Thin Solid Films 435 (2003) 39–43 0040-6090/03/$ - see front matter  2003 Elsevier Science B.V. All rights reserved. doi:10.1016/S0040-6090(03)00374-2 High-rate deposition of highly crystallized silicon films from inductively coupled plasma Nihan Kosku*, Fumitada Kurisu, Miwako Takegoshi, Hiroshi Takahashi, Seiichi Miyazaki Department of Electrical Engineering, Graduate School of Advanced Sciences of Matter, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima 739-8530, Japan Abstract We have studied microcrystalline silicon (mc-Si) film growth from inductively coupled RF plasma (ICP) of monosilane (SiH ) 4 and hydrogen gas mixtures and demonstrated the feasibility of ICP for a high rate growth of highly crystallized Si films at a temperature as low as 250 8C. Using 15% SiH diluted with H , a deposition rate of ;1.0 nm s was achieved for crystalline y1 4 2 films, for which Raman scattering spectra show the TO phonon peak intensity ratio for the crystallineydisordered phase is )5 for film thickness )1 mm. By measuring optical emission from the SiH ICP, we suggest that the relative flux of hydrogen 4 radicals to the growing film surface with respect to the flux of film precursors during monatomic layer growth is a key parameter in obtaining highly crystallized films at a higher growth rate. Strong influence of the crystallinity on the optical and electrical properties has also been confirmed for films prepared with different SiH concentrations or different film thickness. 4  2003 Elsevier Science B.V. All rights reserved. Keywords: Inductively coupled plasma; Microcrystalline silicon; High-rate deposition; Optical emission spectroscopy 1. Introduction Microcrystalline silicon-based (mc-Si) thin films are attracting much attention because of their potential importance in further improving the device performance of amorphous Si-based (a-Si) thin-film transistors and solar cells w1,2x. In particular, requirements for stable and high-efficiency solar cells, which are needed to overcome the light-induced degradation observed a-Si based films and to improve carrier transport and collec- tion, led us to study mc-Si:H intensively w3x. For the application of mc-Si-based films to such large-area electronic devices, one of the major research issues is to increase the deposition rate as high as possible, while keeping the crystallinity high at substrate temperatures lower than 250 8C. To date, mc-Si–H deposition at rates higher than ;2 nm s has been demonstrated using a y1 very-high-frequency (VHF; 60 MHz) plasma w4x and a high-density microwave plasma w5x. In addition to these methods, the use of an inductively coupled plasma (ICP) w6x is another promising method because a uniform and high-density plasma is sustained under a relatively low *Corresponding author. E-mail address: nihan@hiroshima-u.ac.jp (N. Kosku). pressure at low substrate temperature without any exter- nal magnetic field. It has recently been demonstrated that, from a modified ICP of H -diluted SiH , highly 2 4 crystallized Si films can be prepared at temperatures below 300 8C at a deposition rate of ;0.15 nm s . In y1 that regard, uniform and high-rate deposition of highly crystallized Si films from ICP is still a matter of research at temperatures below 250 8C. Previously, we reported that from a pure SiH RF- 4 ICP, device-quality a-Si:H films could be prepared at 150 8C at a deposition rate of approximately 4 nm s y1 w7x and found that the distance between the RF antenna and the substrate is one of the crucial factors for high- rate deposition with a low defect density. In this work we extended our research to the high-rate deposition of highly crystallized films from H -diluted SiH RF-ICP. 2 4 We have studied how the SiH concentration, gas pres- 4 sure and distance between the RF antenna and the substrate influence the deposition rate, crystallinity, and optical and electrical properties of the films. In addition, optical emission spectroscopy (OES) of the ICP plasma was carried out to gain a better understanding of the flux of atomic hydrogen and precursors incident to the growing film surface.