Preparation of Insulating Aluminum Nitride Film by Enhanced Shielded Vacuum

为了制备出具有高绝缘性和高导热性的AlN薄膜，并使其适用于电力器件，开发了一种新型的反应真空电弧沉积系统。在屏蔽法（S-CAD：屏蔽阴极电弧沉积）中，我们发现通过使用不同的衬底偏压可以制备出具有不同晶向的透明AlN薄膜。S-CAD还可用于制备其它氮化物和氧化物（AlO_2、TiN、TiO_2、CrN、ZnO等）的无液滴薄膜。然而，S-CAD具有沉积速率降低1/3至1/5的问题。然后，为了提高沉积速率，设计了增强屏蔽方法（ES-CAD），其中屏蔽后的离子通过外部磁场被引导并聚焦到衬底上，并制造了系统装置。通过优化磁场结构和磁场强度，使ES-CAD的沉积速率提高到S-CAD的5倍以上，甚至比无屏蔽的常规方法更快，并建立了引入超导屏蔽的改进型ES-CAD（ES-CAD），以获得更快的沉积速率。由于超导体的迈斯纳效应，从阴极发射的离子被迂回磁场有效地传输到衬底。ES-CAD具有比ES-CAD更高的沉积速率。此外，开发了具有液滴过滤管道的线性和环形磁过滤电弧沉积（FAD）系统。结果发现，尽管环形FAD能够充分地过滤液滴，但是线性FAD不能过滤液滴。

In order to fabricate the AlN film, which exhibits high electrical insulation property with high thermal conduction and is available for of electric power device, which is available for electric power devices, new reactive vacuum arc deposition system was developed. In the shielded method (S-CAD: shielded cathodic arc deposition), we found that the transparent AlN films with different crystalline orientations could be prepared by using different substrate bias. The S-CAD was further available to prepare various droplet-free films of other nitride and oxides (AlO_2, TiN, TiO_2, CrN, ZnO, etc.). However, the S-CAD has a problem that the deposition rate decreases by 1/3 to 1/5. Then, in order to increase the deposition rate, the enhanced shielded method (ES-CAD) in which the ions behind the shield were conducted and focused to the substrate by external magnetic field, was designed and the system apparatus was fabricated. After optimizing the magnetic filed configuration and magnetic flux density, the deposition rate in ES-CAD was more than 5 times as high as that in S-CAD, and was even faster than that in the non-shielded conventional method.The improved ES-CAD (ES-CAD) in which the superconductor shield employed was then build, in order to obtain much faster deposition rate. The ions emitted from the cathode were effectively transported to the substrate by the detoured magnetic filed due to meissner effect of the superconductor. ES-CAD had higher deposition rate than ES-CAD. Furthermore, linear and torus type magnetically filtered arc deposition (FAD) systems having droplet filtering duct, were developed. As a result, it was found that the liner-FAD was not able to filter the droplets, although the torus-FAD was able to filter the droplets sufficiently.