Kim Hong Bum, Lee Hyoung Cheol, Kim Kyong Nam, Kang Se Koo, Yeom Geun Young
Sungkyun Advanced Institute of Nano Technology (SAINT), Suwon 440-746, Korea.
J Nanosci Nanotechnol. 2009 Dec;9(12):7440-5. doi: 10.1166/jnn.2009.1771.
An internal linear-type inductively coupled plasma (ICP) source with multi-polar permanent magnets was used to deposit nanocrystalline silicon thin films on a large-area substrate (470 mm x 370 mm), and the effects of a magnetic field on the characteristics of the plasma and deposited film were investigated. By applying the magnetic field, it was possible to obtain a high-density plasma of 2.8 x 10(11) cm(-3) at 15 mTorr Ar and 4000 W of RF power, which is about 50% higher than was obtained for the source without the magnetic field. The application of the multi-polar magnet field to the ICP source during the deposition of silicon film using SiH4/H2 also increased the deposition rates of the silicon thin films and the ratio Halpha*/SiH*, which transformed the structure of the silicon films deposited on the glass substrates from amorphous to nanocrystalline. Furthermore, the use of the magnetic field increased crystalline volume fraction and dark conductivity while decreasing the absorption coefficient. The improved characteristics were related to the increase in the ionization rate and the dissociation rate of SiH4/H2, which confined the plasma to the chamber volume and avoided losses to the chamber wall. The decrease in the absorption coefficient of the nanocrystalline silicon film deposited with a higher H2 percentage and with the magnetic field present is also related to the increase in the crystallization volume fraction. At 70% H2 with the magnetic field present, the nanocrystalline silicon thin films had a high crystalline volume fraction (68%), a dark conductivity of 3.4E-7 omega(-1) cm(-1), a deposition rate of 10 angstroms/s, and grain sizes of approximately 15 nm.
采用带有多极永久磁铁的内部线性型电感耦合等离子体（ICP）源，在大面积衬底（470 mm×370 mm）上沉积纳米晶硅薄膜，并研究了磁场对等离子体特性和沉积薄膜的影响。通过施加磁场，在15 mTorr的氩气和4000 W射频功率下可获得密度为2.8×10¹¹ cm⁻³的高密度等离子体，这比无磁场源获得的等离子体密度高出约50%。在使用SiH₄/H₂沉积硅膜过程中，对ICP源施加多极磁场也提高了硅薄膜的沉积速率以及Hα*/SiH*比率，这使得沉积在玻璃衬底上的硅膜结构从非晶态转变为纳米晶态。此外，磁场的使用增加了晶体体积分数和暗电导率，同时降低了吸收系数。这些改善的特性与SiH₄/H₂的电离率和解离率的增加有关，这将等离子体限制在腔室体积内并避免了向腔室壁的损失。在较高氢气百分比且存在磁场的情况下沉积的纳米晶硅膜吸收系数的降低也与结晶体积分数的增加有关。在70%氢气且存在磁场的情况下，纳米晶硅薄膜具有高晶体体积分数（68%）、3.4E - 7 ω⁻¹ cm⁻¹的暗电导率、10 Å/s的沉积速率和约15 nm的晶粒尺寸。
