A study on the design of a vacuum and heater for fabrication of amorphous silicon thin film

A compatible vacuum system is vital for the successful operation of an evaporator for material fabrication process. This thesis describes the method of designing a vacuum system well suit for evaporation and deposition of amorphous silicon thin film. Several factors must be taken into consideration in the design of the vacuum so as to match the use. Analysis of the system was conducted before developing real vacuum system is crucial. Vacuum Simulation (VacSim Multi) is PC sofware for simulating vacuum system used in Vacuum Engineering and it was utilised for the purpose of pump selection. This software application can reduce the cost and time of developing the system using hands-on and test-and-build technique. From analysis, it was found out that a combination of Scroll and Turbo pumps or Rotary vane and Turbo pumps are suitable for use in fabricating the amorphous silicon at pressure not less than 10-5 torr. However, Rotary vane and Turbo pumps is the best since its pressure delivery is the most stable. The calculation of current supply for heater required at 0.295 A for the duration of 1 hour or 3600 s for evaporation of silicon to take place.