Optical Calibration of a Submicrometer Magnification Standard

The calibration of a new submicrometer magnification standard for electron microscopes is described. The new standard is based on the width of a thin thermal-oxide film sandwiched between a silicon single-crystal substrate and a polysilicon capping layer. The calibration is based on an ellipsometric measurement of the oxide thickness before the polysilicon layer is deposited on the oxide. The uncertainty in the derivation of a thickness for the layer from the ellipsometric parameters is also derived.     

Calibration of High-Resolution X-Ray Tomography With Atomic Force Microscopy

For two-dimensional x-ray imaging of thin films, the technique of scanning transmission x-ray microscopy (STXM) has achieved images with feature sizes as small as 40 nm in recent years. However, calibration of three-dimensional tomographic images that are produced with STXM data at this scale has not yet been described in the scientific literature, and the calibration procedure has novel problems that have not been encountered by x-ray tomography carried out at a larger scale. In x-ray microtomography, for example, one always has the option of using optical imaging on a section of the object to verify the x-ray projection measurements; with STXM, on the other hand, the sample features are too small to be resolved by light at optical wavelengths. This fact implies that one must rely on procedures with higher resolution, such as atomic force microscopy (AFM), for the calibration. Such procedures, however, generally depend on a highly destructive sectioning of the sample, and are difficult to interpret because they give surface information rather than depth information. In this article, a procedure for calibration is described that overcomes these limitations and achieves a calibration of an STXM tomography image with an AFM image and a scanning electron microscopy image of the same object.A Ge star-shaped pattern was imaged at a synchrotron with a scanning transmission x-ray microscope. Nineteen high-resolution projection images of 200 × 200 pixels were tomographically reconstructed into a three-dimensional image. Features in two-dimensional images as small as 40 nm and features as small as 80 nm in the three-dimensional reconstruction were resolved. Transverse length scales based on atomic force microscopy, scanning electron microscopy, x-ray transmission and tomographic reconstruction agreed to within 10 nm. Toward the center of the sample, the pattern thickness calculated from projection images was (51 ± 15) nm vs (80 ± 52) nm for tomographic reconstruction, where the uncertainties are evaluated at the level of two standard deviations.     

激光剥离技术制备GaN/metal/Si的结构和光学特性研究

采用激光剥离技术结合金属熔融键合技术将生长在蓝宝石衬底上的GaN外延层转移到Si衬底上.GaN和Si表面分别用电子束蒸发Al/Ti/Au和Ti/Au/In后,在氮气环境下200℃加压实现GaN和Si的键合.采用脉冲宽度30 ns、波长248 nm的准分子脉冲激光透过蓝宝石衬底辐照GaN薄膜,在脉冲激光能量密度为380 mJ/cm2的条件下将蓝宝石衬底剥离下来,实现GaN薄膜向Si衬底的转移.样品截面显微镜和扫描电镜(SEM)照片说明经过键合工艺形成了致密的GaN/Al/Ti/Au/In/Au/Ti/Si结构.对转移衬底后的GaN薄膜进行原子力显微镜(AFM)和光致发光谱(PL)测试,结果表明金属熔融键合和激光剥离工艺没有对GaN薄膜的结构和光学特性带来明显的不利影响.     

Nanotubes in a gradient electric field as revealed by STM TEM technique

We have investigated the behavior of two nanotube systems, carbon and boron nitride, under controlled applied voltages in a high-resolution transmission electron microscope (TEM) equipped with a scanning tunneling microscope (STM) unit. Individual nanotubes (or thin bundles) were positioned between a piezomovable gold electrode and a biased (up to ±140 V) STM tip inside the pole-piece of the microscope. The structures studied include double-and multi-walled carbon nanotubes (the latter having diverse morphologies due to the various synthetic procedures utilized), few-layered boron nitride nanotube bundles and multi-walled boron nitride nanotubes (with or without functionalized surfaces). The electrical breakdown, physical failure, and electrostatic interactions are documented for each system. Electronic Supplementary Material  Supplementary material is available for this article at and is accessible for authorized users.     

纳米测量仪器和纳米加工技术

纳米科技是当今国际上的一个热点。文章对纳米科技作了简要介绍, 纳米测量和加工是纳米科技中的一个不可缺少的重要组成部分。叙述了发展纳米测量和纳米加工技术的两个主要途径：一是发展传统技术,主要是电子显微术以及最近发展起来的聚焦离子束（FIB）- 电子束数控加工中心;二是创造新的测量仪器,建立新原理和新方法,介绍了国内外电子显微镜和扫描探针显微镜这两类纳米测量分析仪器的发展、应用和生产现状。指出我国电子显微仪器和扫描探针显微镜的开发和生产面临困境,应尽快建立和加强自己的电子显微仪器和扫描探针显微镜等纳米测量和纳米加工设备制造产业,并列入国家科技发展规划。     

Calibrating a scanning electron microscope in two coordinates by the use of one certified dimension

A method is proposed for calibrating a scanning electron microscope that corresponds completely to national standards providing unification of measurements in nanotechnology. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 18–20, June, 2008.     

STM及AFM在材料断裂与疲劳研究中的应用

扫描隧道显微镜（ＳＥＭ）和原子力显微镜（ＡＦＭ）具有原子级的极高分辨率,可在纳米尺度上获得实空间的表面微观三维菜貌,且可定量表征,因此可用来研究材料断裂与疲劳的微观机理。简要介绍ＳＴＭ和ＡＦＭ在该领域的应用及所取得的若干进展。     

基于AFM的纳米级表面加工中切屑形成的影响因素

以原子力显微镜（AFM）为加工工具进行了纳米级加工实验,对不同加工条件下的材料去除过程和切屑形态进行了研究．切屑形态通过扫描电子显微镜（SEM）进行观察,分析了不同垂直载荷、循环次数和针尖加工方向下铝铜被加工表面的切屑形成过程．实验结果表明：低栽下切屑呈细小断屑,散布在加工区域周围;随着垂直载荷的增加,切屑逐渐变成连续的带状切屑．不同循环次数、针尖加工面时切屑形成都有很大影响．在此基础上,对比分析了相同实验条件下,不同力学性能材料的切屑形成过程．最后,通过检测被加工表面得出被加工表面质量与切屑的数量和形态之间的关系,提出了改善被加工表面质量的方法,以帮助人们更好地理解基于AFM的纳米级加工技术．     

Evaluation of annular pupil for scanning transmission electron microscope formed by focused ion beam technique

Annular pupils for electron optics were developed using a focused ion beam (FIB) technique to realize an increase in the depth of focus, aberration-free imaging and separation of amplitude and phase images under scanning transmission electron microscopy (STEM). A tantalum plate 30 μm thick was used as the annular pupil material in the present experiment. The annular pupils were designed with various outer diameters from ?120 μm to ?40 μm. The inner diameter was designed at 60 to 80% of the outer diameter. The fabricated annular pupils were inspected by scanning ion beam microscopy and scanning electron microscopy. Annular pupils were successfully obtained at the designed size, although the slits of the pupils were slightly tapered by the ion beam etching process. These annular pupils were loaded on a STEM and confirmed to display no charge-up phenomenon by observation of the projection image on a scintillator using a CCD camera. We confirmed the image taken by annular pupil with narrow width was able to suppress the influence of the normal illumination.     

基于单幅扫描电镜图像的三维重建技术

本文提出了一种对黑硅表面进行三维重建的方法．通过对扫描电子显微镜的成像原理进行建模,该方法可以只使用单幅从黑硅表面正上方垂直向下拍摄的扫描电子显微镜图像获得黑硅表面的三维信息．该方法简单易行．本文对这一方法进行了重建测试．测试结果表明该方法能够获得比较理想的重建效果．     

Accuracy in linear dimensions measurement in scanning electron microscopes in microtechnology and nanotechnology

A study has been made on the effects of scanning electron microscope parameters on the accuracy in measuring the linear dimensions in microtechnology and nanotechnology. Definitions are given of the errors with which these parameters should be known for using such microscopes in such technologies. __________ Translated from Izmeritel’naya Tekhnika, No. 6, pp. 15–18, June, 2008.     

Voltage contrast studies on 0·5 μm integrated circuits by scanning force microscopy

A scanning force microscope (SFM) test system is used for voltage contrast studies on 0·5 μm integrated circuits. Waveform measurements are performed on passivated 0·5 μm conducting lines up to 4 GHz. Additionally two-dimensional measurements at 10 MHz demonstrate the potential for device internal function and failure analysis in the sub-μm regime by direct correlation between voltage contrast and quantitative topography images.     

Methylammonium cation deficient surface for enhanced binding stability at TiO<Subscript>2</Subscript>/CH<Subscript>3</Subscript>NH<Subscript>3</Subscript>PbI<Subscript>3</Subscript> interface

Heterojunction interfaces in perovskite solar cells play an important role in enhancing their photoelectric properties and stability.Till date,the precise lattice arrangement at TiO2/CH3NH3PbI3 heterojunction interfaces has not been investigated clearly.Here,we examined a TiO2/CH3NH3PbI3 interface and found that a heavy atomic layer exists in such interfaces,which is attributed to the vacancies of methylammonium (MA) cation groups.Further,first-principles calculation results suggested that an MA cation-deficient surface structure is beneficial for a strong heterogeneous binding between TiO2 and CH3NH3PbI3 to enhance the interface stability.Our research is helpful for further understanding the detailed interface atom arrangements and provides references for interfacial modification in perovskite solar cells.     

Classification of test objects for use in calibration of scanning electron microscopes in the nanometric range

A classification of test objects for use in calibration of scanning electron microscopes in the nanometric range is created. The shape of the relief profile of the elements of the test objects and the relationship of the profile to the physical mechanisms underlying the formation of the signal generated by a microscope functioning in a mode for the collection of secondary slow electrons is used as the basis of the classification. Translated from Izmeritel’naya Tekhnika, No. 2, pp. 22–26, February, 2009.