Getter sputtering system for high-throughput fabrication of composition spreads

We describe a sputtering system that can deposit composition spreads in an effectively UHV environment but which does not require the high-throughput paradigm to be compromised by a long pump down each time a target is changed. The system deploys four magnetron sputter guns in a cryoshroud (getter sputtering) which allows elements such as Ti and Zr to be deposited with minimal contamination by oxygen or other reactive background gases. The system also relies on custom substrate heaters to give rapid heating and cool down. The effectiveness of the gettering technique is evaluated, and example results obtained for catalytic activity of a pseudoternary composition spread are presented.     

Ion beam sputtering: an improved method of metal coating SEM samples and shadowing CTEM samples

An apparatus to ion beam sputter-coat SEM samples has recently become available. The equipment uses a small saddle-field ion source to sputter deposit metals on to samples. This eliminates the surface artefacts seen at high magnifications on samples coated by diode sputtering. Ion beam sputtering has also been used to shadow samples for CTEM and has been found to result in a grain size of 1.2 nm. This technique isolates the specimens from the high-energy plasma and thus little or no heating of the sample occurs. The removal of the SEM samples from the high-energy plasma and the use of diffusion pump vacuum conditions to prevent contamination are suggested as reasons for the improved coating quality over diode sputtering.     

Specimen coating for high resolution scanning electron microscopy

Thin conducting films, produced by evaporation or soft vacuum sputtering generally show cracks and grain formation, when examined under high resolution scanning electron microscopy (SEM). These artefacts can obscure surface features of coated specimens or cause confusion in the interpretation of micrographs. No such structures have been observed in films produced by ion beam deposition. Ion beam deposition equipment is described in which a cold cathode saddle field ion source, operating at low pressure (15mPa), produces a 2 mm diameter beam of energetic ions (5 keV) and neutrals. With the beam directed onto a target at 30° to glancing incidence, the sputtered material coats the specimens, which are held in a planetary system for good coverage. Conditions favouring fine grain growth are a high nucleation density and low energy transfer to the substrate by thermal conduction or radiation or by particle or photon radiation. These conditions are satisfied by ion beam deposition but evidently not by evaporation or soft vacuum sputtering. With the specimen stationary, sharp shadowing is obtained because the target acts almost as a point source, because of the small diameter of the beam and because there is little scatter at the operating pressure.     

内置皮拉尼计的硅通孔圆片级MEMS真空封装研究

针对现有的圆片级真空封装存在检测难、易泄漏等问题,提出了内置皮拉尼计的硅通孔圆片级MEMS真空封装方法。研制了用于圆片级真空封装导线互连的硅通孔,探讨了玻璃盖板与硅圆片之间阳极键合工艺与硅圆片与硅圆片之间的金硅共晶键合工艺,研制了用于检测封装壳体内部真空度的皮拉尼计; 研制了内置皮拉尼计的4英寸硅通孔圆片级真空封装,研制了低温激活非蒸散型吸气剂。实验研究表明,该研究解决了长时间保持真空度的问题。     

真空装置内部粘合接头的脱气

本文讨论了有内部粘接剂的真空装置内的残余气氛形成的动力学,以及质谱和色谱方法在测定固化胶粘剂中挥发性化合物的比气率的应用.本文给出了各种类型的胶粘剂的脱气比较数据,并证明了胶粘剂接头脱气的有效性.同时也考虑了在各种设备中提供真空的可能选项.对于残余压力(约10-2 Pa)的适当要求下,在几个小时内就足以对粘合剂接头进行脱气.在大约10-4 Pa压力下,在有内部粘合接头的装置中提供真空要困难得多,这需要使用内置的吸气剂和高温去气.在使用真空装置之前短时间(几分钟)激活内置吸气剂,在基本不通或曾经使用过的设备上提供深真空(10-5-10-4 Pa)是有利的.这可以去除主要的残余碳氢化合物气体成分,并在一定的时间间隔内提供必要的真空水平.     

Development of in-vessel components of the microfission chamber for ITER

Microfission chambers (MFCs) will measure the total neutron source strength in ITER. The MFCs will be installed behind blanket modules in the vacuum vessel (VV). Triaxial mineral insulated (MI) cables will carry signals from the MFCs. The joint connecting triaxial MI cables in the VV must be considered because the MFCs and the MI cables will be installed separately at different times. Vacuum tight triaxial connector of the MI cable has been designed and a prototype has been constructed. Performance tests indicate that the connector can be applied to the ITER environment. A small bending-radius test of the MI cable indicates no observed damage at a curvature radius of 100 mm.     

平面磁控溅射薄膜厚度分布模拟

磁控溅射法是制备薄膜的一种重要方法 ,薄膜厚度分布是影响薄膜性能的一个重要因素。本文根据平面磁控溅射的实际 ,提出了一个较为全面的磁控溅射薄膜厚度分布模型 ,该模型综合考虑靶面溅射电流分布、溅射产额与入射角之间的关系、靶面出射粒子的角分布、空间角以及粒子迁移过程中的碰撞等。对建立的模型进行了计算机模拟 ,模拟结果与实验结果较为一致。     

A new vacuum interferometric comparator for calibrating the fine linear encoders and scales

A new one-dimensional laser interferometric comparator has been developed for the calibration of the fine linear encoders and scales up to 1600 mm. In the comparator, the interferometer is fully arranged in vacuum and the calibration objects are mounted under atmospheric conditions. The Abbe’s principle on the alignment of workpiece with the measuring beam is satisfied in the structure of a long measuring range. A travelling slide table, on which the calibration objects are mounted, is supported on guide rails by the air bearing and is driven through a recirculating ballscrew. The exhaust of the air bearing is guided to the exterior of the booth in which the comparator is placed. The travel of the table is measured by a reference interferometer with a beam path in vacuum shielded by an evacuated metal bellow, so that the effect of refractive index is eliminated. The laser beam is led by a polarization plane maintaining glass fiber from a self-designed stabilised He–Ne laser, which is placed in an adjacency room, to the beam inlet of the main unit. The measurement system can input the interferometer signal by the encoder signal or the scale signal, and input the encoder or scale data by the interferometer signal. The system resolution is approximately 0.8 nm and maximum travelling measurement speed is 20 mm/s at continuous measurement. The uncertainly (k=2) of measurement is approximately 30 nm in linear encoders of 500 mm length and, approximately 40 nm in scales of 500 mm, although it depends on the length and the characteristics of encoders and scales. It is successful such a high accuracy that the uncertainty of measurement system is smaller than 40 nm in encoders of 1 m length.     

Novel techniques of preparing TEM samples for characterization of irradiation damage

Focus ion beam preparation of transmission electron microscopy (TEM) samples has become increasingly popular due to the relative ease of extraction of TEM foils from specific locations within a larger sample. However the sputtering damage induced by Ga ion bombardment in focus ion beam means that traditional electropolishing may be a preferable method. First, we describe a special electropolishing method for the preparation of irregular TEM samples from ex‐service nuclear reactor components, spring‐shaped spacers. This method has also been used to prepare samples from a nonirradiated component for a TEM in situ heavy ion irradiation study. Because the specimen size is small (0.7 × 0.7 × 3 mm), a sandwich installation is adopted to obtain high quality polishing. Second, we describe some modifications to a conventional TEM cross‐section sample preparation method that employs Ni electroplating. There are limitations to this method when preparing cross‐section samples from either (1) metals which are difficult to activate for electroplating, or (2) a heavy ion irradiated foil with a very shallow damage layer close to the surface, which may be affected by the electroplating process. As a consequence, a novel technique for preparing cross‐section samples was developed and is described.     

硅微陀螺仪器件级真空封装技术研究

为进一步提高硅微陀螺仪的品质因数及其稳定性,研究了硅微陀螺仪器件级真空封装的高真空获取技术和真空保持技术。首先,以硅微陀螺仪动力学方程为基础,分析了硅微陀螺仪的误差信号与品质因数之间的关系,并采用稀薄气体动力学分析具有高品质因数陀螺仪的空气阻尼。根据早期真空封装陀螺仪的品质因数跟踪测试曲线,分析了品质因数下降原因。采用程序升温脱附职谱分析法（TPD-MS）分析陶瓷管壳和金属盖板的放气特性,并选用了合理的吸气剂。最后,改进了器件级真空封装流程。测试结果表明,采用改进的器件级真空封装的陀螺仪品质因数最高可达162660,约为早期真空封装陀螺仪品质因数的14倍,且在一年内的变化小于0.05%。     

锦屏一级水电站高落差垂直竖井GIL安装与试验

锦屏一级水电站550 kV气体绝缘金属封闭输电线路(GIL)是目前国内该电压等级下安装海拔最高(海拔1 885 m)、垂直竖井形式、垂直安装落差高达225 m、总长度达3 376 m、输送容量大的工程项目。其设备布置、竖井安装的复杂性和高难度在国内少有。介绍了其布置与结构特点、垂直竖井中的安装方法、交流耐压试验,建议合理划分SF6气室,严格控制安装工艺,安装内置超高频局放探头,交流耐压时增加老练时间等,为同类工程的设备选型及安装提供参考。     

Cryopump vibration isolation system for an SEM

A standard commercially available cryopump system has been installed on a scanning electron microscope (SEM) using specially optimized vacuum vibration isolation bellows. This installation was successful in reducing the cryopump-induced vibration to a level that did not degrade the standard performance or resolution of the SEM in the pump-on mode and, in the pump-off (or coasting) mode, eliminated all measurable instrument-induced vibration (i.e., from the vacuum system). This article outlines the manner in which this performance has been accomplished and presents the results of an experiment demonstrating the reduction of specimen contamination provided by this type of vacuum system.     

Modernization of the Element 2 mass spectrometer

To perform direct elemental analysis of solids, it is proposed to complement an Element 2 ICP mass spectrometer commercially produced by Thermo Electron Corp. with a glow-discharge ion source based on a hollow cathode. The analyzed sample, in the form of a rod 1.0–2.5 mm in diameter and 15–20 mm in length, is set along the axis of the cathode cavity with an inner diameter of 15–16 mm and a depth of 15 mm. The cathode is placed in a discharge chamber, which, using a viton seal, is substituted for the ICP-source sampler. The use of a plasma mirror and getter evacuation of the source chamber allows a decrease in the source’s hydrocarbon background by a factor of 10³–10⁴. The ion source is evacuated by a mechanical pump of the mass spectrometer and an additional turbomolecular pump. Ion sources in a mass spectrometer are replaced (a change from one analytical method to another) within 5 min. The ion current extracted from the IS allows analysis of conducting solids with a sensitivity at a level of several ppb (10⁻⁷%) at a resolution of the mass spectrometer of 4000. Combining two easily replaceable ICP and GD ion sources in a single high-resolution analyzer significantly extends the analytical capabilities of the Element 2 mass spectrometer. Original Russian Text ? G.G. Sikharulidze, 2009, published in Pribory i Tekhnika Eksperimenta, 2009, No. 2, pp. 98–100.     

Preparation of carbon films from evaporated fibers and rods at fore-vacuum pressure

Fore-vacuum (pressure ≥ 3 Pa) evaporation of carbon fibers and rods to thin films has been tested and the resulting thicknesses recorded. A modified sputter coater was used as a vacuum evaporator. The quality of the carbon films was evaluated by bright-field and dark-field electron microscopy. Although high-vacuum-evaporated carbon films are superior in quality, low-vacuum-evaporated carbon films were found fully acceptable for routine work in bright field, for both TEM and SEM purposes. Apart from being time-saving, the method presented has the obvious advantage, in SEM preparations, that carbon coating and metal sputtering can be carried out in the same unit without breaking the vacuum.     

Gas discharge source of metal vapor and fast gas atoms

A source of metal atom flow coinciding in time and space with a flow of fast gas atoms has been studied and the study results are presented. The fast particles are produced due to charge exchange collisions of ions accelerated by potential difference between a plasma emitter inside the source and secondary plasma inside a process vacuum chamber. The emitter is the glow discharge plasma, whose electrons are confined in an electrostatic trap formed by a cold hollow cathode and an emissive grid the latter being negative both to the cathode and the chamber. The metal atoms are produced due to sputtering a target placed at the hollow cathode bottom by ions from the plasma emitter with energy up to 3 keV. Sputtered atoms cross the emitter, together with accelerated ions enter the chamber through the emissive grid and deposit on pieces placed therein. When a mixture of argon and nitrogen is used, the metal nitride coatings are being synthesized and interruptedly bombarded during the synthesis by atoms and molecules with energy variable from ～10 to ～300 eV.     

An application of spatial deconvolution to a capillary-based high-pressure chamber for fluorescence microscopy imaging

Capillary‐based high‐pressure chambers for which the wall serves as both the optical window and mechanical support have been reported for fluorescence microscopy imaging. Although capillary chambers are straightforward and economical to construct, the curved capillary wall introduces image aberrations. The significance of these aberrations in imaging sub‐cellular‐dimension objects has yet to be assessed. Using a capillary chamber that is routinely pressurized to between 20 and 30 MPa, a pressure range suitable for studying a wide variety of cellular processes, we demonstrate sub‐cellular‐dimension spatial resolution in the imaging of fluorescent micro‐spheres. Objectives with a range of numerical apertures (0.5–1.3) and working distances (0.1–7.4 mm) are considered. We show that spatial (or point‐spread function, PSF) deconvolution improves image contrast in capillary‐based images by comparing deconvolution results with those obtained from slide‐mounted controls. Furthermore, similar deconvolution results between a measured PSF and a calculated, flat‐geometry PSF indicate that the capillary wall is optically flat on cellular length scales. Results here facilitate the application of contemporary techniques in fluorescence microscopy to high‐pressure imaging fields.     

Cryosputtering—a combined freeze-drying and sputtering method for high-resolution electron microscopy

Preparing cellular structures for visualization by high-resolution scanning electron microscopy (SEM) is a multi-step process which includes fixation, dehydration, drying and metal coating. Drying and metal coating are limiting for high-resolution work. Commonly, the dried samples are exposed to the air before they are inserted into a metal coating apparatus, thereby exposing them to moisture and the accompanying risk of rehydration, which may cause changes in the supramolecular structure. We have modified a freeze-dryer to accommodate a magnetron sputtering head, in order to sputter-coat the frozen-dried samples while still in the drying chamber in the cold, a process we call cryosputtering. A layer of 1·5 nm of tungsten was cryosputtered onto whole mounts of cytoskeletons from detergent-extracted human glioma cells or fibroblasts and the specimens were examined by high-resolution SEM and transmission electron microscopy (TEM). To reduce the effects of backstreaming oil from the vacuum system, a turbomolecular pump backed by a two-stage rotary vane pump was connected to the drying-coating chamber. This pump system provides a high vacuum, making it possible to dry the specimens at — 90°C/183 K, thus reducing the risk for recrystallization of water. Furthermore, the high vacuum minimizes the negative effects of contaminants, which can be deposited onto the specimen surface and affect the quality of the metal coat formed during sputtering.     

Neutral beam dump with cathodic arc titanium gettering

An incomplete neutral beam capture can degrade the plasma performance in neutral beam driven plasma machines. The beam dumps mitigating the shine-through beam recycling must entrap and retain large particle loads while maintaining the beam-exposed surfaces clean of the residual impurities. The cathodic arc gettering, which provides high evaporation rate coupled with a fast time response, is a powerful and versatile technique for depositing clean getter films in vacuum. A compact neutral beam dump utilizing the titanium arc gettering was developed for a field-reversed configuration plasma sustained by 1 MW, 20-40 keV neutral hydrogen beams. The titanium evaporator features a new improved design. The beam dump is capable of handling large pulsed gas loads, has a high sorption capacity, and is robust and reliable. With the beam particle flux density of 5 × 10(17) H∕(cm(2) s) sustained for 3-10 ms, the beam recycling coefficient, defined as twice the ratio of the hydrogen molecular flux leaving the beam dump to the incident flux of high-energy neutral atoms, is ～0.7. The use of the beam dump allows us to significantly reduce the recycling of the shine-through neutral beam as well as to improve the vacuum conditions in the machine.     

Vector control of induced magnetic anisotropy using an in situ quadrupole electromagnet in ultrahigh vacuum sputtering

We demonstrate the incorporation of a quadrupole electromagnet into an ultrahigh vacuum sputtering system for the vector control of induced magnetic anisotropy in magnetic thin-film heterostructures. A stationary quadrupole electromagnet is used to generate a magnetic field, which rotates synchronously with the physical axes of the substrate in situ during sputtering. An arbitrary anisotropy direction can be set for successive ferromagnetic layers by adjusting the phase difference of substrate and field rotation. The ability to rotate the substrate during deposition and change anisotropy without breaking vacuum enables the deposition of magnetically soft heterostructures with arbitrary in-plane anisotropy axes.     

High resolution scanning electron microscopy in biology: artefacts caused by the nature and mode of application of the coating material.

Results of high resolution secondary electron observations of the haemocyanin molecule from the marine whelk Buccinum undatum are given. The choice of metal used for surface coating of the sample (gold, gold--palladium or carbon/gold--palldium) and the mode of application of this metal (thermal vacuum evaporation or diode sputtering) were both found to be of utmost importance when working at high magnifications in the scanning electron microscope. Sputter coating with gold gives poor results because of a granular and cracked appearance of the surface film. The haemocyanin molecules were difficult to recognize in these preparations. Best results were obtained by a thermal vacuum evaporation of gold--palladium. It is suggested that the inferior results seen after sputter coating may be due to the high temperatures wihch the specimen experiences during the sputtering, even when cooling of the specimen stage is carried out. Other specimens (diatom valves and latex spheres) were also studied at high magnification giving the same results as the haemocyanin molecules.