Controlled Fluxes of Silicon Nanoparticles to a Substrate in Pulsed Radio-Frequency Argon–Silane Plasmas

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• 作者：Carlos Larriba-Andaluz ; Steven L. Girshick
• 关键词：Dusty plasmas ; Silicon nanoparticles ; Pulsed RF plasmas
• 刊名：Plasma Chemistry and Plasma Processing
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：37
• 期：1
• 页码：43-58
• 全文大小：
• 刊物类别：Physics and Astronomy
• 刊物主题：Inorganic Chemistry; Classical Mechanics; Characterization and Evaluation of Materials; Mechanical Engineering;
• 出版者：Springer US
• ISSN：1572-8986
• 卷排序：37

文摘

It has been hypothesized that high-energy impact of very small silicon nanoparticles on a substrate may lead to epitaxial growth of silicon films at low substrate temperature. A possible means for producing such energetic nanoparticle fluxes involves pulsing an RF silane-containing plasma, and applying a positive DC bias to the substrate during the afterglow phase of each pulse so as to collect the negatively charged particles generated during the RF power on phase. We here report numerical modeling to provide a preliminary assessment of the feasibility of this scheme. The system modeled is a parallel-plate capacitively-coupled RF argon–silane plasma at pressures around 100 mTorr. Simulation results indicate that it is possible to achieve a periodic steady state in which each pulse delivers a controlled flux of nanoparticles to the biased substrate, that average particle sizes can be kept below 2–3 nm, that impact energies of the negatively-charged nanoparticles that are attracted by the applied bias can be maintained in the ~1 eV/atom range thought to be conducive to epitaxial growth without causing film damage, and that the volume fraction of neutral nanoparticles that deposit by low-velocity diffusion can be kept well below 1 %. The effects of several operating parameters are explored, including RF voltage, pressure, the value of the applied DC bias, and RF power on and off time during each pulse.