Research Of High Oriented (100)-faceted Diamond Films Deposition Using A Novel MPCVD Apparatus

Chemical Vapor deposition diamond film possesses lots of extreme physical and chemical properties, such as high hardness, high thermal conductivity and high electron mobility and so on. All these advanced properties make CVD diamond films become one of the most promising materials. Chemical vapor deposition diamond attracts many researchers to study on it because of the similar properties compared with nature diamond. With the development of recent science and technology, the size and quality of CVD diamond must be increased to fit the different demands of various applications, therefore deeper research of the improvement and optimization on both of MPCVD apparatus and deposition parameters is needed. Due to the outstanding advantages of Microwave-plasma assisted CVD (MPCVD) method, it has attracted many attentions from researchers. In this study, a novel MPCVD apparatus is applied to deposit high oriented and high quality diamond films.This novel MPCVD has a multiple mode chamber. TM01and TM02are the two modes that has been use in the experiment and which can be co-exist in the chamber to stimulate a plasma ball with a large scale. Meanwhile, high energy density is obtained by feeding most of the microwave into the chamber via the mode conversion antenna. Both of these two advantages make the novel MPCVD apparatus a guarantee of depositing high-oriented and high quality CVD diamond films.Parameters of CVD diamond films deposition are researched from the following aspects:substrate temperature, carbon concentration and the oxygen concentration in the apparatus. On the basis of deposition mechanism, the analyzing and discussing on effects of different parameters on the CVD diamond deposition is significant to optimize the parameter to meet the requirements of CVD diamond films that various applications need, like high orientation and high quality. The experiment results show that the CVD diamond films deposited with lower substrate temperature are with higher density of secondary nucleation which obstructs the growth of diamond grains and the higher carbon concentration contributes to the growth rate of CVD diamond films but decreases the quality of CVD diamond films. And the results also show that with the addition of oxygen in the process gas system the orientation of (100)-oriented CVD diamond films improves but the growth of diamond films will be resisted when the oxygen concentration is too high.The various parameters of the experiments are optimized on the grounds of that some interrelationships exist among all the parameters. High-oriented and high quality CVD diamond films are deposited under the optimized parameter whose diameter is80mm and growth rate is8.2μm/h and the average grain size is10μm.General rules of CVD diamond films deposition in the novel MPCVD apparatus are obtained by related researches, which are the foundations of the deposition of high-oriented and high quality diamond films. Meanwhile, the analysis of the influences of parameters on CVD diamond films deposition can form a theory to direct the deposition of diamond growth.