Szafarska Maik, Olszok Vinzent, Holländer Ulrich, Gustus René, Weber Alfred P, Maus-Friedrichs Wolfgang
Clausthal Centre of Materials Technology, Clausthal University of Technology, Leibnizstrasse 9, 38678 Clausthal-Zellerfeld, Germany.
Institute of Particle Technology, Clausthal University of Technology, Leibnizstrasse 19, 38678 Clausthal-Zellerfeld, Germany.
ACS Omega. 2023 Feb 24;8(9):8388-8396. doi: 10.1021/acsomega.2c07209. eCollection 2023 Mar 7.
The interaction of silane and water is discussed controversially in literature: some authors suggest monosilane and water react kinetically and sufficiently fast enough to remove water, while others state the reaction occurs only at elevated temperatures. This question is of technological interest for the removal of unavoidable water residues in Ar gases. Thermodynamic calculations show that virtually complete removal of water is expected with superstoichiometric silane addition. However, mass spectrometric and infrared spectroscopic experiments give evidence that the addition of monosilane to such an Ar gas at room temperature is unable to remove residual water, which disagrees with some current hypotheses in the literature. This holds even for very high SiH concentrations up to 2 vol.-%. Silane reacts with water above temperatures of 555 °C, initiated by the thermal decomposition of silane. A cold dielectric barrier discharge-plasma used for silane and water dissociation enhances reactivity similar to elevated temperatures. Fourier-transformed infrared spectroscopy points toward silanol generation at temperatures between 400 and 550 °C, while quadrupole mass spectrometry indicates the creation of SiOH, SiHOH, SiHOH, and SiHOH. Cold plasmas generate smaller amounts of SiOH, SiHOH, and SiHOH compared to elevated temperatures. Reaction products are hydrogen and nanoscaled particles of non-stoichiometric silicon oxides. The silicon-oxide particles produced differ in elemental composition and shape depending on the prevailing water content during decomposition: SiO generated with residual water appears with relatively smooth surfaces, while the addition of water supports the formation of significantly rougher particle surfaces. Higher initial water contents correlate with higher oxygen contents of the particles.
一些作者认为甲硅烷与水发生动力学反应，且反应速度足够快以去除水分，而另一些人则指出该反应仅在高温下发生。对于去除氩气中不可避免的水分残留，这个问题具有技术上的重要性。热力学计算表明，超化学计量添加硅烷有望几乎完全去除水分。然而，质谱和红外光谱实验表明，在室温下向这种氩气中添加甲硅烷无法去除残留水分，这与文献中一些当前的假设不一致。即使对于高达2体积%的非常高的硅烷浓度也是如此。硅烷在555℃以上与水反应，由硅烷的热分解引发。用于硅烷和水离解的冷介质阻挡放电等离子体增强了类似于高温的反应活性。傅里叶变换红外光谱表明在400至550℃之间的温度下会生成硅醇，而四极质谱表明会生成SiOH、SiHOH、SiHOH和SiHOH。与高温相比，冷等离子体产生的SiOH、SiHOH和SiHOH的量较少。反应产物是氢气和非化学计量的氧化硅纳米颗粒。根据分解过程中存在的水分含量，生成的氧化硅颗粒在元素组成和形状上有所不同：有残留水时生成的SiO表面相对光滑，而添加水则有助于形成明显更粗糙的颗粒表面。初始水分含量越高，颗粒的氧含量越高。
