单晶硅表面氢钝化时效性及其对摩擦学性能的影响

发布时间：2018-01-19 20:48

本文关键词： 纳米摩擦学单晶硅氢钝化摩擦黏着　出处：《西南交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：单晶硅作为典型的半导体材料,目前已被广泛应用于微机电系统以及微纳加工领域。然而,伴随着器械尺度的不断微型化,由表面力引起的黏着及摩擦问题,不仅成为制约微机电系统可靠服役的关键因素,而且对微纳器件的加工质量产生严重的影响。因此,如何实现单晶硅表面的抗黏减摩设计受到越来越多的关注。表面氢钝化作为单晶硅表面化学改性的一种常见方法,因其操作简单,适应性强,目前己广泛应用于集成电路清洗、硅基太阳能电池制造等领域。然而,由于氧化作用等的影响,单晶硅氢钝化表面的斥水性能会逐渐退化,因此有必要系统研究表面氧化对单晶硅氢钝化时效性的影响机制。据此,本文首先通过研究单晶硅氢钝化表面的水接触角及化学成分随放置时间的变化规律,揭示了不同放置环境对氢钝化表面时效性的影响机制。在此基础上,进一步研究了氢钝化时效性对单晶硅表面黏着及摩擦的影响规律。最后,基于单晶硅表面的自然氧化层,提出了一种单晶硅表面小线宽结构的纳米加工方法。本论文的主要研究结果及创新点如下：1.揭示了放置环境对单晶硅表面氢钝化时效性的影响机制。单晶硅氢钝化表面的水接触角在大气、纯水和酒精环境下随放置时间的增加均逐渐降低,其中水环境下的变化程度尤为剧烈,大气环境次之,酒精溶液中变化最小。表面化学成分检测结果显示,单晶硅表面氧含量随着放置时间的增加而不断升高,其中水环境下氧含量上升最为明显,酒精溶液氧含量变化微弱。因此,酒精溶液能在一定程度上抑制单晶硅表面的氧化反应,从而延长单晶硅氢钝化表面的时效性。2.探明了不同放置环境下氢钝化时效性对单晶硅表面黏着和摩擦的影响规律。随着放置时间的增加,三种环境下氢钝化表面的黏着力和摩擦力均呈现上升趋势。但由于受到表面氧化程度和表面斥水性不同的影响,酒精溶液环境下黏着力和摩擦力随放置时间的增加变化较小；大气和水环境下变化较为剧烈,且相比之下水环境下对黏着和摩擦的影响更为显著。因此,单晶硅存放在酒精溶液中有利于降低其表面的黏着和摩擦。3.提出一种单晶硅表面小线宽纳米结构的加工方法。基于小曲率半径氮化硅探针对单晶硅表面(含自然氧化层)的刻划结合后续选择性刻蚀,可以实现单晶硅表面的小线宽纳米结构加工。研究表明,摩擦化学作用下氮化硅探针刻划导致表面氧化层去除后暴露出硅基体,而KOH溶液选择性刻蚀硅基体导致沟槽深度进一步加深。因此,前期的探针刻划载荷和循环刻划次数以及刻蚀时间均会对纳米沟槽的线宽及深度产生一定的影响。为了保证单晶硅表面的加工质量,最佳刻蚀时间大约为7 min。
[Abstract]:Monocrystalline silicon, as a typical semiconductor material, has been widely used in the field of MEMS and micro-nano machining. However, with the continuous miniaturization of the device scale, the adhesion and friction caused by surface force is a problem. It is not only a key factor that restricts the reliable service of MEMS, but also has a serious impact on the machining quality of micro / nano devices. More and more attention has been paid to the design of anti-viscosity and anti-friction of monocrystalline silicon surface. As a common method of chemical modification of monocrystalline silicon surface hydrogen passivation is a common method because of its simple operation and strong adaptability. At present, it has been widely used in the fields of integrated circuit cleaning, silicon based solar cell manufacturing and so on. However, due to the effect of oxidation, the water repellent performance of single crystal silicon hydrogen passivation surface will be degraded gradually. Therefore, it is necessary to systematically study the mechanism of surface oxidation on the aging of single crystal hydrogen passivation. Firstly, the water contact angle and chemical composition of single crystal hydrogen passivated surface with storage time are studied in this paper. On the basis of this, the influence of hydrogen passivation time effect on the adhesion and friction of monocrystalline silicon surface is further studied. Finally, the influence of hydrogen passivation time on the surface adhesion and friction of monocrystalline silicon is studied. Natural oxide layer based on monocrystalline silicon surface. A method of nanocrystalline fabrication with small linewidth structure on the surface of monocrystalline silicon is proposed. The main results and innovations of this thesis are as follows:. 1. The mechanism of the influence of placing environment on the hydrogen passivation time of monocrystalline silicon surface is revealed. The water contact angle of the single crystal silicon hydrogen passivated surface is in the atmosphere. In pure water and alcohol environment, with the increase of storage time, the degree of change is especially sharp, the atmospheric environment is the second, and the change in alcohol solution is the least. The results of surface chemical composition detection show that. The surface oxygen content of monocrystalline silicon increases with the increase of storage time. The oxygen content in water environment is the most obvious, and the oxygen content in alcohol solution is weak. Alcohol solution can inhibit the oxidation of monocrystalline silicon to some extent. The effect of hydrogen passivation time on the adhesion and friction of monocrystalline silicon surface was investigated under different conditions. With the increase of placing time, the effect of hydrogen passivation time on the surface adhesion and friction of monocrystalline silicon was investigated. The adhesion and friction of hydrogen passivated surface increased in three environments, but were influenced by the degree of surface oxidation and the surface water repellency. The viscosity and friction of alcohol solution changed little with the increase of storage time. The changes in the atmosphere and water environment are more severe, and the effects on adhesion and friction are more significant in the water environment than in the water environment. The storage of monocrystalline silicon in alcohol solution can reduce the adhesion and friction on the surface of monocrystalline silicon. A fabrication method of small linewidth nanostructure on the surface of monocrystalline silicon is proposed. Based on the small radius of curvature silicon nitride probe on the surface of monocrystalline silicon (. Characterization and subsequent selective etching. The study shows that the silicon nitride probe scratching results in the removal of the oxide layer on the surface and exposes the silicon substrate under the tribological chemical action of the small linewidth nanocrystalline structure of the monocrystalline silicon surface. The selective etching of silicon substrate by KOH solution leads to deeper groove depth. In order to ensure the machining quality of monocrystalline silicon surface, the probe scratching load, the number of cycles and the etching time will have a certain effect on the linewidth and depth of the nanocrystalline grooves. The optimum etching time is about 7 mins.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN304.12

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