Development of high current liquid metal ion source for large area, high speed surface treatment

我们设计并研制了一种可配备多个尖端和贮液池的强流液态金属离子源。为了避免加热电流随着尖端和储液器的增加而严重增加，尖端和储液器可以串联。我们还检查了热引入电极的材料和配置，以及功率输入的定时。结果表明，采用两个或四个尖端和电极的离子源可以加热到1200 ℃，采用四个尖端和贮液器的离子源可以获得最大9mA的铟离子流，基本达到了最初的离子流目标（10mA）。9毫安的电流受到离子提取电源电流容量的限制。此外，我们还研究了离子源的感应加热，以实现更大离子源的稳定工作。测量了引出束的轮廓，以获得离子束特性的细节。我们指出了在多个发射点操作时束流剖面的各向异性。沿着平行于发射点阵列的方向，子光束被会聚。这种各向异性可归因于相邻尖点的存在。这一事实意味着，电子束可以自动地沿沿着我们很难会聚的方向会聚。根据实验结果，我们研究了适合于表面改性装置的尖端和储液器的布置。还研究了液滴（质量较大的带电粒子）的发射，以获得它们的直径和特殊分布等细节。液滴排放均匀发生。这些液滴的有效利用将有利于高速沉积和表面改性。

We have designed and developed the high current liquid metal ion source in which multiple tip-and-reservoirs can be equipped. In order to avoid the serious increase of the heating current as the increase of the tip-and-reservoirs, the tip-and-reservoirs could be connected electrically in series. We examined also the material of and the configuration of the heat introducing electrode, and the timing of the power input. As a result, the ion source could be heated up to 1200ﾟC with two or four-tip-and-electrodes.With the present source, maximum indium ion current of 9 mA was obtained with four tip-and-reservoirs ; we almost achieved the ion current of the initial objective (10 mA). The current of 9 ma is limited by the current capacity of the ion-extraction power supply. Larger current will be obtained by using the larger power supply.Furthermore, we examined the inductive heating of the ion source to achieve stable operation of much larger source.The profiles of the extracted beams were measured to obtain the details of the ion beam characteristics. We indicated the anisotropy of the beam profils when operated with multiple emission points. Along the direction parallel to the emission points array, the beamlets were converged. This anisotropy would be attributed to the presence of the neighboring cusps. The fact implies that the beam could be automatically converged along the direction which we have much difficulty to converge by the external electric field. From the results, we examined the arrangement of the tip-and-reservoirs suitable to the surface modification apparatus.Emission of droplets, charged particles with fairly large mass, were also investigated to obtain details of them on the matter such as diameter and special distribution. Droplet emission occurred uniformly. The effective use of these droplets will be beneficial for the high speed deposition and surface modification.