgrain boundaries (SGBs). Heat-sink and valley structures have been used to localize these SGBs. Defect-free silicon films have been obtained with good uniformity and reproducibility. The differences between the results obtained with fast scanning and the conventional slow scanning is analyzed. n-channel and p-channel MOSFETs have been fabricated in the recrystallized silicon film to characterize electrical properties such as mobilities and leakage currents, and they show very good characteristics     

Recrystallisation of CVD poly-Si on insulator by dual electron-beam processing

Large areas of ?100? oriented single-crystal films have been produced, using the lateral seeding technique, from polycrystalline silicon deposited on SiO2. One electron beam was used to provide generalised substrate heating, and another swept a localised molten zone in the deposited silicon.     

电子束蒸发法制备六硼化镧薄膜及其特性研究

用电子束蒸发的方法在Ta衬底上制备了LaB6薄膜,用电子显微镜、X射线光电子能谱仪对样品的表面状况、化学组分进行了分析.采用真空热电子发射法测出了LaB6薄膜的逸出功.结果表明,电子束蒸发的方法能够得到化学成分偏差较小、表面状况较好的LaB6薄膜,其逸出功为2.59eV,具有良好的电子发射性能.     

Annealing effects on the formation of semiconducting Mg2Si film using magnetron sputtering deposition

Semiconducting Mg2Si films were synthesized on silicon (11 1) substrates by magnetron sputtering deposition and subsequent annealing in an annealing furnace filled with argon gas,and the effects of heat treatment on the formation and microstructure of Mg2Si films were investigated.The structural and morphological properties were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM),respectively.The results show that the crystal quality of Mg2Si films depends strongly on the annealing temperature,the annealing time and the deposited magnesium film thickness.Annealing at 400 ℃ for 5 h is optimal for the preparation of Mg2Si film.XRD and SEM results show that magnesium silicide film with various orientations is formed on the silicon surface because of the interdiffusion and reaction of magnesium with substrate silicon atoms,and the evolution of surface features on growing films is very dependent on the annealing temperature and time.