Field-emission electron source for vacuum micropump

In the work a conception of a miniature, orbitron ion vacuum micropump for an integration with vacuum MEMS devices is presented. It is made of silicon and glass using microengineering technology. The main part of the device is a lateral field-emission source of electrons, which has been fabricated on oxidized silicon wafer. Both, cold cathode and anode of the source are made of thin gold layer using only one photolithography process. Fabrication process and the preliminary results of electrical tests of the field-emission electron source are presented. Experimental studies have shown its good emission parameters: a low threshold voltage (over a dozen Volts), a high electron current (from tens to several hundred micro amperes), and field enhancement coefficient from 10⁷ to 10⁸ cm⁻¹. These results are promising and give possibility to fabricate orbitron micropump as an integrated part of vacuum MEMS.     

Field-emission electron source for vacuum micropump

In the work a conception of a miniature, orbitron ion vacuum micropump for an integration with vacuum MEMS devices is presented. It is made of silicon and glass using microengineering technology. The main part of the device is a lateral field-emission source of electrons, which has been fabricated on oxidized silicon wafer. Both, cold cathode and anode of the source are made of thin gold layer using only one photolithography process. Fabrication process and the preliminary results of electrical tests of the field-emission electron source are presented. Experimental studies have shown its good emission parameters: a low threshold voltage (over a dozen Volts), a high electron current (from tens to several hundred micro amperes), and field enhancement coefficient from 10⁷ to 10⁸ cm⁻¹. These results are promising and give possibility to fabricate orbitron micropump as an integrated part of vacuum MEMS.     

2000:薄膜与真空器件

回顾了真空电子器件二十年来的发展，并对今后七年薄膜与真空器件研究和生产的若干趋势作了扼要的叙述。在电子束管方面，高清晰度显象管、扁平显示管、飞点管、高分辨率、等离子体监视屏等仍将继续发展并占有重要的地位。在薄膜方面，硬膜、超导膜和亚稳态薄膜的研究将仍然是真空科学方面的热点。真空微电子器件面临的抉择则在于能否得到新构思的支撑。最后对本学科总体的一些问题提出了看法。     

非蒸散型吸气剂在微型离子泵中的应用

为确保小尺寸超高真空密封器件的高可靠和长寿命,开发了一种带非蒸散型吸气剂的微型复合离子泵(Mini-Combination Ion Pumps with NEG).在新建的微型离子泵性能测试系统上,研究了非蒸散型吸气剂对器件存储和微型离子泵启动特性的影响.模拟了微型离子泵与小型真空器件集成为一体时可能遇到不同气体负载时的实际情况,讨论了新结果的可能应用.     

被动型氢原子钟吸气剂泵的应用研究

描述了上海天文台在2008年为提高被动型氢原子钟真空系统的可靠性所研制的由非蒸散型吸气剂泵和小离子泵组成的复合泵的实验过程,吸气剂泵在室温下吸收2.1MPa.l的H2气后仍可达到3.2×10-5Pa的真空度,2l/s的离子泵电流工作在0.30μA,证明了复合泵可以维持氢钟13年以上的正常工作。经过再激活固定了激活工艺,吸气剂最终吸氢6.0 MPa.l仍没有饱和,证明了吸气剂的强大吸氢能力。至今复合泵已成功应用在4台被动型氢钟上。     

一种制备优质有机光学薄膜的新方法

提出了一种用真空蒸发和真空热压相结合的技术来制备优质有机光学薄膜的方法。用它制成的有机光学薄膜中没有任何残留有机溶剂,在放置过程中也不产生晶化,因而不会对光发生散射。在光通讯器件、有机发光、有机光存储器的制作等方面有广泛的应用前景。     

阳极真空电弧镀膜方法及其应用

介绍了阳极真空电弧镀膜方法的镀膜装置、工作原理及电弧等离子体微观过程。就其应用前景进行了展望。     

13 years’ operational experience of SPring-8 vacuum system

The first electron beam was stored in SPring-8 storage ring in March 1997. An overview of the 13 years’ operational experience concerning the vacuum system of the SPring-8 storage ring is presented. The evolution of the vacuum system and their performance are summarized. Moreover, the main vacuum failures and their impact on accelerator operation are described in detail. We analyze the relationship between the difference types of vacuum failure and downtime of user experiment.     

MEMS变发射率真空热控器件研究进展

变发射率热控技术是空间环境下的重要热控手段.微小卫星质量轻,尺寸小,功耗低及其真空环境工作等特点对热控系统提出了新的要求,相应热控器件应具有小质量、大发射率调节比、关闭状态漏热小、响应快等特点.MEMS技术由于其设计灵活性高、功耗低及器件体积、重量方面的优势,可很好地满足这类器件的要求.本文重点对基于MEMS技术的微百页窗,微热开关,微静电换热器等技术的研究进展、关键技术与适用范围进行了归纳总结,将基于MEMS技术的变发射率器件和基于材料研究的电致变色和热致变色这两种技术进行了对比分析,指出了MEMS技术在微小卫星变发射率热制器件中的发展趋势和潜力.     

A vacuum sensor using field emitters made by multiwalled carbon nanotube yarns

A newly developed vacuum sensor using carbon nanotube (CNT) field-emission has been designed. The fabricated device is an ionization gauge with a silk-like CNT yarn cathode, and the vacuum is indicated by the ratio of the ion current to the electron-emission current. The metrological characteristics of the sensor were studied in a dynamic vacuum system. It showed good linearity ranged from 10⁻⁴ to 10⁻¹ Pa. Taking advantage of the field-emission cathode, the power consumption is only about 5.5 mW. Moreover, comparing it to the conventional thermionic cathode, the CNT yarn cathode is more miniature and a cold cathode with no obvious thermal outgassing effect. Due to these features, the sensor described here could have potential applications in measuring vacuum inside sealed and miniaturized devices.     

Micro-CT Imaging of MEMS Components

Micro-Electromechanical Systems (MEMS) have become increasingly commonplace in varied uses such as miniature pumps, motors, and sensors. As MEMS size continues to decrease, the intricacy of their construction has increased. With this increase in complexity comes a need to evaluate the assembly and functionality of these devices in a nondestructive manner. We proposed the utilization of micro-CT imaging as a method of such evaluation for MEMS devices. Computational simulations were performed in order to determine optimal source materials and imaging parameters for micro-CT scans. Multiple MEMS components of various architecture, fabricated by Sandia National Labs, were then imaged in order to verify the simulations, as well as to prove the feasibility of micro-CT imaging of such devices. The raw data from these scans was run through computational simulations to verify the best choice of filter and interpolation method when reconstructing micro-CT images. The results of the simulations, as well as the level of detail present in the three dimensional reconstructed images of various MEMS devices proved the feasibility of micro-CT as an effective tool for the evaluation of such devices.     

变压吸附制氧设备真空风机入口压力低分析和处理

介绍了邯钢动力厂真空变压吸附制氧设备的工艺流程,从切换阀本体、电磁阀及仪表气源等方面分析和总结了真空风机入口压力低引起系统联锁停车故障原因,并介绍了相应的处理措施。     

单缸双作用单级与双级抽气往复式真空泵真空度的对比分析

对单级与双级抽气开平衡通道与不开平衡通道的真空泵的真空度进行了对比分析。导出了相应的真空度的计算公式。得出了开平衡通道的单级抽气可以设计得比不开平衡通道的双级抽气真空泵真空度高的结论。     

Status and performance of MGC-20 cyclotron vacuum system

A variable energy compact cyclotron has been installed at the Nuclear Research Centre NRC, Atomic Energy Authority AEA, Egypt. It is equipped to accelerate protons, deuterons, α-particles and ³He. The vacuum system has to provide high vacuum within the 10⁻⁶ mbar range in order to accelerate particles and to have stable beam. The total vacuum volume includes the acceleration chamber and the ion beam transport line is ≈3 m³. The pump-down time of the system to the steady high vacuum is measured. Results on the performance of the forevacuum and the high-vacuum pumps will be presented. The characteristics of the vacuum system components are evaluated.     

真空预冷过程中真空泵的延迟开启现象研究

VCE-15型真空预冷机在自动预冷模式下,由于受到真空室空气状态的影响,真空泵的开启存在延迟现象,导致真空预冷周期增长.以捕水器的冷负荷为基础,推导出真空泵的延迟开启时间计算式,并利用实验数据验证.结果表明:真空泵的延迟开启时间一般在5分钟之内,时间长短随着真空室空气的起始温度、相对湿度及真空室空载率的增加而增加,随着制冷机组制冷量的增加而缩短.复压时使外部空气经捕水器冷却后再进入真空室,或者提高制冷机组的制冷量,均可以缩短下次真空泵的延迟开启时间.     

Progress in Microelectromechanical Systems

Abstract:  Recent advances in microelectromechanical systems (MEMS) technology have led to the development of a multitude of new devices heretofore impossible. However, applications of these devices are still hampered by challenges posed by their integration and packaging. The current trend in micro/nanosystems is to produce ever smaller, lighter and more capable devices at a lower cost than ever before. In addition, the finished products have to operate at very low power and in very adverse conditions while ensuring durable and reliable performance. Some of the new devices have been developed to function at high operational speeds, and others to make accurate measurements of operating conditions of specific processes. Regardless of their applications, the devices have to be packaged to facilitate their use. MEMS packaging, however, is application-specific and, usually, has to be developed on a case-by-case basis. To facilitate advances of MEMS, educational programmes have been introduced addressing all aspects in their development. This paper addresses progress in MEMS by presenting pertinent aspects in a development of MEMS including, but not limited to, design, analysis, fabrication, characterisation, packaging, and testing. This presentation is illustrated with selected examples.     

发展中的真空电子学及其器件

概述了电真空器件在各个领域里的应用及有待深入研究的课题。给出了扩展视觉的新型器件与改进工艺的方法。     

Validity of the Space-Time Enlargement Law for vacuum breakdown

This paper investigates, theoretically and experimentally, the applicability of the Space-Time Enlargement Law to vacuum-insulated systems. A discussion on how characteristics of possible vacuum breakdown mechanisms determine the distribution function of the breakdown voltage random variable is presented. By superimposing effects of electrode surface enlargement and inter-electrode gap enlargement, expressions for the mean value and standard deviation of the breakdown voltage random variable are obtained. In the case of time extensions, the assumption of complete independence of consecutive discharge processes is discussed. Experimental testing of the Enlargement Law was performed on Rogowski type two-electrode systems, with different electrode surface areas, inter-electrode gaps and vacuum pressures. Measurements were conducted using industrial ac voltage, dc voltage with 50 V/s rate of rise, standard atmospheric pulse voltage (1,2/50 μs), and commutational pulse voltage (250/2500 μs). The final conclusion, based on the comparison of theoretical considerations and the experimental results, is that the Space-Time Enlargement Law can be applied in the design phase during the development of vacuum devices, with certain limitations, regardless of the type of the applied voltage.     

MEMS Technology for the Advancement of Science

In this article we describe the basic principles, advantages and limitations of Microelectromechanical systems (MEMS) technology. We present, examples of experiments in which micromachines are used to do physical measurements that could not be done before. MEMS are miniature mechanical devices with micrometer size movable parts. These devices are playing key roles in many important areas, including health care, transportation, communications, defense systems and a wide array of consumer products. They are an emerging technology, which, when applied to the field of physical sensors, offers not only an obvious advantage of being small and cheap, but more importantly, provides some unique experimental opportunities.     

影响微电子机械系统成品率和可靠性和粘合力和磨擦力

章评述了影响微电子机械系统（MEMS）成品率和可靠性的粘合力和摩擦力问题。在用氢氟酸（HF）腐蚀牺牲层、释放多晶Si微结构、干燥时,由于Si片表面薄层水的表面张力使两片亲水、间隙在微米量级的Si片粘合起来,称为“释放有关粘合”。粘合也发生在封装后器件中,当输入信号过冲时,由于Si片表面的化学状态将Si片粘合起来,称为“使用中粘合”。解决粘合的最好办法是：在MEMS微结构的表面涂以抗粘合薄膜,将成品器件在干燥气氛下封装。介绍了抗粘合薄膜的制备工艺和目前存在的问题。相比之下,具有高速运动的MEMS,其摩擦力问题更为复杂。应和抗粘合薄膜,解决了粘合,也降低了摩擦力,但摩擦依然存在。摩擦带来磨损,降低器件可靠性和寿命。寻找既抗粘合、又耐磨的薄膜,是解决高速运动MEMS可靠性和寿命的一个关键。