Study On Control System Of Miniature EACVD Equipment For Diamond Film Deposition

The CVD(Chemical Vapor Deposition) diamond film possesses remarkable properties in mechanical, thermal, optical and electrical aspects, thus they have potential application in the field of high technology. EACVD (Electron-Assisted CVD) is one of the important methods for diamond film deposition. In this thesis, a kind of intelligent integrated control system based on microcontroller was developed for the miniature EACVD system which can realize the deposition of the diamond film under unmanned situation.The main work and results in this thesis are as follows:The control strategy for the substrate temperature was studied. According to the swing substrate platform and its temperature-control characteristic when preparing diamond films, a fuzzy-PID self-tuning control system was introduced to control the substrate temperature. The simulink module and the NCD module were used to regulate and optimize the parameters of the controller. The controller was analyzed by MATLAB simulation.The hardware of a real-time control system was designed based on C8051F020 microcontroller. The important module of the control system, such as data acquisition, control output, human-machine interface and communication interface were designed in detail.The underlying hardware drivers were developed under Keil C51 development environment. Serial communication protocols such as I2C, SPI and UART were developed. The RTOS systemμC/OS-II has been explant to the platform based on C8051F020 in order to improve system performance and elevate flexibility.Application program of the control system was developed base onμC/OS-II. The Modbus RTU protocol, muti-position temperature measurement, signal collection and data storage, which can realize the function of multitasking and real-time control, were designed in detail.The control system was applied for CVD diamond deposition. The deposition results show that the control system has quick response speed, good stability and high reliability. It can meet the demand of high quality thick or thin CVD diamond film deposition.