Gas supply system of low pressure chemical vapor deposition apparatus for polycrystalline silicon

摘要

The system is for depositing the polysilicon thin film safety and making the system maintenance easy. The silan(SiH4) and nitrogen gases are provided through two main pipes (1,2) so that the system is applicable to any type of the gas injectors adapted to the horizontal tube type reactor depositing the uniform polysicon. An air valve (4) for sequence control is positioned in front of a mass flow regulator (3) so that the mass flow is controlled fast in precision. A nitrogen, a bypass, and an exhaust lines are connected to the lines (1,2) to improve the safety and maintenance of the mass flow regulator. Also, a normal open air valve (14) and a manual valve (25) are installed to clean the reactor automatically in case of the power off.