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

我们设计并开发了可配置多个尖端和储层的大电流液态金属离子源。为避免由于尖顶和蓄热器的增大而使加热电流严重增大，可将尖顶和蓄热器串联起来。我们还检查了热引入电极的材料和配置，以及功率输入的时间。因此，离子源可以用两个或四个尖端和电极加热到1200ºC。在现有的源条件下，4个尖端和贮槽的铟离子电流最大可达9 mA；我们几乎达到了初始目标的离子电流（10毫安）。9毫安的电流受到离子提取电源的电流容量的限制。使用更大的电源将获得更大的电流。此外，我们还研究了离子源的感应加热，以实现更大的离子源的稳定运行。对提取的离子束的轮廓进行了测量，得到了离子束的详细特征。我们指出了当有多个发射点操作时，光束轮廓的各向异性。光束沿平行于发射点阵列方向收敛。这种各向异性可归因于相邻顶点的存在。这一事实表明，光束可以沿外电场难以收敛的方向自动收敛。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层的排列方式。还研究了具有相当大质量的带电粒子液滴的发射，以获得其直径和特殊分布等细节。液滴喷射均匀。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.