Tribology of Si/SiO2 in Humid Air: Transition from Severe Chemical Wear to Wearless Behavior at Nanoscale
Tribology of Si/SiO2 in Humid Air: Transition from Severe Chemical Wear to Wearless Behavior at Nanoscale
复制标题
Si/SiO2 在潮湿空气中的摩擦学：从严重化学磨损到纳米级无磨损行为的转变
DOI：
10.1021/la504333j
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发表时间：
2015-01-13
期刊：
影响因子：
3.9
通讯作者：
Qian, Linmao
中科院分区：
文献类型：
--
作者：
Chen, Lei;He, Hongtu;Qian, Linmao
硅滑动界面的磨损是微电动机电系统（MEMS）应用中纳米制造和装置故障的材料损失的主要原因。但是，仍然缺乏对环境条件下硅纳米级磨损机制的全面了解。在这里，我们报告了单晶硅（一种用于微/纳米级设备的材料）的化学磨损，在潮湿的空气中，在接触压力下低于材料硬度。对磨损轨道的透射电子显微镜（TEM）分析证实，在潮湿条件下硅的磨损源自表面反应，而没有明显的地下损害，例如塑性变形或断裂。当用SIO2球擦拭时，单晶硅表面从中间湿度的严重磨损到两个相反的极端情况下表现出几乎无磨损状态的过渡：（a）低湿度和高滑动速度条件，以及（b）高湿度和低速条件。这些过渡表明，在SI/SIO2的滑动界面上，至少两个不同的介绍反应起着重要作用。一个是在两个滑动界面的羟基之间形成强氢键桥，另一个是从SIO2表面去除羟基。实验数据表明，每个反应的优势随环境湿度和滑动速度而变化。
Wear at sliding interfaces of silicon is a main cause for material loss in nanomanufacturing and device failure in microelectromechanical system (MEMS) applications. However, a comprehensive understanding of the nanoscale wear mechanisms of silicon in ambient conditions is still lacking. Here, we report the chemical wear of single crystalline silicon, a material used for micro/nanoscale devices, in humid air under the contact pressure lower than the material hardness. A transmission electron microscopy (TEM) analysis of the wear track confirmed that the wear of silicon in humid conditions originates from surface reactions without significant subsurface damages such as plastic deformation or fracture. When rubbed with a SiO2 ball, the single crystalline silicon surface exhibited transitions from severe wear in intermediate humidity to nearly wearless states at two opposite extremes: (a) low humidity and high sliding speed conditions and (b) high humidity and low speed conditions. These transitions suggested that at the sliding interfaces of Si/SiO2 at least two different tribochemical reactions play important roles. One would be the formation of a strong hydrogen bonding bridge between hydroxyl groups of two sliding interfaces and the other the removal of hydroxyl groups from the SiO2 surface. The experimental data indicated that the dominance of each reaction varies with the ambient humidity and sliding speed.