MEMS器件内部真空维持技术的研究

论文总字数：24043字

摘 要

MEMS真空维持技术是推动微机电芯片行业发展的重要技术之一，而进一步提高器件内部真空度是MEMS真空维持的核心关键。微型溅射离子泵具有功耗低、器件体积小、结构简单、成本低等优点，能够吸收吸气剂难以处理的惰性气体。作为阴极发射源的碳纳米管电子源也具有发射电流大，热稳定性好的特点。因此，微型溅射离子泵在MEMS真空维持技术中有巨大的应用潜力和价值。本课题对碳纳米管作为发射源的微型溅射离子泵的发射电流、离子流及抽气性能进行了研究，具体工作内容和主要成果如下：
（1）实验中主要通过传统的丝网印刷法制备碳纳米管电子源。在3.84E-4Pa的真空环境下对碳纳米管的发射性能进行了测试：在阴阳极间距为0.7mm的情况下，阳极电压达到1000V时，碳纳米管发射电流为22uA，且随着电压的增大逐渐增大。

1. 在对发射电流进行测试的实验条件下，以1000V阳极电压所对应的22uA的发射电流为例，在栅极处施加电压后，离子流呈先上升后下降的趋势，其峰值为1.46uA。之后，通过调节阴阳极间距，对离子流与发射电流的最大比值进行了测定。最终在0.74mm的阴阳极间距下得到了3%的最大电流比。

（3）本课题中主要研究微泵在由吸气剂维持的真空下对真空室内压强的影响。微型溅射离子泵是基于场发射的三极结构，并对其抽气性能进行了测试。实验表明，该微泵结构对真空管道有一定的抽气效果，并且对于镀膜栅极而言，其抽气性能比未镀膜前有所改善。

关键词：碳纳米管，发射特性，吸气剂，微泵，抽气性能

Abstract

MEMS Vacuum maintenance technology is one of the most important technologies to promote the development of microelectromechanical chip industry, and further improving the internal vacuum of devices is the key to vacuum maintenance of MEMS devices. The micro sputtering ion pump has the advantages of low power consumption, small device volume, simple structure and low cost. It can absorb inert gas which is difficult to deal with by getter. CNTs as cathode emission source also have the characteristics of high emission current and good thermal stability. Therefore, the micro sputtering ion pump has great potential and value in the vacuum maintenance technology of MEMS. In this paper, the emission current, ion current and pumping performance of micro-sputtered ions using carbon nanotubes as emitters are studied. The specific work and main results are as follows:

1. CNTs electronic source was prepared by traditional screen printing method in the experiment. Emission performance of carbon nanotubes was tested in 3.84E-4Pa vacuum environment. When the distance between cathode and anode is 0.7mm, the anode voltage reached 1000V and the emission current of carbon nanotubes reached 22uA, and increased with the increase of voltage.

(2) Under the experimental condition of testing the emission current, taking the 22uA emission current corresponding to 1000V anode voltage as an example, the ion current increases first and then decreases after applying voltage at the gate, and its peak value is 1.46uA. After that, the maximum ratio of ion current to emission current was measured by adjusting the distance between anode and cathode. Finally, the maximum current ratio of 3% is obtained at 0.75 mm between cathode and anode.

(3) In this paper, we mainly study the effect of micropump on the pressure of vacuum chamber under vacuum maintained by getter. The pumping performance of the micro sputtering ion pump based on the triode structure was tested. Experiments show that the structure of the micropump has a certain pumping capacity for the vacuum pipeline, and for the coated grid, its pumping performance is better than that before coating.

Keywords: carbon nanotubes, emission characteristics, getter, micropump, pumping performance

目 录

摘要 ……………………………………………………………………………………………....Ⅰ

Abstract ……………………………………………………………………………………........Ⅱ

第一章 绪论 …………………….…………………………………………………...1

1.1 研究背景 …………………………………………………………..…….1

1.2碳纳米管电子源介绍 …………………....……………………................3

1.2.1 场致发射原理 …………………….....……………………..........3

1.2.2 碳纳米管 ………………………………….......................………4

1.2.3 碳纳米管电子源制备 ........................…………………….............5

1.3 实验条件的准备 …………………….....………............…………….....5

1.4 本课题意义和主要研究内容 ………………………………………….............6

第二章 微泵结构设计及实验方案 ……………………………………….…………7

2.1 微型真空泵结构设计 …………………………………….......................7

2.1.1 微型溅射离子泵结构选择 …………………...............................7

2.1.2 微型溅射离子泵制备 ………………….......................................8

2.2 实验方案设计 .............………………………………………………………...10

第三章 实验结果及分析 …………………….....…………………….....................14

3.1 外加电压对电流强度的影响 ………………….....……………………14

3.1.1 发射电流与阳极电压间的关系 ……………………..................14

3.1.2 离子流与栅极电压间关系 ……………………..........................14

3.2 阴阳极间距对电离效率的影响 …………………….............................15

3.3 微泵抽气性能测试实验 …………………….....……………………....17

3.4 镀膜栅极微泵抽气性能测试 …………………….....………………....19

第四章 总结与展望 …………………………………………………………....…..21

致谢 …………………………………………………………………………………23

参考文献（References） ……………………………………………………………24

第一章 绪论

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