Microwave (MW) plasma in silane-hydrogen and silane-hydrogen-methane mixtures is used effectively for chemical vapor deposition of Si, SiC, diamond, and SiC-diamond composite films; however, the properties of such plasma at pressures of the order of 100 Torr remain largely unexplored. Here we characterize the MW plasma (2.45 GHz) in SiH₄ + H₂ and SiH₄ + СH₄+ H₂ mixtures (72 Torr) with silane content ranging from 0% to 5% in the process gas using high-resolution optical emission (OE) spectroscopy. Besides the OE lines of C₂ dimer, Balmer series of excited atomic hydrogen (H_α, H_β, H_γ, H_δ, and H_ε), and CH radical, we observed atomic Si lines at 263, 288, and 391 nm and a relatively weak SiH emission. Gas temperature T_g of ≈3160 K is assessed from the rotational structure of the C₂ dimer (Δν = 0, λ = 516.5 nm) emission band, and the absorbed microwave power density (MWPD) in the plasma fluctuates in the narrow range between 36 and 43 W/cm³ with a slight tendency to decrease with silane addition. The MWPD, intensity ratio H_α/H_β of hydrogen Balmer series lines (related to excitation temperature T_exc), and Si lines’ intensities in OE spectra as functions of SiH₄ concentration in H₂ and H₂+ CH₄ mixtures all show an extremum or a kink in slope near a special point at ≈0.5% SiH₄. Finally, we produced a silicon carbide film of cubic polytype 3C-SiC on a (111) oriented Si substrate, which was characterized with Raman spectroscopy and x-ray diffraction, and its monocrystalline structure was confirmed.

中文翻译：

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在H2-CH4-SiH4混合物中通过微波等离子体化学气相沉积外延生长3C-SiC膜：发射光谱研究

硅烷-氢和硅烷-氢-甲烷混合物中的微波（MW）等离子可有效地用于化学气相沉积Si，SiC，金刚石和SiC-金刚石复合膜。然而，这种等离子体在100Torr量级的压力下的性质仍未得到充分探索。在这里，我们在的SiH表征MW等离子体（2.45千兆赫）₄  + H ₂和SiH ₄  +СH ₄ + H _2分的混合物（72托）与硅烷含量使用高分辨率光学发射范围从0％到工艺气体中的5％ （OE）光谱学。除了C的OE线₂二聚体，巴尔末串激原子氢（H _α，H _β，H _γ，H _δ，_Hε）和CH自由基，我们观察到263、288和391 nm处的原子Si线以及相对较弱的SiH发射。根据C ₂二聚体（Δν= 0，λ= 516.5 nm）发射带的旋转结构估算出大约3160 K的气体温度T _g，等离子中吸收的微波功率密度（MWPD）在以下范围之间的狭窄范围内波动： 36 W / cm ³和43 W / cm ³，随硅烷的添加略有降低的趋势。的MWPD，强度比ħ _α / H _β的氢巴尔末一系列的线（与激励温度Ť _EXC），和Si线在OE光谱强度作为SiH与功能₄在H +浓度₂和H ₂ + CH _4的混合物均在≈0.5％SiH ₄处的特殊点附近出现极值或扭结。最后，我们在（111）取向的Si衬底上制备了立方多型3C-SiC碳化硅膜，通过拉曼光谱和X射线衍射对其进行了表征，并证实了其单晶结构。