Room Temperature Process for Chemical Vapor Deposition of Amorphous Silicon Carbide Thin Film Using Monomethylsilane Gas

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Room Temperature Process for Chemical Vapor Deposition of Amorphous Silicon Carbide Thin Film Using Monomethylsilane Gas Hitoshi Habuka1, Yusuke Ando1 and Masaki Tsuji1 1 Department of Chemical and Energy Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama 240-8501, Japan. ABSTRACT The silicon carbide thin film formation process, completely performed at room temperature, was developed by argon plasma and a chemical vapor deposition using monomethylsilane gas. Time-of-flight secondary ion mass spectrometry showed that siliconcarbon bonds existed in the obtained film, the surface of which could remain specular after the exposure to hydrogen chloride gas at 800 oC. The silicon dangling bonds formed at the silicon surface by the argon plasma are considered to easily accept the monomethylsilane molecules at room temperature to produce the amorphous silicon carbide film. INTRODUCTION Silicon carbide (SiC) is recognized as a suitable material for various applications, such as a carbon susceptor coating film used in a chemical vapor deposition reactor [1] and a functional material for a microelectromechanical system (MEMS) [2]. Although silicon carbide is robust even in a harsh environment and at high temperatures, one of the major problems of silicon carbide is its very high temperature required for chemical vapor deposition (CVD) [3, 4]. In order to easily coat the various material surfaces, including those having low melting points, the temperature for silicon carbide film deposition should be decreased, desirably to near room temperature. As reported in our previous studies [5-6], the silicon carbide film could be formed at room temperature using monomethylsilane (MMS) gas on a silicon surface which had been made reactive by hydrogen annealing at high temperature, such as 1100 oC. The key role of the reactive surface preparation was to produce reactive silicon sites for accepting the MMS molecule [7]. When the entirely room temperature CVD (RT-CVD) process becomes possible, many materials are expected to be coated with the silicon carbide film. For producing the reactive silicon surface, the plasma etching at room temperature without heating is expected. In this paper, the RT-CVD process was evaluated, employing the argon plasma etching at room temperature for preparing the reactive silicon surface prior to the silicon carbide film deposition using MMS gas at room temperature. EXPERIMENT A (100) silicon substrate manufactured by the Czochralski method was used in this study. In order to prepare the reactive silicon surface, a parallel plate plasma etcher was used. In order to obtain a silicon carbide film by the CVD method, the horizontal reactor was used. This reactor consisted of a gas supply system, a quartz chamber and infrared lamps. The height and the width of the quartz chamber were 10 mm and 40 mm, respectively, similar to those used in our

previous studies [5-9]. The silicon substrate picked up from the plasma etcher was immediately placed horizontally on the bottom wall of the quart