Friction force microscopy study on photodegradation of organosilane self-assembled monolayers irradiated with a vacuum ultraviolet light at 172 nm
Friction force microscopy study on photodegradation of organosilane self-assembled monolayers irradiated with a vacuum ultraviolet light at 172 nm
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DOI：
10.1116/1.1339023
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发表时间：
2001-07-01
影响因子：
2.9
通讯作者：
Hozumi, A
中科院分区：
文献类型：
--
作者：
Sugimura, H;Hayashi, K;Hozumi, A
利用准分子灯发射的波长为172nm的真空紫外（VUV）光对烷基硅烷自组装单层（SAM）进行了微图像化。采用化学气相沉积法，以十八烷基三甲氧基硅烷为前驱体分子，在覆盖天然氧化物的Si衬底上制备了SAM。基于一种简单的光掩模接触方法，证明了SAM的微图像化。由于uv辐照区和未辐照区之间的摩擦系数存在明显差异，因此在摩擦力显微镜下可以清晰地成像光印图案。紫外辐照区比未辐照区表现出更强的摩擦力。通过摩擦力显微镜、水接触角测量和x射线光电子能谱分析证实，由于VUV照射，SAM被分解和去除。这种光降解机制归因于有机硅烷分子中C-C和C-H键的解离激发，随后与大气氧分子的VUV激发同时产生的原子氧自由基进行氧化。在此基础上可以制备宽度小于1atm的微细线。(C) 2001美国真空学会。
An alkylsilane self-assembled monolayer (SAM) has been micropatterned by the use of vacuum ultraviolet (VUV) light at 172 nm in wavelength radiated from an excimer lamp. By a chemical vapor deposition method, the SAM was prepared on Si substrates covered with native oxide from a precursor molecule of octadecyltrimethoxysilane. Micropatterning of the SAM was demonstrated based on a simple photomask-contacting method. Due to a distinct difference in friction coefficient between the VUV-irradiated and unirradiated regions, the photoprinted pattern was clearly imaged in friction force microscopy. The VUV-irradiated region showed stronger friction force than the unirradiated SAM surface. As confirmed by friction force microscopy, water contact angle measurements, and x-ray photoelectron spectroscopy, the SAM was found to be decomposed and removed due to the VUV irradiation. This photodegradation mechanism is ascribed to dissociative excitation of C-C and C-H bondings in the organosilane molecules and to subsequently proceeded oxidation with atomic oxygen radicals generated simultaneously through VUV excitation of atmospheric oxygen molecules. Microlines whose width was less than I Atm could be fabricated based on this VUV lithography. (C) 2001 American Vacuum Society.