Study On Miniature Technology For EACVD Diamond Film Deposition Equipment

EACVD (Electron-Assisted Chemical Vapor Deposition) is one of the important methods for diamond film preparation. Among all the preparation methods, EACVD technique is of simple equipment, low cost as well as convenient for controlling growth process of the film. In order to increase the application of the diamond film in the optical window materials, it is rather urgent needs to develop miniaturized diamond film-preparation equipment. Based on the analysis in detail about the technical requirements of the EACVD method and the influencing factors, miniaturized equipment preparing both the plane and the spherical film has been designed and the key problems are studied.The main work and results are as follows:1. The growth process of the diamond film and the influencing factors has been analyzed. Then the structure of the equipment that satisfies the growth condition is proposed, with the basic parameters determined. The main body system of the miniaturized equipment preparing the diamond film using EACVD method is designed. Also the problems that could emerge due to its miniaturization have been discussed and solved.2. A crank-rocker mechanism has been introduced to realize the swinging movement of the substrate platform. Meanwhile, the simulations about the effects of the swinging parameters toward the substrate temperature field have been done and the results have been optimized. A substrate platform with simple-structure, easy-maintenance and sound-reliability has been designed. The measurement method has also been improved to measure the temperature of several points at the same time.3. In order to realize the auto control during the diamond-film growth process, the hardware of the auto control system have been established, then the structure of the hardware system has been realized based on the key parameters that affect the growth process.4. The control strategy for the substrate temperature has been studied. According to the swingable substrate platform and the temperature-control traits when preparing curved surface diamond-film, fuzzy-PID combined control method and fuzzy-PID self-tuning control method have been introduced. Then, the implementation plan and process about the substrate temperature controller have been established. The Simulink module and the NCD module have also been used to regulate and optimize the parameters. The controllers are analyzed by simulations.