Materials Chemistry and Physics 99 (2006) 240–246 Multiphase structure of hydrogen diluted a-SiC:H deposited by HWCVD Bibhu P. Swain ∗ , Rajiv O. Dusane Department of Metallurgical Engineering and Materials Science, Indian Institute of technology, Bombay Received 14 May 2005; received in revised form 23 August 2005; accepted 21 October 2005 Abstract The structural and optical properties of hydrogenated amorphous silicon carbon (a-SiC:H) thin films, grown from pure SiH 4 ,C 2 H 2 and H 2 mixture by hot wire chemical vapor deposition (HWCVD) technique, were studied. Variable flow rates and other growth conditions were applied. A variety of techniques, including X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, Raman scattering (RS), Atomic force microscopy (AFM), UV–VIS–NIR spectroscopy and photoluminescence (PL) were used to characterize the grown materials. The results confirmed coexisting of the multiphase structure of the grown a-SiC:H thin films: Si C network, carbon-like and silicon-like clusters. The room temperature (RT) PL shows a different result from the previous reports. It is suggested that both graphite-cluster phase and silicon cluster like phase are light-emitting grains. The two types of grains and Si C network are the origin of the PL in hydrogenated amorphous silicon carbide material. © 2005 Elsevier B.V. All rights reserved. Keywords: HWCVD; a-SiC:H; Multiphase; Microstructure; Photoluminescence 1. Introduction The hydrogenated amorphous silicon carbon alloy has received considerable attention in recent years due to its opto- electronic and electronic applications in solar cells [1], light emitting diodes [2], microelectronic dielectric layers [3], color sensors [4] and flat-screen full-color displays, etc. [5,6]. The significance of this material is that its electrical and optical properties can be controlled by the carbon, silicon, and hydro- gen composition of the film. Hydrogenated amorphous silicon carbon films were usually prepared by the glow discharge or plasma-enhanced chemical vapor deposition (PE-CVD), or hot wire chemical vapor deposition (HWCVD). The compositions of the silicon and carbon in the films were found to be strongly dependent on preparation conditions [7,8]. HWCVD technique shows a lot of potential to replace the RF glow discharge method for the processing of all the Si based amorphous alloy thin films such as a-Si:H, a-SiN:H, a-SiC:H and micro-crystalline sili- con. The advantage of employing HWCVD comes from two aspects: ∗ Corresponding author. Tel.: +91 2225764645; fax: +91 225723480. E-mail address: bibhup@iitb.ac.in (B.P. Swain). i. Absence of the deleterious electrons and ions and surface charges. ii. High dissociation rate of source gases. The former relates to the avoiding of powder formation at high pressure and filament temperature and the latter leads to higher deposition rates [8]. In this work, hydrogenated amorphous silicon carbon (a- SiC:H) thin films were grown on Si substrates by (HWCVD) technique, with hydrogen diluted mixtures of SiH 4 and C 2 H 2 as the precursor gases. 2. Experimental details The films were deposited simultaneously on corning 7059 glass and c-Si 〈100〉 wafers in a HW-CVD system, details of which have been described else- where [9]. It consists of a stainless chamber coupled with a turbomolecular pump, which yields a base pressure of <10 -6 Torr. Pure silane (SiH 4 ), Math- eson Semiconductor Grade was used as the source gas. The process pressure was maintained constant by using a manual throttle valve. A tungsten wire of 0.5 mm diameter was used as the filament. The process parameters maintained during the deposition of the films are given in Table 1. A variety of techniques, including FTIR, XPS, AFM, RS, PL, and UV–VIS–NIR spectrophotometer were used to characterize the grown materials. The optical band gap of the a-SiC:H films was deduced from transmittance and reflectance spectra of the films deposited on fused quartz and corning 7059 glass 0254-0584/$ – see front matter © 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.matchemphys.2005.10.018