Deposition rate enhancement in HiPIMS without compromising the ionized fraction of the deposition flux
Deposition rate enhancement in HiPIMS without compromising the ionized fraction of the deposition flux
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DOI：
10.1088/0022-3727/46/20/205205
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发表时间：
2013-05-22
影响因子：
3.4
通讯作者：
Martinu, L.
中科院分区：
文献类型：
--
作者：
Capek, J.;Hala, M.;Martinu, L.
我们系统地研究和量化不同的物理现象影响的沉积速率，a（D），高功率脉冲磁控溅射（HiPIMS）制备的Nb涂层，并提出了一个简单的方法，通过控制磁控管的磁场的沉积速率提高。通过在磁控管表面和靶之间施加具有不同厚度的顺磁性间隔物来控制50 mm直径磁控管的靶表面B处的磁场强度。我们发现，当放电在固定的平均脉冲靶功率密度（2.5 kW cm（-2））下操作时，通过应用2.8 mm厚的间隔物实现的降低B导致a（D）增加近似4.5倍（从10.6 nm min（-1）增加到45.2 nm min（-1））。然而，离子化部分的沉积通量到基板上被发现是可比的，尽管在B-依赖的放电特性（磁控管电压和放电电流）的大的差异。我们表明，在HiPIMS中通常观察到的a（D）的降低（与所提出的实验中的直流磁控溅射相比，范围从33%到84%）由不同的物理过程控制，这取决于B的值：对于高B，靶离子朝向靶的反向吸引是主要效应，而对于低B，离子反向吸引，溅射产率对离子能量的次线性依赖性以及材料传输效应的变化都是重要的。最后，我们提供了一个理论背景的观察结果，表明这里提出的结论可能适用于HiPIMS放电使用不同的金属靶和不同的惰性气体。
We systematically investigate and quantify different physical phenomena influencing the deposition rate, a(D), of Nb coatings prepared by high power impulse magnetron sputtering (HiPIMS), and propose a straightforward approach for deposition rate enhancement through the control of the magnetron's magnetic field. The magnetic field strength at the target surface, B, of a 50 mm diameter magnetron was controlled by the application of paramagnetic spacers with different thicknesses in between the magnetron surface and the target. We found that lowering B achieved by the application of a 2.8 mm thick spacer led to an increase in a(D) by a factor of similar to 4.5 (from 10.6 to 45.2 nm min(-1)) when the discharge was operated at a fixed average pulse target power density (2.5 kW cm(-2)). However, the ionized fraction of the deposition flux onto the substrate was found to be comparable, despite a large difference in B-dependent discharge characteristics (magnetron voltage and discharge current). We show that the decrease in a(D) commonly observed in HiPIMS (ranging from 33% to 84% in comparison with dc magnetron sputtering in the presented experiments) is governed by different physical processes, depending on the value of B: for high B, the back-attraction of the target ions towards the target is the dominant effect, while for low B the ion back-attraction, the sub-linear dependence of the sputtering yield on the ion energy, and the variation in material transport effects are all important. Finally, we offer a theoretical background for the observed results, demonstrating that the here-presented conclusions may be applicable to HiPIMS discharges using different metal targets and different inert gases.