High power impulse magnetron sputtering: Current-voltage-time characteristics indicate the onset of sustained self-sputtering
High power impulse magnetron sputtering: Current-voltage-time characteristics indicate the onset of sustained self-sputtering
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DOI：
10.1063/1.2817812
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发表时间：
2007-12-01
影响因子：
3.2
通讯作者：
Ehiasarian, Arutiun
中科院分区：
文献类型：
--
作者：
Anders, Andre;Andersson, Joakim;Ehiasarian, Arutiun
常用的电流-电压特性不足以描述高功率脉冲磁控溅射 (HIPIMS) 放电的脉冲性质；相反，描述需要扩展到每个初始气压的电流-电压-时间特性。使用不同的靶材料（铜、钛、铌、碳、钨、铝和铬）和脉冲恒压电源，结果表明，HIPIMS 放电通常表现出初始压力相关的电流峰值，随后是功率和材料相关的第二阶段。这表明 HIPIMS 放电脉冲的初始阶段主要由气体离子主导，而后期阶段则主要来自自溅射。对于某些材料，放电会切换为持续自溅射模式。材料之间巨大的差异不能归因于不同的溅射产率，但它们表明二次电子的产生和捕获对电流-电压-时间特性起着重要作用。特别是，有人认为，持续的自溅射阶段与多电荷离子的产生有关，因为只有它们才能引起二次电子的潜在发射，而单电荷金属离子引起的产率小得可以忽略不计。 (C) 2007 年美国物理研究所。
The commonly used current-voltage characteristics are found inadequate for describing the pulsed nature of the high power impulse magnetron sputtering (HIPIMS) discharge; rather, the description needs to be expanded to current-voltage-time characteristics for each initial gas pressure. Using different target materials (Cu, Ti, Nb, C, W, Al, and Cr) and a pulsed constant-voltage supply, it is shown that the HIPIMS discharges typically exhibit an initial pressure dependent current peak followed by a second phase that is power and material dependent. This suggests that the initial phase of a HIPIMS discharge pulse is dominated by gas ions, whereas the later phase has a strong contribution from self-sputtering. For some materials, the discharge switches into a mode of sustained self-sputtering. The very large differences between materials cannot be ascribed to the different sputter yields but they indicate that generation and trapping of secondary electrons play a major role for current-voltage-time characteristics. In particular, it is argued that the sustained self-sputtering phase is associated with the generation of multiply charged ions because only they can cause potential emission of secondary electrons, whereas the yield caused by singly charged metal ions is negligibly small. (C) 2007 American Institute of Physics.