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921.
Reactions of both SF5 and SF2 with O(3
P) and molecular oxygen have been studied at 295 K in a gas flow reactor sampled by a mass spectrometer. For reactions with O(3
P), rate coefficients of (2.0±0.5)×10–11 cm3 s–1 and (10.8±2.0)×10–11 cm3 s–1 were obtained for SF5 and SF2 respectively. The rate coefficients for reactions with O2 are orders of magnitude lower, with an estimated upper limit of 5×10–16 cm3 s–1 for both SF5 and SF2. Reaction of SF2 with O(3
P) leads to the production of SOF which then reacts with O(3
P) with a rate coefficient of (7.9±2.0)×10–11 cm3 s–1. Both SO and SO2 are products in the reaction sequence initiated by reaction between SF2 and O(3
P). Although considerable uncertainty exists for the heat of formation of SOF, it appears that SO arises only from reaction between SOF and O atoms which is also the source of SO2. These results are discussed in terms of a reaction scheme proposed earlier to explain processes occurring during the plasma etching of Si in SF6/O2 plasmas. A comparison between the results obtained here and those reported earlier for reactions of both CF3 and CF2 with O and O2 shows that there is a marked similarity in the free radical chemistry which occurs in SF6/O2 and CF4/O2 plasmas. 相似文献
922.
K. Bourenane A. Keffous G. Nezzal A. Boukezzata S. Naama 《Surface and interface analysis : SIA》2007,39(5):392-396
In this work, an experimental study on the etching of p‐type hot‐pressed silicon carbide (SiC) was carried out in HF/K2S2O8 solutions. The SiC wafers used in this work were p‐type polycrystalline materials, supplied by Goodfellow, with an acceptor concentration of 2.31 × 1012 cm?3. The SiC substrate was a hot‐pressed material, the latter realized from a mixture of 1 part of SiO2 with 3 parts of C (carbon) ‘1SiO2 + 3C’ heated in an oven at 2500 °C. In order to facilitate the chemical etching of the SiC substrate, a thin aluminium film was deposited on the SiC substrate. The morphology of the etched surface was examined with varying K2S2O8 concentration. The surfaces of the etched samples were analysed using secondary ions mass spectrometry (SIMS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR) and photoluminescence (PL). The surface morphology of the samples etched in HF/K2S2O8 is shown to depend on the solution composition. The investigation of the effect of the HF/K2S2O8 solution on SiC samples shows that as K2S2O8 concentration increases, the chemical etching reveals defects with random geometry. Finally, chemical etching of p‐type SiC induces a decrease in the PL intensity, which indicates clearly the defects on the polycrystalline SiC surface. In addition, the result is very interesting, as to date no chemical etching solution at low temperature (<100 °C) has been developed for SiC. Finally, we have proposed a dissolution mechanism of SiC in 2HF/1K2S2O8 solutions. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
923.
Ping Jiang Demetre J. Economou Chee Burm Shin 《Plasma Chemistry and Plasma Processing》1995,15(3):383-396
The effect of power modulation oil radical concentration and uniformity in a single-wafer plasma reactor was investigated with a radical transport and reaction model. Plasma etching of silicon using tetrafluoromethane under relatively high pressure (l torr) high frequency (13.56 MHz) conditions was taken as an example system. Gas velocity, temperature, and radical concentration profiles were obtained numerically by a finite element method. When compared to a contin uous wave plasma, power modulation can alter the relative concentration of radicals and in turn the each rate and uniformity as well as selectivity and anisotropy Uniformity is improved by power modulation except at high flow rates which, however, result in poor utilization of the feedstock gas. 相似文献
924.
同步辐射激发直接光化学刻蚀是近年来发展的一项新技术 ,它不需要常规光刻中的光刻胶工艺 ,用表面光化学反应直接将图形写到半导体材料的表面上。由于所用的同步辐射在真空紫外 (VUV)波段 ,理论上的分辨率可以达到电子学的量子极限 ,且没有常规工艺中的表面损伤和化学污染 ,是一种非常具有应用潜力的技术。本文的最后部份重点讨论了与上述技术密切相关的VUV和软X射线激发的表面光化学反应机理。 相似文献
925.
采用不同的方法裁剪高定向热解石墨(HOPG),制备纳米尺寸的石墨条.首先,发现用聚焦离子束(镓离子)刻蚀高定向热解石墨,可以得到边缘整齐程度在几十纳米的石墨条,另外,用 电子束曝光和反应离子刻蚀的工艺,可以得到最小尺寸为50 nm的纳米石墨图型 (nano-size d graphite pattern,纳米尺寸的多层石墨结构).采用了三种不同的方案制备反应等离子刻 蚀过程中需要的掩膜,分别是PECVD生长的SiO2掩膜,磁控溅射的方法生长的Si O2掩膜和PMMA光刻胶掩膜,并将三种方案的刻蚀结果做了对比.
关键词:
高定向热解石墨
聚焦离子束刻蚀
电子束曝光
反应离子刻蚀 相似文献
926.
J. Skvar 《Radiation measurements》1999,31(1-6):217-222
927.
N. Gomathi 《Applied Surface Science》2009,255(17):7590-7600
Low pressure plasma treatment using radiofrequency (rf) discharge of argon gas was employed to improve the hydrophilicity of polypropylene. The effects of argon plasma on the wettability, surface chemistry and surface morphology of polypropylene were studied using static contact angle measurements, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Increase in surface energy of polypropylene was observed as a result of argon plasma treatment. SEM and AFM images revealed the increased surface roughness. A set of identified process variables (rf power, pressure, argon flow rate and time) were used in this study and were optimized using central composite design (CCD) of response surface methodology (RSM). A statistical model was developed to represent the surface energy in terms of the process variables mentioned above. Accuracy of the model was verified and found to be high. 相似文献
928.
基于液压传递原理,设计出一种用动态化学腐蚀法制备大锥角近场光纤探针的装置.实验结果表明,在传统的化学腐蚀法制备光纤探针的过程中,通过控制腐蚀液液面的上升速度,可以有效地控制探针针尖的形状以及锥角的大小.在此基础上,还论述了分步控制光纤与腐蚀液液面的相对位移的方法在大锥角光纤探针的制备中所具有的独特优越性.利用所制备的大锥角近场光纤探针在扫描近场光学显微镜上对直径为200nm的小球进行探测,其力学像证实该探针具有较高的形貌分辨率(约为50nm).
关键词:
动态化学腐蚀法
大锥角
近场光纤探针 相似文献
929.
930.
Sihai Chen Xinjian Yi Yi Li Miao He Lingbin Kong Hong Ma 《International Journal of Infrared and Millimeter Waves》2001,22(3):393-398
A special method, named step simulation method, is proposed for fabricating Si microlens array to improve the performance of infrared focal plane array (IR FPA). The focus length of rectangle-based multistep microlens array with element dimension of 40 µm×30 µm is 885.4 µm by the method, which is much longer than the focus length of microlens array fabricated by conventional Fresnel binary optics technique., The large-scale 256×256 element microlens array is hybridintegrated with the PtSi Schottky-barrier IR FPA by optical adhesive. The test results show that diffractive spot size of the microlens is 17 µm×15 µm and the average optical response of the IR FPA is increased by a factor of 2.4. 相似文献