Investigation On The Deposition Of High Oriented Diamond Film By MPCVD And Equipment Improvement

Excellent physical and chemical properties of CVD diamond film make it have wide application prospect in many fields.Now MPCVD technology is considered one of the best methods to obtain high quality oriented diamond films. In this paper, the deposition parameters were systematic investigated in R2.0-MPCVD apparatus designed by Woosinent company and home-made 10kW-MPCVD apparatus, in order to deposit high quality oriented diamond films with relative high uniformity. Besides that the 10kW-MPCVD apparatus were improved according to the experimental results. And the improved apparatus can satisfy the requirements of commercial process for the diamond films deposition. The main works included:1. We researched the effects of nucleation and hydrogen plasma treatment on the films by using R2.0-MPCVD apparatus. We found that for the diamond films which is deposited in suitable measure, the finally morphology of diamond films showed good density and good crystallinity. With the extension of the deposition, the diamond films preferred <111>-orientation can be observed when the nucleation density is low and the diamond films preferred <110>-orientation can be observed with lower secondary nucleation rate when the nucleation density is low.Meanwhile, hydrogen plasma treatment can improve the quality of diamond films when the chamber pressure and substrate temperature are both low.2. In the home-made 10kW-MPCVD apparatus, We research methane concentrations and substrate temperature on controllability of surface morphology of micron-diamond films growth, we found that when the substrate temperature is constant, the methane concentration may be oriented diamond film quality, nucleation density and growth rates have a significant impact. In the certain range of temperature, with methane concentration from low to high, the growth of diamond films by <111> orientation to the <100> orientation change. The quality of diamond film with the decrease of methane concentration will gradually increase. In the premise of methane concentration 2%, the surface topography of diamond films has little different from 780 to 940℃, this phenomenon shows that in a moderate methane concentration, substrate temperature has little effect on diamond surface morphology. While this phenomenon also shows that, in a moderate methane concentration, preparation of highly oriented diamond films has a wide selection of process parameters.3. The 10kW-MPCVD apparatus was improved according to the problems found in the experiments. Through some feasible improvements on the antenna, cooling system as well as the gas flow in the reactor chamber. First of all, changed the inaccessible trumpet-shaped structure into a vertical structure to obtain a stable large plasma ball. Secondly, the device cooling system was improved. The substrate now obtain the subregional water cooled to make the cooling effect decrease from the central area to the edge. Finally, improve the flow of the gas in the chamber to improve the utilization efficiency of the reaction gas.Through these studies, we get the general law of CVD diamond film deposition on various process parameters in the new 10Kw-MPCVD devices. It is a good foundation for depositing high quality oriented diamond films. At the same time, the further improving of the device and successfully discharge provide a new elite platform for investigation of high quality oriented diamond films.