Research And Design Of The Second Generation MOCVD Control System Based On PLC

MOCVD technology has been a key technology in developing and manufacturing advanced compound semiconductor materials now. According to the characteristics and requirement second generation MOCVD system of Xidian University, research and design a MOCVD computer control system.This article subjects come from military electronic components research project (0405XE0004):Wide bandgap semiconductor material growth technology and the development of MOCVD equipment. S7-300 as the main controller for control system which is chosen responsible for the operation of the whole system. According to the requirement of technology system, designed using STEP7 PLC-control procedures, including automatic and manual control procedures. In manual control, the system debugging support equipment and materials needed to control the growth of one-to-one. In auto control, the system program design include of step-by-step sequence control, cycle control, Multi-channel analog input sharing, climb analog processing, Analog Output, digital output, alarm and fault handling. Choose WinCC6.0 with powerful function to design the monitor control system, which is visualize and easy to operate. The temperature of reactor is controlled by manual mode or automatic mode. In the automatic mode of growth material, Switching using open-loop and closed-loop control, which solute accuracy of the temperature control requirements.Compares with the first generation of the MOCVD control system, its control precision, response speed, and maneuverability has been advanced greatly, the performance is more stable, perfect. At present, the gallium nitride film with good crystal quality has been grown.