An investigation into which factors control the nanotribological behaviour of thin sputtered carbon films
An investigation into which factors control the nanotribological behaviour of thin sputtered carbon films
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哪些因素控制溅射碳薄膜的纳米摩擦学行为的研究
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
B. Beake
中科院分区：
文献类型：
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作者：
B. Shi;J. Sullivan;B. Beake
在硅表面沉积超薄（20-100纳米）薄膜可以改善其机械和摩擦学性能。作为优化此类超薄膜的垫脚石，本文报告了硅上厚度范围为 200–1000nm 的 a-C 薄膜的实验纳米划痕和纳米磨损数据，旨在 (1) 了解薄膜厚度对纳米划痕行为的作用，(2) 确定厚膜与薄膜是否有相同的因素（基材偏差、H/E 比等），(3) 确定较薄薄膜的可能设计规则，以实现其优化用于 MEMS 应用；(4) 评估多遍（3 次扫描）程序的使用，以明确故障位置。对于第一个近似，纳米划痕测试中整个薄膜失效的临界载荷与厚度成正比，前提是薄膜没有太大的应力。 1μm 的 a-C 薄膜具有非常高的 H/E，在高基底偏压下沉积，在低负载下表现良好，但在更高负载的情况下表现很差。它们不仅表现出低临界负载，而且故障还涉及划痕轨道外的广泛分层。在更薄的薄膜上没有观察到这一点。优化 MEMS 应用薄膜耐磨性的一个合适策略是最大化 H/E。对于此处研究的 200 nm 薄膜，具有最高 H/E 的薄膜表现出略微改善的耐刮擦性。
Ultra-thin (20–100 nm) films deposited on Si surfaces can improve their mechanical and tribological properties. As a stepping stone towards the optimization of such ultra-thin films, herein we report experimental nanoscratch and nanowear data on a-C films of thickness in the range 200–1000 nm on Si aiming to (1) understand the role of film thickness on the nanoscratch behaviour, (2) determine whether the same factors (substrate bias, H/E ratio, etc) are at play for thick films as for the thin films, (3) determine possible design rules for thinner films enabling their optimization for MEMS applications and (4) evaluate the use of the multi-pass (3-scan) procedure for clarifying the locus of failure. To a first approximation, the critical load for total film failure in the nanoscratch test is proportional to thickness provided the films are not too stressed. a-C films of 1 µm with very high H/E, deposited under high substrate bias, perform well at low load but very poorly in more highly loaded situations. Not only do they exhibit low critical loads but also failure involves extensive delamination outside of the scratch track. This is not observed on thinner films. A suitable strategy for optimizing wear resistance for thin films for MEMS applications is to aim to maximize H/E. For the 200 nm films studied here, the films with the highest H/E showed slightly improved scratch resistance.